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PROPOSED STANDARD

Internet Engineering Task Force (IETF)                            X. Liu
Request for Comments: 8795                                Volta Networks
Category: Standards Track                                     I. Bryskin
ISSN: 2070-1721                             Futurewei Technologies, Inc.
                                                               V. Beeram
                                                                 T. Saad
                                                        Juniper Networks
                                                                 H. Shah
                                                                   Ciena
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                             August 2020


        YANG Data Model for Traffic Engineering (TE) Topologies

Abstract

   This document defines a YANG data model for representing, retrieving,
   and manipulating Traffic Engineering (TE) Topologies.  The model
   serves as a base model that other technology-specific TE topology
   models can augment.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8795.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Terminology
     1.2.  Tree Structure
     1.3.  Prefixes in Data Node Names
   2.  Characterizing TE Topologies
   3.  Modeling Abstractions and Transformations
     3.1.  TE Topology
     3.2.  TE Node
     3.3.  TE Link
     3.4.  Transitional TE Link for Multi-layer Topologies
     3.5.  TE Link Termination Point (LTP)
     3.6.  TE Tunnel Termination Point (TTP)
     3.7.  TE Node Connectivity Matrix
     3.8.  TTP Local Link Connectivity List (LLCL)
     3.9.  TE Path
     3.10. TE Inter-layer Lock
     3.11. Underlay TE Topology
     3.12. Overlay TE Topology
     3.13. Abstract TE Topology
   4.  Model Applicability
     4.1.  Native TE Topologies
     4.2.  Customized TE Topologies
     4.3.  Merging TE Topologies Provided by Multiple Providers
     4.4.  Dealing with Multiple Abstract TE Topologies Provided by
           the Same Provider
   5.  Modeling Considerations
     5.1.  Network Topology Building Blocks
     5.2.  Technology-Agnostic TE Topology Model
     5.3.  Model Structure
     5.4.  Topology Identifiers
     5.5.  Generic TE Link Attributes
     5.6.  Generic TE Node Attributes
     5.7.  TED Information Sources
     5.8.  Overlay/Underlay Relationship
     5.9.  Templates
     5.10. Scheduling Parameters
     5.11. Notifications
   6.  Guidance for Writing Technology-Specific TE Topology
           Augmentations
   7.  TE Topology YANG Module
   8.  Security Considerations
   9.  IANA Considerations
   10. References
     10.1.  Normative References
     10.2.  Informative References
   Appendix A.  Complete Model Tree Structure
   Appendix B.  Companion YANG Data Model for Non-NMDA-Compliant
           Implementations
     B.1.  TE Topology State YANG Module
   Appendix C.  Example: YANG Data Model for Technology-Specific
           Augmentations
   Acknowledgments
   Contributors
   Authors' Addresses

1.  Introduction

   The Traffic Engineering Database (TED) is an essential component of
   Traffic Engineered (TE) systems that are based on MPLS-TE [RFC2702]
   and GMPLS [RFC3945].  The TED is a collection of all TE information
   about all TE nodes and TE links in the network.  The TE topology is a
   schematic arrangement of TE nodes and TE links present in a given
   TED.  There could be one or more TE topologies present in a given TE
   system.  A TE topology is the topology on which path computational
   algorithms are run to compute TE paths.

   This document defines a YANG data model [RFC7950] for representing,
   retrieving, and manipulating TE topologies.  This model contains
   technology-agnostic TE topology building blocks that can be augmented
   and used by other technology-specific TE topology models.

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   We assume that the reader is familiar with the general body of work
   captured in currently available RFCs related to Traffic Engineering.
   [RFC7926] serves as a good starting point for those who may be less
   familiar with RFCs related to Traffic Engineering.

   Some of the key terms used in this document are as follows:

   TED:  The Traffic Engineering Database (TED) is a collection of all
      TE information about all TE nodes and TE links in a given network.

   TE topology:  The TE topology is a schematic arrangement of TE nodes
      and TE links in a given TED.  It forms the basis for a graph
      suitable for TE path computations.

   Native TE topology:  A Native TE topology is a topology that is
      native to a given provider network.  A Native TE topology could be
      discovered via various routing protocols and/or subscribe/publish
      techniques.  This is the topology on which path computational
      algorithms are run to compute TE paths.

   Customized TE topology:  A Customized TE topology is a custom
      topology that is produced by a provider for a given client.  This
      topology typically makes abstractions on the provider's Native TE
      topology and is provided to the client.  The client receives the
      Customized TE topology and merges it into the client's Native TE
      topology.  The client's path computational algorithms aren't
      typically run on the Customized TE topology; they are run on the
      client's Native TE topology after the merge.

1.2.  Tree Structure

   A simplified graphical representation of the data model is presented
   in Appendix A of this document.  The tree format defined in [RFC8340]
   is used for the YANG data model tree representation.

1.3.  Prefixes in Data Node Names

   In this document, names of data nodes and other data model objects
   are prefixed using the standard prefix associated with the
   corresponding YANG imported modules, as shown in Table 1.

             +==========+=======================+===========+
             | Prefix   | YANG Module           | Reference |
             +==========+=======================+===========+
             | yang     | ietf-yang-types       | [RFC6991] |
             +----------+-----------------------+-----------+
             | inet     | ietf-inet-types       | [RFC6991] |
             +----------+-----------------------+-----------+
             | nw       | ietf-network          | [RFC8345] |
             +----------+-----------------------+-----------+
             | nt       | ietf-network-topology | [RFC8345] |
             +----------+-----------------------+-----------+
             | te-types | ietf-te-types         | [RFC8776] |
             +----------+-----------------------+-----------+

             Table 1: Prefixes and Corresponding YANG Modules

2.  Characterizing TE Topologies

   The data model defined by this document takes the following
   characteristics of TE topologies into account:

   *  The TE topology is an abstract control-plane representation of the
      data-plane topology.  Hence, attributes specific to the data plane
      must make their way into the corresponding TE topology modeling.
      The TE topology is comprised of dynamic autodiscovered data as
      well as fairly static data associated with data-plane nodes and
      links.  The dynamic data, such as unreserved bandwidth available
      on data-plane links, may change frequently.  The static data, such
      as layer network identification, switching and adaptation
      capabilities and limitations, fate-sharing, and administrative
      colors, rarely changes.  It is possible for a single TE topology
      to encompass TE information at multiple switching layers.

   *  TE topologies are protocol independent.  Information about
      topological elements may be learned via link-state protocols, but
      the topology can exist without being dependent on any particular
      protocol.

   *  The TE topology may not be congruent with the routing topology in
      a given TE system.  The routing topology is constructed based on
      routing adjacencies.  There isn't always a one-to-one association
      between a TE link and a routing adjacency.  For example, the
      presence of a TE link between a pair of nodes doesn't necessarily
      imply the existence of a routing adjacency between these nodes.
      To learn more, see [TEAS-TOPO] and [YANG-L3].

   *  Each TE topological element has at least one information source
      associated with it.  In some scenarios, there could be more than
      one information source associated with any given topological
      element.

   *  TE topologies can be hierarchical.  Each node and link of a given
      TE topology can be associated with a respective underlay topology.
      This means that each node and link of a given TE topology can be
      associated with an independent stack of supporting TE topologies.

   *  TE topologies can be customized.  TE topologies of a given network
      presented by the network provider to its client could be
      customized on a per-client-request basis.  This customization
      could be performed by the provider, by the client, or by
      provider/client negotiation.  The relationship between a
      customized topology and the provider's native topology could be
      captured as hierarchical (overlay/underlay), but otherwise the two
      topologies are decoupled from each other.  A customized topology
      is presented to the client, while the provider's native topology
      is known in its entirety to the provider itself.

3.  Modeling Abstractions and Transformations

3.1.  TE Topology

   A TE topology is a Traffic Engineering representation of one or more
   layers of network topologies.  A TE topology is comprised of TE nodes
   (TE graph vertices) interconnected via TE links (TE graph edges).  A
   TE topology is mapped to a TE graph.

3.2.  TE Node

   A TE node is an element of a TE topology, presented as a vertex on a
   TE graph.  A TE node represents one or several nodes, or a fraction
   of a node, which can be a switch or router that is physical or
   virtual.  A TE node belongs to and is fully defined in exactly one TE
   topology.  A TE node is assigned a unique ID within the TE topology
   scope.  TE node attributes include information related to the
   data-plane aspects of the associated node(s) (e.g., connectivity
   matrix), as well as configuration data (such as the TE node name).  A
   given TE node can be reached on the TE graph over one of the TE links
   terminated by the TE node.

   Multi-layer TE nodes providing switching functions at multiple
   network layers are an example where a physical node can be decomposed
   into multiple logical TE nodes, which are fractions of the physical
   node.  Some of these (logical) TE nodes may reside in the client-
   layer TE topology, while the remaining TE nodes belong to the server-
   layer TE topology.

   In Figure 1, Node-1, Node-2, and Node-3 are TE nodes.

                                | +---+          __
                                | |   | TE Node  \/ TTP  o LTP
                                | +---+
                                |
                                | ----- TE Link
                                | ***** Node Connectivity Matrix,
                                |       TTP Local Link Connectivity
                                | @@@@@ TE Tunnel
                                o----------------------------------

      Node-1                                            Node-3
   +------------+                                    +------------+
   |    TTP-1   |                                    |    TTP-1   |
   |LTP  __     |           TE-Tunnel-1              |     __     |
   |-6   \/@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\/     |
   o    *  *    oLTP-1           Node-2         LTP-6o    *  *    o
   |   *    *   |           +------------+           |   *    *   |
   |  * TTP-2*  |           |            |           |  * TTP-2*  |
   | *   __   * |LTP-2 LTP-6|            |LTP-1 LTP-5| *   __   * |
   o*    \/    *o-----------o************o-----------o*    \/    *o
   |LTP *  *    | Link-12   |          * | Link-23   |    *  *    |
   |-5 *    *   |      LTP-5|        *   |LTP-2      |   *    *   |
   +--o------o--+           o************o           +--o------o--+
    LTP-4  LTP-3            | *   *    * |            LTP-4  LTP-3
                            |  **     *  |
                            +--o------o--+
                             LTP-4  LTP-3

   LTP: Link Termination Point
   TTP: Tunnel Termination Point

                Figure 1: TE Topology Modeling Abstractions

3.3.  TE Link

   A TE link is an element of a TE topology, presented as an edge on a
   TE graph.  The arrows on an edge indicate one or both directions of
   the TE link.  When there are a pair of parallel links of opposite
   directions, an edge without arrows is also used.  A TE link
   represents one or several (physical) links or a fraction of a link.
   A TE link belongs to and is fully defined in exactly one TE topology.
   A TE link is assigned a unique ID within the TE topology scope.  TE
   link attributes include parameters related to the data-plane aspects
   of the associated link(s) (unreserved bandwidth, resource maps /
   resource pools, etc.), as well as the configuration data (remote
   node IDs / link IDs, Shared Risk Link Groups (SRLGs), administrative
   colors, etc.).  A TE link is connected to a TE node, terminating the
   TE link via exactly one TE Link Termination Point (LTP).

   In Figure 1, Link-12 and Link-23 are TE links.

3.4.  Transitional TE Link for Multi-layer Topologies

   Networks are typically composed of multiple network layers where one
   or multiple signals in the client-layer network can be multiplexed
   and encapsulated into a server-layer signal [RFC5212] [G.805].  The
   server-layer signal can be carried in the server-layer network across
   multiple nodes until the server-layer signal is terminated and the
   client-layer signals reappear in the node that terminates the server-
   layer signal.  Examples of multi-layer networks include (1) IP over
   MPLS over Ethernet and (2) low-order Optical Data Unit-k (ODUk)
   signals multiplexed into a high-order ODUl (l>k) carried over an
   Optical Channel (OCh) signal in an Optical Transport Network (OTN) as
   defined in [G.872] and [G.709].

   TE links as defined in Section 3.3 can be used to represent links
   within a network layer.  In the case of a multi-layer network, TE
   nodes and TE links only allow the representation of each network
   layer as a separate TE topology.  Each of these single-layer TE
   topologies would be isolated from their client and their server-layer
   TE topology, if present.  The highest network layer and the lowest
   network layer in the hierarchy only have a single adjacent layer
   below or above, respectively.  Multiplexing client-layer signals and
   encapsulating them into a server-layer signal require a function that
   is provided inside a node (typically realized in hardware).  This
   function is also called "layer transition".

   One of the key requirements for path computation is to be able to
   calculate a path between two endpoints across a multi-layer network
   based on the TE topology representing this multi-layer network.  This
   means that an additional TE construct is needed that represents
   potential layer transitions in the multi-layer TE topology that
   connects the TE topologies representing each separate network layer.
   The so-called transitional TE link is such a construct, and it
   represents the layer transition function residing inside a node that
   is decomposed into multiple logical nodes that are represented as TE
   nodes (also see [G.8080] for the definition of a transitional link
   for the OTN).  Hence, a transitional TE link connects a client-layer
   node with a server-layer node.  A TE link as defined in Section 3.3
   has LTPs of exactly the same kind on each link end, whereas the
   transitional TE link has client-layer LTPs on the client side of the
   transitional link and, in most cases, a single server-layer LTP on
   the server side.  It should be noted that transitional links are a
   helper construct in the multi-layer TE topology and they only exist
   as long as they are not in use, as they represent potential
   connectivity.  When the server-layer trail has been established
   between the server-layer LTP of two transitional links in the server-
   layer network, the resulting client-layer link in the data plane will
   be represented as a normal TE link in the client-layer topology.  The
   transitional TE links will reappear when the server-layer trail has
   been torn down.

                                |                 |
                                | +---+          ---
                                | |   | TE Node  \ / Transitional
                                | +---+           |  Link
                                |
                                | ----- Client-Layer Link
                                | ===== Server-Layer Link
                                | ***** Layer Boundary
                                o----------------------------------

      +-------------------+
      | +-------+         |                          +-------+
   -----|Client-|------+  |             Client- -----|Client-|
      | |Layer  |---+  |  |             Layer        |Layer  |
   -----|Switch |-+ |  |  |             Links   -----|Node   |
      | +------ + | |  |  |                          +-------+
      |           | |  |  | Client                    | |  |
      |           | | ---_| Layer                     --- ---
   ***|***********|*| \ /*|***************************\ /*\ /****
      |           ---  |  | Server       Transitional  |   |
      |    Layer  \ /  |  | Layer               Links  |   |
      |    Term.   |   |  |                            |   |
      |            |   |  |                            |   |
      |         +-------+ |                          +-------+
   =============|Server-|=====           Server- ====|Server-|====
      |         |Layer  | |              Layer       |Layer  |
   =============|Switch |=====           Links   ====|Node   |====
      |         +-------+ |                          +-------+
      +-------------------+

       Physical Node View                       TE Topology View

         Figure 2: Modeling a Multi-layer Node (Dual-layer Example)

3.5.  TE Link Termination Point (LTP)

   A TE Link Termination Point (LTP) is a conceptual point of connection
   of a TE node to one of the TE links, terminated by the TE node.
   Cardinality between an LTP and the associated TE link is 1:0..1.

   In Figure 1, Node-2 has six LTPs: LTP-1 through LTP-6.

3.6.  TE Tunnel Termination Point (TTP)

   A TE Tunnel Termination Point (TTP) is an element of a TE topology
   representing one or several potential transport service termination
   points (i.e., service client adaptation points, such as a WDM/OCh
   transponder).  ("WDM" stands for "Wavelength Division Multiplexing".)
   A TTP is associated with (hosted by) exactly one TE node.  A TTP is
   assigned a unique ID within the TE node scope.  Depending on the TE
   node's internal constraints, a given TTP hosted by the TE node could
   be accessed via one, several, or all TE links terminated by the TE
   node.

   In Figure 1, Node-1 has two TTPs: TTP-1 and TTP-2.

3.7.  TE Node Connectivity Matrix

   A TE node connectivity matrix is a TE node's attribute describing the
   TE node's switching limitations in the form of valid switching
   combinations of the TE node's LTPs (see below).  From the point of
   view of a potential TE path arriving at the TE node at a given
   inbound LTP, the node's connectivity matrix describes valid
   (permissible) outbound LTPs from which the TE path can leave the TE
   node.

   In Figure 1, the connectivity matrix on Node-2 is as follows:

   {<LTP-6, LTP-1>, <LTP-5, LTP-2>, <LTP-5, LTP-4>, <LTP-4, LTP-1>,
   <LTP-3, LTP-2>}

3.8.  TTP Local Link Connectivity List (LLCL)

   A TTP Local Link Connectivity List (LLCL) is a list of TE links
   terminated by the TE node hosting a TTP, to which the TTP could be
   connected.  From the point of view of the potential TE path of a
   connection, an LLCL provides a list of valid TE links the TE path
   needs to start/stop on for the connection to be successfully
   terminated on a TTP.

   In Figure 1, the LLCL on Node-1 is as follows:

   {<TTP-1, LTP-5>, <TTP-1, LTP-2>, <TTP-2, LTP-3>, <TTP-2, LTP-4>}

3.9.  TE Path

   A TE path is an ordered list of TE links and/or TE nodes on the TE
   topology graph; this path interconnects a pair of TTPs to be used by
   a potential connection.  For example, TE paths could be a product of
   successful path computation performed for a given transport service.

   In Figure 1, the TE path for TE-Tunnel-1 is as follows:

   {Node-1:TTP-1, Link-12, Node-2, Link-23, Node-3:TTP-1}

3.10.  TE Inter-layer Lock

   A TE inter-layer lock is a modeling concept describing adaptation
   relationships between the client layer and the server layer and hence
   is important for multi-layer Traffic Engineering.  It is an
   association of M client-layer LTPs and N server-layer TTPs, within
   which data arriving at any of the client-layer LTPs could be adopted
   onto any of the server-layer TTPs.  A TE inter-layer lock is
   identified by an inter-layer lock ID, which is unique across all TE
   topologies provided by the same provider.  The client-layer LTPs and
   the server-layer TTPs associated within a given TE inter-layer lock
   are annotated with the same inter-layer lock ID attribute.

   In Figure 3, a TE inter-layer lock with an ID of IL-1 associates six
   client-layer LTPs (C-LTP-1 through C-LTP-6) with two server-layer
   TTPs (S-TTP-1 and S-TTP-2).  They all have the same attribute -- TE
   inter-layer lock ID IL-1, which is the only thing that indicates the
   association.  A given LTP may have zero, one, or more inter-layer
   lock IDs.  In the latter case, this means that the data arriving at
   the LTP may be adopted onto any of the TTPs associated with all
   specified inter-layer locks.  For example, C-LTP-1 could have two
   inter-layer lock IDs -- IL-1 and IL-2.  This would mean that C-LTP-1
   for adaptation purposes could use not just the TTPs associated with
   inter-layer lock IL-1 (i.e., S-TTP-1 and S-TTP-2 in the figure) but
   any of the TTPs associated with inter-layer lock IL-2 as well.
   Likewise, a given TTP may have one or more inter-layer lock IDs,
   meaning that it can offer the adaptation service to any of the
   client-layer LTPs with an inter-layer lock ID matching one of its
   own.  Additionally, each TTP has an unreserved adaptation bandwidth
   attribute, which announces its remaining adaptation resources that
   are sharable between all potential client-layer LTPs.

                                | +---+          __
                                | |   | TE Node  \/ TTP  o LTP
                                | +---+
                                |
                                | ----- TE Link
                                | ***** TTP Local Link Connectivity
                                o----------------------------------

             (IL-1) C-LTP-1 +------------+   C-LTP-2 (IL-1)
                    --------O   (IL-1)   O--------
             (IL-1) C-LTP-3 |   S-TTP-1  |   C-LTP-4 (IL-1)
                    --------O     __     0--------
             (IL-1) C-LTP-5 |    *\/*    |   C-LTP-6 (IL-1)
                    --------O   *    *   O--------
                            |  *(IL-1)*  |
                    S-LTP-3 | * S-TTP-2* |   S-LTP-4
                    --------o*    __    *o--------
                            |    *\/*    |
                            |   *    *   |
                            +--o------o--+
                       S-LTP-1 |      | S-LTP-2

               Figure 3: TE Inter-layer Lock ID Associations

   LTPs and TTPs associated within the same TE inter-layer lock may be
   hosted by the same (hybrid, multi-layer) TE node or multiple TE nodes
   located in the same or separate TE topologies.  The latter case is
   especially important, since TE topologies of different layer networks
   could be modeled by separate augmentations of the basic (common to
   all layers) TE topology model.

3.11.  Underlay TE Topology

   An underlay TE topology is a TE topology that serves as a base for
   the construction of overlay TE topologies.

3.12.  Overlay TE Topology

   An overlay TE topology is a TE topology that is constructed based on
   one or more underlay TE topologies.  Each TE node of the overlay TE
   topology represents an arbitrary segment of an underlay TE topology;
   each TE link of the overlay TE topology represents an arbitrary TE
   path in one of the underlay TE topologies.  The overlay TE topology
   and the supporting underlay TE topologies may represent distinct
   layer networks (e.g., OTN/ODUk and WDM/OCh, respectively) or the same
   layer network.

3.13.  Abstract TE Topology

   An abstract TE topology is a topology that contains abstract
   topological elements (nodes, links, TTPs).  An abstract TE topology
   is an overlay TE topology created by a topology provider and
   customized for a topology provider's client based on one or more of
   the provider's Native TE topologies (underlay TE topologies), the
   provider's policies, and the client's preferences.  For example, a
   first-level topology provider (such as a domain controller) can
   create an abstract TE topology for its client (e.g., a multi-domain
   service coordinator) based on one or more of the provider's Native TE
   topologies, local policies/profiles, and the client's TE topology
   configuration requests.

   Figure 4 shows an example of an abstract TE topology.

                                | +---+
                                | |   | TE Node
                                | +---+
                                | ----- TE Link
                                o----------------------------------

     +---+              +---+
     |S3 |              |S5 |
     +---+\           / +---+
           \         /
            \       /
             \+---+/                +---+
             /|AN1|\----------------|S8 |
            / +---+ \               +---+
     +---+ /         \ +---+
     |S9 |             |S11|
     +---+             +---+
           Abstract TE Topology

            +---+                    +---+
            |S1 |--------------------|S2 |
            +---+                    +---+
             /                          \
            /                            \
     +---+ /                  +---+       \ +---+
     |S3 |--------------------|S4 |---------|S5 |
     +---+\                   +---+         +---+
           \                      \             \
            \                      \             \
             \+---+                 +---+         +---+
             /|S6 |\                |S7 |---------|S8 |
            / +---+ \               +---+\       /+---+
     +---+ /         \ +---+              +---+ /
     |S9 |-------------|S10|--------------|S11|/
     +---+             +---+              +---+
           Native TE Topology

                       Figure 4: Abstract TE Topology

4.  Model Applicability

4.1.  Native TE Topologies

   The model discussed in this document can be used to represent and
   retrieve Native TE topologies on a given TE system.

   Consider the network topology depicted in Figure 5.  R1 .. R9 are
   nodes representing routers.  An implementation MAY choose to
   construct a Native TE topology using all nodes and links present in
   the given TED as depicted in Figure 6.  The data model defined in
   this document can be used to represent and retrieve this TE topology.

                                | +---+
                                | |   | TE Node
                                | +---+
                                | ----- TE Link
                                o----------------------------------

     +---+       +---+        +---+         +---+         +---+
     | R1|-------| R2|--------| R3|---------| R4|---------| R5|
     +---+       +---+        +---+         +---+         +---+
       |                      /   \         /   \         /
       |                     /     \       /     \       /
       |                    /       \     /       \     /
       |                   /         \   /         \   /
       |                  /           \ /           \ /
     +---+             +---+         +---+         +---+
     | R6|-------------| R7|         | R8|---------| R9|
     +---+             +---+         +---+         +---+

                     Figure 5: Example Network Topology

          ---------------
          | Native      |                   |  [ ] TE Node
          | TE Topology |                   |  +++ TE Link
          ---------------                   o--------------

      [R1] ++++ [R2] ++++ [R3] ++++ [R4] ++++ [R5]
        +                +    +    +    +    +
        +               +      +  +      +  +
        +              +        ++        ++
      [R6] +++++++++ [R7]      [R8] ++++ [R9]

              Figure 6: Native TE Topology as Seen on Node R3

   Consider the case where the topology is split in a way that some
   nodes participate in OSPF-TE while others participate in ISIS-TE
   (Figure 7).  An implementation MAY choose to construct separate TE
   topologies based on the information source.  The Native TE topologies
   constructed using only nodes and links that were learned via a
   specific information source are depicted in Figure 8.  The data model
   defined in this document can be used to represent and retrieve these
   TE topologies.

                                     :
   TE Info Distributed via ISIS-TE   :  TE Info Distributed via OSPF-TE
                                     :
          +---+       +---+        +---+         +---+         +---+
          | R1|-------| R2|--------| R3|---------| R4|---------| R5|
          +---+       +---+        +---+         +---+         +---+
            |                      / : \         /   \         /
            |                     /  :  \       /     \       /
            |                    /   :   \     /       \     /
            |                   /    :    \   /         \   /
            |                  /     :     \ /           \ /
          +---+             +---+    :    +---+         +---+
          | R6|-------------| R7|    :    | R8|---------| R9|
          +---+             +---+    :    +---+         +---+
                                     :

                  Figure 7: Example Split Network Topology

           -----------------------   :  -----------------------
           |Native TE Topology   |   :  |Native TE Topology   |
           |Info-Source: ISIS-TE |   :  |Info-Source: OSPF-TE |
           -----------------------   :  -----------------------
                                     :
            [R1] ++++ [R2] ++++ [R3] : [R3'] ++++ [R4] ++++ [R5]
             +                +      :      +    +    +    +
             +               +       :       +  +      +  +
             +              +        :        ++        ++
            [R6] +++++++++ [R7]      :       [R8] ++++ [R9]

             Figure 8: Native TE Topologies as Seen on Node R3

   Similarly, the data model can be used to represent and retrieve a TE
   topology that is constructed using only nodes and links that belong
   to a particular technology layer.  The data model is flexible enough
   to represent and retrieve many such Native TE topologies.

4.2.  Customized TE Topologies

   A Customized TE topology is a topology that was modified by the
   provider to honor a particular client's requirements or preferences.
   The model discussed in this document can be used to represent,
   retrieve, and manipulate Customized TE topologies.  The model allows
   the provider to present the network in abstract TE terms on a
   per-client basis.  These customized topologies contain sufficient
   information for the client to compute and select paths according to
   its policies.

   Consider the network topology depicted in Figure 9.  This is a
   typical packet optical transport deployment scenario where the WDM-
   layer network domain serves as a server network domain providing
   transport connectivity to the packet-layer network domain (client
   network domain).  Nodes R1, R2, R3, and R4 are IP routers that are
   connected to an optical WDM transport network.  A, B, C, D, E, and F
   are WDM nodes that constitute the server network domain.

                                  | +---+            /-\
                                  | |   | Router    (   ) WDM
                                  | +---+ Node       \-/  Node
                                  |
                                  o----------------------------

     +---+        /-\          /-\           /-\          +---+
     | R1|-------( A )--------( C )---------( E )---------| R3|
     +---+        \-/          \-/           \-/          +---+
                              /   \         /   \
                             /     \       /     \
                            /       \     /       \
                           /         \   /         \
                          /           \ /           \
         +---+          /-\           /-\           /-\          +---+
         | R2|---------( B )---------( D )---------( F )---------| R4|
         +---+          \-/           \-/           \-/          +---+

                 Figure 9: Example Packet Optical Topology

   The goal here is to augment the client's TE topology with a
   Customized TE topology provided by the WDM network.  Given the
   availability of the paths A-E, B-F, and B-E (Figure 10), a Customized
   TE topology as depicted in Figure 11 is provided to the client.  This
   Customized TE topology is merged with the client's Native TE
   topology, and the resulting topology is depicted in Figure 12.

                                            | *****  B-F WDM Path
                                            | @@@@@  B-E WDM Path
                                            | $$$$$  A-E WDM Path
                                            o--------------------

     +---+        /-\ $$$$$$$$ /-\ $$$$$$$$$ /-\          +---+
     | R1|-------( A )--------( C )---------( E )---------| R3|
     +---+        \-/         @\-/ @@@@@@@@@ \-/          +---+
                             @/   \         /   \
                            @/     \       /     \
                           @/       \     /       \
                          @/         \   /         \
                         @/           \ /           \
         +---+          /-\ ********* /-\ ********* /-\          +---+
         | R2|---------( B )---------( D )---------( F )---------| R4|
         +---+          \-/           \-/           \-/          +---+

                Figure 10: Paths within the Provider Domain

                 ++++++++ [A] ++++++++++++++++++++ [E] +++++++++
                                              +++++
                                          ++++
                                      ++++
                                  ++++
                              ++++
                 ++++++++ [B] ++++++++++++++++++++ [F] +++++++++

          Figure 11: Customized TE Topology Provided to the Client

            [R1] ++++++++ [A] ++++++++++++++++++++ [E] +++++++++ [R3]
                                              +++++
                                          ++++
                                      ++++
                                  ++++
                              ++++
            [R2] ++++++++ [B] ++++++++++++++++++++ [F] +++++++++ [R4]

               Figure 12: Customized TE Topology Merged with
                      the Client's Native TE Topology

   The data model defined in this document can be used to represent,
   retrieve, and manipulate the Customized TE topology depicted in
   Figure 11.

   A Customized TE topology is not necessarily an abstract TE topology.
   The provider may produce, for example, an abstract TE topology of a
   certain type (a single-abstract-node-with-connectivity-matrix
   topology, a border-nodes-connected-via-mesh-of-abstract-links
   topology, etc.) and expose it to all or some clients in the
   expectation that the clients will use it without customization.  On
   the other hand, a client may request a customized version of the
   provider's Native TE topology (e.g., by requesting the removal of TE
   links that belong to certain layers, are too slow, are not protected,
   and/or have a certain affinity).  Note that the resulting TE topology
   will not be abstract (because it will not contain abstract elements)
   but will be customized (modified upon the client's instructions).

   The client ID field in the TE topology identifier (Section 5.4)
   indicates which client the TE topology is customized for.  Although
   an authorized client MAY receive a TE topology with the client ID
   field matching some other client, the client can customize only TE
   topologies with the client ID field either set to 0 or matching the
   ID of the client in question.  If the client starts the
   reconfiguration of a topology, its client ID will be automatically
   set in the topology ID field for all future configurations and
   updates with regard to the topology in question.

   The provider, by setting its own ID in the client ID field of the
   topology ID, MAY tell the client that a given TE topology cannot be
   renegotiated.

   Even though this data model allows the access of TE topology
   information across clients, implementations MAY restrict access for
   particular clients to particular data fields.  The Network
   Configuration Access Control Model (NACM) [RFC8341] provides such a
   mechanism.

4.3.  Merging TE Topologies Provided by Multiple Providers

   A client may receive TE topologies provided by multiple providers,
   each of which manages a separate domain of a multi-domain network.
   In order to make use of said topologies, the client is expected to
   merge the provided TE topologies into one or more of its own Native
   TE topologies, each of which homogeneously represents the multi-
   domain network.  This makes it possible for the client to select end-
   to-end TE paths for its services traversing multiple domains.

   In particular, the process of merging TE topologies includes:

   *  Identifying neighboring domains and locking their topologies
      horizontally by connecting their inter-domain open-ended TE links.

   *  Renaming TE node IDs, link IDs, and SRLG IDs to IDs allocated from
      a separate namespace; this is necessary because all TE topologies
      are considered to be, generally speaking, independent, and clashes
      among TE node IDs, link IDs, or SRLG IDs are possible.

   *  Locking, vertically, TE topologies associated with different layer
      networks, according to provided topology inter-layer locks; this
      is done to facilitate inter-layer path computations across
      multiple TE topologies provided by the same topology provider.

   Figure 13 illustrates the process whereby the client merges the TE
   topologies furnished by its providers.

     /---\      +---+    +---+      +---+    +---+      /---\
     |C11|------|S13|----|S15|------|S23|----|S25|------|C21|
     \---/      +---+\   +---+      +---+   /+---+      \---/
                      \                    /
                       \                  /
                        \+---+      +---+/   +---+      /---\
                         |S18|------|S24|    |S28|------|C22|
                         +---+      +---+\  /+---+      \---/
                                          \/
                                          /\
     /---\      +---+    +---+      +---+/  \+---+      /---\
     |C12|------|S19|----|S17|------|S29|----|S27|------|C23|
     \---/      +---+    +---+      +---+    +---+      \---/

        Domain 1 TE Topology             Domain 2 TE Topology

             +---+    +---+                  +---+    +---+
        -----|S13|----|S15|----          ----|S23|----|S25|----
             +---+\   +---+                  +---+   /+---+
                   \                                /
                    \                              /
                     \+---+                  +---+/   +---+
                      |S18|----          ----|S24|    |S28|----
                      +---+                  +---+\  /+---+
                                                   \/
                                                   /\
             +---+    +---+                  +---+/  \+---+
        -----|S19|----|S17|----          ----|S29|----|S27|----
             +---+    +---+                  +---+    +---+

            Figure 13: Merging Domain TE Topologies: An Example

   In Figure 13, each of the two providers caters to the client
   (abstract or Native) TE topology, describing the network domain under
   the respective provider's control.  The client, by consulting such
   attributes of the inter-domain TE links as inter-domain plug IDs or
   remote TE node IDs / link IDs (as defined by the TE topology model),
   is able to determine that:

   1.  the two domains are adjacent and are interconnected via three
       inter-domain TE links, and

   2.  each domain is connected to a separate customer site, connecting
       the domain on the left in the figure to customer devices C11 and
       C12, and the domain on the right to customer devices C21, C22,
       and C23.

   Therefore, the client interconnects the open-ended TE links, as shown
   on the upper part of the figure.

   As mentioned previously, one way to interconnect the open-ended
   inter-domain TE links of neighboring domains is to mandate that the
   providers specify a remote node ID / link ID attribute in the
   provided inter-domain TE links.  However, this may prove not to be
   flexible.  For example, the providers may not know the respective
   remote node IDs / link IDs.  More importantly, this option does not
   allow the client to mix and match multiple topologies (more than one
   topology) catered by the same providers (see below).  Another option
   (which is more flexible) for resolving the open-ended inter-domain TE
   links is to annotate them with the inter-domain plug ID attribute.
   The inter-domain plug ID is a network-wide unique number that
   identifies on the network a connection that supports a given inter-
   domain TE link.  Instead of specifying a remote node ID / link ID, an
   inter-domain TE link may provide a non-zero inter-domain plug ID.  It
   is expected that two neighboring domain TE topologies (provided by
   separate providers) will each have at least one open-ended inter-
   domain TE link with an inter-domain plug ID matching an ID provided
   by its neighbor.  For example, the inter-domain TE link originating
   from node S15 of the Domain 1 TE topology (Figure 13) and the inter-
   domain TE link coming from node S23 of the Domain 2 TE topology may
   specify a matching inter-domain plug ID (e.g., 175344).  This allows
   the client to identify adjacent nodes in the separate neighboring TE
   topologies and resolve the inter-domain TE links connecting them,
   regardless of their respective node IDs / link IDs (which, as
   mentioned previously, could be allocated from independent
   namespaces).  Inter-domain plug IDs may be assigned and managed by a
   central network authority.  Alternatively, inter-domain plug IDs
   could be dynamically autodiscovered (e.g., via the Link Management
   Protocol (LMP)).

   Furthermore, the client renames the TE nodes, links, and SRLGs
   offered in the abstract TE topologies by assigning to them IDs
   allocated from a separate namespace managed by the client.  Such
   renaming is necessary, because the two abstract TE topologies may
   have their own namespaces, generally speaking, independent one from
   another; hence, ID overlaps/clashes are possible.  For example, both
   TE topologies have TE nodes named S7, which, after renaming, appear
   in the merged TE topology as S17 and S27, respectively.

   Once the merging process is complete, the client can use the merged
   TE topology for path computations across both domains -- for example,
   to compute a TE path connecting C11 to C23.

4.4.  Dealing with Multiple Abstract TE Topologies Provided by the Same
      Provider

   Based on local configuration, templates, and/or policies pushed by
   the client, a given provider may expose more than one abstract TE
   topology to the client.  For example, one abstract TE topology could
   be optimized based on a lowest-cost criterion, while another one
   could be based on best possible delay metrics, while yet another one
   could be based on maximum bandwidth availability for the client
   services.  Furthermore, the client may request all or some providers
   to expose additional abstract TE topologies, possibly of a different
   type and/or optimized differently, as compared to already-provided TE
   topologies.  In any case, the client should be prepared for a
   provider to offer to the client more than one abstract TE topology.

   It should be up to the client (based on the client's local
   configuration and/or policies conveyed to the client by the client's
   clients) to decide how to mix and match multiple abstract TE
   topologies provided by each or some of the providers, as well as how
   to merge them into the client's Native TE topologies.  The client
   also decides how many such merged TE topologies it needs to produce
   and maintain.  For example, in addition to the merged TE topology
   depicted in the upper part of Figure 13, the client may merge the
   abstract TE topologies received from the two providers, as shown in
   Figure 14, into the client's additional Native TE topologies, as
   shown in Figure 15.

        Domain 1 Abstract TE Topology 1  Domain 2 Abstract TE Topology 1

             +---+    +---+                  +---+    +---+
        -----|S13|----|S15|----          ----|S23|----|S25|----
             +---+\   +---+                  +---+   /+---+
                   \                                /
                    \                              /
                     \+---+                  +---+/   +---+
                      |S18|----          ----|S24|    |S28|----
                      +---+                  +---+\  /+---+
                                                   \/
                                                   /\
             +---+    +---+                  +---+/  \+---+
        -----|S19|----|S17|----          ----|S29|----|S27|----
             +---+    +---+                  +---+    +---+

        Domain 1 Abstract TE Topology 2  Domain 2 Abstract TE Topology 2

             +------------+                  +------------+
        -----|            |----          ----|            |----
             |            |                  |            |
             |    AN1     |----          ----|    AN1     |----
             |            |                  |            |
        -----|            |----          ----|            |----
             +------------+                  +------------+

          Figure 14: Merging Domain TE Topologies: Another Example

                Client's Merged TE Topology 2

     /---\      +------------+      +------------+      /---\
     |C11|------|            |------|            |------|C21|
     \---/      |            |      |            |      \---/
                |            |      |            |
                |            |      |            |
                |            |      |            |      /---\
                |    AN11    |------|    AN21    |------|C22|
                |            |      |            |      \---/
                |            |      |            |
                |            |      |            |
     /---\      |            |      |            |      /---\
     |C12|------|            |------|            |------|C23|
     \---/      +------------+      +------------+      \---/

                Client's Merged TE Topology 3

     /---\      +------------+      +---+    +---+      /---\
     |C11|------|            |------|S23|----|S25|------|C21|
     \---/      |            |      +---+   /+---+      \---/
                |            |             /
                |            |            /
                |            |      +---+/   +---+      /---\
                |    AN11    |------|S24|    |S28|------|C22|
                |            |      +---+\  /+---+      \---/
                |            |            \/
                |            |            /\
     /---\      |            |      +---+/  \+---+      /---\
     |C12|------|            |------|S29|----|S27|------|C23|
     \---/      +------------+      +---+    +---+      \---/

         Figure 15: Multiple Native (Merged) Client's TE Topologies

   Note that allowing the client to mix and match multiple TE topologies
   assumes that inter-domain plug IDs (rather than a remote node ID /
   link ID) are used as the option for identifying neighboring domains
   and inter-domain TE link resolution.

   It is important to note that each of the three Native (merged) TE
   topologies could be used by the client for computing TE paths for any
   of the multi-domain services.  The choice of which topology to use
   for a given service depends on the service parameters/requirements,
   the topology's style and optimization criteria, and the level of
   detail.

5.  Modeling Considerations

5.1.  Network Topology Building Blocks

   The network topology building blocks are discussed in [RFC8345].  The
   TE topology model defined in this document augments and uses the
   "ietf-network-topology" module defined in [RFC8345].

                        +------------------------+
                        | Network Topology Model |
                        | (ietf-network-topology)|
                        +------------------------+
                                     |
                                     |
                                     |
                                     V
                        +------------------------+
                        |       TE Topology      |
                        |         Model          |
                        +------------------------+

              Figure 16: Augmenting the Network Topology Model

5.2.  Technology-Agnostic TE Topology Model

   The TE topology model defined in this document is meant to be network
   technology agnostic.  Other technology-specific TE topology models
   can augment and use the building blocks provided by this model, as
   illustrated in Figure 17.

                   +-----------------------------+
                   |      TE Topology Model      |
                   +-----------------------------+
                                  |
             +-------------+-------------+-------------+
             |             |             |             |
             V             V             V             V
      +-------------+                            +-------------+
      | Technology- |                            | Technology- |
      |  Specific   |   ......................   |  Specific   |
      | TE Topology |                            | TE Topology |
      |   Model 1   |                            |   Model n   |
      +-------------+                            +-------------+

      Figure 17: Augmenting the Technology-Agnostic TE Topology Model

5.3.  Model Structure

   The high-level model structure defined by this document is as shown
   below:

   module: ietf-te-topology
     augment /nw:networks/nw:network/nw:network-types:
       +--rw te-topology!

     augment /nw:networks:
       +--rw te!
          +--rw templates
             +--rw node-template* [name] {template}?
             |  ............
             +--rw link-template* [name] {template}?
                ............

     augment /nw:networks/nw:network:
       +--rw te-topology-identifier
       |  +--rw provider-id?   te-global-id
       |  +--rw client-id?     te-global-id
       |  +--rw topology-id?   te-topology-id
       +--rw te!
          |  ............

     augment /nw:networks/nw:network/nw:node:
       +--rw te-node-id?   te-types:te-node-id
       +--rw te!
          |  ............
          +--rw tunnel-termination-point* [tunnel-tp-id]
             +--rw tunnel-tp-id    binary
             |  ............
             +--rw supporting-tunnel-termination-point*
                     [node-ref tunnel-tp-ref]
                |  ............

     augment /nw:networks/nw:network/nt:link:
       +--rw te!
          |  ..........

     augment /nw:networks/nw:network/nw:node/nt:termination-point:
       +--rw te-tp-id?   te-types:te-tp-id
       +--rw te!
          |  ............

5.4.  Topology Identifiers

   The TE topology is uniquely identified by a key that has three
   constituents -- "topology-id", "provider-id", and "client-id".  The
   combination of "provider-id" and "topology-id" uniquely identifies a
   Native TE topology on a given provider.  "client-id" is used only
   when Customized TE topologies come into play; a "client-id" value of
   "0" is used for Native TE topologies.

     augment /nw:networks/nw:network:
       +--rw te-topology-identifier
       |  +--rw provider-id?   te-global-id
       |  +--rw client-id?     te-global-id
       |  +--rw topology-id?   te-topology-id
       +--rw te!
          |  ............

5.5.  Generic TE Link Attributes

   The model covers the definitions for generic TE link attributes --
   bandwidth, administrative groups, SRLGs, switching capabilities, TE
   metric extensions, etc.

     +--rw te-link-attributes
        .....................
        +--rw admin-status?                     te-admin-status
        |  .....................
        +--rw link-index?                       uint64
        +--rw administrative-group?             te-types:admin-groups
        +--rw link-protection-type?             enumeration
        +--rw max-link-bandwidth?               te-bandwidth
        +--rw max-resv-link-bandwidth?          te-bandwidth
        +--rw unreserved-bandwidth* [priority]
        |  .....................
        +--rw te-default-metric?                uint32
        |  .....................
        +--rw te-srlgs
        +--rw te-nsrlgs {nsrlg}?        .....................

5.6.  Generic TE Node Attributes

   The model covers the definitions for generic TE node attributes.

   The definition of a generic connectivity matrix is shown below:

     +--rw te-node-attributes
        ...........
        +--rw connectivity-matrices
        ...........
        |  +--rw connectivity-matrix* [id]
        |  |  +--rw id            uint32
        |  |  +--rw from
        |  |  |  +--rw tp-ref?        leafref
        |  |  |  +--rw label-restrictions
        |  |  +--rw to
        |  |  |  +--rw tp-ref?        leafref
        |  |  |  +--rw label-restrictions
        |  |  +--rw is-allowed?   boolean
        ...........
        |  |  +--rw underlay! {te-topology-hierarchy}?
        ...........
        |  |  +--rw path-constraints
        ...........
        |  |  +--rw optimizations
        ...........
        |  |  +--ro path-properties
        ...........

   The definition of a TTP Local Link Connectivity List is shown below:

     +--rw tunnel-termination-point* [tunnel-tp-id]
        +--rw tunnel-tp-id               binary
        +--rw admin-status?              te-types:te-admin-status
        +--rw name?                      string
        +--rw switching-capability?      identityref
        +--rw encoding?                  identityref
        +--rw inter-layer-lock-id*       uint32
        +--rw protection-type?           identityref
        +--rw client-layer-adaptation
        ...........
        +--rw local-link-connectivities
        ...........
        |  +--rw local-link-connectivity* [link-tp-ref]
        |     +--rw link-tp-ref                leafref
        |     +--rw label-restrictions
        ...........
        |     +--rw is-allowed?                 boolean
        |     +--rw underlay {te-topology-hierarchy}?
        ...........
        |     +--rw path-constraints
        ...........
        |     +--rw optimizations
        ...........
        |     +--ro path-properties
        ...........
        +--rw supporting-tunnel-termination-point*
                [node-ref tunnel-tp-ref]
           +--rw node-ref         inet:uri
           +--rw tunnel-tp-ref    binary

   The attributes directly under container "connectivity-matrices" are
   the default attributes for all connectivity matrix entries when the
   per-entry corresponding attribute is not specified.  When a per-entry
   attribute is specified, it overrides the corresponding attribute
   directly under the container "connectivity-matrices".  The same rule
   applies to the attributes directly under container
   "local-link-connectivities".

   Each TTP MAY be supported by one or more supporting TTPs.  If the TE
   node hosting the TTP in question refers to a supporting TE node, then
   the supporting TTPs are hosted by the supporting TE node.  If the TE
   node refers to an underlay TE topology, the supporting TTPs are
   hosted by one or more specified TE nodes of the underlay TE topology.

5.7.  TED Information Sources

   The model allows each TE topological element to have multiple TE
   information sources (OSPF-TE, ISIS-TE, Border Gateway Protocol - Link
   State (BGP-LS), user-configured, system-processed, other).  Each
   information source is associated with a credibility preference to
   indicate precedence.  In scenarios where a Customized TE topology is
   merged into a client's Native TE topology, the merged topological
   elements would point to the corresponding Customized TE topology as
   its information source.

     augment /nw:networks/nw:network/nw:node:
       +--rw te!
          ...........
          +--ro information-source?            te-info-source
          +--ro information-source-instance?   string
          +--ro information-source-state
          |  +--ro credibility-preference?    uint16
          |  +--ro logical-network-element?   string
          |  +--ro network-instance?          string
          |  +--ro topology
          |     +--ro node-ref?      leafref
          |     +--ro network-ref?   leafref
          +--ro information-source-entry*
          |       [information-source information-source-instance]
          |  +--ro information-source             te-info-source
          |  +--ro information-source-instance    string
                ............

     augment /nw:networks/nw:network/nt:link:
       +--rw te!
          ...........
          +--ro information-source?            te-info-source
          +--ro information-source-instance?   string
          +--ro information-source-state
          |  +--ro credibility-preference?    uint16
          |  +--ro logical-network-element?   string
          |  +--ro network-instance?          string
          |  +--ro topology
          |     +--ro link-ref?      leafref
          |     +--ro network-ref?   leafref
          +--ro information-source-entry*
          |       [information-source information-source-instance]
          |  +--ro information-source                te-info-source
          |  +--ro information-source-instance       string
                ............

5.8.  Overlay/Underlay Relationship

   The model captures the overlay and underlay relationship for TE
   nodes/links.  For example, in networks where multiple TE topologies
   are built hierarchically, this model allows the user to start from a
   specific topological element in the topmost topology and traverse all
   the way down to the supporting topological elements in the bottommost
   topology.

   This relationship is captured via the "underlay-topology" field for
   the node and via the "underlay" field for the link.  The use of these
   fields is optional, and this functionality is tagged as a "feature"
   ("te-topology-hierarchy").

     augment /nw:networks/nw:network/nw:node:
       +--rw te-node-id?   te-types:te-node-id
       +--rw te!
          +--rw te-node-template*           leafref {template}?
          +--rw te-node-attributes
          |  +--rw admin-status?            te-types:te-admin-status
          |  |  ....................
          |  +--rw underlay-topology {te-topology-hierarchy}?
          |     +--rw network-ref?   leafref

     augment /nw:networks/nw:network/nt:link:
       +--rw te!
          +--rw te-link-attributes
          |  ....................
          |  +--rw underlay {te-topology-hierarchy}?
          |  |  +--rw enabled?                     boolean
          |  |  +--rw primary-path
          |  |  |  +--rw network-ref?    leafref
          |  |  |     ....................
          |  |  +--rw backup-path* [index]
          |  |  |  +--rw index           uint32
          |  |  |  +--rw network-ref?    leafref
          |  |  |     ....................
          |  |  +--rw protection-type?             identityref
          |  |  +--rw tunnel-termination-points
          |  |  |  +--rw source?        binary
          |  |  |  +--rw destination?   binary
          |  |  +--rw tunnels
          |  |  |  ....................

5.9.  Templates

   The data model provides users with the ability to define templates
   and apply them to link and node configurations.  The use of the
   "template" configuration is optional, and this functionality is
   tagged as a "feature" ("template").

     augment /nw:networks/nw:network/nw:node:
       +--rw te-node-id?   te-types:te-node-id
       +--rw te!
          +--rw te-node-template*
          |       -> ../../../../te/templates/node-template/name
          |       {template}?

     augment /nw:networks/nw:network/nt:link:
       +--rw te!
          +--rw te-link-template*
          |       -> ../../../../te/templates/link-template/name
          |       {template}?

     augment /nw:networks:
       +--rw te!
          +--rw templates
             +--rw node-template* [name] {template}?
             |  +--rw name
             |  |       te-types:te-template-name
             |  +--rw priority?                  uint16
             |  +--rw reference-change-policy?   enumeration
             |  +--rw te-node-attributes
                ..........
             +--rw link-template* [name] {template}?
                +--rw name
                |       te-types:te-template-name
                +--rw priority?                  uint16
                +--rw reference-change-policy?   enumeration
                +--rw te-link-attributes
                ..........

   Multiple templates can be specified for a configuration element.
   When two or more templates specify values for the same configuration
   field, the value from the template with the highest priority is used.
   The range of the priority is from 0 to 65535, with a lower number
   indicating a higher priority.  The "reference-change-policy"
   parameter specifies the action that needs to be taken when the
   template changes on a configuration element that has a reference to
   this template.  The choices of action include taking no action,
   rejecting the change to the template, and applying the change to the
   corresponding configuration.

5.10.  Scheduling Parameters

   The model allows time-scheduling parameters to be specified for each
   topological element or for the topology as a whole.  These parameters
   allow the provider to present different topological views to the
   client at different time slots.  The use of time-scheduling
   parameters is optional.

   The YANG data model for configuration scheduling is defined in
   [YANG-CFG-SCHED], which allows specifying configuration schedules
   without altering this data model.

5.11.  Notifications

   Notifications are a key component of any topology data model.

   [RFC8639] and [RFC8641] define a subscription mechanism and a push
   mechanism for YANG datastores.  These mechanisms currently allow the
   user to:

   *  Subscribe to notifications on a per-client basis.

   *  Specify subtree filters or XML Path Language (XPath) filters so
      that only contents of interest will be sent.

   *  Specify either periodic or on-demand notifications.

6.  Guidance for Writing Technology-Specific TE Topology Augmentations

   The TE topology model defined in this document is technology
   agnostic, as it defines concepts, abstractions, and attributes that
   are common across multiple network technologies.  It is envisioned
   that this base model will be widely used when defining technology-
   specific TE topology models for various layer networks.  [YANG-WSON],
   [YANG-OTN], and [YANG-L3] are some examples of technology-specific TE
   topology models.  Writers of such models are encouraged to augment
   the basic TE topology model's containers, such as those for TE
   topologies, TE nodes, TE links, Link Termination Points (LTPs),
   Tunnel Termination Points (TTPs), bandwidth, and labels, with the
   layer-specific attributes instead of defining new containers.

   Consider the following technology-specific example-topology model:

   module: example-topology
     augment /nw:networks/nw:network/nw:network-types/tet:te-topology:
       +--rw example-topology!
     augment /nw:networks/nw:network/tet:te:
       +--rw attributes
          +--rw attribute-1?   uint8
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes:
       +--rw attributes
          +--rw attribute-2?   uint8
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices:
       +--rw attributes
          +--rw attribute-3?   uint8
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix:
       +--rw attributes
          +--rw attribute-3?   uint8
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point:
       +--rw attributes
          +--rw attribute-4?   uint8
     augment /nw:networks/nw:network/nw:node/nt:termination-point
               /tet:te:
       +--rw attributes
          +--rw attribute-5?   uint8
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes:
       +--rw attributes
          +--rw attribute-6?   uint8

   The technology-specific TE bandwidth for this example topology can be
   specified using the following augment statements:

     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes
               /tet:interface-switching-capability/tet:max-lsp-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:max-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:max-resv-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:unreserved-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:path-constraints/tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:path-constraints
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:path-constraints/tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:path-constraints
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point/tet:client-layer-adaptation
               /tet:switching-capability/tet:te-bandwidth
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:path-constraints
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:path-constraints
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes
               /tet:interface-switching-capability/tet:max-lsp-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:max-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:max-resv-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry
               /tet:interface-switching-capability/tet:max-lsp-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry/tet:max-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry/tet:max-resv-link-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry/tet:unreserved-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--ro example
             +--ro bandwidth-1?   uint32
     augment /nw:networks/nw:network/nw:node/nt:termination-point/tet:te
               /tet:interface-switching-capability/tet:max-lsp-bandwidth
               /tet:te-bandwidth/tet:technology:
       +--:(example)
          +--rw example
             +--rw bandwidth-1?   uint32

   The technology-specific TE label for this example topology can be
   specified using the following augment statements:

     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:underlay/tet:primary-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:underlay/tet:backup-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/tet:te/tet:templates/tet:link-template
               /tet:te-link-attributes/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:label-restrictions/tet:label-restriction
               /tet:label-start/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:label-restrictions/tet:label-restriction
               /tet:label-end/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:underlay/tet:primary-path/tet:path-element/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:underlay/tet:backup-path/tet:path-element/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:path-properties/tet:path-route-objects
               /tet:path-route-object/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:from/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:from/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:to/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:to/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:underlay/tet:primary-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:underlay/tet:backup-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:te-node-attributes/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:path-properties
               /tet:path-route-objects/tet:path-route-object/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:label-restrictions/tet:label-restriction
               /tet:label-start/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:label-restrictions/tet:label-restriction
               /tet:label-end/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:underlay/tet:primary-path/tet:path-element/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:underlay/tet:backup-path/tet:path-element/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:path-properties/tet:path-route-objects
               /tet:path-route-object/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:from/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:from/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:to/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:to/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:underlay/tet:primary-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:underlay/tet:backup-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:information-source-entry/tet:connectivity-matrices
               /tet:connectivity-matrix/tet:path-properties
               /tet:path-route-objects/tet:path-route-object/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:underlay
               /tet:primary-path/tet:path-element/tet:type/tet:label
               /tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:underlay
               /tet:backup-path/tet:path-element/tet:type/tet:label
               /tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities/tet:path-properties
               /tet:path-route-objects/tet:path-route-object/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:underlay
               /tet:primary-path/tet:path-element/tet:type/tet:label
               /tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:underlay/tet:backup-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nw:node/tet:te
               /tet:tunnel-termination-point
               /tet:local-link-connectivities
               /tet:local-link-connectivity/tet:path-properties
               /tet:path-route-objects/tet:path-route-object/tet:type
               /tet:label/tet:label-hop/tet:te-label/tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:underlay/tet:primary-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:te-link-attributes/tet:underlay/tet:backup-path
               /tet:path-element/tet:type/tet:label/tet:label-hop
               /tet:te-label/tet:technology:
       +--:(example)
          +--rw example
             +--rw label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry/tet:label-restrictions
               /tet:label-restriction/tet:label-start/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32
     augment /nw:networks/nw:network/nt:link/tet:te
               /tet:information-source-entry/tet:label-restrictions
               /tet:label-restriction/tet:label-end/tet:te-label
               /tet:technology:
       +--:(example)
          +--ro example
             +--ro label-1?   uint32

   The example YANG module that implements the above example topology is
   provided in Appendix C.

7.  TE Topology YANG Module

   This module references [RFC1195], [RFC3209], [RFC3272], [RFC3471],
   [RFC3630], [RFC3785], [RFC4201], [RFC4202], [RFC4203], [RFC4206],
   [RFC4872], [RFC5152], [RFC5212], [RFC5305], [RFC5316], [RFC5392],
   [RFC6001], [RFC6241], [RFC6991], [RFC7308], [RFC7471], [RFC7579],
   [RFC7752], [RFC8345], and [RFC8776].

   <CODE BEGINS> file "ietf-te-topology@2020-08-06.yang"
   module ietf-te-topology {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-te-topology";
     prefix tet;

     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-te-types {
       prefix te-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering";
     }
     import ietf-network {
       prefix nw;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }
     import ietf-network-topology {
       prefix nt;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }

     organization
       "IETF Traffic Engineering Architecture and Signaling (TEAS)
        Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/teas/>
        WG List:  <mailto:teas@ietf.org>

        Editor:   Xufeng Liu
                  <mailto:xufeng.liu.ietf@gmail.com>

        Editor:   Igor Bryskin
                  <mailto:i_bryskin@yahoo.com>

        Editor:   Vishnu Pavan Beeram
                  <mailto:vbeeram@juniper.net>

        Editor:   Tarek Saad
                  <mailto:tsaad@juniper.net>

        Editor:   Himanshu Shah
                  <mailto:hshah@ciena.com>

        Editor:   Oscar Gonzalez de Dios
                  <mailto:oscar.gonzalezdedios@telefonica.com>";
     description
       "This YANG module defines a TE topology model for representing,
        retrieving, and manipulating technology-agnostic TE topologies.

        Copyright (c) 2020 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Simplified BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC 8795; see the
        RFC itself for full legal notices.";

     revision 2020-08-06 {
       description
         "Initial revision.";
       reference
         "RFC 8795: YANG Data Model for Traffic Engineering (TE)
          Topologies";
     }

     /*
      * Features
      */

     feature nsrlg {
       description
         "This feature indicates that the system supports NSRLGs
          (Non-Shared Risk Link Groups).";
     }

     feature te-topology-hierarchy {
       description
         "This feature indicates that the system allows an underlay
          and/or overlay TE topology hierarchy.";
     }

     feature template {
       description
         "This feature indicates that the system supports
          template configuration.";
     }

     /*
      * Typedefs
      */

     typedef geographic-coordinate-degree {
       type decimal64 {
         fraction-digits 8;
       }
       description
         "Decimal degree (DD) used to express latitude and longitude
          geographic coordinates.";
     }
     // geographic-coordinate-degree

     typedef te-info-source {
       type enumeration {
         enum unknown {
           description
             "The source is unknown.";
         }
         enum locally-configured {
           description
             "Configured entity.";
         }
         enum ospfv2 {
           description
             "OSPFv2.";
         }
         enum ospfv3 {
           description
             "OSPFv3.";
         }
         enum isis {
           description
             "IS-IS.";
         }
         enum bgp-ls {
           description
             "BGP-LS.";
           reference
             "RFC 7752: North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP";
         }
         enum system-processed {
           description
             "System-processed entity.";
         }
         enum other {
           description
             "Other source.";
         }
       }
       description
         "Describes the type of source that has provided the
          related information, and the source's credibility.";
     }
     // te-info-source

     /*
      * Groupings
      */

     grouping connectivity-matrix-entry-path-attributes {
       description
         "Attributes of a connectivity matrix entry.";
       leaf is-allowed {
         type boolean;
         description
           "'true' - switching is allowed;
            'false' - switching is disallowed.";
       }
       container underlay {
         if-feature "te-topology-hierarchy";
         description
           "Attributes of the TE link underlay.";
         reference
           "RFC 4206: Label Switched Paths (LSP) Hierarchy with
            Generalized Multi-Protocol Label Switching (GMPLS)
            Traffic Engineering (TE)";
         uses te-link-underlay-attributes;
       }
       uses te-types:generic-path-constraints;
       uses te-types:generic-path-optimization;
       uses te-types:generic-path-properties;
     }
     // connectivity-matrix-entry-path-attributes

     grouping geolocation-container {
       description
         "Contains a GPS location.";
       container geolocation {
         config false;
         description
           "Contains a GPS location.";
         leaf altitude {
           type int64;
           units "millimeters";
           description
             "Distance above sea level.";
         }
         leaf latitude {
           type geographic-coordinate-degree {
             range "-90..90";
           }
           description
             "Relative position north or south on the Earth's surface.";
         }
         leaf longitude {
           type geographic-coordinate-degree {
             range "-180..180";
           }
           description
             "Angular distance east or west on the Earth's surface.";
         }
       }
       // geolocation
     }
     // geolocation-container

     grouping information-source-state-attributes {
       description
         "The attributes identifying the source that has provided the
          related information, and the source's credibility.";
       leaf credibility-preference {
         type uint16;
         description
           "The preference value for calculating the Traffic
            Engineering database credibility value used for
            tie-break selection between different information-source
            values.  A higher value is preferable.";
       }
       leaf logical-network-element {
         type string;
         description
           "When applicable, this is the name of a logical network
            element from which the information is learned.";
       }
       leaf network-instance {
         type string;
         description
           "When applicable, this is the name of a network instance
            from which the information is learned.";
       }
     }
     // information-source-state-attributes

     grouping information-source-per-link-attributes {
       description
         "Per-node container of the attributes identifying the source
          that has provided the related information, and the source's
          credibility.";
       leaf information-source {
         type te-info-source;
         config false;
         description
           "Indicates the type of information source.";
       }
       leaf information-source-instance {
         type string;
         config false;
         description
           "The name indicating the instance of the information
            source.";
       }
       container information-source-state {
         config false;
         description
           "Contains state attributes related to the information
            source.";
         uses information-source-state-attributes;
         container topology {
           description
             "When the information is processed by the system,
              the attributes in this container indicate which topology
              is used to generate the result information.";
           uses nt:link-ref;
         }
       }
     }
     // information-source-per-link-attributes

     grouping information-source-per-node-attributes {
       description
         "Per-node container of the attributes identifying the source
          that has provided the related information, and the source's
          credibility.";
       leaf information-source {
         type te-info-source;
         config false;
         description
           "Indicates the type of information source.";
       }
       leaf information-source-instance {
         type string;
         config false;
         description
           "The name indicating the instance of the information
            source.";
       }
       container information-source-state {
         config false;
         description
           "Contains state attributes related to the information
            source.";
         uses information-source-state-attributes;
         container topology {
           description
             "When the information is processed by the system,
              the attributes in this container indicate which topology
              is used to generate the result information.";
           uses nw:node-ref;
         }
       }
     }
     // information-source-per-node-attributes

     grouping interface-switching-capability-list {
       description
         "List of Interface Switching Capability Descriptors (ISCDs).";
       list interface-switching-capability {
         key "switching-capability encoding";
         description
           "List of ISCDs for this link.";
         reference
           "RFC 3471: Generalized Multi-Protocol Label Switching (GMPLS)
            Signaling Functional Description
            RFC 4203: OSPF Extensions in Support of Generalized
            Multi-Protocol Label Switching (GMPLS)";
         leaf switching-capability {
           type identityref {
             base te-types:switching-capabilities;
           }
           description
             "Switching capability for this interface.";
         }
         leaf encoding {
           type identityref {
             base te-types:lsp-encoding-types;
           }
           description
             "Encoding supported by this interface.";
         }
         uses te-link-iscd-attributes;
       }
       // interface-switching-capability
     }
     // interface-switching-capability-list

     grouping statistics-per-link {
       description
         "Statistics attributes per TE link.";
       leaf discontinuity-time {
         type yang:date-and-time;
         description
           "The time of the most recent occasion at which any one or
            more of this interface's counters suffered a
            discontinuity.  If no such discontinuities have occurred
            since the last re-initialization of the local management
            subsystem, then this node contains the time the local
            management subsystem re-initialized itself.";
       }
       /* Administrative attributes */
       leaf disables {
         type yang:counter32;
         description
           "Number of times that a link was disabled.";
       }
       leaf enables {
         type yang:counter32;
         description
           "Number of times that a link was enabled.";
       }
       leaf maintenance-clears {
         type yang:counter32;
         description
           "Number of times that a link was taken out of maintenance.";
       }
       leaf maintenance-sets {
         type yang:counter32;
         description
           "Number of times that a link was put in maintenance.";
       }
       leaf modifies {
         type yang:counter32;
         description
           "Number of times that a link was modified.";
       }
       /* Operational attributes */
       leaf downs {
         type yang:counter32;
         description
           "Number of times that a link was set to an operational state
            of 'down'.";
       }
       leaf ups {
         type yang:counter32;
         description
           "Number of times that a link was set to an operational state
            of 'up'.";
       }
       /* Recovery attributes */
       leaf fault-clears {
         type yang:counter32;
         description
           "Number of times that a link experienced a fault-clear
            event.";
       }
       leaf fault-detects {
         type yang:counter32;
         description
           "Number of times that a link experienced fault detection.";
       }
       leaf protection-switches {
         type yang:counter32;
         description
           "Number of times that a link experienced protection
            switchover.";
       }
       leaf protection-reverts {
         type yang:counter32;
         description
           "Number of times that a link experienced protection
            reversion.";
       }
       leaf restoration-failures {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            failure.";
       }
       leaf restoration-starts {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            start.";
       }
       leaf restoration-successes {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            success.";
       }
       leaf restoration-reversion-failures {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            reversion failure.";
       }
       leaf restoration-reversion-starts {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            reversion start.";
       }
       leaf restoration-reversion-successes {
         type yang:counter32;
         description
           "Number of times that a link experienced restoration
            reversion success.";
       }
     }
     // statistics-per-link

     grouping statistics-per-node {
       description
         "Statistics attributes per TE node.";
       leaf discontinuity-time {
         type yang:date-and-time;
         description
           "The time of the most recent occasion at which any one or
            more of this interface's counters suffered a
            discontinuity.  If no such discontinuities have occurred
            since the last re-initialization of the local management
            subsystem, then this node contains the time the local
            management subsystem re-initialized itself.";
       }
       container node {
         description
           "Contains statistics attributes at the TE node level.";
         leaf disables {
           type yang:counter32;
           description
             "Number of times that a node was disabled.";
         }
         leaf enables {
           type yang:counter32;
           description
             "Number of times that a node was enabled.";
         }
         leaf maintenance-sets {
           type yang:counter32;
           description
             "Number of times that a node was put in maintenance.";
         }
         leaf maintenance-clears {
           type yang:counter32;
           description
             "Number of times that a node was taken out of
              maintenance.";
         }
         leaf modifies {
           type yang:counter32;
           description
             "Number of times that a node was modified.";
         }
       }
       // node
       container connectivity-matrix-entry {
         description
           "Contains statistics attributes at the level of a
            connectivity matrix entry.";
         leaf creates {
           type yang:counter32;
           description
             "Number of times that a connectivity matrix entry was
              created.";
           reference
             "RFC 6241: Network Configuration Protocol (NETCONF),
                        Section 7.2, 'create' operation";
         }
         leaf deletes {
           type yang:counter32;
           description
             "Number of times that a connectivity matrix entry was
              deleted.";
           reference
             "RFC 6241: Network Configuration Protocol (NETCONF),
                        Section 7.2, 'delete' operation";
         }
         leaf disables {
           type yang:counter32;
           description
             "Number of times that a connectivity matrix entry was
              disabled.";
         }
         leaf enables {
           type yang:counter32;
           description
             "Number of times that a connectivity matrix entry was
              enabled.";
         }
         leaf modifies {
           type yang:counter32;
           description
             "Number of times that a connectivity matrix entry was
              modified.";
         }
       }
       // connectivity-matrix-entry
     }
     // statistics-per-node

     grouping statistics-per-ttp {
       description
         "Statistics attributes per TE TTP (Tunnel Termination Point).";
       leaf discontinuity-time {
         type yang:date-and-time;
         description
           "The time of the most recent occasion at which any one or
            more of this interface's counters suffered a
            discontinuity.  If no such discontinuities have occurred
            since the last re-initialization of the local management
            subsystem, then this node contains the time the local
            management subsystem re-initialized itself.";
       }
       container tunnel-termination-point {
         description
           "Contains statistics attributes at the TE TTP level.";
         /* Administrative attributes */
         leaf disables {
           type yang:counter32;
           description
             "Number of times that a TTP was disabled.";
         }
         leaf enables {
           type yang:counter32;
           description
             "Number of times that a TTP was enabled.";
         }
         leaf maintenance-clears {
           type yang:counter32;
           description
             "Number of times that a TTP was taken out of maintenance.";
         }
         leaf maintenance-sets {
           type yang:counter32;
           description
             "Number of times that a TTP was put in maintenance.";
         }
         leaf modifies {
           type yang:counter32;
           description
             "Number of times that a TTP was modified.";
         }
         /* Operational attributes */
         leaf downs {
           type yang:counter32;
           description
             "Number of times that a TTP was set to an operational state
              of 'down'.";
         }
         leaf ups {
           type yang:counter32;
           description
             "Number of times that a TTP was set to an operational state
              of 'up'.";
         }
         leaf in-service-clears {
           type yang:counter32;
           description
             "Number of times that a TTP was taken out of service
              (TE tunnel was released).";
         }
         leaf in-service-sets {
           type yang:counter32;
           description
             "Number of times that a TTP was put in service by a TE
              tunnel (TE tunnel was set up).";
         }
       }
       // tunnel-termination-point
       container local-link-connectivity {
         description
           "Contains statistics attributes at the TE LLCL (Local Link
            Connectivity List) level.";
         leaf creates {
           type yang:counter32;
           description
             "Number of times that an LLCL entry was created.";
           reference
             "RFC 6241: Network Configuration Protocol (NETCONF),
                        Section 7.2, 'create' operation";
         }
         leaf deletes {
           type yang:counter32;
           description
             "Number of times that an LLCL entry was deleted.";
           reference
             "RFC 6241: Network Configuration Protocol (NETCONF),
                        Section 7.2, 'delete' operation";
         }
         leaf disables {
           type yang:counter32;
           description
             "Number of times that an LLCL entry was disabled.";
         }
         leaf enables {
           type yang:counter32;
           description
             "Number of times that an LLCL entry was enabled.";
         }
         leaf modifies {
           type yang:counter32;
           description
             "Number of times that an LLCL entry was modified.";
         }
       }
       // local-link-connectivity
     }
     // statistics-per-ttp

     grouping te-link-augment {
       description
         "Augmentation for a TE link.";
       uses te-link-config;
       uses te-link-state-derived;
       container statistics {
         config false;
         description
           "Statistics data.";
         uses statistics-per-link;
       }
     }
     // te-link-augment

     grouping te-link-config {
       description
         "TE link configuration grouping.";
       choice bundle-stack-level {
         description
           "The TE link can be partitioned into bundled links or
            component links.";
         case bundle {
           container bundled-links {
             description
               "A set of bundled links.";
             reference
               "RFC 4201: Link Bundling in MPLS Traffic
                Engineering (TE)";
             list bundled-link {
               key "sequence";
               description
                 "Specifies a bundled interface that is
                  further partitioned.";
               leaf sequence {
                 type uint32;
                 description
                   "Identifies the sequence in the bundle.";
               }
             }
           }
         }
         case component {
           container component-links {
             description
               "A set of component links.";
             list component-link {
               key "sequence";
               description
                 "Specifies a component interface that is
                  sufficient to unambiguously identify the
                  appropriate resources.";
               leaf sequence {
                 type uint32;
                 description
                   "Identifies the sequence in the bundle.";
               }
               leaf src-interface-ref {
                 type string;
                 description
                   "Reference to a component link interface on the
                    source node.";
               }
               leaf des-interface-ref {
                 type string;
                 description
                   "Reference to a component link interface on the
                    destination node.";
               }
             }
           }
         }
       }
       // bundle-stack-level
       leaf-list te-link-template {
         if-feature "template";
         type leafref {
           path "../../../../te/templates/link-template/name";
         }
         description
           "The reference to a TE link template.";
       }
       uses te-link-config-attributes;
     }
     // te-link-config

     grouping te-link-config-attributes {
       description
         "Link configuration attributes in a TE topology.";
       container te-link-attributes {
         description
           "Link attributes in a TE topology.";
         leaf access-type {
           type te-types:te-link-access-type;
           description
             "Link access type, which can be point-to-point or
              multi-access.";
         }
         container external-domain {
           description
             "For an inter-domain link, specifies the attributes of
              the remote end of the link, to facilitate the signaling at
              the local end.";
           uses nw:network-ref;
           leaf remote-te-node-id {
             type te-types:te-node-id;
             description
               "Remote TE node identifier, used together with
                'remote-te-link-tp-id' to identify the remote Link
                Termination Point (LTP) in a different domain.";
           }
           leaf remote-te-link-tp-id {
             type te-types:te-tp-id;
             description
               "Remote TE LTP identifier, used together with
                'remote-te-node-id' to identify the remote LTP in a
                different domain.";
           }
         }
         leaf is-abstract {
           type empty;
           description
             "Present if the link is abstract.";
         }
         leaf name {
           type string;
           description
             "Link name.";
         }
         container underlay {
           if-feature "te-topology-hierarchy";
           description
             "Attributes of the TE link underlay.";
           reference
             "RFC 4206: Label Switched Paths (LSP) Hierarchy with
              Generalized Multi-Protocol Label Switching (GMPLS)
              Traffic Engineering (TE)";
           uses te-link-underlay-attributes;
         }
         leaf admin-status {
           type te-types:te-admin-status;
           description
             "The administrative state of the link.";
         }
         uses te-link-info-attributes;
       }
       // te-link-attributes
     }
     // te-link-config-attributes

     grouping te-link-info-attributes {
       description
         "Advertised TE information attributes.";
       leaf link-index {
         type uint64;
         description
           "The link identifier.  If OSPF is used, this object
            represents an ospfLsdbID.  If IS-IS is used, this object
            represents an isisLSPID.  If a locally configured link is
            used, this object represents a unique value, which is
            locally defined in a router.";
       }
       leaf administrative-group {
         type te-types:admin-groups;
         description
           "Administrative group or color of the link.
            This attribute covers both administrative groups (defined
            in RFCs 3630 and 5305) and Extended Administrative Groups
            (defined in RFC 7308).";
         reference
           "RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2
            RFC 5305: IS-IS Extensions for Traffic Engineering
            RFC 7308: Extended Administrative Groups in MPLS Traffic
            Engineering (MPLS-TE)";
       }
       uses interface-switching-capability-list;
       uses te-types:label-set-info;
       leaf link-protection-type {
         type identityref {
           base te-types:link-protection-type;
         }
         description
           "Link Protection Type desired for this link.";
         reference
           "RFC 4202: Routing Extensions in Support of
            Generalized Multi-Protocol Label Switching (GMPLS)";
       }
       container max-link-bandwidth {
         uses te-types:te-bandwidth;
         description
           "Maximum bandwidth that can be seen on this link in this
            direction.  Units are in bytes per second.";
         reference
           "RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2
            RFC 5305: IS-IS Extensions for Traffic Engineering";
       }
       container max-resv-link-bandwidth {
         uses te-types:te-bandwidth;
         description
           "Maximum amount of bandwidth that can be reserved in this
            direction in this link.  Units are in bytes per second.";
         reference
           "RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2
            RFC 5305: IS-IS Extensions for Traffic Engineering";
       }
       list unreserved-bandwidth {
         key "priority";
         max-elements 8;
         description
           "Unreserved bandwidth for priority levels 0-7.  Units are in
            bytes per second.";
         reference
           "RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2
            RFC 5305: IS-IS Extensions for Traffic Engineering";
         leaf priority {
           type uint8 {
             range "0..7";
           }
           description
             "Priority.";
         }
         uses te-types:te-bandwidth;
       }
       leaf te-default-metric {
         type uint32;
         description
           "Traffic Engineering metric.";
         reference
           "RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2
            RFC 5305: IS-IS Extensions for Traffic Engineering";
       }
       leaf te-delay-metric {
         type uint32;
         description
           "Traffic Engineering delay metric.";
         reference
           "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions";
       }
       leaf te-igp-metric {
         type uint32;
         description
           "IGP metric used for Traffic Engineering.";
         reference
           "RFC 3785: Use of Interior Gateway Protocol (IGP) Metric as a
            second MPLS Traffic Engineering (TE) Metric";
       }
       container te-srlgs {
         description
           "Contains a list of SRLGs.";
         leaf-list value {
           type te-types:srlg;
           description
             "SRLG value.";
           reference
             "RFC 4202: Routing Extensions in Support of
              Generalized Multi-Protocol Label Switching (GMPLS)";
         }
       }
       container te-nsrlgs {
         if-feature "nsrlg";
         description
           "Contains a list of NSRLGs (Non-Shared Risk Link Groups).
            When an abstract TE link is configured, this list specifies
            the request that underlay TE paths need to be mutually
            disjoint with other TE links in the same groups.";
         leaf-list id {
           type uint32;
           description
             "NSRLG ID, uniquely configured within a topology.";
           reference
             "RFC 4872: RSVP-TE Extensions in Support of End-to-End
              Generalized Multi-Protocol Label Switching (GMPLS)
              Recovery";
         }
       }
     }
     // te-link-info-attributes

     grouping te-link-iscd-attributes {
       description
         "TE link ISCD attributes.";
       reference
         "RFC 4203: OSPF Extensions in Support of Generalized
          Multi-Protocol Label Switching (GMPLS), Section 1.4";
       list max-lsp-bandwidth {
         key "priority";
         max-elements 8;
         description
           "Maximum Label Switched Path (LSP) bandwidth at
            priorities 0-7.";
         leaf priority {
           type uint8 {
             range "0..7";
           }
           description
             "Priority.";
         }
         uses te-types:te-bandwidth;
       }
     }
     // te-link-iscd-attributes

     grouping te-link-state-derived {
       description
         "Link state attributes in a TE topology.";
       leaf oper-status {
         type te-types:te-oper-status;
         config false;
         description
           "The current operational state of the link.";
       }
       leaf is-transitional {
         type empty;
         config false;
         description
           "Present if the link is transitional; used as an
            alternative approach in lieu of 'inter-layer-lock-id'
            for path computation in a TE topology covering multiple
            layers or multiple regions.";
         reference
           "RFC 5212: Requirements for GMPLS-Based Multi-Region and
            Multi-Layer Networks (MRN/MLN)
            RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
            for Multi-Layer and Multi-Region Networks (MLN/MRN)";
       }
       uses information-source-per-link-attributes;
       list information-source-entry {
         key "information-source information-source-instance";
         config false;
         description
           "A list of information sources learned, including the source
            that is used.";
         uses information-source-per-link-attributes;
         uses te-link-info-attributes;
       }
       container recovery {
         config false;
         description
           "Status of the recovery process.";
         leaf restoration-status {
           type te-types:te-recovery-status;
           description
             "Restoration status.";
         }
         leaf protection-status {
           type te-types:te-recovery-status;
           description
             "Protection status.";
         }
       }
       container underlay {
         if-feature "te-topology-hierarchy";
         config false;
         description
           "State attributes for the TE link underlay.";
         leaf dynamic {
           type boolean;
           description
             "'true' if the underlay is dynamically created.";
         }
         leaf committed {
           type boolean;
           description
             "'true' if the underlay is committed.";
         }
       }
     }
     // te-link-state-derived

     grouping te-link-underlay-attributes {
       description
         "Attributes for the TE link underlay.";
       reference
         "RFC 4206: Label Switched Paths (LSP) Hierarchy with
          Generalized Multi-Protocol Label Switching (GMPLS)
          Traffic Engineering (TE)";
       leaf enabled {
         type boolean;
         description
           "'true' if the underlay is enabled.
            'false' if the underlay is disabled.";
       }
       container primary-path {
         description
           "The service path on the underlay topology that
            supports this link.";
         uses nw:network-ref;
         list path-element {
           key "path-element-id";
           description
             "A list of path elements describing the service path.";
           leaf path-element-id {
             type uint32;
             description
               "To identify the element in a path.";
           }
           uses te-path-element;
         }
       }
       // primary-path
       list backup-path {
         key "index";
         description
           "A list of backup service paths on the underlay topology that
            protect the underlay primary path.  If the primary path is
            not protected, the list contains zero elements.  If the
            primary path is protected, the list contains one or more
            elements.";
         leaf index {
           type uint32;
           description
             "A sequence number to identify a backup path.";
         }
         uses nw:network-ref;
         list path-element {
           key "path-element-id";
           description
             "A list of path elements describing the backup service
              path.";
           leaf path-element-id {
             type uint32;
             description
               "To identify the element in a path.";
           }
           uses te-path-element;
         }
       }
       // backup-path
       leaf protection-type {
         type identityref {
           base te-types:lsp-protection-type;
         }
         description
           "Underlay protection type desired for this link.";
       }
       container tunnel-termination-points {
         description
           "Underlay TTPs desired for this link.";
         leaf source {
           type binary;
           description
             "Source TTP identifier.";
         }
         leaf destination {
           type binary;
           description
             "Destination TTP identifier.";
         }
       }
       container tunnels {
         description
           "Underlay TE tunnels supporting this TE link.";
         leaf sharing {
           type boolean;
           default "true";
           description
             "'true' if the underlay tunnel can be shared with other
              TE links;
              'false' if the underlay tunnel is dedicated to this
              TE link.
              This leaf is the default option for all TE tunnels
              and may be overridden by the per-TE-tunnel value.";
         }
         list tunnel {
           key "tunnel-name";
           description
             "Zero, one, or more underlay TE tunnels that support this
              TE link.";
           leaf tunnel-name {
             type string;
             description
               "A tunnel name uniquely identifies an underlay TE tunnel,
                used together with the 'source-node' value for this
                link.";
             reference
               "RFC 3209: RSVP-TE: Extensions to RSVP for LSP Tunnels";
           }
           leaf sharing {
             type boolean;
             description
               "'true' if the underlay tunnel can be shared with other
                TE links;
                'false' if the underlay tunnel is dedicated to this
                TE link.";
           }
         }
         // tunnel
       }
       // tunnels
     }
     // te-link-underlay-attributes

     grouping te-node-augment {
       description
         "Augmentation for a TE node.";
       uses te-node-config;
       uses te-node-state-derived;
       container statistics {
         config false;
         description
           "Statistics data.";
         uses statistics-per-node;
       }
       list tunnel-termination-point {
         key "tunnel-tp-id";
         description
           "A termination point can terminate a tunnel.";
         leaf tunnel-tp-id {
           type binary;
           description
             "TTP identifier.";
         }
         uses te-node-tunnel-termination-point-config;
         leaf oper-status {
           type te-types:te-oper-status;
           config false;
           description
             "The current operational state of the TTP.";
         }
         uses geolocation-container;
         container statistics {
           config false;
           description
             "Statistics data.";
           uses statistics-per-ttp;
         }
         // Relationship to other TTPs
         list supporting-tunnel-termination-point {
           key "node-ref tunnel-tp-ref";
           description
             "Identifies the TTPs on which this TTP depends.";
           leaf node-ref {
             type inet:uri;
             description
               "This leaf identifies the node in which the supporting
                TTP is present.
                This node is either the supporting node or a node in
                an underlay topology.";
           }
           leaf tunnel-tp-ref {
             type binary;
             description
               "Reference to a TTP that is in either the supporting node
                or a node in an underlay topology.";
           }
         }
         // supporting-tunnel-termination-point
       }
       // tunnel-termination-point
     }
     // te-node-augment

     grouping te-node-config {
       description
         "TE node configuration grouping.";
       leaf-list te-node-template {
         if-feature "template";
         type leafref {
           path "../../../../te/templates/node-template/name";
         }
         description
           "The reference to a TE node template.";
       }
       uses te-node-config-attributes;
     }
     // te-node-config

     grouping te-node-config-attributes {
       description
         "Configuration node attributes in a TE topology.";
       container te-node-attributes {
         description
           "Contains node attributes in a TE topology.";
         leaf admin-status {
           type te-types:te-admin-status;
           description
             "The administrative state of the link.";
         }
         uses te-node-connectivity-matrices;
         uses te-node-info-attributes;
       }
     }
     // te-node-config-attributes

     grouping te-node-config-attributes-template {
       description
         "Configuration node attributes for a template in a TE
          topology.";
       container te-node-attributes {
         description
           "Contains node attributes in a TE topology.";
         leaf admin-status {
           type te-types:te-admin-status;
           description
             "The administrative state of the link.";
         }
         uses te-node-info-attributes;
       }
     }
     // te-node-config-attributes-template

     grouping te-node-connectivity-matrices {
       description
         "Connectivity matrix on a TE node.";
       container connectivity-matrices {
         description
           "Contains a connectivity matrix on a TE node.";
         leaf number-of-entries {
           type uint16;
           description
             "The number of connectivity matrix entries.
              If this number is specified in the configuration request,
              the number is the requested number of entries, which may
              not all be listed in the list;
              if this number is reported in the state data,
              the number is the current number of operational entries.";
         }
         uses te-types:label-set-info;
         uses connectivity-matrix-entry-path-attributes;
         list connectivity-matrix {
           key "id";
           description
             "Represents a node's switching limitations, i.e.,
              limitations in the interconnecting network TE links
              across the node.";
           reference
             "RFC 7579: General Network Element Constraint Encoding
              for GMPLS-Controlled Networks";
           leaf id {
             type uint32;
             description
               "Identifies the connectivity matrix entry.";
           }
         }
         // connectivity-matrix
       }
       // connectivity-matrices
     }
     // te-node-connectivity-matrices

     grouping te-node-connectivity-matrix-attributes {
       description
         "Termination point references of a connectivity matrix entry.";
       container from {
         description
           "Reference to a source LTP.";
         leaf tp-ref {
           type leafref {
             path "../../../../../../nt:termination-point/nt:tp-id";
           }
           description
             "Relative reference to a termination point.";
         }
         uses te-types:label-set-info;
       }
       container to {
         description
           "Reference to a destination LTP.";
         leaf tp-ref {
           type leafref {
             path "../../../../../../nt:termination-point/nt:tp-id";
           }
           description
             "Relative reference to a termination point.";
         }
         uses te-types:label-set-info;
       }
       uses connectivity-matrix-entry-path-attributes;
     }
     // te-node-connectivity-matrix-attributes

     grouping te-node-info-attributes {
       description
         "Advertised TE information attributes.";
       leaf domain-id {
         type uint32;
         description
           "Identifies the domain to which this node belongs.
            This attribute is used to support inter-domain links.";
         reference
           "RFC 5152: A Per-Domain Path Computation Method for
            Establishing Inter-Domain Traffic Engineering (TE)
            Label Switched Paths (LSPs)
            RFC 5316: ISIS Extensions in Support of Inter-Autonomous
            System (AS) MPLS and GMPLS Traffic Engineering
            RFC 5392: OSPF Extensions in Support of Inter-Autonomous
            System (AS) MPLS and GMPLS Traffic Engineering";
       }
       leaf is-abstract {
         type empty;
         description
           "Present if the node is abstract; not present if the node
            is actual.";
       }
       leaf name {
         type string;
         description
           "Node name.";
       }
       leaf-list signaling-address {
         type inet:ip-address;
         description
           "The node's signaling address.";
       }
       container underlay-topology {
         if-feature "te-topology-hierarchy";
         description
           "When an abstract node encapsulates a topology, the
            attributes in this container point to said topology.";
         uses nw:network-ref;
       }
     }
     // te-node-info-attributes

     grouping te-node-state-derived {
       description
         "Node state attributes in a TE topology.";
       leaf oper-status {
         type te-types:te-oper-status;
         config false;
         description
           "The current operational state of the node.";
       }
       uses geolocation-container;
       leaf is-multi-access-dr {
         type empty;
         config false;
         description
           "The presence of this attribute indicates that this TE node
            is a pseudonode elected as a designated router.";
         reference
           "RFC 1195: Use of OSI IS-IS for Routing in TCP/IP and Dual
            Environments
            RFC 3630: Traffic Engineering (TE) Extensions to OSPF
            Version 2";
       }
       uses information-source-per-node-attributes;
       list information-source-entry {
         key "information-source information-source-instance";
         config false;
         description
           "A list of information sources learned, including the source
            that is used.";
         uses information-source-per-node-attributes;
         uses te-node-connectivity-matrices;
         uses te-node-info-attributes;
       }
     }
     // te-node-state-derived

     grouping te-node-tunnel-termination-point-config {
       description
         "Termination capability of a TTP on a TE node.";
       uses te-node-tunnel-termination-point-config-attributes;
       container local-link-connectivities {
         description
           "Contains an LLCL for a TTP on a TE node.";
         leaf number-of-entries {
           type uint16;
           description
             "The number of LLCL entries.
              If this number is specified in the configuration request,
              the number is the requested number of entries, which may
              not all be listed in the list;
              if this number is reported in the state data,
              the number is the current number of operational entries.";
         }
         uses te-types:label-set-info;
         uses connectivity-matrix-entry-path-attributes;
       }
     }
     // te-node-tunnel-termination-point-config

     grouping te-node-tunnel-termination-point-config-attributes {
       description
         "Configuration attributes of a TTP on a TE node.";
       leaf admin-status {
         type te-types:te-admin-status;
         description
           "The administrative state of the TTP.";
       }
       leaf name {
         type string;
         description
           "A descriptive name for the TTP.";
       }
       leaf switching-capability {
         type identityref {
           base te-types:switching-capabilities;
         }
         description
           "Switching capability for this interface.";
       }
       leaf encoding {
         type identityref {
           base te-types:lsp-encoding-types;
         }
         description
           "Encoding supported by this interface.";
       }
       leaf-list inter-layer-lock-id {
         type uint32;
         description
           "Inter-layer lock ID, used for path computation in a TE
            topology covering multiple layers or multiple regions.";
         reference
           "RFC 5212: Requirements for GMPLS-Based Multi-Region and
            Multi-Layer Networks (MRN/MLN)
            RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
            for Multi-Layer and Multi-Region Networks (MLN/MRN)";
       }
       leaf protection-type {
         type identityref {
           base te-types:lsp-protection-type;
         }
         description
           "The protection type that this TTP is capable of.";
       }
       container client-layer-adaptation {
         description
           "Contains capability information to support a client-layer
            adaptation in a multi-layer topology.";
         list switching-capability {
           key "switching-capability encoding";
           description
             "List of supported switching capabilities.";
           reference
             "RFC 4202: Routing Extensions in Support of
              Generalized Multi-Protocol Label Switching (GMPLS)
              RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
              for Multi-Layer and Multi-Region Networks (MLN/MRN)";
           leaf switching-capability {
             type identityref {
               base te-types:switching-capabilities;
             }
             description
               "Switching capability for the client-layer adaptation.";
           }
           leaf encoding {
             type identityref {
               base te-types:lsp-encoding-types;
             }
             description
               "Encoding supported by the client-layer adaptation.";
           }
           uses te-types:te-bandwidth;
         }
       }
     }
     // te-node-tunnel-termination-point-config-attributes

     grouping te-node-tunnel-termination-point-llc-list {
       description
         "LLCL of a TTP on a TE node.";
       list local-link-connectivity {
         key "link-tp-ref";
         description
           "The termination capabilities between the TTP and the LTP.
            This capability information can be used to compute
            the tunnel path.
            The Interface Adjustment Capability Descriptors (IACDs)
            (defined in RFC 6001) on each LTP can be derived from
            this list.";
         reference
           "RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
            for Multi-Layer and Multi-Region Networks (MLN/MRN)";
         leaf link-tp-ref {
           type leafref {
             path "../../../../../nt:termination-point/nt:tp-id";
           }
           description
             "LTP.";
         }
         uses te-types:label-set-info;
         uses connectivity-matrix-entry-path-attributes;
       }
     }
     // te-node-tunnel-termination-point-llc-list

     grouping te-path-element {
       description
         "A group of attributes defining an element in a TE path,
          such as a TE node, TE link, TE atomic resource, or label.";
       uses te-types:explicit-route-hop;
     }
     // te-path-element

     grouping te-termination-point-augment {
       description
         "Augmentation for a TE termination point.";
       leaf te-tp-id {
         type te-types:te-tp-id;
         description
           "An identifier that uniquely identifies a TE termination
            point.";
       }
       container te {
         must '../te-tp-id';
         presence "TE support";
         description
           "Indicates TE support.";
         uses te-termination-point-config;
         leaf oper-status {
           type te-types:te-oper-status;
           config false;
           description
             "The current operational state of the LTP.";
         }
         uses geolocation-container;
       }
     }
     // te-termination-point-augment

     grouping te-termination-point-config {
       description
         "TE termination point configuration grouping.";
       leaf admin-status {
         type te-types:te-admin-status;
         description
           "The administrative state of the LTP.";
       }
       leaf name {
         type string;
         description
           "A descriptive name for the LTP.";
       }
       uses interface-switching-capability-list;
       leaf inter-domain-plug-id {
         type binary;
         description
           "A network-wide unique number that identifies on the
            network a connection that supports a given inter-domain
            TE link.  This is a more flexible alternative to specifying
            'remote-te-node-id' and 'remote-te-link-tp-id' on a TE link
            when the provider either does not know 'remote-te-node-id'
            and 'remote-te-link-tp-id' or needs to give the client the
            flexibility to mix and match multiple topologies.";
       }
       leaf-list inter-layer-lock-id {
         type uint32;
         description
           "Inter-layer lock ID, used for path computation in a TE
            topology covering multiple layers or multiple regions.";
         reference
           "RFC 5212: Requirements for GMPLS-Based Multi-Region and
            Multi-Layer Networks (MRN/MLN)
            RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
            for Multi-Layer and Multi-Region Networks (MLN/MRN)";
       }
     }
     // te-termination-point-config

     grouping te-topologies-augment {
       description
         "Augmentation for TE topologies.";
       container te {
         presence "TE support";
         description
           "Indicates TE support.";
         container templates {
           description
             "Configuration parameters for templates used for a TE
              topology.";
           list node-template {
             if-feature "template";
             key "name";
             leaf name {
               type te-types:te-template-name;
               description
                 "The name to identify a TE node template.";
             }
             description
               "The list of TE node templates used to define sharable
                and reusable TE node attributes.";
             uses template-attributes;
             uses te-node-config-attributes-template;
           }
           // node-template
           list link-template {
             if-feature "template";
             key "name";
             leaf name {
               type te-types:te-template-name;
               description
                 "The name to identify a TE link template.";
             }
             description
               "The list of TE link templates used to define sharable
                and reusable TE link attributes.";
             uses template-attributes;
             uses te-link-config-attributes;
           }
           // link-template
         }
         // templates
       }
       // te
     }
     // te-topologies-augment

     grouping te-topology-augment {
       description
         "Augmentation for a TE topology.";
       uses te-types:te-topology-identifier;
       container te {
         must '../te-topology-identifier/provider-id'
            + ' and ../te-topology-identifier/client-id'
            + ' and ../te-topology-identifier/topology-id';
         presence "TE support";
         description
           "Indicates TE support.";
         uses te-topology-config;
         uses geolocation-container;
       }
     }
     // te-topology-augment

     grouping te-topology-config {
       description
         "TE topology configuration grouping.";
       leaf name {
         type string;
         description
           "Name of the TE topology.  This attribute is optional and can
            be specified by the operator to describe the TE topology,
            which can be useful when 'network-id' (RFC 8345) is not
            descriptive and not modifiable because of being generated
            by the system.";
         reference
           "RFC 8345: A YANG Data Model for Network Topologies";
       }
       leaf preference {
         type uint8 {
           range "1..255";
         }
         description
           "Specifies a preference for this topology.  A lower number
            indicates a higher preference.";
       }
       leaf optimization-criterion {
         type identityref {
           base te-types:objective-function-type;
         }
         description
           "Optimization criterion applied to this topology.";
         reference
           "RFC 3272: Overview and Principles of Internet Traffic
            Engineering";
       }
       list nsrlg {
         if-feature "nsrlg";
         key "id";
         description
           "List of NSRLGs (Non-Shared Risk Link Groups).";
         reference
           "RFC 4872: RSVP-TE Extensions in Support of End-to-End
            Generalized Multi-Protocol Label Switching (GMPLS)
            Recovery";
         leaf id {
           type uint32;
           description
             "Identifies the NSRLG entry.";
         }
         leaf disjointness {
           type te-types:te-path-disjointness;
           description
             "The type of resource disjointness.";
         }
       }
       // nsrlg
     }
     // te-topology-config

     grouping template-attributes {
       description
         "Common attributes for all templates.";
       leaf priority {
         type uint16;
         description
           "The preference value for resolving conflicts between
            different templates.  When two or more templates specify
            values for one configuration attribute, the value from the
            template with the highest priority is used.
            A lower number indicates a higher priority.  The highest
            priority is 0.";
       }
       leaf reference-change-policy {
         type enumeration {
           enum no-action {
             description
               "When an attribute changes in this template, the
                configuration node referring to this template does
                not take any action.";
           }
           enum not-allowed {
             description
               "When any configuration object has a reference to this
                template, changing this template is not allowed.";
           }
           enum cascade {
             description
               "When an attribute changes in this template, the
                configuration object referring to this template applies
                the new attribute value to the corresponding
                configuration.";
           }
         }
         description
           "This attribute specifies the action taken for a
            configuration node that has a reference to this template.";
       }
     }
     // template-attributes

     /*
      * Data nodes
      */

     augment "/nw:networks/nw:network/nw:network-types" {
       description
         "Introduces a new network type for a TE topology.";
       container te-topology {
         presence "Indicates a TE topology";
         description
           "Its presence identifies the TE topology type.";
       }
     }

     augment "/nw:networks" {
       description
         "Augmentation parameters for TE topologies.";
       uses te-topologies-augment;
     }

     augment "/nw:networks/nw:network" {
       when 'nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for a TE topology.";
       uses te-topology-augment;
     }

     augment "/nw:networks/nw:network/nw:node" {
       when '../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the node level.";
       leaf te-node-id {
         type te-types:te-node-id;
         description
           "The identifier of a node in the TE topology.
            A node is specific to a topology to which it belongs.";
       }
       container te {
         must '../te-node-id' {
           description
             "'te-node-id' is mandatory.";
         }
         must 'count(../nw:supporting-node)<=1' {
           description
             "For a node in a TE topology, there cannot be more
              than one supporting node.  If multiple nodes are
              abstracted, the 'underlay-topology' field is used.";
         }
         presence "TE support";
         description
           "Indicates TE support.";
         uses te-node-augment;
       }
     }

     augment "/nw:networks/nw:network/nt:link" {
       when '../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the link level.";
       container te {
         must 'count(../nt:supporting-link)<=1' {
           description
             "For a link in a TE topology, there cannot be more
              than one supporting link.  If one or more link paths are
              abstracted, the underlay is used.";
         }
         presence "TE support";
         description
           "Indicates TE support.";
         uses te-link-augment;
       }
     }

     augment "/nw:networks/nw:network/nw:node/"
           + "nt:termination-point" {
       when '../../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the termination point
          level.";
       uses te-termination-point-augment;
     }

     augment "/nw:networks/nw:network/nt:link/te/bundle-stack-level/"
           + "bundle/bundled-links/bundled-link" {
       when '../../../../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for a TE bundled link.";
       leaf src-tp-ref {
         type leafref {
           path "../../../../../nw:node[nw:node-id = "
              + "current()/../../../../nt:source/"
              + "nt:source-node]/"
              + "nt:termination-point/nt:tp-id";
           require-instance true;
         }
         description
           "Reference to another TE termination point on the
            same source node.";
       }
       leaf des-tp-ref {
         type leafref {
           path "../../../../../nw:node[nw:node-id = "
              + "current()/../../../../nt:destination/"
              + "nt:dest-node]/"
              + "nt:termination-point/nt:tp-id";
           require-instance true;
         }
         description
           "Reference to another TE termination point on the
            same destination node.";
       }
     }

     augment "/nw:networks/nw:network/nw:node/te/"
           + "information-source-entry/connectivity-matrices/"
           + "connectivity-matrix" {
       when '../../../../../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for the TE node connectivity matrix.";
       uses te-node-connectivity-matrix-attributes;
     }

     augment "/nw:networks/nw:network/nw:node/te/te-node-attributes/"
           + "connectivity-matrices/connectivity-matrix" {
       when '../../../../../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for the TE node connectivity matrix.";
       uses te-node-connectivity-matrix-attributes;
     }

     augment "/nw:networks/nw:network/nw:node/te/"
           + "tunnel-termination-point/local-link-connectivities" {
       when '../../../../nw:network-types/tet:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for TE node TTP LLCs (Local Link
          Connectivities).";
       uses te-node-tunnel-termination-point-llc-list;
     }
   }
   <CODE ENDS>

8.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The Network Configuration Access Control Model (NACM) [RFC8341]
   provides the means to restrict access for particular NETCONF or
   RESTCONF users to a preconfigured subset of all available NETCONF or
   RESTCONF protocol operations and content.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   *  /nw:networks/nw:network/nw:network-types/tet:te-topology

      This subtree specifies the TE topology type.  Modifying the
      configurations can render the TE topology type invalid.  By making
      such modifications, a malicious attacker may disable the TE
      capabilities on the related networks and cause traffic to be
      disrupted or misrouted.

   *  /nw:networks/tet:te

      This subtree specifies the TE node templates and TE link
      templates.  Modifying the configurations in this subtree will
      change the related future TE configurations.  By making such
      modifications, a malicious attacker may change TE capabilities
      scheduled at a future time and cause traffic to be disrupted or
      misrouted.

   *  /nw:networks/nw:network

      This subtree specifies the topology-wide configurations, including
      the TE topology ID and topology-wide policies.  Modifying the
      configurations in this subtree can add, remove, or modify TE
      topologies.  By adding a TE topology, a malicious attacker may
      create an unauthorized traffic network.  By removing or modifying
      a TE topology, a malicious attacker may cause traffic to be
      disabled or misrouted in the specified TE topology.  Such traffic
      changes may also affect the traffic in the connected TE
      topologies.

   *  /nw:networks/nw:network/nw:node

      This subtree specifies the configurations for TE nodes.  Modifying
      the configurations in this subtree can add, remove, or modify TE
      nodes.  By adding a TE node, a malicious attacker may create an
      unauthorized traffic path.  By removing or modifying a TE node, a
      malicious attacker may cause traffic to be disabled or misrouted
      in the specified TE node.  Such traffic changes may also affect
      the traffic on the surrounding TE nodes and TE links in this TE
      topology and the connected TE topologies.

   *  /nw:networks/nw:network/nt:link/tet:te

      This subtree specifies the configurations for TE links.  Modifying
      the configurations in this subtree can add, remove, or modify TE
      links.  By adding a TE link, a malicious attacker may create an
      unauthorized traffic path.  By removing or modifying a TE link, a
      malicious attacker may cause traffic to be disabled or misrouted
      on the specified TE link.  Such traffic changes may also affect
      the traffic on the surrounding TE nodes and TE links in this TE
      topology and the connected TE topologies.

   *  /nw:networks/nw:network/nw:node/nt:termination-point

      This subtree specifies the configurations of TE LTPs.  Modifying
      the configurations in this subtree can add, remove, or modify TE
      LTPs.  By adding a TE LTP, a malicious attacker may create an
      unauthorized traffic path.  By removing or modifying a TE LTP, a
      malicious attacker may cause traffic to be disabled or misrouted
      on the specified TE LTP.  Such traffic changes may also affect the
      traffic on the surrounding TE nodes and TE links in this TE
      topology and the connected TE topologies.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   *  /nw:networks/nw:network/nw:network-types/tet:te-topology

      Unauthorized access to this subtree can disclose the TE topology
      type.

   *  /nw:networks/tet:te

      Unauthorized access to this subtree can disclose the TE node
      templates and TE link templates.

   *  /nw:networks/nw:network

      Unauthorized access to this subtree can disclose the topology-wide
      configurations, including the TE topology ID, the topology-wide
      policies, and the topology geolocation.

   *  /nw:networks/nw:network/nw:node

      Unauthorized access to this subtree can disclose the operational
      state information of TE nodes.

   *  /nw:networks/nw:network/nt:link/tet:te

      Unauthorized access to this subtree can disclose the operational
      state information of TE links.

   *  /nw:networks/nw:network/nw:node/nt:termination-point

      Unauthorized access to this subtree can disclose the operational
      state information of TE LTPs.

9.  IANA Considerations

   IANA has registered the following URIs in the "ns" subregistry within
   the "IETF XML Registry" [RFC3688].

   URI:  urn:ietf:params:xml:ns:yang:ietf-te-topology
   Registrant Contact:  The IESG.
   XML:  N/A; the requested URI is an XML namespace.

   URI:  urn:ietf:params:xml:ns:yang:ietf-te-topology-state
   Registrant Contact:  The IESG.
   XML:  N/A; the requested URI is an XML namespace.

   IANA has registered the following YANG modules in the "YANG Module
   Names" subregistry [RFC6020] within the "YANG Parameters" registry.

   Name:  ietf-te-topology
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-te-topology
   Prefix:  tet
   Reference:  RFC 8795

   Name:  ietf-te-topology-state
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-te-topology-state
   Prefix:  tet-s
   Reference:  RFC 8795

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC3945]  Mannie, E., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Architecture", RFC 3945,
              DOI 10.17487/RFC3945, October 2004,
              <https://www.rfc-editor.org/info/rfc3945>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7926]  Farrel, A., Ed., Drake, J., Bitar, N., Swallow, G.,
              Ceccarelli, D., and X. Zhang, "Problem Statement and
              Architecture for Information Exchange between
              Interconnected Traffic-Engineered Networks", BCP 206,
              RFC 7926, DOI 10.17487/RFC7926, July 2016,
              <https://www.rfc-editor.org/info/rfc7926>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8345]  Clemm, A., Medved, J., Varga, R., Bahadur, N.,
              Ananthakrishnan, H., and X. Liu, "A YANG Data Model for
              Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March
              2018, <https://www.rfc-editor.org/info/rfc8345>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

10.2.  Informative References

   [G.709]    ITU-T, "Interfaces for the optical transport network",
              ITU-T Recommendation G.709, June 2020,
              <https://www.itu.int/rec/T-REC-G.709/>.

   [G.805]    ITU-T, "Generic functional architecture of transport
              networks", ITU-T Recommendation G.805, March 2000,
              <https://www.itu.int/rec/T-REC-G.805/en>.

   [G.8080]   ITU-T, "Architecture for the automatically switched
              optical network", ITU-T Recommendation G.8080, February
              2012, <https://www.itu.int/rec/T-REC-G.8080/en>.

   [G.872]    ITU-T, "Architecture of optical transport networks",
              ITU-T Recommendation G.872, December 2019,
              <https://www.itu.int/rec/T-REC-G.872/en>.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, DOI 10.17487/RFC1195,
              December 1990, <https://www.rfc-editor.org/info/rfc1195>.

   [RFC2702]  Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
              McManus, "Requirements for Traffic Engineering Over MPLS",
              RFC 2702, DOI 10.17487/RFC2702, September 1999,
              <https://www.rfc-editor.org/info/rfc2702>.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
              <https://www.rfc-editor.org/info/rfc3209>.

   [RFC3272]  Awduche, D., Chiu, A., Elwalid, A., Widjaja, I., and X.
              Xiao, "Overview and Principles of Internet Traffic
              Engineering", RFC 3272, DOI 10.17487/RFC3272, May 2002,
              <https://www.rfc-editor.org/info/rfc3272>.

   [RFC3471]  Berger, L., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Signaling Functional Description",
              RFC 3471, DOI 10.17487/RFC3471, January 2003,
              <https://www.rfc-editor.org/info/rfc3471>.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <https://www.rfc-editor.org/info/rfc3630>.

   [RFC3785]  Le Faucheur, F., Uppili, R., Vedrenne, A., Merckx, P., and
              T. Telkamp, "Use of Interior Gateway Protocol (IGP) Metric
              as a second MPLS Traffic Engineering (TE) Metric", BCP 87,
              RFC 3785, DOI 10.17487/RFC3785, May 2004,
              <https://www.rfc-editor.org/info/rfc3785>.

   [RFC4201]  Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
              in MPLS Traffic Engineering (TE)", RFC 4201,
              DOI 10.17487/RFC4201, October 2005,
              <https://www.rfc-editor.org/info/rfc4201>.

   [RFC4202]  Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005,
              <https://www.rfc-editor.org/info/rfc4202>.

   [RFC4203]  Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
              Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
              <https://www.rfc-editor.org/info/rfc4203>.

   [RFC4206]  Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
              Hierarchy with Generalized Multi-Protocol Label Switching
              (GMPLS) Traffic Engineering (TE)", RFC 4206,
              DOI 10.17487/RFC4206, October 2005,
              <https://www.rfc-editor.org/info/rfc4206>.

   [RFC4872]  Lang, J.P., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
              Ed., "RSVP-TE Extensions in Support of End-to-End
              Generalized Multi-Protocol Label Switching (GMPLS)
              Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007,
              <https://www.rfc-editor.org/info/rfc4872>.

   [RFC5152]  Vasseur, JP., Ed., Ayyangar, A., Ed., and R. Zhang, "A
              Per-Domain Path Computation Method for Establishing Inter-
              Domain Traffic Engineering (TE) Label Switched Paths
              (LSPs)", RFC 5152, DOI 10.17487/RFC5152, February 2008,
              <https://www.rfc-editor.org/info/rfc5152>.

   [RFC5212]  Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux,
              M., and D. Brungard, "Requirements for GMPLS-Based Multi-
              Region and Multi-Layer Networks (MRN/MLN)", RFC 5212,
              DOI 10.17487/RFC5212, July 2008,
              <https://www.rfc-editor.org/info/rfc5212>.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.

   [RFC5316]  Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316,
              December 2008, <https://www.rfc-editor.org/info/rfc5316>.

   [RFC5392]  Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392,
              January 2009, <https://www.rfc-editor.org/info/rfc5392>.

   [RFC6001]  Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
              D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
              Extensions for Multi-Layer and Multi-Region Networks (MLN/
              MRN)", RFC 6001, DOI 10.17487/RFC6001, October 2010,
              <https://www.rfc-editor.org/info/rfc6001>.

   [RFC7308]  Osborne, E., "Extended Administrative Groups in MPLS
              Traffic Engineering (MPLS-TE)", RFC 7308,
              DOI 10.17487/RFC7308, July 2014,
              <https://www.rfc-editor.org/info/rfc7308>.

   [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
              Previdi, "OSPF Traffic Engineering (TE) Metric
              Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
              <https://www.rfc-editor.org/info/rfc7471>.

   [RFC7579]  Bernstein, G., Ed., Lee, Y., Ed., Li, D., Imajuku, W., and
              J. Han, "General Network Element Constraint Encoding for
              GMPLS-Controlled Networks", RFC 7579,
              DOI 10.17487/RFC7579, June 2015,
              <https://www.rfc-editor.org/info/rfc7579>.

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8639]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Subscription to YANG Notifications",
              RFC 8639, DOI 10.17487/RFC8639, September 2019,
              <https://www.rfc-editor.org/info/rfc8639>.

   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

   [TEAS-TOPO]
              Bryskin, I., Beeram, V., Saad, T., and X. Liu, "TE
              Topology and Tunnel Modeling for Transport Networks", Work
              in Progress, Internet-Draft, draft-ietf-teas-te-topo-and-
              tunnel-modeling-06, 12 July 2020,
              <https://tools.ietf.org/html/draft-ietf-teas-te-topo-and-
              tunnel-modeling-06>.

   [YANG-CFG-SCHED]
              Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
              O. Gonzalez de Dios, "A YANG Data Model for Configuration
              Scheduling", Work in Progress, Internet-Draft, draft-liu-
              netmod-yang-schedule-05, 1 March 2018,
              <https://tools.ietf.org/html/draft-liu-netmod-yang-
              schedule-05>.

   [YANG-L3]  Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
              O. Gonzalez de Dios, "YANG Data Model for Layer 3 TE
              Topologies", Work in Progress, Internet-Draft, draft-ietf-
              teas-yang-l3-te-topo-08, 12 July 2020,
              <https://tools.ietf.org/html/draft-ietf-teas-yang-l3-te-
              topo-08>.

   [YANG-OTN] Zheng, H., Busi, I., Liu, X., Belotti, S., and O. Gonzalez
              de Dios, "A YANG Data Model for Optical Transport Network
              Topology", Work in Progress, Internet-Draft, draft-ietf-
              ccamp-otn-topo-yang-10, 9 March 2020,
              <https://tools.ietf.org/html/draft-ietf-ccamp-otn-topo-
              yang-10>.

   [YANG-WSON]
              Zheng, H., Lee, Y., Guo, A., Lopez, V., and D. King, "A
              YANG Data Model for WSON (Wavelength Switched Optical
              Networks)", Work in Progress, Internet-Draft, draft-ietf-
              ccamp-wson-yang-25, 19 May 2020,
              <https://tools.ietf.org/html/draft-ietf-ccamp-wson-yang-
              25>.

Appendix A.  Complete Model Tree Structure

   module: ietf-te-topology
     augment /nw:networks/nw:network/nw:network-types:
       +--rw te-topology!
     augment /nw:networks:
       +--rw te!
          +--rw templates
             +--rw node-template* [name] {template}?
             |  +--rw name
             |  |       te-types:te-template-name
             |  +--rw priority?                  uint16
             |  +--rw reference-change-policy?   enumeration
             |  +--rw te-node-attributes
             |     +--rw admin-status?        te-types:te-admin-status
             |     +--rw domain-id?           uint32
             |     +--rw is-abstract?         empty
             |     +--rw name?                string
             |     +--rw signaling-address*   inet:ip-address
             |     +--rw underlay-topology {te-topology-hierarchy}?
             |        +--rw network-ref?
             |                -> /nw:networks/network/network-id
             +--rw link-template* [name] {template}?
                +--rw name
                |       te-types:te-template-name
                +--rw priority?                  uint16
                +--rw reference-change-policy?   enumeration
                +--rw te-link-attributes
                   +--rw access-type?
                   |       te-types:te-link-access-type
                   +--rw external-domain
                   |  +--rw network-ref?
                   |  |       -> /nw:networks/network/network-id
                   |  +--rw remote-te-node-id?      te-types:te-node-id
                   |  +--rw remote-te-link-tp-id?   te-types:te-tp-id
                   +--rw is-abstract?                      empty
                   +--rw name?                             string
                   +--rw underlay {te-topology-hierarchy}?
                   |  +--rw enabled?                     boolean
                   |  +--rw primary-path
                   |  |  +--rw network-ref?
                   |  |  |       -> /nw:networks/network/network-id
                   |  |  +--rw path-element* [path-element-id]
                   |  |     +--rw path-element-id              uint32
                   |  |     +--rw (type)?
                   |  |        +--:(numbered-node-hop)
                   |  |        |  +--rw numbered-node-hop
                   |  |        |     +--rw node-id     te-node-id
                   |  |        |     +--rw hop-type?   te-hop-type
                   |  |        +--:(numbered-link-hop)
                   |  |        |  +--rw numbered-link-hop
                   |  |        |     +--rw link-tp-id    te-tp-id
                   |  |        |     +--rw hop-type?     te-hop-type
                   |  |        |     +--rw direction?
                   |  |        |             te-link-direction
                   |  |        +--:(unnumbered-link-hop)
                   |  |        |  +--rw unnumbered-link-hop
                   |  |        |     +--rw link-tp-id    te-tp-id
                   |  |        |     +--rw node-id       te-node-id
                   |  |        |     +--rw hop-type?     te-hop-type
                   |  |        |     +--rw direction?
                   |  |        |             te-link-direction
                   |  |        +--:(as-number)
                   |  |        |  +--rw as-number-hop
                   |  |        |     +--rw as-number    inet:as-number
                   |  |        |     +--rw hop-type?    te-hop-type
                   |  |        +--:(label)
                   |  |           +--rw label-hop
                   |  |              +--rw te-label
                   |  |                 +--rw (technology)?
                   |  |                 |  +--:(generic)
                   |  |                 |     +--rw generic?
                   |  |                 |             rt-
   types:generalized-label
                   |  |                 +--rw direction?
                   |  |                         te-label-direction
                   |  +--rw backup-path* [index]
                   |  |  +--rw index           uint32
                   |  |  +--rw network-ref?
                   |  |  |       -> /nw:networks/network/network-id
                   |  |  +--rw path-element* [path-element-id]
                   |  |     +--rw path-element-id              uint32
                   |  |     +--rw (type)?
                   |  |        +--:(numbered-node-hop)
                   |  |        |  +--rw numbered-node-hop
                   |  |        |     +--rw node-id     te-node-id
                   |  |        |     +--rw hop-type?   te-hop-type
                   |  |        +--:(numbered-link-hop)
                   |  |        |  +--rw numbered-link-hop
                   |  |        |     +--rw link-tp-id    te-tp-id
                   |  |        |     +--rw hop-type?     te-hop-type
                   |  |        |     +--rw direction?
                   |  |        |             te-link-direction
                   |  |        +--:(unnumbered-link-hop)
                   |  |        |  +--rw unnumbered-link-hop
                   |  |        |     +--rw link-tp-id    te-tp-id
                   |  |        |     +--rw node-id       te-node-id
                   |  |        |     +--rw hop-type?     te-hop-type
                   |  |        |     +--rw direction?
                   |  |        |             te-link-direction
                   |  |        +--:(as-number)
                   |  |        |  +--rw as-number-hop
                   |  |        |     +--rw as-number    inet:as-number
                   |  |        |     +--rw hop-type?    te-hop-type
                   |  |        +--:(label)
                   |  |           +--rw label-hop
                   |  |              +--rw te-label
                   |  |                 +--rw (technology)?
                   |  |                 |  +--:(generic)
                   |  |                 |     +--rw generic?
                   |  |                 |             rt-
   types:generalized-label
                   |  |                 +--rw direction?
                   |  |                         te-label-direction
                   |  +--rw protection-type?             identityref
                   |  +--rw tunnel-termination-points
                   |  |  +--rw source?        binary
                   |  |  +--rw destination?   binary
                   |  +--rw tunnels
                   |     +--rw sharing?   boolean
                   |     +--rw tunnel* [tunnel-name]
                   |        +--rw tunnel-name    string
                   |        +--rw sharing?       boolean
                   +--rw admin-status?
                   |       te-types:te-admin-status
                   +--rw link-index?                       uint64
                   +--rw administrative-group?
                   |       te-types:admin-groups
                   +--rw interface-switching-capability*
                   |       [switching-capability encoding]
                   |  +--rw switching-capability    identityref
                   |  +--rw encoding                identityref
                   |  +--rw max-lsp-bandwidth* [priority]
                   |     +--rw priority        uint8
                   |     +--rw te-bandwidth
                   |        +--rw (technology)?
                   |           +--:(generic)
                   |              +--rw generic?   te-bandwidth
                   +--rw label-restrictions
                   |  +--rw label-restriction* [index]
                   |     +--rw restriction?    enumeration
                   |     +--rw index           uint32
                   |     +--rw label-start
                   |     |  +--rw te-label
                   |     |     +--rw (technology)?
                   |     |     |  +--:(generic)
                   |     |     |     +--rw generic?
                   |     |     |             rt-types:generalized-label
                   |     |     +--rw direction?       te-label-direction
                   |     +--rw label-end
                   |     |  +--rw te-label
                   |     |     +--rw (technology)?
                   |     |     |  +--:(generic)
                   |     |     |     +--rw generic?
                   |     |     |             rt-types:generalized-label
                   |     |     +--rw direction?       te-label-direction
                   |     +--rw label-step
                   |     |  +--rw (technology)?
                   |     |     +--:(generic)
                   |     |        +--rw generic?   int32
                   |     +--rw range-bitmap?   yang:hex-string
                   +--rw link-protection-type?             identityref
                   +--rw max-link-bandwidth
                   |  +--rw te-bandwidth
                   |     +--rw (technology)?
                   |        +--:(generic)
                   |           +--rw generic?   te-bandwidth
                   +--rw max-resv-link-bandwidth
                   |  +--rw te-bandwidth
                   |     +--rw (technology)?
                   |        +--:(generic)
                   |           +--rw generic?   te-bandwidth
                   +--rw unreserved-bandwidth* [priority]
                   |  +--rw priority        uint8
                   |  +--rw te-bandwidth
                   |     +--rw (technology)?
                   |        +--:(generic)
                   |           +--rw generic?   te-bandwidth
                   +--rw te-default-metric?                uint32
                   +--rw te-delay-metric?                  uint32
                   +--rw te-igp-metric?                    uint32
                   +--rw te-srlgs
                   |  +--rw value*   te-types:srlg
                   +--rw te-nsrlgs {nsrlg}?
                      +--rw id*   uint32
     augment /nw:networks/nw:network:
       +--rw te-topology-identifier
       |  +--rw provider-id?   te-global-id
       |  +--rw client-id?     te-global-id
       |  +--rw topology-id?   te-topology-id
       +--rw te!
          +--rw name?                     string
          +--rw preference?               uint8
          +--rw optimization-criterion?   identityref
          +--rw nsrlg* [id] {nsrlg}?
          |  +--rw id              uint32
          |  +--rw disjointness?   te-types:te-path-disjointness
          +--ro geolocation
             +--ro altitude?    int64
             +--ro latitude?    geographic-coordinate-degree
             +--ro longitude?   geographic-coordinate-degree
     augment /nw:networks/nw:network/nw:node:
       +--rw te-node-id?   te-types:te-node-id
       +--rw te!
          +--rw te-node-template*
          |       -> ../../../../te/templates/node-template/name
          |       {template}?
          +--rw te-node-attributes
          |  +--rw admin-status?            te-types:te-admin-status
          |  +--rw connectivity-matrices
          |  |  +--rw number-of-entries?     uint16
          |  |  +--rw label-restrictions
          |  |  |  +--rw label-restriction* [index]
          |  |  |     +--rw restriction?    enumeration
          |  |  |     +--rw index           uint32
          |  |  |     +--rw label-start
          |  |  |     |  +--rw te-label
          |  |  |     |     +--rw (technology)?
          |  |  |     |     |  +--:(generic)
          |  |  |     |     |     +--rw generic?
          |  |  |     |     |             rt-types:generalized-label
          |  |  |     |     +--rw direction?       te-label-direction
          |  |  |     +--rw label-end
          |  |  |     |  +--rw te-label
          |  |  |     |     +--rw (technology)?
          |  |  |     |     |  +--:(generic)
          |  |  |     |     |     +--rw generic?
          |  |  |     |     |             rt-types:generalized-label
          |  |  |     |     +--rw direction?       te-label-direction
          |  |  |     +--rw label-step
          |  |  |     |  +--rw (technology)?
          |  |  |     |     +--:(generic)
          |  |  |     |        +--rw generic?   int32
          |  |  |     +--rw range-bitmap?   yang:hex-string
          |  |  +--rw is-allowed?            boolean
          |  |  +--rw underlay {te-topology-hierarchy}?
          |  |  |  +--rw enabled?                     boolean
          |  |  |  +--rw primary-path
          |  |  |  |  +--rw network-ref?
          |  |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  |  +--rw path-element* [path-element-id]
          |  |  |  |     +--rw path-element-id              uint32
          |  |  |  |     +--rw (type)?
          |  |  |  |        +--:(numbered-node-hop)
          |  |  |  |        |  +--rw numbered-node-hop
          |  |  |  |        |     +--rw node-id     te-node-id
          |  |  |  |        |     +--rw hop-type?   te-hop-type
          |  |  |  |        +--:(numbered-link-hop)
          |  |  |  |        |  +--rw numbered-link-hop
          |  |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |  |        |     +--rw direction?    te-link-direction
          |  |  |  |        +--:(unnumbered-link-hop)
          |  |  |  |        |  +--rw unnumbered-link-hop
          |  |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |  |        |     +--rw node-id       te-node-id
          |  |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |  |        |     +--rw direction?    te-link-direction
          |  |  |  |        +--:(as-number)
          |  |  |  |        |  +--rw as-number-hop
          |  |  |  |        |     +--rw as-number    inet:as-number
          |  |  |  |        |     +--rw hop-type?    te-hop-type
          |  |  |  |        +--:(label)
          |  |  |  |           +--rw label-hop
          |  |  |  |              +--rw te-label
          |  |  |  |                 +--rw (technology)?
          |  |  |  |                 |  +--:(generic)
          |  |  |  |                 |     +--rw generic?
          |  |  |  |                 |             rt-types:generalized-
   label
          |  |  |  |                 +--rw direction?
          |  |  |  |                         te-label-direction
          |  |  |  +--rw backup-path* [index]
          |  |  |  |  +--rw index           uint32
          |  |  |  |  +--rw network-ref?
          |  |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  |  +--rw path-element* [path-element-id]
          |  |  |  |     +--rw path-element-id              uint32
          |  |  |  |     +--rw (type)?
          |  |  |  |        +--:(numbered-node-hop)
          |  |  |  |        |  +--rw numbered-node-hop
          |  |  |  |        |     +--rw node-id     te-node-id
          |  |  |  |        |     +--rw hop-type?   te-hop-type
          |  |  |  |        +--:(numbered-link-hop)
          |  |  |  |        |  +--rw numbered-link-hop
          |  |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |  |        |     +--rw direction?    te-link-direction
          |  |  |  |        +--:(unnumbered-link-hop)
          |  |  |  |        |  +--rw unnumbered-link-hop
          |  |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |  |        |     +--rw node-id       te-node-id
          |  |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |  |        |     +--rw direction?    te-link-direction
          |  |  |  |        +--:(as-number)
          |  |  |  |        |  +--rw as-number-hop
          |  |  |  |        |     +--rw as-number    inet:as-number
          |  |  |  |        |     +--rw hop-type?    te-hop-type
          |  |  |  |        +--:(label)
          |  |  |  |           +--rw label-hop
          |  |  |  |              +--rw te-label
          |  |  |  |                 +--rw (technology)?
          |  |  |  |                 |  +--:(generic)
          |  |  |  |                 |     +--rw generic?
          |  |  |  |                 |             rt-types:generalized-
   label
          |  |  |  |                 +--rw direction?
          |  |  |  |                         te-label-direction
          |  |  |  +--rw protection-type?             identityref
          |  |  |  +--rw tunnel-termination-points
          |  |  |  |  +--rw source?        binary
          |  |  |  |  +--rw destination?   binary
          |  |  |  +--rw tunnels
          |  |  |     +--rw sharing?   boolean
          |  |  |     +--rw tunnel* [tunnel-name]
          |  |  |        +--rw tunnel-name    string
          |  |  |        +--rw sharing?       boolean
          |  |  +--rw path-constraints
          |  |  |  +--rw te-bandwidth
          |  |  |  |  +--rw (technology)?
          |  |  |  |     +--:(generic)
          |  |  |  |        +--rw generic?   te-bandwidth
          |  |  |  +--rw link-protection?          identityref
          |  |  |  +--rw setup-priority?           uint8
          |  |  |  +--rw hold-priority?            uint8
          |  |  |  +--rw signaling-type?           identityref
          |  |  |  +--rw path-metric-bounds
          |  |  |  |  +--rw path-metric-bound* [metric-type]
          |  |  |  |     +--rw metric-type    identityref
          |  |  |  |     +--rw upper-bound?   uint64
          |  |  |  +--rw path-affinities-values
          |  |  |  |  +--rw path-affinities-value* [usage]
          |  |  |  |     +--rw usage    identityref
          |  |  |  |     +--rw value?   admin-groups
          |  |  |  +--rw path-affinity-names
          |  |  |  |  +--rw path-affinity-name* [usage]
          |  |  |  |     +--rw usage            identityref
          |  |  |  |     +--rw affinity-name* [name]
          |  |  |  |        +--rw name    string
          |  |  |  +--rw path-srlgs-lists
          |  |  |  |  +--rw path-srlgs-list* [usage]
          |  |  |  |     +--rw usage     identityref
          |  |  |  |     +--rw values*   srlg
          |  |  |  +--rw path-srlgs-names
          |  |  |  |  +--rw path-srlgs-name* [usage]
          |  |  |  |     +--rw usage    identityref
          |  |  |  |     +--rw names*   string
          |  |  |  +--rw disjointness?             te-path-disjointness
          |  |  +--rw optimizations
          |  |  |  +--rw (algorithm)?
          |  |  |     +--:(metric) {path-optimization-metric}?
          |  |  |     |  +--rw optimization-metric* [metric-type]
          |  |  |     |  |  +--rw metric-type
          |  |  |     |  |  |       identityref
          |  |  |     |  |  +--rw weight?
          |  |  |     |  |  |       uint8
          |  |  |     |  |  +--rw explicit-route-exclude-objects
          |  |  |     |  |  |  +--rw route-object-exclude-object*
          |  |  |     |  |  |          [index]
          |  |  |     |  |  |     +--rw index
          |  |  |     |  |  |     |       uint32
          |  |  |     |  |  |     +--rw (type)?
          |  |  |     |  |  |        +--:(numbered-node-hop)
          |  |  |     |  |  |        |  +--rw numbered-node-hop
          |  |  |     |  |  |        |     +--rw node-id     te-node-id
          |  |  |     |  |  |        |     +--rw hop-type?   te-hop-type
          |  |  |     |  |  |        +--:(numbered-link-hop)
          |  |  |     |  |  |        |  +--rw numbered-link-hop
          |  |  |     |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |     |  |  |        |     +--rw hop-type?
          |  |  |     |  |  |        |     |       te-hop-type
          |  |  |     |  |  |        |     +--rw direction?
          |  |  |     |  |  |        |             te-link-direction
          |  |  |     |  |  |        +--:(unnumbered-link-hop)
          |  |  |     |  |  |        |  +--rw unnumbered-link-hop
          |  |  |     |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |     |  |  |        |     +--rw node-id
          |  |  |     |  |  |        |     |       te-node-id
          |  |  |     |  |  |        |     +--rw hop-type?
          |  |  |     |  |  |        |     |       te-hop-type
          |  |  |     |  |  |        |     +--rw direction?
          |  |  |     |  |  |        |             te-link-direction
          |  |  |     |  |  |        +--:(as-number)
          |  |  |     |  |  |        |  +--rw as-number-hop
          |  |  |     |  |  |        |     +--rw as-number
          |  |  |     |  |  |        |     |       inet:as-number
          |  |  |     |  |  |        |     +--rw hop-type?
          |  |  |     |  |  |        |             te-hop-type
          |  |  |     |  |  |        +--:(label)
          |  |  |     |  |  |        |  +--rw label-hop
          |  |  |     |  |  |        |     +--rw te-label
          |  |  |     |  |  |        |        +--rw (technology)?
          |  |  |     |  |  |        |        |  +--:(generic)
          |  |  |     |  |  |        |        |     +--rw generic?
          |  |  |     |  |  |        |        |             rt-
   types:generalized-label
          |  |  |     |  |  |        |        +--rw direction?
          |  |  |     |  |  |        |                te-label-direction
          |  |  |     |  |  |        +--:(srlg)
          |  |  |     |  |  |           +--rw srlg
          |  |  |     |  |  |              +--rw srlg?   uint32
          |  |  |     |  |  +--rw explicit-route-include-objects
          |  |  |     |  |     +--rw route-object-include-object*
          |  |  |     |  |             [index]
          |  |  |     |  |        +--rw index
          |  |  |     |  |        |       uint32
          |  |  |     |  |        +--rw (type)?
          |  |  |     |  |           +--:(numbered-node-hop)
          |  |  |     |  |           |  +--rw numbered-node-hop
          |  |  |     |  |           |     +--rw node-id     te-node-id
          |  |  |     |  |           |     +--rw hop-type?   te-hop-type
          |  |  |     |  |           +--:(numbered-link-hop)
          |  |  |     |  |           |  +--rw numbered-link-hop
          |  |  |     |  |           |     +--rw link-tp-id    te-tp-id
          |  |  |     |  |           |     +--rw hop-type?
          |  |  |     |  |           |     |       te-hop-type
          |  |  |     |  |           |     +--rw direction?
          |  |  |     |  |           |             te-link-direction
          |  |  |     |  |           +--:(unnumbered-link-hop)
          |  |  |     |  |           |  +--rw unnumbered-link-hop
          |  |  |     |  |           |     +--rw link-tp-id    te-tp-id
          |  |  |     |  |           |     +--rw node-id
          |  |  |     |  |           |     |       te-node-id
          |  |  |     |  |           |     +--rw hop-type?
          |  |  |     |  |           |     |       te-hop-type
          |  |  |     |  |           |     +--rw direction?
          |  |  |     |  |           |             te-link-direction
          |  |  |     |  |           +--:(as-number)
          |  |  |     |  |           |  +--rw as-number-hop
          |  |  |     |  |           |     +--rw as-number
          |  |  |     |  |           |     |       inet:as-number
          |  |  |     |  |           |     +--rw hop-type?
          |  |  |     |  |           |             te-hop-type
          |  |  |     |  |           +--:(label)
          |  |  |     |  |              +--rw label-hop
          |  |  |     |  |                 +--rw te-label
          |  |  |     |  |                    +--rw (technology)?
          |  |  |     |  |                    |  +--:(generic)
          |  |  |     |  |                    |     +--rw generic?
          |  |  |     |  |                    |             rt-
   types:generalized-label
          |  |  |     |  |                    +--rw direction?
          |  |  |     |  |                            te-label-direction
          |  |  |     |  +--rw tiebreakers
          |  |  |     |     +--rw tiebreaker* [tiebreaker-type]
          |  |  |     |        +--rw tiebreaker-type    identityref
          |  |  |     +--:(objective-function)
          |  |  |              {path-optimization-objective-function}?
          |  |  |        +--rw objective-function
          |  |  |           +--rw objective-function-type?   identityref
          |  |  +--ro path-properties
          |  |  |  +--ro path-metric* [metric-type]
          |  |  |  |  +--ro metric-type           identityref
          |  |  |  |  +--ro accumulative-value?   uint64
          |  |  |  +--ro path-affinities-values
          |  |  |  |  +--ro path-affinities-value* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro value?   admin-groups
          |  |  |  +--ro path-affinity-names
          |  |  |  |  +--ro path-affinity-name* [usage]
          |  |  |  |     +--ro usage            identityref
          |  |  |  |     +--ro affinity-name* [name]
          |  |  |  |        +--ro name    string
          |  |  |  +--ro path-srlgs-lists
          |  |  |  |  +--ro path-srlgs-list* [usage]
          |  |  |  |     +--ro usage     identityref
          |  |  |  |     +--ro values*   srlg
          |  |  |  +--ro path-srlgs-names
          |  |  |  |  +--ro path-srlgs-name* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro names*   string
          |  |  |  +--ro path-route-objects
          |  |  |     +--ro path-route-object* [index]
          |  |  |        +--ro index                        uint32
          |  |  |        +--ro (type)?
          |  |  |           +--:(numbered-node-hop)
          |  |  |           |  +--ro numbered-node-hop
          |  |  |           |     +--ro node-id     te-node-id
          |  |  |           |     +--ro hop-type?   te-hop-type
          |  |  |           +--:(numbered-link-hop)
          |  |  |           |  +--ro numbered-link-hop
          |  |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |           |     +--ro hop-type?     te-hop-type
          |  |  |           |     +--ro direction?    te-link-direction
          |  |  |           +--:(unnumbered-link-hop)
          |  |  |           |  +--ro unnumbered-link-hop
          |  |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |           |     +--ro node-id       te-node-id
          |  |  |           |     +--ro hop-type?     te-hop-type
          |  |  |           |     +--ro direction?    te-link-direction
          |  |  |           +--:(as-number)
          |  |  |           |  +--ro as-number-hop
          |  |  |           |     +--ro as-number    inet:as-number
          |  |  |           |     +--ro hop-type?    te-hop-type
          |  |  |           +--:(label)
          |  |  |              +--ro label-hop
          |  |  |                 +--ro te-label
          |  |  |                    +--ro (technology)?
          |  |  |                    |  +--:(generic)
          |  |  |                    |     +--ro generic?
          |  |  |                    |             rt-types:generalized-
   label
          |  |  |                    +--ro direction?
          |  |  |                            te-label-direction
          |  |  +--rw connectivity-matrix* [id]
          |  |     +--rw id                  uint32
          |  |     +--rw from
          |  |     |  +--rw tp-ref?               leafref
          |  |     |  +--rw label-restrictions
          |  |     |     +--rw label-restriction* [index]
          |  |     |        +--rw restriction?    enumeration
          |  |     |        +--rw index           uint32
          |  |     |        +--rw label-start
          |  |     |        |  +--rw te-label
          |  |     |        |     +--rw (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--rw generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--rw direction?
          |  |     |        |             te-label-direction
          |  |     |        +--rw label-end
          |  |     |        |  +--rw te-label
          |  |     |        |     +--rw (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--rw generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--rw direction?
          |  |     |        |             te-label-direction
          |  |     |        +--rw label-step
          |  |     |        |  +--rw (technology)?
          |  |     |        |     +--:(generic)
          |  |     |        |        +--rw generic?   int32
          |  |     |        +--rw range-bitmap?   yang:hex-string
          |  |     +--rw to
          |  |     |  +--rw tp-ref?               leafref
          |  |     |  +--rw label-restrictions
          |  |     |     +--rw label-restriction* [index]
          |  |     |        +--rw restriction?    enumeration
          |  |     |        +--rw index           uint32
          |  |     |        +--rw label-start
          |  |     |        |  +--rw te-label
          |  |     |        |     +--rw (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--rw generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--rw direction?
          |  |     |        |             te-label-direction
          |  |     |        +--rw label-end
          |  |     |        |  +--rw te-label
          |  |     |        |     +--rw (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--rw generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--rw direction?
          |  |     |        |             te-label-direction
          |  |     |        +--rw label-step
          |  |     |        |  +--rw (technology)?
          |  |     |        |     +--:(generic)
          |  |     |        |        +--rw generic?   int32
          |  |     |        +--rw range-bitmap?   yang:hex-string
          |  |     +--rw is-allowed?         boolean
          |  |     +--rw underlay {te-topology-hierarchy}?
          |  |     |  +--rw enabled?                     boolean
          |  |     |  +--rw primary-path
          |  |     |  |  +--rw network-ref?
          |  |     |  |  |       -> /nw:networks/network/network-id
          |  |     |  |  +--rw path-element* [path-element-id]
          |  |     |  |     +--rw path-element-id              uint32
          |  |     |  |     +--rw (type)?
          |  |     |  |        +--:(numbered-node-hop)
          |  |     |  |        |  +--rw numbered-node-hop
          |  |     |  |        |     +--rw node-id     te-node-id
          |  |     |  |        |     +--rw hop-type?   te-hop-type
          |  |     |  |        +--:(numbered-link-hop)
          |  |     |  |        |  +--rw numbered-link-hop
          |  |     |  |        |     +--rw link-tp-id    te-tp-id
          |  |     |  |        |     +--rw hop-type?     te-hop-type
          |  |     |  |        |     +--rw direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(unnumbered-link-hop)
          |  |     |  |        |  +--rw unnumbered-link-hop
          |  |     |  |        |     +--rw link-tp-id    te-tp-id
          |  |     |  |        |     +--rw node-id       te-node-id
          |  |     |  |        |     +--rw hop-type?     te-hop-type
          |  |     |  |        |     +--rw direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(as-number)
          |  |     |  |        |  +--rw as-number-hop
          |  |     |  |        |     +--rw as-number    inet:as-number
          |  |     |  |        |     +--rw hop-type?    te-hop-type
          |  |     |  |        +--:(label)
          |  |     |  |           +--rw label-hop
          |  |     |  |              +--rw te-label
          |  |     |  |                 +--rw (technology)?
          |  |     |  |                 |  +--:(generic)
          |  |     |  |                 |     +--rw generic?
          |  |     |  |                 |             rt-
   types:generalized-label
          |  |     |  |                 +--rw direction?
          |  |     |  |                         te-label-direction
          |  |     |  +--rw backup-path* [index]
          |  |     |  |  +--rw index           uint32
          |  |     |  |  +--rw network-ref?
          |  |     |  |  |       -> /nw:networks/network/network-id
          |  |     |  |  +--rw path-element* [path-element-id]
          |  |     |  |     +--rw path-element-id              uint32
          |  |     |  |     +--rw (type)?
          |  |     |  |        +--:(numbered-node-hop)
          |  |     |  |        |  +--rw numbered-node-hop
          |  |     |  |        |     +--rw node-id     te-node-id
          |  |     |  |        |     +--rw hop-type?   te-hop-type
          |  |     |  |        +--:(numbered-link-hop)
          |  |     |  |        |  +--rw numbered-link-hop
          |  |     |  |        |     +--rw link-tp-id    te-tp-id
          |  |     |  |        |     +--rw hop-type?     te-hop-type
          |  |     |  |        |     +--rw direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(unnumbered-link-hop)
          |  |     |  |        |  +--rw unnumbered-link-hop
          |  |     |  |        |     +--rw link-tp-id    te-tp-id
          |  |     |  |        |     +--rw node-id       te-node-id
          |  |     |  |        |     +--rw hop-type?     te-hop-type
          |  |     |  |        |     +--rw direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(as-number)
          |  |     |  |        |  +--rw as-number-hop
          |  |     |  |        |     +--rw as-number    inet:as-number
          |  |     |  |        |     +--rw hop-type?    te-hop-type
          |  |     |  |        +--:(label)
          |  |     |  |           +--rw label-hop
          |  |     |  |              +--rw te-label
          |  |     |  |                 +--rw (technology)?
          |  |     |  |                 |  +--:(generic)
          |  |     |  |                 |     +--rw generic?
          |  |     |  |                 |             rt-
   types:generalized-label
          |  |     |  |                 +--rw direction?
          |  |     |  |                         te-label-direction
          |  |     |  +--rw protection-type?             identityref
          |  |     |  +--rw tunnel-termination-points
          |  |     |  |  +--rw source?        binary
          |  |     |  |  +--rw destination?   binary
          |  |     |  +--rw tunnels
          |  |     |     +--rw sharing?   boolean
          |  |     |     +--rw tunnel* [tunnel-name]
          |  |     |        +--rw tunnel-name    string
          |  |     |        +--rw sharing?       boolean
          |  |     +--rw path-constraints
          |  |     |  +--rw te-bandwidth
          |  |     |  |  +--rw (technology)?
          |  |     |  |     +--:(generic)
          |  |     |  |        +--rw generic?   te-bandwidth
          |  |     |  +--rw link-protection?          identityref
          |  |     |  +--rw setup-priority?           uint8
          |  |     |  +--rw hold-priority?            uint8
          |  |     |  +--rw signaling-type?           identityref
          |  |     |  +--rw path-metric-bounds
          |  |     |  |  +--rw path-metric-bound* [metric-type]
          |  |     |  |     +--rw metric-type    identityref
          |  |     |  |     +--rw upper-bound?   uint64
          |  |     |  +--rw path-affinities-values
          |  |     |  |  +--rw path-affinities-value* [usage]
          |  |     |  |     +--rw usage    identityref
          |  |     |  |     +--rw value?   admin-groups
          |  |     |  +--rw path-affinity-names
          |  |     |  |  +--rw path-affinity-name* [usage]
          |  |     |  |     +--rw usage            identityref
          |  |     |  |     +--rw affinity-name* [name]
          |  |     |  |        +--rw name    string
          |  |     |  +--rw path-srlgs-lists
          |  |     |  |  +--rw path-srlgs-list* [usage]
          |  |     |  |     +--rw usage     identityref
          |  |     |  |     +--rw values*   srlg
          |  |     |  +--rw path-srlgs-names
          |  |     |  |  +--rw path-srlgs-name* [usage]
          |  |     |  |     +--rw usage    identityref
          |  |     |  |     +--rw names*   string
          |  |     |  +--rw disjointness?
          |  |     |          te-path-disjointness
          |  |     +--rw optimizations
          |  |     |  +--rw (algorithm)?
          |  |     |     +--:(metric) {path-optimization-metric}?
          |  |     |     |  +--rw optimization-metric* [metric-type]
          |  |     |     |  |  +--rw metric-type
          |  |     |     |  |  |       identityref
          |  |     |     |  |  +--rw weight?
          |  |     |     |  |  |       uint8
          |  |     |     |  |  +--rw explicit-route-exclude-objects
          |  |     |     |  |  |  +--rw route-object-exclude-object*
          |  |     |     |  |  |          [index]
          |  |     |     |  |  |     +--rw index
          |  |     |     |  |  |     |       uint32
          |  |     |     |  |  |     +--rw (type)?
          |  |     |     |  |  |        +--:(numbered-node-hop)
          |  |     |     |  |  |        |  +--rw numbered-node-hop
          |  |     |     |  |  |        |     +--rw node-id
          |  |     |     |  |  |        |     |       te-node-id
          |  |     |     |  |  |        |     +--rw hop-type?
          |  |     |     |  |  |        |             te-hop-type
          |  |     |     |  |  |        +--:(numbered-link-hop)
          |  |     |     |  |  |        |  +--rw numbered-link-hop
          |  |     |     |  |  |        |     +--rw link-tp-id
          |  |     |     |  |  |        |     |       te-tp-id
          |  |     |     |  |  |        |     +--rw hop-type?
          |  |     |     |  |  |        |     |       te-hop-type
          |  |     |     |  |  |        |     +--rw direction?
          |  |     |     |  |  |        |             te-link-direction
          |  |     |     |  |  |        +--:(unnumbered-link-hop)
          |  |     |     |  |  |        |  +--rw unnumbered-link-hop
          |  |     |     |  |  |        |     +--rw link-tp-id
          |  |     |     |  |  |        |     |       te-tp-id
          |  |     |     |  |  |        |     +--rw node-id
          |  |     |     |  |  |        |     |       te-node-id
          |  |     |     |  |  |        |     +--rw hop-type?
          |  |     |     |  |  |        |     |       te-hop-type
          |  |     |     |  |  |        |     +--rw direction?
          |  |     |     |  |  |        |             te-link-direction
          |  |     |     |  |  |        +--:(as-number)
          |  |     |     |  |  |        |  +--rw as-number-hop
          |  |     |     |  |  |        |     +--rw as-number
          |  |     |     |  |  |        |     |       inet:as-number
          |  |     |     |  |  |        |     +--rw hop-type?
          |  |     |     |  |  |        |             te-hop-type
          |  |     |     |  |  |        +--:(label)
          |  |     |     |  |  |        |  +--rw label-hop
          |  |     |     |  |  |        |     +--rw te-label
          |  |     |     |  |  |        |        +--rw (technology)?
          |  |     |     |  |  |        |        |  +--:(generic)
          |  |     |     |  |  |        |        |     +--rw generic?
          |  |     |     |  |  |        |        |             rt-
   types:generalized-label
          |  |     |     |  |  |        |        +--rw direction?
          |  |     |     |  |  |        |                te-label-
   direction
          |  |     |     |  |  |        +--:(srlg)
          |  |     |     |  |  |           +--rw srlg
          |  |     |     |  |  |              +--rw srlg?   uint32
          |  |     |     |  |  +--rw explicit-route-include-objects
          |  |     |     |  |     +--rw route-object-include-object*
          |  |     |     |  |             [index]
          |  |     |     |  |        +--rw index
          |  |     |     |  |        |       uint32
          |  |     |     |  |        +--rw (type)?
          |  |     |     |  |           +--:(numbered-node-hop)
          |  |     |     |  |           |  +--rw numbered-node-hop
          |  |     |     |  |           |     +--rw node-id
          |  |     |     |  |           |     |       te-node-id
          |  |     |     |  |           |     +--rw hop-type?
          |  |     |     |  |           |             te-hop-type
          |  |     |     |  |           +--:(numbered-link-hop)
          |  |     |     |  |           |  +--rw numbered-link-hop
          |  |     |     |  |           |     +--rw link-tp-id
          |  |     |     |  |           |     |       te-tp-id
          |  |     |     |  |           |     +--rw hop-type?
          |  |     |     |  |           |     |       te-hop-type
          |  |     |     |  |           |     +--rw direction?
          |  |     |     |  |           |             te-link-direction
          |  |     |     |  |           +--:(unnumbered-link-hop)
          |  |     |     |  |           |  +--rw unnumbered-link-hop
          |  |     |     |  |           |     +--rw link-tp-id
          |  |     |     |  |           |     |       te-tp-id
          |  |     |     |  |           |     +--rw node-id
          |  |     |     |  |           |     |       te-node-id
          |  |     |     |  |           |     +--rw hop-type?
          |  |     |     |  |           |     |       te-hop-type
          |  |     |     |  |           |     +--rw direction?
          |  |     |     |  |           |             te-link-direction
          |  |     |     |  |           +--:(as-number)
          |  |     |     |  |           |  +--rw as-number-hop
          |  |     |     |  |           |     +--rw as-number
          |  |     |     |  |           |     |       inet:as-number
          |  |     |     |  |           |     +--rw hop-type?
          |  |     |     |  |           |             te-hop-type
          |  |     |     |  |           +--:(label)
          |  |     |     |  |              +--rw label-hop
          |  |     |     |  |                 +--rw te-label
          |  |     |     |  |                    +--rw (technology)?
          |  |     |     |  |                    |  +--:(generic)
          |  |     |     |  |                    |     +--rw generic?
          |  |     |     |  |                    |             rt-
   types:generalized-label
          |  |     |     |  |                    +--rw direction?
          |  |     |     |  |                            te-label-
   direction
          |  |     |     |  +--rw tiebreakers
          |  |     |     |     +--rw tiebreaker* [tiebreaker-type]
          |  |     |     |        +--rw tiebreaker-type    identityref
          |  |     |     +--:(objective-function)
          |  |     |              {path-optimization-objective-
   function}?
          |  |     |        +--rw objective-function
          |  |     |           +--rw objective-function-type?
          |  |     |                   identityref
          |  |     +--ro path-properties
          |  |        +--ro path-metric* [metric-type]
          |  |        |  +--ro metric-type           identityref
          |  |        |  +--ro accumulative-value?   uint64
          |  |        +--ro path-affinities-values
          |  |        |  +--ro path-affinities-value* [usage]
          |  |        |     +--ro usage    identityref
          |  |        |     +--ro value?   admin-groups
          |  |        +--ro path-affinity-names
          |  |        |  +--ro path-affinity-name* [usage]
          |  |        |     +--ro usage            identityref
          |  |        |     +--ro affinity-name* [name]
          |  |        |        +--ro name    string
          |  |        +--ro path-srlgs-lists
          |  |        |  +--ro path-srlgs-list* [usage]
          |  |        |     +--ro usage     identityref
          |  |        |     +--ro values*   srlg
          |  |        +--ro path-srlgs-names
          |  |        |  +--ro path-srlgs-name* [usage]
          |  |        |     +--ro usage    identityref
          |  |        |     +--ro names*   string
          |  |        +--ro path-route-objects
          |  |           +--ro path-route-object* [index]
          |  |              +--ro index                        uint32
          |  |              +--ro (type)?
          |  |                 +--:(numbered-node-hop)
          |  |                 |  +--ro numbered-node-hop
          |  |                 |     +--ro node-id     te-node-id
          |  |                 |     +--ro hop-type?   te-hop-type
          |  |                 +--:(numbered-link-hop)
          |  |                 |  +--ro numbered-link-hop
          |  |                 |     +--ro link-tp-id    te-tp-id
          |  |                 |     +--ro hop-type?     te-hop-type
          |  |                 |     +--ro direction?
          |  |                 |             te-link-direction
          |  |                 +--:(unnumbered-link-hop)
          |  |                 |  +--ro unnumbered-link-hop
          |  |                 |     +--ro link-tp-id    te-tp-id
          |  |                 |     +--ro node-id       te-node-id
          |  |                 |     +--ro hop-type?     te-hop-type
          |  |                 |     +--ro direction?
          |  |                 |             te-link-direction
          |  |                 +--:(as-number)
          |  |                 |  +--ro as-number-hop
          |  |                 |     +--ro as-number    inet:as-number
          |  |                 |     +--ro hop-type?    te-hop-type
          |  |                 +--:(label)
          |  |                    +--ro label-hop
          |  |                       +--ro te-label
          |  |                          +--ro (technology)?
          |  |                          |  +--:(generic)
          |  |                          |     +--ro generic?
          |  |                          |             rt-
   types:generalized-label
          |  |                          +--ro direction?
          |  |                                  te-label-direction
          |  +--rw domain-id?               uint32
          |  +--rw is-abstract?             empty
          |  +--rw name?                    string
          |  +--rw signaling-address*       inet:ip-address
          |  +--rw underlay-topology {te-topology-hierarchy}?
          |     +--rw network-ref?   -> /nw:networks/network/network-id
          +--ro oper-status?                   te-types:te-oper-status
          +--ro geolocation
          |  +--ro altitude?    int64
          |  +--ro latitude?    geographic-coordinate-degree
          |  +--ro longitude?   geographic-coordinate-degree
          +--ro is-multi-access-dr?            empty
          +--ro information-source?            te-info-source
          +--ro information-source-instance?   string
          +--ro information-source-state
          |  +--ro credibility-preference?    uint16
          |  +--ro logical-network-element?   string
          |  +--ro network-instance?          string
          |  +--ro topology
          |     +--ro node-ref?      leafref
          |     +--ro network-ref?   -> /nw:networks/network/network-id
          +--ro information-source-entry*
          |       [information-source information-source-instance]
          |  +--ro information-source             te-info-source
          |  +--ro information-source-instance    string
          |  +--ro information-source-state
          |  |  +--ro credibility-preference?    uint16
          |  |  +--ro logical-network-element?   string
          |  |  +--ro network-instance?          string
          |  |  +--ro topology
          |  |     +--ro node-ref?      leafref
          |  |     +--ro network-ref?
          |  |             -> /nw:networks/network/network-id
          |  +--ro connectivity-matrices
          |  |  +--ro number-of-entries?     uint16
          |  |  +--ro label-restrictions
          |  |  |  +--ro label-restriction* [index]
          |  |  |     +--ro restriction?    enumeration
          |  |  |     +--ro index           uint32
          |  |  |     +--ro label-start
          |  |  |     |  +--ro te-label
          |  |  |     |     +--ro (technology)?
          |  |  |     |     |  +--:(generic)
          |  |  |     |     |     +--ro generic?
          |  |  |     |     |             rt-types:generalized-label
          |  |  |     |     +--ro direction?       te-label-direction
          |  |  |     +--ro label-end
          |  |  |     |  +--ro te-label
          |  |  |     |     +--ro (technology)?
          |  |  |     |     |  +--:(generic)
          |  |  |     |     |     +--ro generic?
          |  |  |     |     |             rt-types:generalized-label
          |  |  |     |     +--ro direction?       te-label-direction
          |  |  |     +--ro label-step
          |  |  |     |  +--ro (technology)?
          |  |  |     |     +--:(generic)
          |  |  |     |        +--ro generic?   int32
          |  |  |     +--ro range-bitmap?   yang:hex-string
          |  |  +--ro is-allowed?            boolean
          |  |  +--ro underlay {te-topology-hierarchy}?
          |  |  |  +--ro enabled?                     boolean
          |  |  |  +--ro primary-path
          |  |  |  |  +--ro network-ref?
          |  |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  |  +--ro path-element* [path-element-id]
          |  |  |  |     +--ro path-element-id              uint32
          |  |  |  |     +--ro (type)?
          |  |  |  |        +--:(numbered-node-hop)
          |  |  |  |        |  +--ro numbered-node-hop
          |  |  |  |        |     +--ro node-id     te-node-id
          |  |  |  |        |     +--ro hop-type?   te-hop-type
          |  |  |  |        +--:(numbered-link-hop)
          |  |  |  |        |  +--ro numbered-link-hop
          |  |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |  |        |     +--ro hop-type?     te-hop-type
          |  |  |  |        |     +--ro direction?    te-link-direction
          |  |  |  |        +--:(unnumbered-link-hop)
          |  |  |  |        |  +--ro unnumbered-link-hop
          |  |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |  |        |     +--ro node-id       te-node-id
          |  |  |  |        |     +--ro hop-type?     te-hop-type
          |  |  |  |        |     +--ro direction?    te-link-direction
          |  |  |  |        +--:(as-number)
          |  |  |  |        |  +--ro as-number-hop
          |  |  |  |        |     +--ro as-number    inet:as-number
          |  |  |  |        |     +--ro hop-type?    te-hop-type
          |  |  |  |        +--:(label)
          |  |  |  |           +--ro label-hop
          |  |  |  |              +--ro te-label
          |  |  |  |                 +--ro (technology)?
          |  |  |  |                 |  +--:(generic)
          |  |  |  |                 |     +--ro generic?
          |  |  |  |                 |             rt-types:generalized-
   label
          |  |  |  |                 +--ro direction?
          |  |  |  |                         te-label-direction
          |  |  |  +--ro backup-path* [index]
          |  |  |  |  +--ro index           uint32
          |  |  |  |  +--ro network-ref?
          |  |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  |  +--ro path-element* [path-element-id]
          |  |  |  |     +--ro path-element-id              uint32
          |  |  |  |     +--ro (type)?
          |  |  |  |        +--:(numbered-node-hop)
          |  |  |  |        |  +--ro numbered-node-hop
          |  |  |  |        |     +--ro node-id     te-node-id
          |  |  |  |        |     +--ro hop-type?   te-hop-type
          |  |  |  |        +--:(numbered-link-hop)
          |  |  |  |        |  +--ro numbered-link-hop
          |  |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |  |        |     +--ro hop-type?     te-hop-type
          |  |  |  |        |     +--ro direction?    te-link-direction
          |  |  |  |        +--:(unnumbered-link-hop)
          |  |  |  |        |  +--ro unnumbered-link-hop
          |  |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |  |        |     +--ro node-id       te-node-id
          |  |  |  |        |     +--ro hop-type?     te-hop-type
          |  |  |  |        |     +--ro direction?    te-link-direction
          |  |  |  |        +--:(as-number)
          |  |  |  |        |  +--ro as-number-hop
          |  |  |  |        |     +--ro as-number    inet:as-number
          |  |  |  |        |     +--ro hop-type?    te-hop-type
          |  |  |  |        +--:(label)
          |  |  |  |           +--ro label-hop
          |  |  |  |              +--ro te-label
          |  |  |  |                 +--ro (technology)?
          |  |  |  |                 |  +--:(generic)
          |  |  |  |                 |     +--ro generic?
          |  |  |  |                 |             rt-types:generalized-
   label
          |  |  |  |                 +--ro direction?
          |  |  |  |                         te-label-direction
          |  |  |  +--ro protection-type?             identityref
          |  |  |  +--ro tunnel-termination-points
          |  |  |  |  +--ro source?        binary
          |  |  |  |  +--ro destination?   binary
          |  |  |  +--ro tunnels
          |  |  |     +--ro sharing?   boolean
          |  |  |     +--ro tunnel* [tunnel-name]
          |  |  |        +--ro tunnel-name    string
          |  |  |        +--ro sharing?       boolean
          |  |  +--ro path-constraints
          |  |  |  +--ro te-bandwidth
          |  |  |  |  +--ro (technology)?
          |  |  |  |     +--:(generic)
          |  |  |  |        +--ro generic?   te-bandwidth
          |  |  |  +--ro link-protection?          identityref
          |  |  |  +--ro setup-priority?           uint8
          |  |  |  +--ro hold-priority?            uint8
          |  |  |  +--ro signaling-type?           identityref
          |  |  |  +--ro path-metric-bounds
          |  |  |  |  +--ro path-metric-bound* [metric-type]
          |  |  |  |     +--ro metric-type    identityref
          |  |  |  |     +--ro upper-bound?   uint64
          |  |  |  +--ro path-affinities-values
          |  |  |  |  +--ro path-affinities-value* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro value?   admin-groups
          |  |  |  +--ro path-affinity-names
          |  |  |  |  +--ro path-affinity-name* [usage]
          |  |  |  |     +--ro usage            identityref
          |  |  |  |     +--ro affinity-name* [name]
          |  |  |  |        +--ro name    string
          |  |  |  +--ro path-srlgs-lists
          |  |  |  |  +--ro path-srlgs-list* [usage]
          |  |  |  |     +--ro usage     identityref
          |  |  |  |     +--ro values*   srlg
          |  |  |  +--ro path-srlgs-names
          |  |  |  |  +--ro path-srlgs-name* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro names*   string
          |  |  |  +--ro disjointness?             te-path-disjointness
          |  |  +--ro optimizations
          |  |  |  +--ro (algorithm)?
          |  |  |     +--:(metric) {path-optimization-metric}?
          |  |  |     |  +--ro optimization-metric* [metric-type]
          |  |  |     |  |  +--ro metric-type
          |  |  |     |  |  |       identityref
          |  |  |     |  |  +--ro weight?
          |  |  |     |  |  |       uint8
          |  |  |     |  |  +--ro explicit-route-exclude-objects
          |  |  |     |  |  |  +--ro route-object-exclude-object*
          |  |  |     |  |  |          [index]
          |  |  |     |  |  |     +--ro index
          |  |  |     |  |  |     |       uint32
          |  |  |     |  |  |     +--ro (type)?
          |  |  |     |  |  |        +--:(numbered-node-hop)
          |  |  |     |  |  |        |  +--ro numbered-node-hop
          |  |  |     |  |  |        |     +--ro node-id     te-node-id
          |  |  |     |  |  |        |     +--ro hop-type?   te-hop-type
          |  |  |     |  |  |        +--:(numbered-link-hop)
          |  |  |     |  |  |        |  +--ro numbered-link-hop
          |  |  |     |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |     |  |  |        |     +--ro hop-type?
          |  |  |     |  |  |        |     |       te-hop-type
          |  |  |     |  |  |        |     +--ro direction?
          |  |  |     |  |  |        |             te-link-direction
          |  |  |     |  |  |        +--:(unnumbered-link-hop)
          |  |  |     |  |  |        |  +--ro unnumbered-link-hop
          |  |  |     |  |  |        |     +--ro link-tp-id    te-tp-id
          |  |  |     |  |  |        |     +--ro node-id
          |  |  |     |  |  |        |     |       te-node-id
          |  |  |     |  |  |        |     +--ro hop-type?
          |  |  |     |  |  |        |     |       te-hop-type
          |  |  |     |  |  |        |     +--ro direction?
          |  |  |     |  |  |        |             te-link-direction
          |  |  |     |  |  |        +--:(as-number)
          |  |  |     |  |  |        |  +--ro as-number-hop
          |  |  |     |  |  |        |     +--ro as-number
          |  |  |     |  |  |        |     |       inet:as-number
          |  |  |     |  |  |        |     +--ro hop-type?
          |  |  |     |  |  |        |             te-hop-type
          |  |  |     |  |  |        +--:(label)
          |  |  |     |  |  |        |  +--ro label-hop
          |  |  |     |  |  |        |     +--ro te-label
          |  |  |     |  |  |        |        +--ro (technology)?
          |  |  |     |  |  |        |        |  +--:(generic)
          |  |  |     |  |  |        |        |     +--ro generic?
          |  |  |     |  |  |        |        |             rt-
   types:generalized-label
          |  |  |     |  |  |        |        +--ro direction?
          |  |  |     |  |  |        |                te-label-direction
          |  |  |     |  |  |        +--:(srlg)
          |  |  |     |  |  |           +--ro srlg
          |  |  |     |  |  |              +--ro srlg?   uint32
          |  |  |     |  |  +--ro explicit-route-include-objects
          |  |  |     |  |     +--ro route-object-include-object*
          |  |  |     |  |             [index]
          |  |  |     |  |        +--ro index
          |  |  |     |  |        |       uint32
          |  |  |     |  |        +--ro (type)?
          |  |  |     |  |           +--:(numbered-node-hop)
          |  |  |     |  |           |  +--ro numbered-node-hop
          |  |  |     |  |           |     +--ro node-id     te-node-id
          |  |  |     |  |           |     +--ro hop-type?   te-hop-type
          |  |  |     |  |           +--:(numbered-link-hop)
          |  |  |     |  |           |  +--ro numbered-link-hop
          |  |  |     |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |     |  |           |     +--ro hop-type?
          |  |  |     |  |           |     |       te-hop-type
          |  |  |     |  |           |     +--ro direction?
          |  |  |     |  |           |             te-link-direction
          |  |  |     |  |           +--:(unnumbered-link-hop)
          |  |  |     |  |           |  +--ro unnumbered-link-hop
          |  |  |     |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |     |  |           |     +--ro node-id
          |  |  |     |  |           |     |       te-node-id
          |  |  |     |  |           |     +--ro hop-type?
          |  |  |     |  |           |     |       te-hop-type
          |  |  |     |  |           |     +--ro direction?
          |  |  |     |  |           |             te-link-direction
          |  |  |     |  |           +--:(as-number)
          |  |  |     |  |           |  +--ro as-number-hop
          |  |  |     |  |           |     +--ro as-number
          |  |  |     |  |           |     |       inet:as-number
          |  |  |     |  |           |     +--ro hop-type?
          |  |  |     |  |           |             te-hop-type
          |  |  |     |  |           +--:(label)
          |  |  |     |  |              +--ro label-hop
          |  |  |     |  |                 +--ro te-label
          |  |  |     |  |                    +--ro (technology)?
          |  |  |     |  |                    |  +--:(generic)
          |  |  |     |  |                    |     +--ro generic?
          |  |  |     |  |                    |             rt-
   types:generalized-label
          |  |  |     |  |                    +--ro direction?
          |  |  |     |  |                            te-label-direction
          |  |  |     |  +--ro tiebreakers
          |  |  |     |     +--ro tiebreaker* [tiebreaker-type]
          |  |  |     |        +--ro tiebreaker-type    identityref
          |  |  |     +--:(objective-function)
          |  |  |              {path-optimization-objective-function}?
          |  |  |        +--ro objective-function
          |  |  |           +--ro objective-function-type?   identityref
          |  |  +--ro path-properties
          |  |  |  +--ro path-metric* [metric-type]
          |  |  |  |  +--ro metric-type           identityref
          |  |  |  |  +--ro accumulative-value?   uint64
          |  |  |  +--ro path-affinities-values
          |  |  |  |  +--ro path-affinities-value* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro value?   admin-groups
          |  |  |  +--ro path-affinity-names
          |  |  |  |  +--ro path-affinity-name* [usage]
          |  |  |  |     +--ro usage            identityref
          |  |  |  |     +--ro affinity-name* [name]
          |  |  |  |        +--ro name    string
          |  |  |  +--ro path-srlgs-lists
          |  |  |  |  +--ro path-srlgs-list* [usage]
          |  |  |  |     +--ro usage     identityref
          |  |  |  |     +--ro values*   srlg
          |  |  |  +--ro path-srlgs-names
          |  |  |  |  +--ro path-srlgs-name* [usage]
          |  |  |  |     +--ro usage    identityref
          |  |  |  |     +--ro names*   string
          |  |  |  +--ro path-route-objects
          |  |  |     +--ro path-route-object* [index]
          |  |  |        +--ro index                        uint32
          |  |  |        +--ro (type)?
          |  |  |           +--:(numbered-node-hop)
          |  |  |           |  +--ro numbered-node-hop
          |  |  |           |     +--ro node-id     te-node-id
          |  |  |           |     +--ro hop-type?   te-hop-type
          |  |  |           +--:(numbered-link-hop)
          |  |  |           |  +--ro numbered-link-hop
          |  |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |           |     +--ro hop-type?     te-hop-type
          |  |  |           |     +--ro direction?    te-link-direction
          |  |  |           +--:(unnumbered-link-hop)
          |  |  |           |  +--ro unnumbered-link-hop
          |  |  |           |     +--ro link-tp-id    te-tp-id
          |  |  |           |     +--ro node-id       te-node-id
          |  |  |           |     +--ro hop-type?     te-hop-type
          |  |  |           |     +--ro direction?    te-link-direction
          |  |  |           +--:(as-number)
          |  |  |           |  +--ro as-number-hop
          |  |  |           |     +--ro as-number    inet:as-number
          |  |  |           |     +--ro hop-type?    te-hop-type
          |  |  |           +--:(label)
          |  |  |              +--ro label-hop
          |  |  |                 +--ro te-label
          |  |  |                    +--ro (technology)?
          |  |  |                    |  +--:(generic)
          |  |  |                    |     +--ro generic?
          |  |  |                    |             rt-types:generalized-
   label
          |  |  |                    +--ro direction?
          |  |  |                            te-label-direction
          |  |  +--ro connectivity-matrix* [id]
          |  |     +--ro id                  uint32
          |  |     +--ro from
          |  |     |  +--ro tp-ref?               leafref
          |  |     |  +--ro label-restrictions
          |  |     |     +--ro label-restriction* [index]
          |  |     |        +--ro restriction?    enumeration
          |  |     |        +--ro index           uint32
          |  |     |        +--ro label-start
          |  |     |        |  +--ro te-label
          |  |     |        |     +--ro (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--ro generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--ro direction?
          |  |     |        |             te-label-direction
          |  |     |        +--ro label-end
          |  |     |        |  +--ro te-label
          |  |     |        |     +--ro (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--ro generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--ro direction?
          |  |     |        |             te-label-direction
          |  |     |        +--ro label-step
          |  |     |        |  +--ro (technology)?
          |  |     |        |     +--:(generic)
          |  |     |        |        +--ro generic?   int32
          |  |     |        +--ro range-bitmap?   yang:hex-string
          |  |     +--ro to
          |  |     |  +--ro tp-ref?               leafref
          |  |     |  +--ro label-restrictions
          |  |     |     +--ro label-restriction* [index]
          |  |     |        +--ro restriction?    enumeration
          |  |     |        +--ro index           uint32
          |  |     |        +--ro label-start
          |  |     |        |  +--ro te-label
          |  |     |        |     +--ro (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--ro generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--ro direction?
          |  |     |        |             te-label-direction
          |  |     |        +--ro label-end
          |  |     |        |  +--ro te-label
          |  |     |        |     +--ro (technology)?
          |  |     |        |     |  +--:(generic)
          |  |     |        |     |     +--ro generic?
          |  |     |        |     |             rt-types:generalized-
   label
          |  |     |        |     +--ro direction?
          |  |     |        |             te-label-direction
          |  |     |        +--ro label-step
          |  |     |        |  +--ro (technology)?
          |  |     |        |     +--:(generic)
          |  |     |        |        +--ro generic?   int32
          |  |     |        +--ro range-bitmap?   yang:hex-string
          |  |     +--ro is-allowed?         boolean
          |  |     +--ro underlay {te-topology-hierarchy}?
          |  |     |  +--ro enabled?                     boolean
          |  |     |  +--ro primary-path
          |  |     |  |  +--ro network-ref?
          |  |     |  |  |       -> /nw:networks/network/network-id
          |  |     |  |  +--ro path-element* [path-element-id]
          |  |     |  |     +--ro path-element-id              uint32
          |  |     |  |     +--ro (type)?
          |  |     |  |        +--:(numbered-node-hop)
          |  |     |  |        |  +--ro numbered-node-hop
          |  |     |  |        |     +--ro node-id     te-node-id
          |  |     |  |        |     +--ro hop-type?   te-hop-type
          |  |     |  |        +--:(numbered-link-hop)
          |  |     |  |        |  +--ro numbered-link-hop
          |  |     |  |        |     +--ro link-tp-id    te-tp-id
          |  |     |  |        |     +--ro hop-type?     te-hop-type
          |  |     |  |        |     +--ro direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(unnumbered-link-hop)
          |  |     |  |        |  +--ro unnumbered-link-hop
          |  |     |  |        |     +--ro link-tp-id    te-tp-id
          |  |     |  |        |     +--ro node-id       te-node-id
          |  |     |  |        |     +--ro hop-type?     te-hop-type
          |  |     |  |        |     +--ro direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(as-number)
          |  |     |  |        |  +--ro as-number-hop
          |  |     |  |        |     +--ro as-number    inet:as-number
          |  |     |  |        |     +--ro hop-type?    te-hop-type
          |  |     |  |        +--:(label)
          |  |     |  |           +--ro label-hop
          |  |     |  |              +--ro te-label
          |  |     |  |                 +--ro (technology)?
          |  |     |  |                 |  +--:(generic)
          |  |     |  |                 |     +--ro generic?
          |  |     |  |                 |             rt-
   types:generalized-label
          |  |     |  |                 +--ro direction?
          |  |     |  |                         te-label-direction
          |  |     |  +--ro backup-path* [index]
          |  |     |  |  +--ro index           uint32
          |  |     |  |  +--ro network-ref?
          |  |     |  |  |       -> /nw:networks/network/network-id
          |  |     |  |  +--ro path-element* [path-element-id]
          |  |     |  |     +--ro path-element-id              uint32
          |  |     |  |     +--ro (type)?
          |  |     |  |        +--:(numbered-node-hop)
          |  |     |  |        |  +--ro numbered-node-hop
          |  |     |  |        |     +--ro node-id     te-node-id
          |  |     |  |        |     +--ro hop-type?   te-hop-type
          |  |     |  |        +--:(numbered-link-hop)
          |  |     |  |        |  +--ro numbered-link-hop
          |  |     |  |        |     +--ro link-tp-id    te-tp-id
          |  |     |  |        |     +--ro hop-type?     te-hop-type
          |  |     |  |        |     +--ro direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(unnumbered-link-hop)
          |  |     |  |        |  +--ro unnumbered-link-hop
          |  |     |  |        |     +--ro link-tp-id    te-tp-id
          |  |     |  |        |     +--ro node-id       te-node-id
          |  |     |  |        |     +--ro hop-type?     te-hop-type
          |  |     |  |        |     +--ro direction?
          |  |     |  |        |             te-link-direction
          |  |     |  |        +--:(as-number)
          |  |     |  |        |  +--ro as-number-hop
          |  |     |  |        |     +--ro as-number    inet:as-number
          |  |     |  |        |     +--ro hop-type?    te-hop-type
          |  |     |  |        +--:(label)
          |  |     |  |           +--ro label-hop
          |  |     |  |              +--ro te-label
          |  |     |  |                 +--ro (technology)?
          |  |     |  |                 |  +--:(generic)
          |  |     |  |                 |     +--ro generic?
          |  |     |  |                 |             rt-
   types:generalized-label
          |  |     |  |                 +--ro direction?
          |  |     |  |                         te-label-direction
          |  |     |  +--ro protection-type?             identityref
          |  |     |  +--ro tunnel-termination-points
          |  |     |  |  +--ro source?        binary
          |  |     |  |  +--ro destination?   binary
          |  |     |  +--ro tunnels
          |  |     |     +--ro sharing?   boolean
          |  |     |     +--ro tunnel* [tunnel-name]
          |  |     |        +--ro tunnel-name    string
          |  |     |        +--ro sharing?       boolean
          |  |     +--ro path-constraints
          |  |     |  +--ro te-bandwidth
          |  |     |  |  +--ro (technology)?
          |  |     |  |     +--:(generic)
          |  |     |  |        +--ro generic?   te-bandwidth
          |  |     |  +--ro link-protection?          identityref
          |  |     |  +--ro setup-priority?           uint8
          |  |     |  +--ro hold-priority?            uint8
          |  |     |  +--ro signaling-type?           identityref
          |  |     |  +--ro path-metric-bounds
          |  |     |  |  +--ro path-metric-bound* [metric-type]
          |  |     |  |     +--ro metric-type    identityref
          |  |     |  |     +--ro upper-bound?   uint64
          |  |     |  +--ro path-affinities-values
          |  |     |  |  +--ro path-affinities-value* [usage]
          |  |     |  |     +--ro usage    identityref
          |  |     |  |     +--ro value?   admin-groups
          |  |     |  +--ro path-affinity-names
          |  |     |  |  +--ro path-affinity-name* [usage]
          |  |     |  |     +--ro usage            identityref
          |  |     |  |     +--ro affinity-name* [name]
          |  |     |  |        +--ro name    string
          |  |     |  +--ro path-srlgs-lists
          |  |     |  |  +--ro path-srlgs-list* [usage]
          |  |     |  |     +--ro usage     identityref
          |  |     |  |     +--ro values*   srlg
          |  |     |  +--ro path-srlgs-names
          |  |     |  |  +--ro path-srlgs-name* [usage]
          |  |     |  |     +--ro usage    identityref
          |  |     |  |     +--ro names*   string
          |  |     |  +--ro disjointness?
          |  |     |          te-path-disjointness
          |  |     +--ro optimizations
          |  |     |  +--ro (algorithm)?
          |  |     |     +--:(metric) {path-optimization-metric}?
          |  |     |     |  +--ro optimization-metric* [metric-type]
          |  |     |     |  |  +--ro metric-type
          |  |     |     |  |  |       identityref
          |  |     |     |  |  +--ro weight?
          |  |     |     |  |  |       uint8
          |  |     |     |  |  +--ro explicit-route-exclude-objects
          |  |     |     |  |  |  +--ro route-object-exclude-object*
          |  |     |     |  |  |          [index]
          |  |     |     |  |  |     +--ro index
          |  |     |     |  |  |     |       uint32
          |  |     |     |  |  |     +--ro (type)?
          |  |     |     |  |  |        +--:(numbered-node-hop)
          |  |     |     |  |  |        |  +--ro numbered-node-hop
          |  |     |     |  |  |        |     +--ro node-id
          |  |     |     |  |  |        |     |       te-node-id
          |  |     |     |  |  |        |     +--ro hop-type?
          |  |     |     |  |  |        |             te-hop-type
          |  |     |     |  |  |        +--:(numbered-link-hop)
          |  |     |     |  |  |        |  +--ro numbered-link-hop
          |  |     |     |  |  |        |     +--ro link-tp-id
          |  |     |     |  |  |        |     |       te-tp-id
          |  |     |     |  |  |        |     +--ro hop-type?
          |  |     |     |  |  |        |     |       te-hop-type
          |  |     |     |  |  |        |     +--ro direction?
          |  |     |     |  |  |        |             te-link-direction
          |  |     |     |  |  |        +--:(unnumbered-link-hop)
          |  |     |     |  |  |        |  +--ro unnumbered-link-hop
          |  |     |     |  |  |        |     +--ro link-tp-id
          |  |     |     |  |  |        |     |       te-tp-id
          |  |     |     |  |  |        |     +--ro node-id
          |  |     |     |  |  |        |     |       te-node-id
          |  |     |     |  |  |        |     +--ro hop-type?
          |  |     |     |  |  |        |     |       te-hop-type
          |  |     |     |  |  |        |     +--ro direction?
          |  |     |     |  |  |        |             te-link-direction
          |  |     |     |  |  |        +--:(as-number)
          |  |     |     |  |  |        |  +--ro as-number-hop
          |  |     |     |  |  |        |     +--ro as-number
          |  |     |     |  |  |        |     |       inet:as-number
          |  |     |     |  |  |        |     +--ro hop-type?
          |  |     |     |  |  |        |             te-hop-type
          |  |     |     |  |  |        +--:(label)
          |  |     |     |  |  |        |  +--ro label-hop
          |  |     |     |  |  |        |     +--ro te-label
          |  |     |     |  |  |        |        +--ro (technology)?
          |  |     |     |  |  |        |        |  +--:(generic)
          |  |     |     |  |  |        |        |     +--ro generic?
          |  |     |     |  |  |        |        |             rt-
   types:generalized-label
          |  |     |     |  |  |        |        +--ro direction?
          |  |     |     |  |  |        |                te-label-
   direction
          |  |     |     |  |  |        +--:(srlg)
          |  |     |     |  |  |           +--ro srlg
          |  |     |     |  |  |              +--ro srlg?   uint32
          |  |     |     |  |  +--ro explicit-route-include-objects
          |  |     |     |  |     +--ro route-object-include-object*
          |  |     |     |  |             [index]
          |  |     |     |  |        +--ro index
          |  |     |     |  |        |       uint32
          |  |     |     |  |        +--ro (type)?
          |  |     |     |  |           +--:(numbered-node-hop)
          |  |     |     |  |           |  +--ro numbered-node-hop
          |  |     |     |  |           |     +--ro node-id
          |  |     |     |  |           |     |       te-node-id
          |  |     |     |  |           |     +--ro hop-type?
          |  |     |     |  |           |             te-hop-type
          |  |     |     |  |           +--:(numbered-link-hop)
          |  |     |     |  |           |  +--ro numbered-link-hop
          |  |     |     |  |           |     +--ro link-tp-id
          |  |     |     |  |           |     |       te-tp-id
          |  |     |     |  |           |     +--ro hop-type?
          |  |     |     |  |           |     |       te-hop-type
          |  |     |     |  |           |     +--ro direction?
          |  |     |     |  |           |             te-link-direction
          |  |     |     |  |           +--:(unnumbered-link-hop)
          |  |     |     |  |           |  +--ro unnumbered-link-hop
          |  |     |     |  |           |     +--ro link-tp-id
          |  |     |     |  |           |     |       te-tp-id
          |  |     |     |  |           |     +--ro node-id
          |  |     |     |  |           |     |       te-node-id
          |  |     |     |  |           |     +--ro hop-type?
          |  |     |     |  |           |     |       te-hop-type
          |  |     |     |  |           |     +--ro direction?
          |  |     |     |  |           |             te-link-direction
          |  |     |     |  |           +--:(as-number)
          |  |     |     |  |           |  +--ro as-number-hop
          |  |     |     |  |           |     +--ro as-number
          |  |     |     |  |           |     |       inet:as-number
          |  |     |     |  |           |     +--ro hop-type?
          |  |     |     |  |           |             te-hop-type
          |  |     |     |  |           +--:(label)
          |  |     |     |  |              +--ro label-hop
          |  |     |     |  |                 +--ro te-label
          |  |     |     |  |                    +--ro (technology)?
          |  |     |     |  |                    |  +--:(generic)
          |  |     |     |  |                    |     +--ro generic?
          |  |     |     |  |                    |             rt-
   types:generalized-label
          |  |     |     |  |                    +--ro direction?
          |  |     |     |  |                            te-label-
   direction
          |  |     |     |  +--ro tiebreakers
          |  |     |     |     +--ro tiebreaker* [tiebreaker-type]
          |  |     |     |        +--ro tiebreaker-type    identityref
          |  |     |     +--:(objective-function)
          |  |     |              {path-optimization-objective-
   function}?
          |  |     |        +--ro objective-function
          |  |     |           +--ro objective-function-type?
          |  |     |                   identityref
          |  |     +--ro path-properties
          |  |        +--ro path-metric* [metric-type]
          |  |        |  +--ro metric-type           identityref
          |  |        |  +--ro accumulative-value?   uint64
          |  |        +--ro path-affinities-values
          |  |        |  +--ro path-affinities-value* [usage]
          |  |        |     +--ro usage    identityref
          |  |        |     +--ro value?   admin-groups
          |  |        +--ro path-affinity-names
          |  |        |  +--ro path-affinity-name* [usage]
          |  |        |     +--ro usage            identityref
          |  |        |     +--ro affinity-name* [name]
          |  |        |        +--ro name    string
          |  |        +--ro path-srlgs-lists
          |  |        |  +--ro path-srlgs-list* [usage]
          |  |        |     +--ro usage     identityref
          |  |        |     +--ro values*   srlg
          |  |        +--ro path-srlgs-names
          |  |        |  +--ro path-srlgs-name* [usage]
          |  |        |     +--ro usage    identityref
          |  |        |     +--ro names*   string
          |  |        +--ro path-route-objects
          |  |           +--ro path-route-object* [index]
          |  |              +--ro index                        uint32
          |  |              +--ro (type)?
          |  |                 +--:(numbered-node-hop)
          |  |                 |  +--ro numbered-node-hop
          |  |                 |     +--ro node-id     te-node-id
          |  |                 |     +--ro hop-type?   te-hop-type
          |  |                 +--:(numbered-link-hop)
          |  |                 |  +--ro numbered-link-hop
          |  |                 |     +--ro link-tp-id    te-tp-id
          |  |                 |     +--ro hop-type?     te-hop-type
          |  |                 |     +--ro direction?
          |  |                 |             te-link-direction
          |  |                 +--:(unnumbered-link-hop)
          |  |                 |  +--ro unnumbered-link-hop
          |  |                 |     +--ro link-tp-id    te-tp-id
          |  |                 |     +--ro node-id       te-node-id
          |  |                 |     +--ro hop-type?     te-hop-type
          |  |                 |     +--ro direction?
          |  |                 |             te-link-direction
          |  |                 +--:(as-number)
          |  |                 |  +--ro as-number-hop
          |  |                 |     +--ro as-number    inet:as-number
          |  |                 |     +--ro hop-type?    te-hop-type
          |  |                 +--:(label)
          |  |                    +--ro label-hop
          |  |                       +--ro te-label
          |  |                          +--ro (technology)?
          |  |                          |  +--:(generic)
          |  |                          |     +--ro generic?
          |  |                          |             rt-
   types:generalized-label
          |  |                          +--ro direction?
          |  |                                  te-label-direction
          |  +--ro domain-id?                     uint32
          |  +--ro is-abstract?                   empty
          |  +--ro name?                          string
          |  +--ro signaling-address*             inet:ip-address
          |  +--ro underlay-topology {te-topology-hierarchy}?
          |     +--ro network-ref?   -> /nw:networks/network/network-id
          +--ro statistics
          |  +--ro discontinuity-time?          yang:date-and-time
          |  +--ro node
          |  |  +--ro disables?             yang:counter32
          |  |  +--ro enables?              yang:counter32
          |  |  +--ro maintenance-sets?     yang:counter32
          |  |  +--ro maintenance-clears?   yang:counter32
          |  |  +--ro modifies?             yang:counter32
          |  +--ro connectivity-matrix-entry
          |     +--ro creates?    yang:counter32
          |     +--ro deletes?    yang:counter32
          |     +--ro disables?   yang:counter32
          |     +--ro enables?    yang:counter32
          |     +--ro modifies?   yang:counter32
          +--rw tunnel-termination-point* [tunnel-tp-id]
             +--rw tunnel-tp-id                           binary
             +--rw admin-status?
             |       te-types:te-admin-status
             +--rw name?                                  string
             +--rw switching-capability?                  identityref
             +--rw encoding?                              identityref
             +--rw inter-layer-lock-id*                   uint32
             +--rw protection-type?                       identityref
             +--rw client-layer-adaptation
             |  +--rw switching-capability*
             |          [switching-capability encoding]
             |     +--rw switching-capability    identityref
             |     +--rw encoding                identityref
             |     +--rw te-bandwidth
             |        +--rw (technology)?
             |           +--:(generic)
             |              +--rw generic?   te-bandwidth
             +--rw local-link-connectivities
             |  +--rw number-of-entries?         uint16
             |  +--rw label-restrictions
             |  |  +--rw label-restriction* [index]
             |  |     +--rw restriction?    enumeration
             |  |     +--rw index           uint32
             |  |     +--rw label-start
             |  |     |  +--rw te-label
             |  |     |     +--rw (technology)?
             |  |     |     |  +--:(generic)
             |  |     |     |     +--rw generic?
             |  |     |     |             rt-types:generalized-label
             |  |     |     +--rw direction?       te-label-direction
             |  |     +--rw label-end
             |  |     |  +--rw te-label
             |  |     |     +--rw (technology)?
             |  |     |     |  +--:(generic)
             |  |     |     |     +--rw generic?
             |  |     |     |             rt-types:generalized-label
             |  |     |     +--rw direction?       te-label-direction
             |  |     +--rw label-step
             |  |     |  +--rw (technology)?
             |  |     |     +--:(generic)
             |  |     |        +--rw generic?   int32
             |  |     +--rw range-bitmap?   yang:hex-string
             |  +--rw is-allowed?                boolean
             |  +--rw underlay {te-topology-hierarchy}?
             |  |  +--rw enabled?                     boolean
             |  |  +--rw primary-path
             |  |  |  +--rw network-ref?
             |  |  |  |       -> /nw:networks/network/network-id
             |  |  |  +--rw path-element* [path-element-id]
             |  |  |     +--rw path-element-id              uint32
             |  |  |     +--rw (type)?
             |  |  |        +--:(numbered-node-hop)
             |  |  |        |  +--rw numbered-node-hop
             |  |  |        |     +--rw node-id     te-node-id
             |  |  |        |     +--rw hop-type?   te-hop-type
             |  |  |        +--:(numbered-link-hop)
             |  |  |        |  +--rw numbered-link-hop
             |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |  |        |     +--rw hop-type?     te-hop-type
             |  |  |        |     +--rw direction?    te-link-direction
             |  |  |        +--:(unnumbered-link-hop)
             |  |  |        |  +--rw unnumbered-link-hop
             |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |  |        |     +--rw node-id       te-node-id
             |  |  |        |     +--rw hop-type?     te-hop-type
             |  |  |        |     +--rw direction?    te-link-direction
             |  |  |        +--:(as-number)
             |  |  |        |  +--rw as-number-hop
             |  |  |        |     +--rw as-number    inet:as-number
             |  |  |        |     +--rw hop-type?    te-hop-type
             |  |  |        +--:(label)
             |  |  |           +--rw label-hop
             |  |  |              +--rw te-label
             |  |  |                 +--rw (technology)?
             |  |  |                 |  +--:(generic)
             |  |  |                 |     +--rw generic?
             |  |  |                 |             rt-types:generalized-
   label
             |  |  |                 +--rw direction?
             |  |  |                         te-label-direction
             |  |  +--rw backup-path* [index]
             |  |  |  +--rw index           uint32
             |  |  |  +--rw network-ref?
             |  |  |  |       -> /nw:networks/network/network-id
             |  |  |  +--rw path-element* [path-element-id]
             |  |  |     +--rw path-element-id              uint32
             |  |  |     +--rw (type)?
             |  |  |        +--:(numbered-node-hop)
             |  |  |        |  +--rw numbered-node-hop
             |  |  |        |     +--rw node-id     te-node-id
             |  |  |        |     +--rw hop-type?   te-hop-type
             |  |  |        +--:(numbered-link-hop)
             |  |  |        |  +--rw numbered-link-hop
             |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |  |        |     +--rw hop-type?     te-hop-type
             |  |  |        |     +--rw direction?    te-link-direction
             |  |  |        +--:(unnumbered-link-hop)
             |  |  |        |  +--rw unnumbered-link-hop
             |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |  |        |     +--rw node-id       te-node-id
             |  |  |        |     +--rw hop-type?     te-hop-type
             |  |  |        |     +--rw direction?    te-link-direction
             |  |  |        +--:(as-number)
             |  |  |        |  +--rw as-number-hop
             |  |  |        |     +--rw as-number    inet:as-number
             |  |  |        |     +--rw hop-type?    te-hop-type
             |  |  |        +--:(label)
             |  |  |           +--rw label-hop
             |  |  |              +--rw te-label
             |  |  |                 +--rw (technology)?
             |  |  |                 |  +--:(generic)
             |  |  |                 |     +--rw generic?
             |  |  |                 |             rt-types:generalized-
   label
             |  |  |                 +--rw direction?
             |  |  |                         te-label-direction
             |  |  +--rw protection-type?             identityref
             |  |  +--rw tunnel-termination-points
             |  |  |  +--rw source?        binary
             |  |  |  +--rw destination?   binary
             |  |  +--rw tunnels
             |  |     +--rw sharing?   boolean
             |  |     +--rw tunnel* [tunnel-name]
             |  |        +--rw tunnel-name    string
             |  |        +--rw sharing?       boolean
             |  +--rw path-constraints
             |  |  +--rw te-bandwidth
             |  |  |  +--rw (technology)?
             |  |  |     +--:(generic)
             |  |  |        +--rw generic?   te-bandwidth
             |  |  +--rw link-protection?          identityref
             |  |  +--rw setup-priority?           uint8
             |  |  +--rw hold-priority?            uint8
             |  |  +--rw signaling-type?           identityref
             |  |  +--rw path-metric-bounds
             |  |  |  +--rw path-metric-bound* [metric-type]
             |  |  |     +--rw metric-type    identityref
             |  |  |     +--rw upper-bound?   uint64
             |  |  +--rw path-affinities-values
             |  |  |  +--rw path-affinities-value* [usage]
             |  |  |     +--rw usage    identityref
             |  |  |     +--rw value?   admin-groups
             |  |  +--rw path-affinity-names
             |  |  |  +--rw path-affinity-name* [usage]
             |  |  |     +--rw usage            identityref
             |  |  |     +--rw affinity-name* [name]
             |  |  |        +--rw name    string
             |  |  +--rw path-srlgs-lists
             |  |  |  +--rw path-srlgs-list* [usage]
             |  |  |     +--rw usage     identityref
             |  |  |     +--rw values*   srlg
             |  |  +--rw path-srlgs-names
             |  |  |  +--rw path-srlgs-name* [usage]
             |  |  |     +--rw usage    identityref
             |  |  |     +--rw names*   string
             |  |  +--rw disjointness?             te-path-disjointness
             |  +--rw optimizations
             |  |  +--rw (algorithm)?
             |  |     +--:(metric) {path-optimization-metric}?
             |  |     |  +--rw optimization-metric* [metric-type]
             |  |     |  |  +--rw metric-type
             |  |     |  |  |       identityref
             |  |     |  |  +--rw weight?
             |  |     |  |  |       uint8
             |  |     |  |  +--rw explicit-route-exclude-objects
             |  |     |  |  |  +--rw route-object-exclude-object*
             |  |     |  |  |          [index]
             |  |     |  |  |     +--rw index
             |  |     |  |  |     |       uint32
             |  |     |  |  |     +--rw (type)?
             |  |     |  |  |        +--:(numbered-node-hop)
             |  |     |  |  |        |  +--rw numbered-node-hop
             |  |     |  |  |        |     +--rw node-id     te-node-id
             |  |     |  |  |        |     +--rw hop-type?   te-hop-type
             |  |     |  |  |        +--:(numbered-link-hop)
             |  |     |  |  |        |  +--rw numbered-link-hop
             |  |     |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |     |  |  |        |     +--rw hop-type?
             |  |     |  |  |        |     |       te-hop-type
             |  |     |  |  |        |     +--rw direction?
             |  |     |  |  |        |             te-link-direction
             |  |     |  |  |        +--:(unnumbered-link-hop)
             |  |     |  |  |        |  +--rw unnumbered-link-hop
             |  |     |  |  |        |     +--rw link-tp-id    te-tp-id
             |  |     |  |  |        |     +--rw node-id
             |  |     |  |  |        |     |       te-node-id
             |  |     |  |  |        |     +--rw hop-type?
             |  |     |  |  |        |     |       te-hop-type
             |  |     |  |  |        |     +--rw direction?
             |  |     |  |  |        |             te-link-direction
             |  |     |  |  |        +--:(as-number)
             |  |     |  |  |        |  +--rw as-number-hop
             |  |     |  |  |        |     +--rw as-number
             |  |     |  |  |        |     |       inet:as-number
             |  |     |  |  |        |     +--rw hop-type?
             |  |     |  |  |        |             te-hop-type
             |  |     |  |  |        +--:(label)
             |  |     |  |  |        |  +--rw label-hop
             |  |     |  |  |        |     +--rw te-label
             |  |     |  |  |        |        +--rw (technology)?
             |  |     |  |  |        |        |  +--:(generic)
             |  |     |  |  |        |        |     +--rw generic?
             |  |     |  |  |        |        |             rt-
   types:generalized-label
             |  |     |  |  |        |        +--rw direction?
             |  |     |  |  |        |                te-label-direction
             |  |     |  |  |        +--:(srlg)
             |  |     |  |  |           +--rw srlg
             |  |     |  |  |              +--rw srlg?   uint32
             |  |     |  |  +--rw explicit-route-include-objects
             |  |     |  |     +--rw route-object-include-object*
             |  |     |  |             [index]
             |  |     |  |        +--rw index
             |  |     |  |        |       uint32
             |  |     |  |        +--rw (type)?
             |  |     |  |           +--:(numbered-node-hop)
             |  |     |  |           |  +--rw numbered-node-hop
             |  |     |  |           |     +--rw node-id     te-node-id
             |  |     |  |           |     +--rw hop-type?   te-hop-type
             |  |     |  |           +--:(numbered-link-hop)
             |  |     |  |           |  +--rw numbered-link-hop
             |  |     |  |           |     +--rw link-tp-id    te-tp-id
             |  |     |  |           |     +--rw hop-type?
             |  |     |  |           |     |       te-hop-type
             |  |     |  |           |     +--rw direction?
             |  |     |  |           |             te-link-direction
             |  |     |  |           +--:(unnumbered-link-hop)
             |  |     |  |           |  +--rw unnumbered-link-hop
             |  |     |  |           |     +--rw link-tp-id    te-tp-id
             |  |     |  |           |     +--rw node-id
             |  |     |  |           |     |       te-node-id
             |  |     |  |           |     +--rw hop-type?
             |  |     |  |           |     |       te-hop-type
             |  |     |  |           |     +--rw direction?
             |  |     |  |           |             te-link-direction
             |  |     |  |           +--:(as-number)
             |  |     |  |           |  +--rw as-number-hop
             |  |     |  |           |     +--rw as-number
             |  |     |  |           |     |       inet:as-number
             |  |     |  |           |     +--rw hop-type?
             |  |     |  |           |             te-hop-type
             |  |     |  |           +--:(label)
             |  |     |  |              +--rw label-hop
             |  |     |  |                 +--rw te-label
             |  |     |  |                    +--rw (technology)?
             |  |     |  |                    |  +--:(generic)
             |  |     |  |                    |     +--rw generic?
             |  |     |  |                    |             rt-
   types:generalized-label
             |  |     |  |                    +--rw direction?
             |  |     |  |                            te-label-direction
             |  |     |  +--rw tiebreakers
             |  |     |     +--rw tiebreaker* [tiebreaker-type]
             |  |     |        +--rw tiebreaker-type    identityref
             |  |     +--:(objective-function)
             |  |              {path-optimization-objective-function}?
             |  |        +--rw objective-function
             |  |           +--rw objective-function-type?   identityref
             |  +--ro path-properties
             |  |  +--ro path-metric* [metric-type]
             |  |  |  +--ro metric-type           identityref
             |  |  |  +--ro accumulative-value?   uint64
             |  |  +--ro path-affinities-values
             |  |  |  +--ro path-affinities-value* [usage]
             |  |  |     +--ro usage    identityref
             |  |  |     +--ro value?   admin-groups
             |  |  +--ro path-affinity-names
             |  |  |  +--ro path-affinity-name* [usage]
             |  |  |     +--ro usage            identityref
             |  |  |     +--ro affinity-name* [name]
             |  |  |        +--ro name    string
             |  |  +--ro path-srlgs-lists
             |  |  |  +--ro path-srlgs-list* [usage]
             |  |  |     +--ro usage     identityref
             |  |  |     +--ro values*   srlg
             |  |  +--ro path-srlgs-names
             |  |  |  +--ro path-srlgs-name* [usage]
             |  |  |     +--ro usage    identityref
             |  |  |     +--ro names*   string
             |  |  +--ro path-route-objects
             |  |     +--ro path-route-object* [index]
             |  |        +--ro index                        uint32
             |  |        +--ro (type)?
             |  |           +--:(numbered-node-hop)
             |  |           |  +--ro numbered-node-hop
             |  |           |     +--ro node-id     te-node-id
             |  |           |     +--ro hop-type?   te-hop-type
             |  |           +--:(numbered-link-hop)
             |  |           |  +--ro numbered-link-hop
             |  |           |     +--ro link-tp-id    te-tp-id
             |  |           |     +--ro hop-type?     te-hop-type
             |  |           |     +--ro direction?    te-link-direction
             |  |           +--:(unnumbered-link-hop)
             |  |           |  +--ro unnumbered-link-hop
             |  |           |     +--ro link-tp-id    te-tp-id
             |  |           |     +--ro node-id       te-node-id
             |  |           |     +--ro hop-type?     te-hop-type
             |  |           |     +--ro direction?    te-link-direction
             |  |           +--:(as-number)
             |  |           |  +--ro as-number-hop
             |  |           |     +--ro as-number    inet:as-number
             |  |           |     +--ro hop-type?    te-hop-type
             |  |           +--:(label)
             |  |              +--ro label-hop
             |  |                 +--ro te-label
             |  |                    +--ro (technology)?
             |  |                    |  +--:(generic)
             |  |                    |     +--ro generic?
             |  |                    |             rt-types:generalized-
   label
             |  |                    +--ro direction?
             |  |                            te-label-direction
             |  +--rw local-link-connectivity* [link-tp-ref]
             |     +--rw link-tp-ref
             |     |       -> ../../../../../nt:termination-point/tp-id
             |     +--rw label-restrictions
             |     |  +--rw label-restriction* [index]
             |     |     +--rw restriction?    enumeration
             |     |     +--rw index           uint32
             |     |     +--rw label-start
             |     |     |  +--rw te-label
             |     |     |     +--rw (technology)?
             |     |     |     |  +--:(generic)
             |     |     |     |     +--rw generic?
             |     |     |     |             rt-types:generalized-label
             |     |     |     +--rw direction?       te-label-direction
             |     |     +--rw label-end
             |     |     |  +--rw te-label
             |     |     |     +--rw (technology)?
             |     |     |     |  +--:(generic)
             |     |     |     |     +--rw generic?
             |     |     |     |             rt-types:generalized-label
             |     |     |     +--rw direction?       te-label-direction
             |     |     +--rw label-step
             |     |     |  +--rw (technology)?
             |     |     |     +--:(generic)
             |     |     |        +--rw generic?   int32
             |     |     +--rw range-bitmap?   yang:hex-string
             |     +--rw is-allowed?           boolean
             |     +--rw underlay {te-topology-hierarchy}?
             |     |  +--rw enabled?                     boolean
             |     |  +--rw primary-path
             |     |  |  +--rw network-ref?
             |     |  |  |       -> /nw:networks/network/network-id
             |     |  |  +--rw path-element* [path-element-id]
             |     |  |     +--rw path-element-id              uint32
             |     |  |     +--rw (type)?
             |     |  |        +--:(numbered-node-hop)
             |     |  |        |  +--rw numbered-node-hop
             |     |  |        |     +--rw node-id     te-node-id
             |     |  |        |     +--rw hop-type?   te-hop-type
             |     |  |        +--:(numbered-link-hop)
             |     |  |        |  +--rw numbered-link-hop
             |     |  |        |     +--rw link-tp-id    te-tp-id
             |     |  |        |     +--rw hop-type?     te-hop-type
             |     |  |        |     +--rw direction?
             |     |  |        |             te-link-direction
             |     |  |        +--:(unnumbered-link-hop)
             |     |  |        |  +--rw unnumbered-link-hop
             |     |  |        |     +--rw link-tp-id    te-tp-id
             |     |  |        |     +--rw node-id       te-node-id
             |     |  |        |     +--rw hop-type?     te-hop-type
             |     |  |        |     +--rw direction?
             |     |  |        |             te-link-direction
             |     |  |        +--:(as-number)
             |     |  |        |  +--rw as-number-hop
             |     |  |        |     +--rw as-number    inet:as-number
             |     |  |        |     +--rw hop-type?    te-hop-type
             |     |  |        +--:(label)
             |     |  |           +--rw label-hop
             |     |  |              +--rw te-label
             |     |  |                 +--rw (technology)?
             |     |  |                 |  +--:(generic)
             |     |  |                 |     +--rw generic?
             |     |  |                 |             rt-
   types:generalized-label
             |     |  |                 +--rw direction?
             |     |  |                         te-label-direction
             |     |  +--rw backup-path* [index]
             |     |  |  +--rw index           uint32
             |     |  |  +--rw network-ref?
             |     |  |  |       -> /nw:networks/network/network-id
             |     |  |  +--rw path-element* [path-element-id]
             |     |  |     +--rw path-element-id              uint32
             |     |  |     +--rw (type)?
             |     |  |        +--:(numbered-node-hop)
             |     |  |        |  +--rw numbered-node-hop
             |     |  |        |     +--rw node-id     te-node-id
             |     |  |        |     +--rw hop-type?   te-hop-type
             |     |  |        +--:(numbered-link-hop)
             |     |  |        |  +--rw numbered-link-hop
             |     |  |        |     +--rw link-tp-id    te-tp-id
             |     |  |        |     +--rw hop-type?     te-hop-type
             |     |  |        |     +--rw direction?
             |     |  |        |             te-link-direction
             |     |  |        +--:(unnumbered-link-hop)
             |     |  |        |  +--rw unnumbered-link-hop
             |     |  |        |     +--rw link-tp-id    te-tp-id
             |     |  |        |     +--rw node-id       te-node-id
             |     |  |        |     +--rw hop-type?     te-hop-type
             |     |  |        |     +--rw direction?
             |     |  |        |             te-link-direction
             |     |  |        +--:(as-number)
             |     |  |        |  +--rw as-number-hop
             |     |  |        |     +--rw as-number    inet:as-number
             |     |  |        |     +--rw hop-type?    te-hop-type
             |     |  |        +--:(label)
             |     |  |           +--rw label-hop
             |     |  |              +--rw te-label
             |     |  |                 +--rw (technology)?
             |     |  |                 |  +--:(generic)
             |     |  |                 |     +--rw generic?
             |     |  |                 |             rt-
   types:generalized-label
             |     |  |                 +--rw direction?
             |     |  |                         te-label-direction
             |     |  +--rw protection-type?             identityref
             |     |  +--rw tunnel-termination-points
             |     |  |  +--rw source?        binary
             |     |  |  +--rw destination?   binary
             |     |  +--rw tunnels
             |     |     +--rw sharing?   boolean
             |     |     +--rw tunnel* [tunnel-name]
             |     |        +--rw tunnel-name    string
             |     |        +--rw sharing?       boolean
             |     +--rw path-constraints
             |     |  +--rw te-bandwidth
             |     |  |  +--rw (technology)?
             |     |  |     +--:(generic)
             |     |  |        +--rw generic?   te-bandwidth
             |     |  +--rw link-protection?          identityref
             |     |  +--rw setup-priority?           uint8
             |     |  +--rw hold-priority?            uint8
             |     |  +--rw signaling-type?           identityref
             |     |  +--rw path-metric-bounds
             |     |  |  +--rw path-metric-bound* [metric-type]
             |     |  |     +--rw metric-type    identityref
             |     |  |     +--rw upper-bound?   uint64
             |     |  +--rw path-affinities-values
             |     |  |  +--rw path-affinities-value* [usage]
             |     |  |     +--rw usage    identityref
             |     |  |     +--rw value?   admin-groups
             |     |  +--rw path-affinity-names
             |     |  |  +--rw path-affinity-name* [usage]
             |     |  |     +--rw usage            identityref
             |     |  |     +--rw affinity-name* [name]
             |     |  |        +--rw name    string
             |     |  +--rw path-srlgs-lists
             |     |  |  +--rw path-srlgs-list* [usage]
             |     |  |     +--rw usage     identityref
             |     |  |     +--rw values*   srlg
             |     |  +--rw path-srlgs-names
             |     |  |  +--rw path-srlgs-name* [usage]
             |     |  |     +--rw usage    identityref
             |     |  |     +--rw names*   string
             |     |  +--rw disjointness?
             |     |          te-path-disjointness
             |     +--rw optimizations
             |     |  +--rw (algorithm)?
             |     |     +--:(metric) {path-optimization-metric}?
             |     |     |  +--rw optimization-metric* [metric-type]
             |     |     |  |  +--rw metric-type
             |     |     |  |  |       identityref
             |     |     |  |  +--rw weight?
             |     |     |  |  |       uint8
             |     |     |  |  +--rw explicit-route-exclude-objects
             |     |     |  |  |  +--rw route-object-exclude-object*
             |     |     |  |  |          [index]
             |     |     |  |  |     +--rw index
             |     |     |  |  |     |       uint32
             |     |     |  |  |     +--rw (type)?
             |     |     |  |  |        +--:(numbered-node-hop)
             |     |     |  |  |        |  +--rw numbered-node-hop
             |     |     |  |  |        |     +--rw node-id
             |     |     |  |  |        |     |       te-node-id
             |     |     |  |  |        |     +--rw hop-type?
             |     |     |  |  |        |             te-hop-type
             |     |     |  |  |        +--:(numbered-link-hop)
             |     |     |  |  |        |  +--rw numbered-link-hop
             |     |     |  |  |        |     +--rw link-tp-id
             |     |     |  |  |        |     |       te-tp-id
             |     |     |  |  |        |     +--rw hop-type?
             |     |     |  |  |        |     |       te-hop-type
             |     |     |  |  |        |     +--rw direction?
             |     |     |  |  |        |             te-link-direction
             |     |     |  |  |        +--:(unnumbered-link-hop)
             |     |     |  |  |        |  +--rw unnumbered-link-hop
             |     |     |  |  |        |     +--rw link-tp-id
             |     |     |  |  |        |     |       te-tp-id
             |     |     |  |  |        |     +--rw node-id
             |     |     |  |  |        |     |       te-node-id
             |     |     |  |  |        |     +--rw hop-type?
             |     |     |  |  |        |     |       te-hop-type
             |     |     |  |  |        |     +--rw direction?
             |     |     |  |  |        |             te-link-direction
             |     |     |  |  |        +--:(as-number)
             |     |     |  |  |        |  +--rw as-number-hop
             |     |     |  |  |        |     +--rw as-number
             |     |     |  |  |        |     |       inet:as-number
             |     |     |  |  |        |     +--rw hop-type?
             |     |     |  |  |        |             te-hop-type
             |     |     |  |  |        +--:(label)
             |     |     |  |  |        |  +--rw label-hop
             |     |     |  |  |        |     +--rw te-label
             |     |     |  |  |        |        +--rw (technology)?
             |     |     |  |  |        |        |  +--:(generic)
             |     |     |  |  |        |        |     +--rw generic?
             |     |     |  |  |        |        |             rt-
   types:generalized-label
             |     |     |  |  |        |        +--rw direction?
             |     |     |  |  |        |                te-label-
   direction
             |     |     |  |  |        +--:(srlg)
             |     |     |  |  |           +--rw srlg
             |     |     |  |  |              +--rw srlg?   uint32
             |     |     |  |  +--rw explicit-route-include-objects
             |     |     |  |     +--rw route-object-include-object*
             |     |     |  |             [index]
             |     |     |  |        +--rw index
             |     |     |  |        |       uint32
             |     |     |  |        +--rw (type)?
             |     |     |  |           +--:(numbered-node-hop)
             |     |     |  |           |  +--rw numbered-node-hop
             |     |     |  |           |     +--rw node-id
             |     |     |  |           |     |       te-node-id
             |     |     |  |           |     +--rw hop-type?
             |     |     |  |           |             te-hop-type
             |     |     |  |           +--:(numbered-link-hop)
             |     |     |  |           |  +--rw numbered-link-hop
             |     |     |  |           |     +--rw link-tp-id
             |     |     |  |           |     |       te-tp-id
             |     |     |  |           |     +--rw hop-type?
             |     |     |  |           |     |       te-hop-type
             |     |     |  |           |     +--rw direction?
             |     |     |  |           |             te-link-direction
             |     |     |  |           +--:(unnumbered-link-hop)
             |     |     |  |           |  +--rw unnumbered-link-hop
             |     |     |  |           |     +--rw link-tp-id
             |     |     |  |           |     |       te-tp-id
             |     |     |  |           |     +--rw node-id
             |     |     |  |           |     |       te-node-id
             |     |     |  |           |     +--rw hop-type?
             |     |     |  |           |     |       te-hop-type
             |     |     |  |           |     +--rw direction?
             |     |     |  |           |             te-link-direction
             |     |     |  |           +--:(as-number)
             |     |     |  |           |  +--rw as-number-hop
             |     |     |  |           |     +--rw as-number
             |     |     |  |           |     |       inet:as-number
             |     |     |  |           |     +--rw hop-type?
             |     |     |  |           |             te-hop-type
             |     |     |  |           +--:(label)
             |     |     |  |              +--rw label-hop
             |     |     |  |                 +--rw te-label
             |     |     |  |                    +--rw (technology)?
             |     |     |  |                    |  +--:(generic)
             |     |     |  |                    |     +--rw generic?
             |     |     |  |                    |             rt-
   types:generalized-label
             |     |     |  |                    +--rw direction?
             |     |     |  |                            te-label-
   direction
             |     |     |  +--rw tiebreakers
             |     |     |     +--rw tiebreaker* [tiebreaker-type]
             |     |     |        +--rw tiebreaker-type    identityref
             |     |     +--:(objective-function)
             |     |              {path-optimization-objective-
   function}?
             |     |        +--rw objective-function
             |     |           +--rw objective-function-type?
             |     |                   identityref
             |     +--ro path-properties
             |        +--ro path-metric* [metric-type]
             |        |  +--ro metric-type           identityref
             |        |  +--ro accumulative-value?   uint64
             |        +--ro path-affinities-values
             |        |  +--ro path-affinities-value* [usage]
             |        |     +--ro usage    identityref
             |        |     +--ro value?   admin-groups
             |        +--ro path-affinity-names
             |        |  +--ro path-affinity-name* [usage]
             |        |     +--ro usage            identityref
             |        |     +--ro affinity-name* [name]
             |        |        +--ro name    string
             |        +--ro path-srlgs-lists
             |        |  +--ro path-srlgs-list* [usage]
             |        |     +--ro usage     identityref
             |        |     +--ro values*   srlg
             |        +--ro path-srlgs-names
             |        |  +--ro path-srlgs-name* [usage]
             |        |     +--ro usage    identityref
             |        |     +--ro names*   string
             |        +--ro path-route-objects
             |           +--ro path-route-object* [index]
             |              +--ro index                        uint32
             |              +--ro (type)?
             |                 +--:(numbered-node-hop)
             |                 |  +--ro numbered-node-hop
             |                 |     +--ro node-id     te-node-id
             |                 |     +--ro hop-type?   te-hop-type
             |                 +--:(numbered-link-hop)
             |                 |  +--ro numbered-link-hop
             |                 |     +--ro link-tp-id    te-tp-id
             |                 |     +--ro hop-type?     te-hop-type
             |                 |     +--ro direction?
             |                 |             te-link-direction
             |                 +--:(unnumbered-link-hop)
             |                 |  +--ro unnumbered-link-hop
             |                 |     +--ro link-tp-id    te-tp-id
             |                 |     +--ro node-id       te-node-id
             |                 |     +--ro hop-type?     te-hop-type
             |                 |     +--ro direction?
             |                 |             te-link-direction
             |                 +--:(as-number)
             |                 |  +--ro as-number-hop
             |                 |     +--ro as-number    inet:as-number
             |                 |     +--ro hop-type?    te-hop-type
             |                 +--:(label)
             |                    +--ro label-hop
             |                       +--ro te-label
             |                          +--ro (technology)?
             |                          |  +--:(generic)
             |                          |     +--ro generic?
             |                          |             rt-
   types:generalized-label
             |                          +--ro direction?
             |                                  te-label-direction
             +--ro oper-status?
             |       te-types:te-oper-status
             +--ro geolocation
             |  +--ro altitude?    int64
             |  +--ro latitude?    geographic-coordinate-degree
             |  +--ro longitude?   geographic-coordinate-degree
             +--ro statistics
             |  +--ro discontinuity-time?         yang:date-and-time
             |  +--ro tunnel-termination-point
             |  |  +--ro disables?             yang:counter32
             |  |  +--ro enables?              yang:counter32
             |  |  +--ro maintenance-clears?   yang:counter32
             |  |  +--ro maintenance-sets?     yang:counter32
             |  |  +--ro modifies?             yang:counter32
             |  |  +--ro downs?                yang:counter32
             |  |  +--ro ups?                  yang:counter32
             |  |  +--ro in-service-clears?    yang:counter32
             |  |  +--ro in-service-sets?      yang:counter32
             |  +--ro local-link-connectivity
             |     +--ro creates?    yang:counter32
             |     +--ro deletes?    yang:counter32
             |     +--ro disables?   yang:counter32
             |     +--ro enables?    yang:counter32
             |     +--ro modifies?   yang:counter32
             +--rw supporting-tunnel-termination-point*
                     [node-ref tunnel-tp-ref]
                +--rw node-ref         inet:uri
                +--rw tunnel-tp-ref    binary
     augment /nw:networks/nw:network/nt:link:
       +--rw te!
          +--rw (bundle-stack-level)?
          |  +--:(bundle)
          |  |  +--rw bundled-links
          |  |     +--rw bundled-link* [sequence]
          |  |        +--rw sequence      uint32
          |  |        +--rw src-tp-ref?   leafref
          |  |        +--rw des-tp-ref?   leafref
          |  +--:(component)
          |     +--rw component-links
          |        +--rw component-link* [sequence]
          |           +--rw sequence             uint32
          |           +--rw src-interface-ref?   string
          |           +--rw des-interface-ref?   string
          +--rw te-link-template*
          |       -> ../../../../te/templates/link-template/name
          |       {template}?
          +--rw te-link-attributes
          |  +--rw access-type?
          |  |       te-types:te-link-access-type
          |  +--rw external-domain
          |  |  +--rw network-ref?
          |  |  |       -> /nw:networks/network/network-id
          |  |  +--rw remote-te-node-id?      te-types:te-node-id
          |  |  +--rw remote-te-link-tp-id?   te-types:te-tp-id
          |  +--rw is-abstract?                      empty
          |  +--rw name?                             string
          |  +--rw underlay {te-topology-hierarchy}?
          |  |  +--rw enabled?                     boolean
          |  |  +--rw primary-path
          |  |  |  +--rw network-ref?
          |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  +--rw path-element* [path-element-id]
          |  |  |     +--rw path-element-id              uint32
          |  |  |     +--rw (type)?
          |  |  |        +--:(numbered-node-hop)
          |  |  |        |  +--rw numbered-node-hop
          |  |  |        |     +--rw node-id     te-node-id
          |  |  |        |     +--rw hop-type?   te-hop-type
          |  |  |        +--:(numbered-link-hop)
          |  |  |        |  +--rw numbered-link-hop
          |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |        |     +--rw direction?    te-link-direction
          |  |  |        +--:(unnumbered-link-hop)
          |  |  |        |  +--rw unnumbered-link-hop
          |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |        |     +--rw node-id       te-node-id
          |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |        |     +--rw direction?    te-link-direction
          |  |  |        +--:(as-number)
          |  |  |        |  +--rw as-number-hop
          |  |  |        |     +--rw as-number    inet:as-number
          |  |  |        |     +--rw hop-type?    te-hop-type
          |  |  |        +--:(label)
          |  |  |           +--rw label-hop
          |  |  |              +--rw te-label
          |  |  |                 +--rw (technology)?
          |  |  |                 |  +--:(generic)
          |  |  |                 |     +--rw generic?
          |  |  |                 |             rt-types:generalized-
   label
          |  |  |                 +--rw direction?
          |  |  |                         te-label-direction
          |  |  +--rw backup-path* [index]
          |  |  |  +--rw index           uint32
          |  |  |  +--rw network-ref?
          |  |  |  |       -> /nw:networks/network/network-id
          |  |  |  +--rw path-element* [path-element-id]
          |  |  |     +--rw path-element-id              uint32
          |  |  |     +--rw (type)?
          |  |  |        +--:(numbered-node-hop)
          |  |  |        |  +--rw numbered-node-hop
          |  |  |        |     +--rw node-id     te-node-id
          |  |  |        |     +--rw hop-type?   te-hop-type
          |  |  |        +--:(numbered-link-hop)
          |  |  |        |  +--rw numbered-link-hop
          |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |        |     +--rw direction?    te-link-direction
          |  |  |        +--:(unnumbered-link-hop)
          |  |  |        |  +--rw unnumbered-link-hop
          |  |  |        |     +--rw link-tp-id    te-tp-id
          |  |  |        |     +--rw node-id       te-node-id
          |  |  |        |     +--rw hop-type?     te-hop-type
          |  |  |        |     +--rw direction?    te-link-direction
          |  |  |        +--:(as-number)
          |  |  |        |  +--rw as-number-hop
          |  |  |        |     +--rw as-number    inet:as-number
          |  |  |        |     +--rw hop-type?    te-hop-type
          |  |  |        +--:(label)
          |  |  |           +--rw label-hop
          |  |  |              +--rw te-label
          |  |  |                 +--rw (technology)?
          |  |  |                 |  +--:(generic)
          |  |  |                 |     +--rw generic?
          |  |  |                 |             rt-types:generalized-
   label
          |  |  |                 +--rw direction?
          |  |  |                         te-label-direction
          |  |  +--rw protection-type?             identityref
          |  |  +--rw tunnel-termination-points
          |  |  |  +--rw source?        binary
          |  |  |  +--rw destination?   binary
          |  |  +--rw tunnels
          |  |     +--rw sharing?   boolean
          |  |     +--rw tunnel* [tunnel-name]
          |  |        +--rw tunnel-name    string
          |  |        +--rw sharing?       boolean
          |  +--rw admin-status?
          |  |       te-types:te-admin-status
          |  +--rw link-index?                       uint64
          |  +--rw administrative-group?
          |  |       te-types:admin-groups
          |  +--rw interface-switching-capability*
          |  |       [switching-capability encoding]
          |  |  +--rw switching-capability    identityref
          |  |  +--rw encoding                identityref
          |  |  +--rw max-lsp-bandwidth* [priority]
          |  |     +--rw priority        uint8
          |  |     +--rw te-bandwidth
          |  |        +--rw (technology)?
          |  |           +--:(generic)
          |  |              +--rw generic?   te-bandwidth
          |  +--rw label-restrictions
          |  |  +--rw label-restriction* [index]
          |  |     +--rw restriction?    enumeration
          |  |     +--rw index           uint32
          |  |     +--rw label-start
          |  |     |  +--rw te-label
          |  |     |     +--rw (technology)?
          |  |     |     |  +--:(generic)
          |  |     |     |     +--rw generic?
          |  |     |     |             rt-types:generalized-label
          |  |     |     +--rw direction?       te-label-direction
          |  |     +--rw label-end
          |  |     |  +--rw te-label
          |  |     |     +--rw (technology)?
          |  |     |     |  +--:(generic)
          |  |     |     |     +--rw generic?
          |  |     |     |             rt-types:generalized-label
          |  |     |     +--rw direction?       te-label-direction
          |  |     +--rw label-step
          |  |     |  +--rw (technology)?
          |  |     |     +--:(generic)
          |  |     |        +--rw generic?   int32
          |  |     +--rw range-bitmap?   yang:hex-string
          |  +--rw link-protection-type?             identityref
          |  +--rw max-link-bandwidth
          |  |  +--rw te-bandwidth
          |  |     +--rw (technology)?
          |  |        +--:(generic)
          |  |           +--rw generic?   te-bandwidth
          |  +--rw max-resv-link-bandwidth
          |  |  +--rw te-bandwidth
          |  |     +--rw (technology)?
          |  |        +--:(generic)
          |  |           +--rw generic?   te-bandwidth
          |  +--rw unreserved-bandwidth* [priority]
          |  |  +--rw priority        uint8
          |  |  +--rw te-bandwidth
          |  |     +--rw (technology)?
          |  |        +--:(generic)
          |  |           +--rw generic?   te-bandwidth
          |  +--rw te-default-metric?                uint32
          |  +--rw te-delay-metric?                  uint32
          |  +--rw te-igp-metric?                    uint32
          |  +--rw te-srlgs
          |  |  +--rw value*   te-types:srlg
          |  +--rw te-nsrlgs {nsrlg}?
          |     +--rw id*   uint32
          +--ro oper-status?                   te-types:te-oper-status
          +--ro is-transitional?               empty
          +--ro information-source?            te-info-source
          +--ro information-source-instance?   string
          +--ro information-source-state
          |  +--ro credibility-preference?    uint16
          |  +--ro logical-network-element?   string
          |  +--ro network-instance?          string
          |  +--ro topology
          |     +--ro link-ref?      leafref
          |     +--ro network-ref?   -> /nw:networks/network/network-id
          +--ro information-source-entry*
          |       [information-source information-source-instance]
          |  +--ro information-source                te-info-source
          |  +--ro information-source-instance       string
          |  +--ro information-source-state
          |  |  +--ro credibility-preference?    uint16
          |  |  +--ro logical-network-element?   string
          |  |  +--ro network-instance?          string
          |  |  +--ro topology
          |  |     +--ro link-ref?      leafref
          |  |     +--ro network-ref?
          |  |             -> /nw:networks/network/network-id
          |  +--ro link-index?                       uint64
          |  +--ro administrative-group?
          |  |       te-types:admin-groups
          |  +--ro interface-switching-capability*
          |  |       [switching-capability encoding]
          |  |  +--ro switching-capability    identityref
          |  |  +--ro encoding                identityref
          |  |  +--ro max-lsp-bandwidth* [priority]
          |  |     +--ro priority        uint8
          |  |     +--ro te-bandwidth
          |  |        +--ro (technology)?
          |  |           +--:(generic)
          |  |              +--ro generic?   te-bandwidth
          |  +--ro label-restrictions
          |  |  +--ro label-restriction* [index]
          |  |     +--ro restriction?    enumeration
          |  |     +--ro index           uint32
          |  |     +--ro label-start
          |  |     |  +--ro te-label
          |  |     |     +--ro (technology)?
          |  |     |     |  +--:(generic)
          |  |     |     |     +--ro generic?
          |  |     |     |             rt-types:generalized-label
          |  |     |     +--ro direction?       te-label-direction
          |  |     +--ro label-end
          |  |     |  +--ro te-label
          |  |     |     +--ro (technology)?
          |  |     |     |  +--:(generic)
          |  |     |     |     +--ro generic?
          |  |     |     |             rt-types:generalized-label
          |  |     |     +--ro direction?       te-label-direction
          |  |     +--ro label-step
          |  |     |  +--ro (technology)?
          |  |     |     +--:(generic)
          |  |     |        +--ro generic?   int32
          |  |     +--ro range-bitmap?   yang:hex-string
          |  +--ro link-protection-type?             identityref
          |  +--ro max-link-bandwidth
          |  |  +--ro te-bandwidth
          |  |     +--ro (technology)?
          |  |        +--:(generic)
          |  |           +--ro generic?   te-bandwidth
          |  +--ro max-resv-link-bandwidth
          |  |  +--ro te-bandwidth
          |  |     +--ro (technology)?
          |  |        +--:(generic)
          |  |           +--ro generic?   te-bandwidth
          |  +--ro unreserved-bandwidth* [priority]
          |  |  +--ro priority        uint8
          |  |  +--ro te-bandwidth
          |  |     +--ro (technology)?
          |  |        +--:(generic)
          |  |           +--ro generic?   te-bandwidth
          |  +--ro te-default-metric?                uint32
          |  +--ro te-delay-metric?                  uint32
          |  +--ro te-igp-metric?                    uint32
          |  +--ro te-srlgs
          |  |  +--ro value*   te-types:srlg
          |  +--ro te-nsrlgs {nsrlg}?
          |     +--ro id*   uint32
          +--ro recovery
          |  +--ro restoration-status?   te-types:te-recovery-status
          |  +--ro protection-status?    te-types:te-recovery-status
          +--ro underlay {te-topology-hierarchy}?
          |  +--ro dynamic?     boolean
          |  +--ro committed?   boolean
          +--ro statistics
             +--ro discontinuity-time?                yang:date-and-time
             +--ro disables?                          yang:counter32
             +--ro enables?                           yang:counter32
             +--ro maintenance-clears?                yang:counter32
             +--ro maintenance-sets?                  yang:counter32
             +--ro modifies?                          yang:counter32
             +--ro downs?                             yang:counter32
             +--ro ups?                               yang:counter32
             +--ro fault-clears?                      yang:counter32
             +--ro fault-detects?                     yang:counter32
             +--ro protection-switches?               yang:counter32
             +--ro protection-reverts?                yang:counter32
             +--ro restoration-failures?              yang:counter32
             +--ro restoration-starts?                yang:counter32
             +--ro restoration-successes?             yang:counter32
             +--ro restoration-reversion-failures?    yang:counter32
             +--ro restoration-reversion-starts?      yang:counter32
             +--ro restoration-reversion-successes?   yang:counter32
     augment /nw:networks/nw:network/nw:node/nt:termination-point:
       +--rw te-tp-id?   te-types:te-tp-id
       +--rw te!
          +--rw admin-status?
          |       te-types:te-admin-status
          +--rw name?                             string
          +--rw interface-switching-capability*
          |       [switching-capability encoding]
          |  +--rw switching-capability    identityref
          |  +--rw encoding                identityref
          |  +--rw max-lsp-bandwidth* [priority]
          |     +--rw priority        uint8
          |     +--rw te-bandwidth
          |        +--rw (technology)?
          |           +--:(generic)
          |              +--rw generic?   te-bandwidth
          +--rw inter-domain-plug-id?             binary
          +--rw inter-layer-lock-id*              uint32
          +--ro oper-status?
          |       te-types:te-oper-status
          +--ro geolocation
             +--ro altitude?    int64
             +--ro latitude?    geographic-coordinate-degree
             +--ro longitude?   geographic-coordinate-degree

Appendix B.  Companion YANG Data Model for Non-NMDA-Compliant
             Implementations

   The YANG module "ietf-te-topology" defined in Section 7 is designed
   to be used in conjunction with implementations that support the
   Network Management Datastore Architecture (NMDA) defined in
   [RFC8342].  In order to allow implementations to use the model even
   in cases where NMDA is not supported, the following companion module,
   "ietf-te-topology-state", is defined as a state model that mirrors
   the module "ietf-te-topology".  However, all data nodes in this
   "ietf-te-topology-state" companion module are non-configurable; they
   are provided to represent the applied configuration or the derived
   operational states.

   This companion module is redundant and SHOULD NOT be supported by
   implementations that support NMDA; therefore, we define it below
   rather than in the main body of this document.

   As the structure of the module "ietf-te-topology-state" mirrors that
   of the module "ietf-te-topology", the YANG tree of the module
   "ietf-te-topology-state" is not depicted separately.

B.1.  TE Topology State YANG Module

   This module references [RFC6001], [RFC8345], and [RFC8776].

   <CODE BEGINS> file "ietf-te-topology-state@2020-08-06.yang"
   module ietf-te-topology-state {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-te-topology-state";
     prefix tet-s;

     import ietf-te-types {
       prefix te-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering";
     }
     import ietf-te-topology {
       prefix tet;
       reference
         "RFC 8795: YANG Data Model for Traffic Engineering (TE)
          Topologies";
     }
     import ietf-network-state {
       prefix nw-s;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }
     import ietf-network-topology-state {
       prefix nt-s;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }

     organization
       "IETF Traffic Engineering Architecture and Signaling (TEAS)
        Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/teas/>
        WG List:  <mailto:teas@ietf.org>

        Editor:   Xufeng Liu
                  <mailto:xufeng.liu.ietf@gmail.com>

        Editor:   Igor Bryskin
                  <mailto:i_bryskin@yahoo.com>

        Editor:   Vishnu Pavan Beeram
                  <mailto:vbeeram@juniper.net>

        Editor:   Tarek Saad
                  <mailto:tsaad@juniper.net>

        Editor:   Himanshu Shah
                  <mailto:hshah@ciena.com>

        Editor:   Oscar Gonzalez de Dios
                  <mailto:oscar.gonzalezdedios@telefonica.com>";
     description
       "This YANG module defines a TE topology state model.

        Copyright (c) 2020 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Simplified BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC 8795; see the
        RFC itself for full legal notices.";

     revision 2020-08-06 {
       description
         "Initial revision.";
       reference
         "RFC 8795: YANG Data Model for Traffic Engineering (TE)
          Topologies";
     }

     /*
      * Groupings
      */

     grouping te-node-connectivity-matrix-attributes {
       description
         "Termination point references of a connectivity matrix entry.";
       container from {
         description
           "Reference to a source Link Termination Point (LTP).";
         leaf tp-ref {
           type leafref {
             path "../../../../../../nt-s:termination-point/nt-s:tp-id";
           }
           description
             "Relative reference to a termination point.";
         }
         uses te-types:label-set-info;
       }
       container to {
         description
           "Reference to a destination LTP.";
         leaf tp-ref {
           type leafref {
             path "../../../../../../nt-s:termination-point/nt-s:tp-id";
           }
           description
             "Relative reference to a termination point.";
         }
         uses te-types:label-set-info;
       }
       uses tet:connectivity-matrix-entry-path-attributes;
     }
     // te-node-connectivity-matrix-attributes

     grouping te-node-tunnel-termination-point-llc-list {
       description
         "Local Link Connectivity List (LLCL) of a Tunnel Termination
          Point (TTP) on a TE node.";
       list local-link-connectivity {
         key "link-tp-ref";
         description
           "The termination capabilities between the TTP and the LTP.
            This capability information can be used to compute
            the tunnel path.
            The Interface Adjustment Capability Descriptors (IACDs)
            (defined in RFC 6001) on each LTP can be derived from
            this list.";
         reference
           "RFC 6001: Generalized MPLS (GMPLS) Protocol Extensions
            for Multi-Layer and Multi-Region Networks (MLN/MRN)";
         leaf link-tp-ref {
           type leafref {
             path "../../../../../nt-s:termination-point/nt-s:tp-id";
           }
           description
             "LTP.";
         }
         uses te-types:label-set-info;
         uses tet:connectivity-matrix-entry-path-attributes;
       }
       // local-link-connectivity
     }
     // te-node-tunnel-termination-point-llc-list

     /*
      * Data nodes
      */

     augment "/nw-s:networks/nw-s:network/nw-s:network-types" {
       description
         "Introduces a new network type for a TE topology.";
       container te-topology {
         presence "Indicates a TE topology";
         description
           "Its presence identifies the TE topology type.";
       }
     }

     augment "/nw-s:networks" {
       description
         "Augmentation parameters for TE topologies.";
       uses tet:te-topologies-augment;
     }

     augment "/nw-s:networks/nw-s:network" {
       when 'nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for a TE topology.";
       uses tet:te-topology-augment;
     }

     augment "/nw-s:networks/nw-s:network/nw-s:node" {
       when '../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the node level.";
       leaf te-node-id {
         type te-types:te-node-id;
         description
           "The identifier of a node in the TE topology.
            A node is specific to a topology to which it belongs.";
       }
       container te {
         must '../te-node-id' {
           description
             "'te-node-id' is mandatory.";
         }
         must 'count(../nw-s:supporting-node)<=1' {
           description
             "For a node in a TE topology, there cannot be more
              than one supporting node.  If multiple nodes are
              abstracted, the 'underlay-topology' field is used.";
         }
         presence "TE support";
         description
           "Indicates TE support.";
         uses tet:te-node-augment;
       }
     }

     augment "/nw-s:networks/nw-s:network/nt-s:link" {
       when '../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the link level.";
       container te {
         must 'count(../nt-s:supporting-link)<=1' {
           description
             "For a link in a TE topology, there cannot be more
              than one supporting link.  If one or more link paths are
              abstracted, the underlay is used.";
         }
         presence "TE support";
         description
           "Indicates TE support.";
         uses tet:te-link-augment;
       }
     }

     augment "/nw-s:networks/nw-s:network/nw-s:node/"
           + "nt-s:termination-point" {
       when '../../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Configuration parameters for TE at the termination point
          level.";
       uses tet:te-termination-point-augment;
     }

     augment "/nw-s:networks/nw-s:network/nt-s:link/te/"
           + "bundle-stack-level/bundle/bundled-links/bundled-link" {
       when '../../../../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for a TE bundled link.";
       leaf src-tp-ref {
         type leafref {
           path "../../../../../nw-s:node[nw-s:node-id = "
              + "current()/../../../../nt-s:source/"
              + "nt-s:source-node]/"
              + "nt-s:termination-point/nt-s:tp-id";
           require-instance true;
         }
         description
           "Reference to another TE termination point on the
            same source node.";
       }
       leaf des-tp-ref {
         type leafref {
           path "../../../../../nw-s:node[nw-s:node-id = "
              + "current()/../../../../nt-s:destination/"
              + "nt-s:dest-node]/"
              + "nt-s:termination-point/nt-s:tp-id";
           require-instance true;
         }
         description
           "Reference to another TE termination point on the
            same destination node.";
       }
     }

     augment "/nw-s:networks/nw-s:network/nw-s:node/te/"
           + "information-source-entry/connectivity-matrices/"
           + "connectivity-matrix" {
       when '../../../../../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for the TE node connectivity matrix.";
       uses te-node-connectivity-matrix-attributes;
     }

     augment "/nw-s:networks/nw-s:network/nw-s:node/te/"
           + "te-node-attributes/connectivity-matrices/"
           + "connectivity-matrix" {
       when '../../../../../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for the TE node connectivity matrix.";
       uses te-node-connectivity-matrix-attributes;
     }

     augment "/nw-s:networks/nw-s:network/nw-s:node/te/"
           + "tunnel-termination-point/local-link-connectivities" {
       when '../../../../nw-s:network-types/tet-s:te-topology' {
         description
           "Augmentation parameters apply only for networks with a
            TE topology type.";
       }
       description
         "Augmentation for TE node TTP LLCs (Local Link
          Connectivities).";
       uses te-node-tunnel-termination-point-llc-list;
     }
   }
   <CODE ENDS>

Appendix C.  Example: YANG Data Model for Technology-Specific
             Augmentations

   This appendix provides an example YANG module that defines a
   technology-specific TE topology model for the example-topology model
   described in Section 6.

   This module references [RFC8345].

   module example-topology {
     yang-version 1.1;
     namespace "https://example.com/example-topology";
     prefix ex-topo;

     import ietf-network {
       prefix nw;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }
     import ietf-network-topology {
       prefix nt;
       reference
         "RFC 8345: A YANG Data Model for Network Topologies";
     }
     import ietf-te-topology {
       prefix tet;
       reference
         "RFC 8795: YANG Data Model for Traffic Engineering (TE)
          Topologies";
     }

     organization
       "Example Organization";
     contact
       "Editor: Example Author";
     description
       "This module defines a topology data model for the example
        technology.";

     revision 2020-06-29 {
       description
         "Initial revision.";
       reference
         "Example reference";
     }

     /*
      * Data nodes
      */

     augment "/nw:networks/nw:network/nw:network-types/"
           + "tet:te-topology" {
       description
         "Augmentation for network types to define an example topology
          type.";
       container example-topology {
         presence "Introduces a new network type for an example
                   topology";
         description
           "Its presence identifies the example topology type.";
       }
     }

     augment "/nw:networks/nw:network/tet:te" {
       when '../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for the network topology.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-1 {
           type uint8;
           description
             "Attribute 1 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes" {
       when '../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for node attributes.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-2 {
           type uint8;
           description
             "Attribute 2 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices" {
       when '../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for node connectivity matrices.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-3 {
           type uint8;
           description
             "Attribute 3 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for the node connectivity matrix.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-3 {
           type uint8;
           description
             "Attribute 3 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point" {
       when '../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for a TTP.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-4 {
           type uint8;
           description
             "Attribute 4 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node/nt:termination-point/"
           + "tet:te" {
       when '../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for an LTP.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-5 {
           type uint8;
           description
             "Attribute 5 for the example technology.";
         }
       }
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes" {
       when '../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       description
         "Augmentation for link attributes.";
       container attributes {
         description
           "Attributes for the example technology.";
         leaf attribute-6 {
           type uint8;
           description
             "Attribute 6 for the example technology.";
         }
       }
     }

     /*
      * Augmentations for TE bandwidth.
      */

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:interface-switching-capability/tet:max-lsp-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:max-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:max-resv-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:unreserved-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:path-constraints/tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:path-constraints/tet:te-bandwidth/tet:technology" {
       when '../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:path-constraints/tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:path-constraints/tet:te-bandwidth/tet:technology" {
       when '../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:client-layer-adaptation/tet:switching-capability/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:path-constraints/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:path-constraints/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/"
           + "tet:interface-switching-capability/tet:max-lsp-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/"
           + "tet:max-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/"
           + "tet:max-resv-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/"
           + "tet:interface-switching-capability/tet:max-lsp-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/"
           + "tet:max-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/"
           + "tet:max-resv-link-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/"
           + "tet:unreserved-bandwidth/"
           + "tet:te-bandwidth/tet:technology" {
       when '../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     augment "/nw:networks/nw:network/nw:node/nt:termination-point/"
           + "tet:te/tet:interface-switching-capability/"
           + "tet:max-lsp-bandwidth/tet:te-bandwidth/tet:technology" {
       when '../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf bandwidth-1 {
             type uint32;
             description
               "Bandwidth 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for TE bandwidth.";
     }

     /*
      * Augmentations for the TE label.
      */

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:underlay/tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:underlay/tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/tet:te/tet:templates/"
           + "tet:link-template/tet:te-link-attributes/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under te-node-attributes/connectivity-matrices */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:underlay/tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:underlay/tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:path-properties/tet:path-route-objects/"
           + "tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under te-node-attributes/.../connectivity-matrix */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:from/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-start/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:from/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:to/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-start/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:to/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:underlay/tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:underlay/tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:te-node-attributes/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:path-properties/tet:path-route-objects/"
           + "tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under information-source-entry/connectivity-matrices */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:underlay/tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:underlay/tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:path-properties/tet:path-route-objects/"
           + "tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under information-source-entry/.../connectivity-matrix */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:from/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:from/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:to/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/tet:to/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-end/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:underlay/tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:underlay/tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:information-source-entry/tet:connectivity-matrices/"
           + "tet:connectivity-matrix/"
           + "tet:path-properties/tet:path-route-objects/"
           + "tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under tunnel-termination-point/local-link-connectivities */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-start/tet:te-label/"
           + "tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-end/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/tet:te-topology/'
          + 'ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:underlay/"
           + "tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:underlay/"
           + "tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/tet:path-properties/"
           + "tet:path-route-objects/tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under tunnel-termination-point/.../local-link-connectivity */

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-start/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-end/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:underlay/"
           + "tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:underlay/"
           + "tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nw:node/tet:te/"
           + "tet:tunnel-termination-point/"
           + "tet:local-link-connectivities/"
           + "tet:local-link-connectivity/tet:path-properties/"
           + "tet:path-route-objects/tet:path-route-object/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under te-link-attributes */

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/"
           + "tet:label-restrictions/tet:label-restriction/"
           + "tet:label-start/tet:te-label/tet:technology" {
       when '../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-end/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/tet:underlay/"
           + "tet:primary-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:te-link-attributes/tet:underlay/"
           + "tet:backup-path/tet:path-element/tet:type/"
           + "tet:label/tet:label-hop/tet:te-label/tet:technology" {
       when '../../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     /* Under TE link information-source-entry */

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-start/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }

     augment "/nw:networks/nw:network/nt:link/tet:te/"
           + "tet:information-source-entry/tet:label-restrictions/"
           + "tet:label-restriction/tet:label-end/"
           + "tet:te-label/tet:technology" {
       when '../../../../../../../nw:network-types/'
          + 'tet:te-topology/ex-topo:example-topology' {
         description
           "Augmentation parameters apply only for networks with an
            example topology type.";
       }
       case example {
         container example {
           description
             "Attributes for the example technology.";
           leaf label-1 {
             type uint32;
             description
               "Label 1 for the example technology.";
           }
         }
       }
       description
         "Augmentation for the TE label.";
     }
   }

Acknowledgments

   The authors would like to thank Lou Berger, Sue Hares, Mazen Khaddam,
   Cyril Margaria, and Zafar Ali for participating in design discussions
   and providing valuable insights.

Contributors

   Sergio Belotti
   Nokia

   Email: sergio.belotti@nokia.com


   Dieter Beller
   Nokia

   Email: Dieter.Beller@nokia.com


   Carlo Perocchio
   Ericsson

   Email: carlo.perocchio@ericsson.com


   Italo Busi
   Huawei Technologies

   Email: Italo.Busi@huawei.com


Authors' Addresses

   Xufeng Liu
   Volta Networks

   Email: xufeng.liu.ietf@gmail.com


   Igor Bryskin
   Futurewei Technologies, Inc.

   Email: i_bryskin@yahoo.com


   Vishnu Pavan Beeram
   Juniper Networks

   Email: vbeeram@juniper.net


   Tarek Saad
   Juniper Networks

   Email: tsaad@juniper.net


   Himanshu Shah
   Ciena

   Email: hshah@ciena.com


   Oscar Gonzalez de Dios
   Telefonica

   Email: oscar.gonzalezdedios@telefonica.com


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