Internet                                                        D. Yeung
Internet-Draft                                                     Y. Qu
Intended status: Informational                             Cisco Systems
Expires: March 5, April 21, 2016                                         J. Zhang
                                                        Juniper Networks
                                                           D. Bogdanovic

                                                           K. Sreenivasa
                                                           Cisco Systems
                                                       September 2,
                                                        October 19, 2015

                   Yang Data Model for OSPF Protocol
                        draft-ietf-ospf-yang-02
                        draft-ietf-ospf-yang-03

Abstract

   This document defines a YANG data model that can be used to configure
   and manage OSPF.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 5, April 21, 2016.

Copyright Notice

   Copyright (c) 2015 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Design of Data Model  . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  OSPFv2 and OSPFv3 . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Optional Features . . . . . . . . . . . . . . . . . . . .   5
     2.4.  Inheritance . . . . . . . . . . . . . . . . . . . . . . .   5
     2.5.  OSPF Router Configuration . . . . . . . . . . . . . . . .   5   6
     2.6.  OSPF Instance Configuration . . . . . . . . . . . . . . .   6
     2.7.  OSPF Area Configuration . . . . . . . . . . . . . . . . .   7
     2.8.  OSPF Interface Configuration  . . . . . . . . . . . . . .   9  10
     2.9.  OSPF notification . . . . . . . . . . . . . . . . . . . .  11
   3.  OSPF Segment Routing  . . . . . . . . . . . . . . . . . . . .  14
   4.  OSPF BFD Yang Module  . . . . . . . . . . . . . . . . . . . .  21
   5.  OSPF Yang Module  . .  20
   5. . . . . . . . . . . . . . . . . . . . .  22
   6.  OSPF Segment Routing Yang Module  . . . . . . . . . . . . . .  89
   7.  OSPF BFD Yang Module  . . . . . . . . . . . . . . . . . . . . 103
   8.  Security Considerations . . . . . . . . . . . . . . . . . . . 104
   6. 106
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 104
   7. 106
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . 105
     7.1. 106
     10.1.  Normative References . . . . . . . . . . . . . . . . . . 105
     7.2. 106
     10.2.  Informative References . . . . . . . . . . . . . . . . . 106 108
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 106 108

1.  Overview

   YANG [RFC6020] is a data definition language that was introduced used to define the
   contents of a conceptual data store that allows networked devices to
   be managed using NETCONF [RFC6241].  YANG is proving relevant beyond
   its initial confines, as bindings to other interfaces
   (e.g. (e.g., ReST)
   and encodings other than XML (e.g. (e.g., JSON) are being defined.
   Furthermore, YANG data models can be used as the basis of
   implementation for
   implementation of other interfaces, such as CLI and programmatic
   APIs.

   This document defines a YANG data model that can be used to configure
   and manage OSPF and it is an augmentation to the core routing data
   model.  A core routing data model is defined in
   [I-D.ietf-netmod-routing-cfg], and it proposes a provides the basis for the
   development of data models for routing protocols.  The interface data
   model is defined in [RFC7223] and is used for referencing interface interfaces
   from the routing protocol.  The key-chain data model used for OSPF
   authentication is defined in [I-D.acee-rtg-yang-key-chain] and is used for referencing key-chains
   provides both a reference to configured for authentication key-chains and for the an enumeration
   of cryptographic algorithms, also used for authentication.  This
   document defines a YANG data model that can be used to configure and
   manage OSPF and it is an augment to the core routing data model. algorithms.

   Both OSPFv2 [RFC2328] and OSPFv3 [RFC5340] are supported.  In
   additional
   addition to the core OSPF protocol, features described in different
   separate other OSPF
   RFCs are also supported.  They includes demand circuit [RFC1793],
   traffic engineering [RFC3630], multiple address family [RFC5838],
   graceful restart [RFC3623] [RFC5187], NSSA [RFC3101] [RFC3101], and sham link
   [RFC4577].  Those  These non-core features are made optional in the OSPF
   data model provided. model.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.  Design of Data Model

   Although the basis of OSPF configuration elements like routers, areas
   areas, and interfaces remains the same, the detailed configuration
   model varies among different router vendors.  Differences are observed in term terms
   of how the protocol engine is tied to routing domain, how multiple
   protocol engines could are be instantiated instantiated, and configuration inheritance, just to
   name a few.
   among others.

   The goal of this document is to define a data model which that provides a
   common user interface to the OSPFv2 and OSPFv3 protocol.  There is
   very little information that is designated as "mandatory", providing
   freedom to for vendors to adapt this data model to their respective
   product
   implementation. implementations.

2.1.  Overview

   The OSPF YANG module defined in this document has all the common
   building blocks for the OSPF protocol.

   The OSPF YANG module augments the routing/routing-instance/routing-
   protocols/routing-protocol path of defined in the ietf-routing module.

   module: ospf
   +--rw routing
    +--rw routing-instance [name]
     +--rw routing-protocols
      +--rw routing-protocol [name]
        +--rw ospf
              .
              .
           +--rw all-instances-inherit {instance-inheritance}?
           |   .
           |   .
           +--rw instance* [routing-instance af]
                 .
                 .
             +--rw areas
             |  +--rw area* [area-id]
             |     .
             |     .
             |     +--rw all-interfaces-inherit {interface-inheritance}?
             |     .
             |     .
             |     +--rw virtual-links
             |     |  +--rw virtual-link* [router-id]
             |     |     .
             |     |     .
             |     +--rw sham-links
             |     |  +--rw sham-link* [local-id remote-id]
             |     |     .
             |     |     .
             |     +--rw interfaces
             |     |  +--rw interface* [interface]
             |     |     .
             |     |     .
             |     .
             |     .
             +--rw topologies
                +--rw topology* [name]

   The ospf module is intended to match to the vendor specific OSPF
   configuration construct which that is identified by a local identifier
   'name'.  The field 'version' allows support for OSPFv2 and OSPFv3.

   The ospf container includes one or more OSPF protocol engines, each
   encapsulated
   enclosed in the a separate instance entity.  Each instance includes
   information for the routing domain it is running on based on the [routing-instance af]
   specification.  There is no default routing domain assumed by the
   data model.  For example, to enable OSPF on the a vendor's default IPv4
   routing domain of the vendor, this model requires domain, an explicit instance entity with the a specification like

   ["default"
   "ipv4-unicast"]. "ipv4-unicast"] is required.  The instance also contains
   OSPF router level configuration

   The instance/area and instance/area/interface container contain containers respectively
   define the OSPF configuration for the area OSPF areas and interface level respectively interfaces.

   The instance/topology container contain defines the OSPF configuration for
   topology
   OSPF topologies when the multi-topology feature is enabled supported.

2.2.  OSPFv2 and OSPFv3

   The defined data model defined herein supports both OSPFv2 and OSPFv3.

   The field 'version' is used to indicate the OSPF version and is a
   mandatory.  Based on the version set, configured version, the data model changes
   accordingly varies to
   accommodate the difference differences between OSPFv2 and OSPFv3.

2.3.  Optional Features

   Optional features are features beyond the basic of OSPF
   configurations configuration and it is up to a
   the responsibility of each vendor to decide the whether to support of a
   particular
   given feature on a particular device.

   This model has declared defines a number of features, such as NSR, max-LSA
   etc.. max-LSA, etc.
   It is expected that vendors will extend the feature list. support additional features through
   vendor specific augmentations.

2.4.  Inheritance

   This data model supports configuration inheritance at different
   levels, e.g.
   levels including instance-level, area-level area-level, and interface-level
   inheritance.

   The all-instances-inherit, all-areas-inherit all-areas-inherit, and all-interfaces-
   inherit containers are defined to provide a consistent way to
   configure inheritable commands. configuration parameters.  For example,
   parameters defined in the all-instances-inherit container apply to
   all OSPF instances, and instances.  However, a particular instance configuration can
   override this inheritance with its own configuration. inheritance.

   Inheritance is defined as an optional feature, and vendors are
   expected
   permitted to augment the above inheritance containers with their own
   implementations. vendor
   specific parameters.

2.5.  OSPF Router Configuration

   The container ospf container is the top level container in this data model.  It
   contains shared information among different the OSPF instances under configured
   within the container.

       module: ospf
          +--rw ospf
             +--rw all-instances-inherit {instance-inheritance}?
             |  +--rw area
             |  +--rw interface
             +--rw operation-mode?          identityref
             +--rw instance* [af]
                .
                .

2.6.  OSPF Instance Configuration

   The container instance container represents an OSPF protocol engine.  Each
   instance indicates the routing domain it is associated with based on
   [routing-instance af] engine and
   contains the router level configurations. configuration.  The routing domain for each
   instance is dictated through the specification of [routing-instance
   af].

   The all-areas-inherit container contains area configuration that
   could may
   be inherited to all by configured OSPF areas defined. areas.

   module: ospf

      +--rw ospf
           .
           .
         +--rw instance* [af]
            +--rw af                   identityref
            +--rw router-id?           yang:dotted-quad {router-id}?
            +--rw admin-distance
            |  +--rw (scope)?
            |     +--:(single-value)
            |     |  +--rw all?          uint8
            |     +--:(multi-values)
            |        +--rw (granularity)?
            |        |  +--:(detail)
            |        |  |  +--rw intra-area?   uint8
            |        |  |  +--rw inter-area?   uint8
            |        |  +--:(coarse)
            |        |     +--rw internal?     uint8
            |        +--rw external?     uint8
            +--rw nsr {nsr}?
            |  +--rw enable?   boolean
            +--rw graceful-restart {graceful-restart}?
            |  +--rw enable?                       boolean
            |  +--rw helper-enable?                boolean
            |  +--rw restart-interval?             uint16
            |  +--rw helper-strict-lsa-checking?   boolean
            +--rw enable?              boolean {admin-control}?
            +--rw auto-cost {auto-cost}?
            |  +--rw enable?                boolean
            |  +--rw reference-bandwidth?   uint32
            +--rw spf-control
            |  +--rw paths?   uint16 {max-ecmp}?
            +--rw database-control
            |  +--rw max-lsa?   uint32 {max-lsa}?
            +--rw stub-router {stub-router}?
            |  +--rw (trigger)?
            |     +--:(always)
            |        +--rw always!
            +--rw mpls
            |  +--rw te-rid {te-rid}?
            |  |  +--rw (source)?
            |  |     +--:(interface)
            |  |     |  +--rw interface?   if:interface-ref
            |  |     +--:(explicit)
            |  |        +--rw router-id?   inet:ipv4-address
            |  +--rw ldp
            |     +--rw igp-sync?     boolean {ldp-igp-sync}?
            |     +--rw autoconfig?   boolean {ldp-igp-autoconfig}?
            +--rw fast-reroute {fast-reroute}?
            |  +--rw lfa {lfa}?
            +--rw all-areas-inherit {area-inheritance}?
            |  +--rw area
            |  +--rw interface

2.7.  OSPF Area Configuration

   The container area container contains configurations of that OSPF area configuration and the list of
   interface containers represent representing all the OSPF interfaces active in the enclosing
   area.

   The all-interfaces-inherit contains interface configuration that
   could may
   be inherited to by all the OSPF interfaces defined in the area. area interfaces.

   module: ospf
   +--rw ospf
      .
      .
    +--rw instance* [routing-instance af]
       .

       .
     +--rw areas
     |  +--rw area* [area-id]
     |    +--rw area-id                   area-id-type
     |    +--rw area-type?                identityref
     |    +--rw summary?                  boolean
     |    +--rw default-cost?             uint32
     |    +--rw ranges
     |    |  +--rw range* [prefix]
     |    |     +--rw prefix       inet:ip-prefix
     |    |     +--rw advertise?   boolean
     |    |     +--rw cost?        uint24
     |    +--rw all-interfaces-inherit {interface-inheritance}?
     |    |  +--rw interface
     |    +--rw virtual-links
     |    |  +--rw virtual-link* [router-id]
     |    |     +--rw router-id            yang:dotted-quad
     |    |     +--rw cost?                uint16
     |    |     +--rw hello-interval?      uint16
     |    |     +--rw dead-interval?       uint16
     |    |     +--rw retransmit-interval? uint16
     |    |     +--rw transmit-delay?      uint16
     |    |     +--rw mtu-ignore?          boolean {mtu-ignore}?
     |    |     +--rw lls?                 boolean {lls}?
     |    |     +--rw prefix-suppression?  boolean {prefix-suppression}?
     |    |     +--rw bfd?                 boolean {bfd}?
     |    |     +--rw ttl-security {ttl-security}?
     |    |     |  +--rw enable?   boolean
     |    |     |  +--rw hops?     uint8
     |    |     +--rw enable?                boolean {admin-control}?
     |    |     +--rw authentication
     |    |        +--rw (auth-type-selection)?
     |    |           +--:(auth-ipsec) {ospfv3-authentication-ipsec}?
     |    |           |  +--rw sa?                 string
     |    |           +--:(auth-trailer-key-chain)
     |    |           |  +--rw key-chain?        key-chain:key-chain-ref
     |    |           +--:(auth-trailer-key)
     |    |              +--rw key?              string
     |    |              +--rw crypto-algorithm
     |    |               +--rw (algorithm)?
     |    |                  +--:(hmac-sha-1-12) {crypto-hmac-sha-1-12}?
     |    |                  |  +--rw hmac-sha1-12?   empty
     |    |                  +--:(md5)
     |    |                  |  +--rw md5?            empty
     |    |                  +--:(sha-1)
     |    |                  |  +--rw sha-1?          empty
     |    |                  +--:(hmac-sha-1)
     |    |                  |  +--rw hmac-sha-1?     empty
     |    |                  +--:(hmac-sha-256)
     |    |                  |  +--rw hmac-sha-256?   empty
     |    |                  +--:(hmac-sha-384)
     |    |                  |  +--rw hmac-sha-384?   empty
     |    |                  +--:(hmac-sha-512)
     |    |                     +--rw hmac-sha-512?   empty
     |    +--rw sham-link
     |    |  +--rw sham-link* [local-id remote-id]
     |    |     +--rw local-id             inet:ip-address
     |    |     +--rw remote-id            inet:ip-address
     |    |     +--rw cost?                uint16
     |    |     +--rw hello-interval?      uint16
     |    |     +--rw dead-interval?       uint16
     |    |     +--rw retransmit-interval? uint16
     |    |     +--rw transmit-delay?      uint16
     |    |     +--rw mtu-ignore?          boolean {mtu-ignore}?
     |    |     +--rw lls?                 boolean {lls}?
     |    |     +--rw prefix-suppression?  boolean {prefix-suppression}?
     |    |     +--rw bfd?                 boolean {bfd}?
     |    |     +--rw ttl-security {ttl-security}?
     |    |     |  +--rw enable?   boolean
     |    |     |  +--rw hops?     uint8
     |    |     +--rw enable?                boolean {admin-control}?
     |    |     +--rw authentication
     |    |        +--rw (auth-type-selection)?
     |    |           +--:(auth-ipsec) {ospfv3-authentication-ipsec}?
     |    |           |  +--rw sa?                 string
     |    |           +--:(auth-trailer-key-chain)
     |    |           |  +--rw key-chain?        key-chain:key-chain-ref
     |    |           +--:(auth-trailer-key)
     |    |              +--rw key?              string
     |    |              +--rw crypto-algorithm
     |    |               +--rw (algorithm)?
     |    |                  +--:(hmac-sha-1-12) {crypto-hmac-sha-1-12}?
     |    |                  |  +--rw hmac-sha1-12?   empty
     |    |                  +--:(md5)
     |    |                  |  +--rw md5?            empty
     |    |                  +--:(sha-1)
     |    |                  |  +--rw sha-1?          empty
     |    |                  +--:(hmac-sha-1)
     |    |                  |  +--rw hmac-sha-1?     empty
     |    |                  +--:(hmac-sha-256)
     |    |                  |  +--rw hmac-sha-256?   empty
     |    |                  +--:(hmac-sha-384)
     |    |                  |  +--rw hmac-sha-384?   empty
     |    |                  +--:(hmac-sha-512)
     |    |                     +--rw hmac-sha-512?   empty

2.8.  OSPF Interface Configuration

   The container interface container contains configurations of that interface. OSPF interface configuration.

   module: ospf
   +--rw ospf
       .
       .
    +--rw instance* [routing-instance af]
       .
       .
     +--rw areas
      |  +--rw area* [area-id]
            .
            .
      |     +--rw interfaces
      |      +--rw interface* [interface]
      |         +--rw interface              if:interface-ref
      |         +--rw network-type?          enumeration
      |         +--rw passive?               boolean
      |         +--rw demand-circuit?        boolean {demand-circuit}?
      |         +--rw multi-areas
      |         |  +--rw multi-area* [multi-area-id] {multi-area-adj}?
      |         |     +--rw multi-area-id    area-id-type
      |         |     +--rw cost?            uint16
      |         +--rw static-neighbors
      |         |  +--rw neighbor* [address]
      |         |     +--rw address          inet:ip-address
      |         |     +--rw cost?            uint16
      |         |     +--rw poll-interval?   uint16
      |         |     +--rw priority?        uint8
      |         +--rw node-flag?             boolean {node-flag}?
      |         +--rw fast-reroute {fast-reroute}?
      |         |  +--rw lfa {lfa}?
      |         |     +--rw candidate-disabled?   boolean
      |         |     +--rw enabled?              boolean
      |         |     +--rw remote-lfa {remote-lfa}?
      |         |        +--rw enabled?   boolean
      |         +--rw cost?                uint16
      |         +--rw hello-interval?      uint16
      |         +--rw dead-interval?       uint16
      |         +--rw retransmit-interval? uint16
      |         +--rw transmit-delay?      uint16
      |         +--rw mtu-ignore?          boolean {mtu-ignore}?
      |         +--rw lls?                 boolean {lls}?
      |         +--rw prefix-suppression?  boolean {prefix-suppression}?
      |         +--rw bfd?                 boolean {bfd}?
      |         +--rw ttl-security {ttl-security}?
      |         |  +--rw enable?   boolean
      |         |  +--rw hops?     uint8
      |         +--rw enable?                boolean {admin-control}?
      |         +--rw authentication
      |         |  +--rw (auth-type-selection)?
      |         |   +--:(auth-ipsec) {ospfv3-authentication-ipsec}?
      |         |   |  +--rw sa?                 string
      |         |   +--:(auth-trailer-key-chain)
      |         |   |  +--rw key-chain?        key-chain:key-chain-ref
      |         |   +--:(auth-trailer-key)
      |         |      +--rw key?              string
      |         |      +--rw crypto-algorithm
      |         |         +--rw (algorithm)?
      |         |            +--:(hmac-sha-1-12) {crypto-hmac-sha-1-12}?
      |         |            |  +--rw hmac-sha1-12?   empty
      |         |            +--:(md5)
      |         |            |  +--rw md5?            empty
      |         |            +--:(sha-1)
      |         |            |  +--rw sha-1?          empty
      |         |            +--:(hmac-sha-1)
      |         |            |  +--rw hmac-sha-1?     empty
      |         |            +--:(hmac-sha-256)
      |         |            |  +--rw hmac-sha-256?   empty
      |         |            +--:(hmac-sha-384)
      |         |            |  +--rw hmac-sha-384?   empty
      |         |            +--:(hmac-sha-512)
      |         |               +--rw hmac-sha-512?   empty
      |         +--rw topologies
      |            +--rw topology* [name]
      |               +--rw name    leafref
      |               +--rw cost?   uint32

2.9.  OSPF notification

   This YANG model defines a list of notifications to that inform client YANG
   clients of important events detected during the protocol operation.  The
   notifications
   defined notifications cover the common set of traps from the OSPFv2
   MIB [RFC4750] and OSPFv3 MIB [RFC5643].

   module: ospf
   notifications:
      +---n if-state-change
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro link-type?               identityref (if-link-type-selection)?
      |  |  +--:(interface)
      |  |  |  +--ro interface
      |  |  |     +--ro interface?   if:interface-ref
      |  |  +--:(virtual-link)
      |  |  |  +--ro virtual-link
      |  |  |     +--ro area-id?              uint32              area-id-type
      |  |  |     +--ro neighbor-router-id?   yang:dotted-quad
      |  |  +--:(sham-link)
      |  |     +--ro sham-link
      |  |        +--ro area-id?          uint32          area-id-type
      |  |        +--ro local-ip-addr?    inet:ip-address
      |  |        +--ro remote-ip-addr?   inet:ip-address
      |  +--ro state?                   if-state-type
      +---n if-config-error
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro link-type?               identityref (if-link-type-selection)?
      |  |  +--:(interface)
      |  |  |  +--ro interface
      |  |  |     +--ro interface?   if:interface-ref
      |  |  +--ro packet-source?   yang:dotted-quad  +--:(virtual-link)
      |  |  |  +--ro virtual-link
      |  |  |     +--ro area-id?              uint32              area-id-type
      |  |  |     +--ro neighbor-router-id?   yang:dotted-quad
      |  |  +--:(sham-link)
      |  |     +--ro sham-link
      |  |        +--ro area-id?          uint32          area-id-type
      |  |        +--ro local-ip-addr?    inet:ip-address
      |  |        +--ro remote-ip-addr?   inet:ip-address
      |  +--ro packet-source?           yang:dotted-quad
      |  +--ro packet-type?             packet-type
      |  +--ro error?                   enumeration
      +---n nbr-state-change
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro link-type?               identityref (if-link-type-selection)?
      |  |  +--:(interface)
      |  |  |  +--ro interface
      |  |  |     +--ro interface?   if:interface-ref
      |  |  +--ro neighbor-router-id?   yang:dotted-quad  +--:(virtual-link)
      |  |  +--ro neighbor-ip-addr?     yang:dotted-quad  |  +--ro virtual-link
      |  |  |     +--ro area-id?              uint32              area-id-type
      |  |  |     +--ro neighbor-router-id?   yang:dotted-quad
      |  |  +--:(sham-link)
      |  |     +--ro sham-link
      |  |        +--ro area-id?              uint32          area-id-type
      |  |        +--ro local-ip-addr?    inet:ip-address
      |  |        +--ro remote-ip-addr?   inet:ip-address
      |  +--ro neighbor-router-id?      yang:dotted-quad
      |  |  +--ro neighbor-ip-addr?        yang:dotted-quad
      |  +--ro state?                   nbr-state-type
      +---n nbr-restart-helper-status-change
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro link-type?               identityref (if-link-type-selection)?
      |  |  +--:(interface)
      |  |  |  +--ro interface
      |  |  |     +--ro interface?   if:interface-ref
      |  |  +--:(virtual-link)
      |  |  |  +--ro neighbor-router-id?   yang:dotted-quad virtual-link
      |  |  |     +--ro neighbor-ip-addr? area-id?              area-id-type
      |  |  |     +--ro neighbor-router-id?   yang:dotted-quad
      |  |  +--:(sham-link)
      |  |     +--ro virtual-link sham-link
      |  |        +--ro area-id?              uint32          area-id-type
      |  |        +--ro local-ip-addr?    inet:ip-address
      |  |        +--ro remote-ip-addr?   inet:ip-address
      |  +--ro neighbor-router-id?      yang:dotted-quad
      |  +--ro neighbor-ip-addr?        yang:dotted-quad
      |  +--ro status?                  restart-helper-status-type
      |  +--ro age?                     uint32
      |  +--ro exit-reason?             restart-exit-reason-type
      +---n rx-bad-packet
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro link-type?               identityref (if-link-type-selection)?
      |  |  +--:(interface)
      |  |  |  +--ro interface
      |  +--ro interface  |  |     +--ro interface?   if:interface-ref
      |  |  +--ro packet-source?   yang:dotted-quad  +--:(virtual-link)
      |  |  |  +--ro virtual-link
      |  |  |     +--ro area-id?              uint32              area-id-type
      |  |  |     +--ro neighbor-router-id?   yang:dotted-quad
      |  |  +--:(sham-link)
      |  |     +--ro sham-link
      |  |        +--ro area-id?          uint32          area-id-type
      |  |        +--ro local-ip-addr?    inet:ip-address
      |  |        +--ro remote-ip-addr?   inet:ip-address
      |  +--ro packet-source?           yang:dotted-quad
      |  +--ro packet-type?             packet-type
      +---n lsdb-approaching-overflow
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro ext-lsdb-limit?          uint32
      +---n lsdb-overflow
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro ext-lsdb-limit?          uint32
      +---n nssa-translator-status-change
      |  +--ro routing-instance?        rt:routing-instance-ref
      |  +--ro routing-protocol-type?   leafref   -> ...
      |  +--ro routing-protocol-name?   leafref   -> ...
      |  +--ro af?                      leafref                      -> ...
      |  +--ro area-id?                 uint32                 area-id-type
      |  +--ro status?                  nssa-translator-state-type
      +---n restart-status-change
         +--ro routing-instance?        rt:routing-instance-ref
         +--ro routing-protocol-type?   leafref   -> ...
         +--ro routing-protocol-name?   leafref   -> ...
         +--ro af?                      leafref                      -> ...
         +--ro status?                  restart-status-type
         +--ro restart-interval?        uint16
         +--ro exit-reason?             restart-exit-reason-type

3.  OSPF Segment Routing

   In addition to the OSPF base YANG model, this document also defines a
   model for the OSPF segment routing feature.

   The OSPF SR YANG module requires support for the base segment routing
   module
   [I-D.ietf-spring-sr-yang] to be supported, [I-D.ietf-spring-sr-yang], which defines the basic global segment
   routing configurations outside configuration independent of any specific routing
   protocol. protocol
   configuration.

   module: ietf-ospf-sr
   augment /rt:routing/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance: /rt:routing/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance:
      +--rw segment-routing
      |  +--rw enabled?    boolean
      |  +--rw bindings
      |     +--rw advertise
      |     |  +--rw policies*   string
      |     +--rw receive?     boolean
      +--rw protocol-srgb {sr:protocol-srgb}?
         +--rw srgb* [lower-bound upper-bound]
            +--rw lower-bound    uint32
            +--rw upper-bound    uint32
   augment /rt:routing/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:interfaces/ospf:interface: /rt:routing/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:interfaces/ospf:interface:
      +--rw segment-routing
         +--rw adjacency-sid
            +--rw advertise-adj-group-sid* [group-id]
            |  +--rw group-id    uint32
            +--rw advertise-protection?      enumeration
   augment /rt:routing/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:interfaces/ospf:interface/ospf:fast-reroute: /rt:routing/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas
           /ospf:area/ospf:interfaces/ospf:interface/ospf:fast-reroute:
      +--rw ti-lfa {ti-lfa}?
         +--rw enable?   boolean
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance:
      +--ro segment-routing
      |  +--ro enabled?    boolean
      |  +--ro bindings
      |     +--ro advertise
      |     |  +--ro policies*   string
      |     +--ro receive?     boolean
      +--ro protocol-srgb {sr:protocol-srgb}?
         +--ro srgb* [lower-bound upper-bound]
            +--ro lower-bound    uint32
            +--ro upper-bound    uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:interfaces/ospf:interface: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:interfaces/ospf:interface:
      +--ro segment-routing
         +--ro adjacency-sid
            +--ro advertise-adj-group-sid* [group-id]
            |  +--ro group-id    uint32
            +--ro advertise-protection?      enumeration
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:interfaces/ospf:interface/ospf:database/
            ospf:link-scope-lsa-type/ospf:link-scope-lsas/
            ospf:link-scope-lsa/ospf:version/ospf:ospfv2/ospf:ospfv2/
            ospf:body/ospf:opaque/ospf:extended-prefix-tlvs/
            ospf:extended-prefix-tlv: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas
           /ospf:area/ospf:interfaces/ospf:interface/ospf:database
           /ospf:link-scope-lsa-type/ospf:link-scope-lsas
           /ospf:link-scope-lsa/ospf:version/ospf:ospfv2
           /ospf:ospfv2/ospf:body/ospf:opaque
           /ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv:
      +--ro perfix-sid-sub-tlvs
      |  +--ro prefix-sid-sub-tlv*
      |     +--ro flags?       bits
      |     +--ro mt-id?       uint8
      |     +--ro algorithm?   uint8
      |     +--ro sid?         uint32
      +--ro sid-binding-sub-tlvs
         +--ro sid-binding-sub-tlv*
            +--ro flags?                           bits
            +--ro mt-id?                           uint8
            +--ro weight?                          uint8
            +--ro sid-sub-tlv
            |  +--ro sid?   uint32
            +--ro ero-metric-sub-tlv
            |  +--ro metric?   uint32
            +--ro ipv4-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro router-id?      yang:dotted-quad
            |  +--ro interface-id?   uint32
            +--ro ipv4-backup-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-backup-ero-sub-tlv
               +--ro flags?          bits
               +--ro router-id?      yang:dotted-quad
               +--ro interface-id?   uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:database/ospf:area-scope-lsa-type/
            ospf:area-scope-lsas/ospf:area-scope-lsa/ospf:version/
            ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque/
            ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:database
           /ospf:area-scope-lsa-type/ospf:area-scope-lsas
           /ospf:area-scope-lsa/ospf:version/ospf:ospfv2
           /ospf:ospfv2/ospf:body/ospf:opaque
           /ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv:
      +--ro perfix-sid-sub-tlvs
      |  +--ro prefix-sid-sub-tlv*
      |     +--ro flags?       bits
      |     +--ro mt-id?       uint8
      |     +--ro algorithm?   uint8
      |     +--ro sid?         uint32
      +--ro sid-binding-sub-tlvs
         +--ro sid-binding-sub-tlv*
            +--ro flags?                           bits
            +--ro mt-id?                           uint8
            +--ro weight?                          uint8
            +--ro sid-sub-tlv
            |  +--ro sid?   uint32
            +--ro ero-metric-sub-tlv
            |  +--ro metric?   uint32
            +--ro ipv4-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro router-id?      yang:dotted-quad
            |  +--ro interface-id?   uint32
            +--ro ipv4-backup-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-backup-ero-sub-tlv
               +--ro flags?          bits
               +--ro router-id?      yang:dotted-quad
               +--ro interface-id?   uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:database/
            ospf:as-scope-lsa-type/ospf:as-scope-lsas/ospf:as-scope-lsa/
            ospf:version/ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque/
            ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:database/ospf:as-scope-lsa-type/ospf:as-scope-lsas
           /ospf:as-scope-lsa/ospf:version/ospf:ospfv2
           /ospf:ospfv2/ospf:body/ospf:opaque
           /ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv:
      +--ro perfix-sid-sub-tlvs
      |  +--ro prefix-sid-sub-tlv*
      |     +--ro flags?       bits
      |     +--ro mt-id?       uint8
      |     +--ro algorithm?   uint8
      |     +--ro sid?         uint32
      +--ro sid-binding-sub-tlvs
         +--ro sid-binding-sub-tlv*
            +--ro flags?                           bits
            +--ro mt-id?                           uint8
            +--ro weight?                          uint8
            +--ro sid-sub-tlv
            |  +--ro sid?   uint32
            +--ro ero-metric-sub-tlv
            |  +--ro metric?   uint32
            +--ro ipv4-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro router-id?      yang:dotted-quad
            |  +--ro interface-id?   uint32
            +--ro ipv4-backup-ero-sub-tlv
            |  +--ro flags?          bits
            |  +--ro ipv4-address?   inet:ipv4-address
            +--ro unnumbered-backup-ero-sub-tlv
               +--ro flags?          bits
               +--ro router-id?      yang:dotted-quad
               +--ro interface-id?   uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:database/ospf:area-scope-lsa-type/
            ospf:area-scope-lsas/ospf:area-scope-lsa/ospf:version/
            ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque/
            ospf:extended-link-tlvs/ospf:extended-link-tlv: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:database
           /ospf:area-scope-lsa-type/ospf:area-scope-lsas
           /ospf:area-scope-lsa/ospf:version/ospf:ospfv2
           /ospf:ospfv2/ospf:body/ospf:opaque
           /ospf:extended-link-tlvs/ospf:extended-link-tlv:
      +--ro adj-sid-sub-tlvs
      |  +--ro adj-sid-sub-tlv*
      |     +--ro flags?    bits
      |     +--ro mt-id?    uint8
      |     +--ro weight?   uint8
      |     +--ro sid?      uint32
      +--ro lan-adj-sid-sub-tlvs
         +--ro lan-adj-sid-sub-tlv*
            +--ro flags?                bits
            +--ro mt-id?                uint8
            +--ro weight?               uint8
            +--ro neighbor-router-id?   yang:dotted-quad
            +--ro sid?                  uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/
            ospf:areas/ospf:area/ospf:interfaces/ospf:interface/
            ospf:database/ospf:link-scope-lsa-type/
            ospf:link-scope-lsas/ospf:link-scope-lsa/ospf:version/
            ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas
           /ospf:area/ospf:interfaces/ospf:interface
           /ospf:database/ospf:link-scope-lsa-type/ospf:link-scope-lsas
           /ospf:link-scope-lsa/ospf:version/ospf:ospfv2
           /ospf:ospfv2/ospf:body/ospf:opaque:
      +--ro extended-prefix-range-tlvs
      |  +--ro extended-prefix-range-tlv*
      |     +--ro range-size?             uint16
      |     +--ro flags?                  bits
      |     +--ro prefix?                 inet:ip-prefix
      |     +--ro perfix-sid-sub-tlvs
      |     |  +--ro prefix-sid-sub-tlv*
      |     |     +--ro flags?       bits
      |     |     +--ro mt-id?       uint8
      |     |     +--ro algorithm?   uint8
      |     |     +--ro sid?         uint32
      |     +--ro sid-binding-sub-tlvs
      |     |  +--ro sid-binding-sub-tlv*
      |     |     +--ro flags?                           bits
      |     |     +--ro mt-id?                           uint8
      |     |     +--ro weight?                          uint8
      |     |     +--ro sid-sub-tlv
      |     |     |  +--ro sid?   uint32
      |     |     +--ro ero-metric-sub-tlv
      |     |     |  +--ro metric?   uint32
      |     |     +--ro ipv4-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro router-id?      yang:dotted-quad
      |     |     |  +--ro interface-id?   uint32
      |     |     +--ro ipv4-backup-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-backup-ero-sub-tlv
      |     |        +--ro flags?          bits
      |     |        +--ro router-id?      yang:dotted-quad
      |     |        +--ro interface-id?   uint32
      |     +--ro unknown-tlvs
      |        +--ro unknown-tlv*
      |           +--ro type?     uint16
      |           +--ro length?   uint16
      |           +--ro value?    yang:hex-string
      +--ro sr-algorithm-tlv
      |  +--ro sr-algorithm*   uint8
      +--ro sid-range-tlvs
         +--ro sid-range-tlv*
            +--ro range-size?    ospf:uint24
            +--ro sid-sub-tlv
               +--ro sid?   uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas/
            ospf:area/ospf:database/ospf:area-scope-lsa-type/
            ospf:area-scope-lsas/ospf:area-scope-lsa/ospf:version/
            ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance/ospf:areas
           /ospf:area/ospf:database/ospf:area-scope-lsa-type
           /ospf:area-scope-lsas/ospf:area-scope-lsa
           /ospf:version/ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque:
      +--ro extended-prefix-range-tlvs
      |  +--ro extended-prefix-range-tlv*
      |     +--ro range-size?             uint16
      |     +--ro flags?                  bits
      |     +--ro prefix?                 inet:ip-prefix
      |     +--ro perfix-sid-sub-tlvs
      |     |  +--ro prefix-sid-sub-tlv*
      |     |     +--ro flags?       bits
      |     |     +--ro mt-id?       uint8
      |     |     +--ro algorithm?   uint8
      |     |     +--ro sid?         uint32
      |     +--ro sid-binding-sub-tlvs
      |     |  +--ro sid-binding-sub-tlv*
      |     |     +--ro flags?                           bits
      |     |     +--ro mt-id?                           uint8
      |     |     +--ro weight?                          uint8
      |     |     +--ro sid-sub-tlv
      |     |     |  +--ro sid?   uint32
      |     |     +--ro ero-metric-sub-tlv
      |     |     |  +--ro metric?   uint32
      |     |     +--ro ipv4-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro router-id?      yang:dotted-quad
      |     |     |  +--ro interface-id?   uint32
      |     |     +--ro ipv4-backup-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-backup-ero-sub-tlv
      |     |        +--ro flags?          bits
      |     |        +--ro router-id?      yang:dotted-quad
      |     |        +--ro interface-id?   uint32
      |     +--ro unknown-tlvs
      |        +--ro unknown-tlv*
      |           +--ro type?     uint16
      |           +--ro length?   uint16
      |           +--ro value?    yang:hex-string
      +--ro sr-algorithm-tlv
      |  +--ro sr-algorithm*   uint8
      +--ro sid-range-tlvs
         +--ro sid-range-tlv*
            +--ro range-size?    ospf:uint24
            +--ro sid-sub-tlv
               +--ro sid?   uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols/'
            rt:routing-protocol/ospf:ospf/ospf:instance/ospf:database/
            ospf:as-scope-lsa-type/ospf:as-scope-lsas/ospf:as-scope-lsa/
            ospf:version/ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque: /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance/ospf:database
           /ospf:as-scope-lsa-type/ospf:as-scope-lsas/ospf:as-scope-lsa
           /ospf:version/ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque:
      +--ro extended-prefix-range-tlvs
      |  +--ro extended-prefix-range-tlv*
      |     +--ro range-size?             uint16
      |     +--ro flags?                  bits
      |     +--ro prefix?                 inet:ip-prefix
      |     +--ro perfix-sid-sub-tlvs
      |     |  +--ro prefix-sid-sub-tlv*
      |     |     +--ro flags?       bits
      |     |     +--ro mt-id?       uint8
      |     |     +--ro algorithm?   uint8
      |     |     +--ro sid?         uint32
      |     +--ro sid-binding-sub-tlvs
      |     |  +--ro sid-binding-sub-tlv*
      |     |     +--ro flags?                           bits
      |     |     +--ro mt-id?                           uint8
      |     |     +--ro weight?                          uint8
      |     |     +--ro sid-sub-tlv
      |     |     |  +--ro sid?   uint32
      |     |     +--ro ero-metric-sub-tlv
      |     |     |  +--ro metric?   uint32
      |     |     +--ro ipv4-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro router-id?      yang:dotted-quad
      |     |     |  +--ro interface-id?   uint32
      |     |     +--ro ipv4-backup-ero-sub-tlv
      |     |     |  +--ro flags?          bits
      |     |     |  +--ro ipv4-address?   inet:ipv4-address
      |     |     +--ro unnumbered-backup-ero-sub-tlv
      |     |        +--ro flags?          bits
      |     |        +--ro router-id?      yang:dotted-quad
      |     |        +--ro interface-id?   uint32
      |     +--ro unknown-tlvs
      |        +--ro unknown-tlv*
      |           +--ro type?     uint16
      |           +--ro length?   uint16
      |           +--ro value?    yang:hex-string
      +--ro sr-algorithm-tlv
      |  +--ro sr-algorithm*   uint8
      +--ro sid-range-tlvs
         +--ro sid-range-tlv*
            +--ro range-size?    ospf:uint24
            +--ro sid-sub-tlv
               +--ro sid?   uint32

4.  OSPF BFD Yang Module

   Additionally this document defines a module that can be used to
   configure and monitor the OSPF BFD feature.

   Bidirectional Forwarding Detection (BFD) [RFC5880] is a network
   protocol that is used for liveness detection of arbitrary paths
   between systems.  A YANG data model is defined in [I-D.ietf-bfd-yang]
   that supports BFD configuration and management.

   As a client of BFD, the OSPF protocol uses the services provided by
   BFD.  The OSPF BFD YANG augments the base OSPF module and is defined
   as a separate module.  So any implementation that does not support
   BFD can still use the OSPF base model without having to import the
   BFD module [I-D.ietf-bfd-yang].

   module: ietf-ospf-bfd
   augment /rt:routing/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:interfaces/ospf:interface:
      +--rw bfd
         +--rw enabled?                    boolean
         +--rw local-multiplier?           multiplier
         +--rw (interval-config-type)?
            +--:(tx-rx-intervals)
            |  +--rw desired-min-tx-interval     uint32
            |  +--rw required-min-rx-interval    uint32
            +--:(single-interval)
               +--rw min-interval                uint32
   augment /rt:routing-state/rt:routing-instance/rt:routing-protocols
           /rt:routing-protocol/ospf:ospf/ospf:instance
           /ospf:areas/ospf:area/ospf:interfaces/ospf:interface:
      +--ro bfd
         +--ro enabled?                    boolean
         +--ro local-multiplier?           multiplier
         +--ro (interval-config-type)?
            +--:(tx-rx-intervals)
            |  +--ro desired-min-tx-interval     uint32
            |  +--ro required-min-rx-interval    uint32
            +--:(single-interval)
               +--ro min-interval                uint32

5.  OSPF Yang Module

   <CODE BEGINS> file "ietf-ospf@2015-09-02.yang" "ietf-ospf@2015-10-19.yang"
   module ietf-ospf {
     namespace "urn:ietf:params:xml:ns:yang:ietf-ospf";

     prefix ospf;

     import ietf-inet-types {
       prefix "inet";
     }

     import ietf-yang-types {
       prefix "yang";
     }

     import ietf-interfaces {
       prefix "if";
     }

     import ietf-routing {
       prefix "rt";

     }

     import ietf-key-chain {
       prefix "key-chain";
     }

     organization
       "Cisco Systems
        170 West Tasman Drive
        San Jose, CA 95134-1706
        USA";

     contact
        "WG Web:   <http://tools.ietf.org/wg/ospf/>
         WG List:  <mailto:ospf@ietf.org>

         WG Chair: Acee Lindem
                   <mailto:acee@cisco.com>

         WG Chair: Abhay Roy
                   <mailto:akr@cisco.com>

         Editor:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Yingzhen Qu
                   <mailto:yiqu@cisco.com>
         Author:   Jeffrey Zhang
                   <mailto:zzhang@juniper.net>
         Author:   Ing-Wher Chen
                   <mailto:ing-wher.chen@ericsson.com>
         Author:   Dean Bogdanovic
                   <mailto:ivandean@gmail.com>
         Author:   Kiran Agrahara Sreenivasa
                   <mailto:kkoushik@cisco.com>";

     description
       "This YANG module defines the generic configuration
        data and
        operational state for OSPF, which is the OSPF protocol common across to all of the
        vendor
        implementations of the protocol. implementations. It is intended that the module
        will be extended by vendors to define vendor-specific
        OSPF configuration parameters and policies,
        for example route maps or route policies.

        Terms and Acronyms

        OSPF (ospf): Open Shortest Path First
        IP (ip): Internet Protocol

        IPv4 (ipv4):Internet Protocol Version 4

        IPv6 (ipv6): Internet Protocol Version 6

        MTU (mtu) Maximum Transmission Unit
       ";

     revision 2015-09-02 2015-10-19 {
       description
         "* Author information update. Remove the abstract identity ospf.
          * Make area-id-type dotted-quad only.
          * Use area-id-type for all area-id leafs.
          * Restructure notifications.
          * Move BFD support to the new ietf-ospf-bfd module.
          * Update author information.
          * Editorial changes"; changes.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF"; OSPF.";
     }

     revision 2015-07-06 2015-09-02 {
       description
         "* Remove support for protocol-centric config. Author information update.
          * Editorial changes";
       reference
         "RFC XXXX: A YANG Data Model for OSPF.";
     }

     revision 2015-07-06 {
       description
         "* Remove support for protocol-centric config.
          * Enclose list in container, except for instance.
          * Replace protocol-shutdown with admin-control.
          * Add IPFRR IP-FRR per-interface config.
          * Reorganize max-path etc node.
          * Add node-flag.
          * Align config/operation hierarchy.
          * Use relative path for reference to rib.
          * Add ability to set single admin distance.
          * Make unreserved bandwidth into list.
          * Add F and T bit to OSPFv3 external LSA.
          * Remove key statement inside LSA body.
          * Add stub router support.
          * Fix usage of af-area-config.
          * Add statistics to operation data.
          * Add local rib.

          * Use dotted-quad for all router-id fields.
          * Support more than one multi-area per interface.
          * Use uint16 for LSA type.
          * Update grouping notification-instance-hdr.
          * Rework condition for opaque type and id in OSPFv2 LSA.
          * Rename local-remote-ipv4-addr with remote-if-ipv4-addr.
          * Add virtual-link/sham-link to operation state.
          * Allow multiple link TLVs in one LSA.
          * Fix bug in as-scope-lsas.
          * Remove OSPFv3 restriction in link-scope-lsas.
          * Editorial changes.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF"; OSPF.";
     }

     revision 2015-03-09 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF";
     }

     identity ospf {
       base "rt:routing-protocol";
       description "OSPF Protocol"; OSPF.";
     }

     identity ospfv2 {
       base "ospf"; "rt:routing-protocol";
       description "OSPFv2";
     }

     identity ospfv3 {
       base "ospf"; "rt:routing-protocol";
       description "OSPFv3";
     }

     identity operation-mode {
       description
         "OSPF operation mode.";
     }

     identity ships-in-the-night {
       base operation-mode;
       description
         "Ships-in-the-night operation mode in which
         each OSPF instance carries only one address family";
     }

     identity area-type {
       description "Base identity for OSPF area type.";
     }
     identity normal {
       base area-type;
       description "OSPF normal area.";
     }

     identity stub {
       base area-type;
       description "OSPF stub area.";
     }

     identity nssa {
       base area-type;
       description "OSPF NSSA area.";
     }

     typedef uint24 {
       type uint32 {
         range "0 .. 16777215";
       }
       description
         "24-bit unsigned integer.";
     }

     typedef area-id-type {
       type union {
         type uint32;
         type yang:dotted-quad;
       }
       description
         "Area ID type.";
     }

     typedef route-type {
       type enumeration {
         enum intra-area {
           description "OSPF intra-area route.";
         }
         enum inter-area {
           description "OSPF inter-area route.";
         }
         enum external-1 {
           description "OSPF external route type 1."; 1 external route.";
         }
         enum external-2 {
           description "OSPF External route type 2."; 2 external route.";
         }
         enum nssa-1 {
           description "OSPF NSSA external route type 1."; 1 NSSA route.";
         }
         enum nssa-2 {
           description "OSPF NSSA external route type 2."; 2 NSSA route.";

         }
       }
       description "OSPF route type.";
     }

     typedef if-state-type {
       type enumeration {
         enum Down {
           value "1";
           description
             "Interface down state.";
         }
         enum Loopback {
           value "2";
           description
             "Interface loopback state.";
         }
         enum Waiting {
           value "3";
           description
             "Interface waiting state.";
         }
         enum Point-to-Point {
           value "4";
           description
             "Interface point-to-point state.";
         }
         enum DR {
           value "5";
           description
             "Interface Designated Router (DR) state.";
         }
         enum BDR {
           value "6";
           description
             "Interface Backup Designated Router (BDR) state.";
         }
         enum DR-Other {
           value "7";
           description
             "Interface Other Designated Router state.";
         }
       }
       description
         "OSPF interface state type.";
     }

     typedef nbr-state-type {
       type enumeration {
         enum Down {
           value "1";
           description
             "Neighbor down state.";
         }
         enum Attempt {
           value "2";
           description
             "Neighbor attempt state.";
         }
         enum Init {
           value "3";
           description
             "Neighbor init state.";
         }
         enum 2-Way {
           value "4";
           description
             "Neighbor 2-Way state.";
         }
         enum ExStart {
           value "5";
           description
             "Neighbor exchange start state.";
         }
         enum Exchange {
           value "6";
           description
             "Neighbor exchange state.";
         }
         enum Loading {
           value "7";
           description
             "Neighbor loading state.";
         }
         enum Full {
           value "8";
           description
             "Neighbor full state.";
         }
       }
       description
         "OSPF neighbor state type.";
     }

     typedef restart-helper-status-type {
       type enumeration {
         enum Not-Helping {
           value "1";
           description
             "Restart helper status not helping.";
         }
         enum Helping {
           value "2";
           description
             "Restart helper status helping.";
         }
       }
       description
         "Restart helper status type.";
     }

     typedef restart-exit-reason-type {
       type enumeration {
         enum None {
           value "1";
           description
             "Not attempted.";
         }
         enum InProgress {
           value "2";
           description
             "Restart in progress.";
         }
         enum Completed {
           value "3";
           description
             "Successfully completed.";
         }
         enum TimedOut {
           value "4";
           description
             "Timed out.";
         }
         enum TopologyChanged {
           value "5";
           description
             "Aborted due to topology change.";
         }
       }
       description
         "Describes the outcome of the last attempt at a
         graceful restart, either by itself or acting
         as a helper.";
     }
     typedef packet-type {
       type enumeration {
         enum Hello {
           value "1";
           description
             "OSPF hello packet.";
         }
         enum Database-Descripton {
           value "2";
           description
             "OSPF database description packet.";
         }
         enum Link-State-Request {
           value "3";
           description
             "OSPF link state request packet.";
         }
         enum Link-State-Update {
           value "4";
           description
             "OSPF link state update packet.";
         }
         enum Link-State-Ack {
           value "5";
           description
             "OSPF link state acknowlegement packet.";
         }
       }
       description
         "OSPF packet type.";
     }

     typedef nssa-translator-state-type {
       type enumeration {
         enum Enabled {
           value "1";
           description
             "NSSA translator enabled state.";
         }
         enum Elected {
           description
             "NSSA translator elected state.";
         }
         enum Disabled {
           value "3";
           description
             "NSSA translator disabled state.";
         }

       }
       description
         "OSPF NSSA translator state type.";
     }

     typedef restart-status-type {
       type enumeration {
         enum Not-Restarting {
           value "1";
           description
             "Router is not restarting.";
         }
         enum Planned-Restart {
           description
             "Router is going through planned restart.";
         }
         enum Unplanned-Restart {
           value "3";
           description
             "Router is going through unplanned restart.";
         }
       }
       description
         "OSPF graceful restart status type.";
     }

     feature multi-topology {
       description
         "Support MTR."; Multiple-Topolgy Routing (MTR).";
     }

     feature multi-area-adj {
       description
         "OSPF multi-area adjacency support as in RFC 5185.";
     }
     feature router-id {
       description
         "Set router ID Router-ID per instance.";
     }

     feature demand-circuit {
       description
         "OSPF demand circuit support as in RFC 1793.";
     }

     feature mtu-ignore {
       description
         "Disable OSPF Database Description packet MTU
          mismatch detection on receiving
          DBD packets."; checking.";
     }

     feature lls {
       description
         "OSPF link-local signaling (LLS) as in RFC 5613.";
     }

     feature prefix-suppression {
       description
         "OSPF prefix suppression support as in RFC 6860.";
     }

     feature bfd {
       description
         "OSPF BFD support.";
     }

     feature ttl-security {
       description
         "OSPF ttl TTL security check.";
     }

     feature nsr {
       description
         "Non-Stop-Routing (NSR).";
     }

     feature graceful-restart {
       description
         "Graceful OSPF Restart as defined in RFC3623 RFC 3623 and RFC5187.";
          RFC 5187.";
     }

     feature admin-control {
       description
         "Administrative control of the protocol state.";
     }

     feature auto-cost {
       description
         "Calculate OSPF interface cost according to
          reference bandwidth.";
     }

     feature max-ecmp {
       description
         "Setting maximum number of ECMP paths.";
     }

     feature max-lsa {
       description
         "Setting maximum number of LSAs the OSPF instance
          will receive."; accept.";
     }

     feature te-rid {
       description
         "TE router-id."; Router-ID.";
     }

     feature ldp-igp-sync {
       description
         "LDP IGP synchronization.";
     }

     feature ldp-igp-autoconfig {
       description
         "LDP IGP auto-config.";
     }

     feature ospfv3-authentication-ipsec {
       description
         "Use IPsec for OSPFv3 authentication.";
     }

     feature fast-reroute {
      description
        "Support of IPFRR."; IP Fast Reroute (IP-FRR).";
     }

     feature node-flag {
      description
        "Support of node flag.";
     }
     feature lfa {
      description
        "Support of Loop Free Alternates."; Alternates (LFAs).";
     }

     feature remote-lfa {
      description
        "Support of remote Remote Loop Free Alternates."; Alternates (R-LFA).";
     }

     feature stub-router {
       description
         "Support of RFC6987 RFC 6987 OSPF Stub Router Advertisement"; Advertisement.";
     }

     feature instance-inheritance {
       description
         "Support instance inheritance";
     }

     feature area-inheritance {
       description
         "Support area inheritance";
     }

     feature interface-inheritance {
       description
         "Support interface inheritance";
     }

     grouping instance-stat {
       description "Per-instance statistics";
       leaf originate-new-lsa-count {
         type yang:counter32;
         description "The number of new LSAs originated.";
       }
       leaf rx-new-lsas-count {
         type yang:counter32;
         description "The number of LSAs received.";
       }
       leaf as-scope-lsa-count {
         type yang:gauge32;
         description "The number of as-scope AS Scope LSAs.";
       }
       leaf as-scope-lsa-chksum-sum {
         type uint32;
         description
           "The sum of the LS checksums."; LSA checksums for AS Scope LSAs.";
       }
       container database {
         description "Container for per AS scope AS-scope LSA statistics.";
         list as-scope-lsa-type {
           description "List of AS scope AS-scope LSA statistics";
           leaf lsa-type {
             type uint16;
             description "AS scope "AS-scope LSA type.";
           }
           leaf lsa-count {
             type yang:gauge32;
             description "The number of LSAs of the given LSA type.";
           }
           leaf lsa-cksum-sum {
             type int32;
             description
               "The sum of the LS LSA checksums of the given LSA type.";
           }
         }
       }
     }

     grouping area-stat {
       description "Per-area statistics.";
       leaf spf-runs-count {
         type yang:counter32;
         description
           "The number of times that the intra-area spf runs."; SPF has run.";
       }
       leaf abr-count {
         type yang:gauge32;
         description
           "The total number of area border routers Area Border Routers (ABRs)
            reachable within this area.";
       }
       leaf asbr-count {
         type yang:gauge32;
         description
           "The total number of AS border routers."; Border Routers (ASBRs).";
       }
       leaf ar-nssa-translator-event-count {
         type yang:counter32;
         description
           "The number of translator state NSSA translator-state changes.";
       }
       leaf area-scope-lsa-count {
         type yang:gauge32;
         description
           "The number of area scope LSAs in this area, excluding
            as-external LSAs."; the area.";
       }
       leaf area-scope-lsa-cksum-sum {
         type int32;
         description "The sum of the area scope LSAs checksums.";
       }
       container database {
         description "Container for area scope LSA type statistics.";
         list area-scope-lsa-type {
           description "List of area scope LSA statistics";
           leaf lsa-type {
             type uint16;
             description "Area scope LSA type.";
           }
           leaf lsa-count {
             type yang:gauge32;
             description "The number of LSAs of the given LSA type.";
           }
           leaf lsa-cksum-sum {
             type int32;
             description
               "The sum of the LS LSA checksums of the given LSA type.";
           }
         }
       }
     }

     grouping interface-stat {
       description "Per-interface statistics";
       leaf if-event-count {
         type yang:counter32;
         description
           "The number of times this interface has changed its
            state or an error has occurred.";
       }
       leaf link-scope-lsa-count {
         type yang:gauge32;
         description "The number of link scope LSAs.";
       }
       leaf link-scope-lsa-cksum-sum {
         type uint32;
         description "The sum of LSAs LS link scope LSA checksums.";
       }
       container database {
         description "Container for link scope LSA type statistics.";
         list link-scope-lsa-type {
           description "List of link scope LSA statistics";
           leaf lsa-type {
             type uint16;
             description "Link scope LSA type.";
           }
           leaf lsa-count {
             type yang:gauge32;
             description "The number of LSAs of the given LSA type.";
           }
           leaf lsa-cksum-sum {
             type int32;
             description
               "The sum of the LS LSA checksums of the given LSA type.";
           }
         }
       }
     }
     grouping neighbor-stat {
       description "Per-instance statistics"; "Per-neighbor statistics.";
       leaf nbr-event-count {
         type yang:counter32;
         description
           "The number of times this neighbor has changed
            state or an error has occurred.";
       }
       leaf nbr-retrans-qlen {
         type yang:gauge32;
         description
           "The current length of the retransmission queue.";
       }
     }

     grouping instance-fast-reroute-config {
       description
         "This group defines global configuration of IPFRR."; IP-FRR.";
       container fast-reroute {
         if-feature fast-reroute;
         description
           "This container may be augmented with global
            parameters for IPFRR."; IP-FRR.";
         container lfa {
           if-feature lfa;
           description
             "This container may be augmented with
              global parameters for LFA.
              Creating the container Container creation
              has no effect on LFA activation.";
         }
       }
     }

     grouping interface-fast-reroute-config {
       description
         "This group defines interface configuration of IPFRR."; IP-FRR.";
       container fast-reroute {
         if-feature fast-reroute;
         container lfa {
           if-feature lfa;
           leaf candidate-disabled {
             type boolean;
             description
               "Prevent the interface to be used as backup.";
           }
           leaf enabled {
             type boolean;
             description
               "Activates LFA.
                This model assumes activation of per-prefix LFA."; LFA - Per-prefix LFA computation
                is assumed.";
           }
           container remote-lfa {
             if-feature remote-lfa;
             leaf enabled {
               type boolean;
               description
               "Activates remote LFA."; Remote LFA (R-LFA).";
             }
             description
               "Remote LFA configuration.";
           }
           description
             "LFA configuration.";
         }
         description
           "Fast-reroute
           "IP Fast-reroute configuration.";
       }
     }

     grouping interface-common-config {
       description
         "Common configuration for all types of interfaces,
          including virtual link links and sham link"; links.";

       leaf cost {
         type uint16 {
           range "1..65535";
         }
         description
           "Interface cost.";
       }
       leaf hello-interval {
         type uint16 {
           range "1..65535";
         }
         units seconds;
         description
           "Time
           "Interval between hello packets."; packets in seconds.";
       }

       leaf dead-interval {
         type uint16 {
           range "1..65535";
         }
         units seconds;
         must "../dead-interval > ../hello-interval" {
           error-message "The dead interval must be "
                       + "larger than the hello interval";
           description
             "The value MUST be greater than 'hello-internval'.";
         }
         description
           "Interval after which a neighbor is
            declared dead."; down in seconds.";
       }

       leaf retransmit-interval {
         type uint16 {
           range "1..65535";
         }
         units seconds;
         description
           "Time
           "Interval between retransmitting unacknowledged Link
            State Advertisements (LSAs)."; (LSAs) in seconds.";
       }

       leaf transmit-delay {
         type uint16 {
           range "1..65535";
         }
         units seconds;
         description
           "Estimated time needed to send link-state update."; transmit Link State Update
            packets on the interface in seconds.";
       }

       leaf mtu-ignore {
         if-feature mtu-ignore;
         type boolean;
         description
           "Enable/Disable ignoring of bypassing the MTU mismatch check in DBD
            Database Description packets.";
       }

       leaf lls {
         if-feature lls;
         type boolean;
         description
           "Enable/Disable link-local signaling (LLS) support.";
       }

       leaf prefix-suppression {
         if-feature prefix-suppression;
         type boolean;
         description
           "Suppress advertisement of the prefixes.";
       }

       leaf bfd {
         if-feature bfd;
         type boolean;
         description
           "Enable/disable bfd."; prefixes associated
            with the interface.";
       }

       container ttl-security {
         if-feature ttl-security;
         description "TTL security check.";
         leaf enable {
           type boolean;
           description
             "Enable/Disable TTL security check.";
         }
         leaf hops {
           type uint8 {
             range "1..254";
           }
           description
             "Maximum number of hops that a an OSPF packet may
              have traveled."; traversed before reception.";
         }
       }
       leaf enable {
         if-feature admin-control;
         type boolean;
         default true;
         description
           "Enable/disable protocol on the interface.";
       }

       container authentication {
         description "Authentication configuration.";
         choice auth-type-selection {
           description
             "Options for expressing authentication setting.";
           case auth-ipsec {
             when "../../../../../../../rt:type = 'ospfv3'" 'ospf:ospfv3'" {
               description "Applied to OSPFv3 only.";
             }
             if-feature ospfv3-authentication-ipsec;
             leaf sa {
                 type string;
                 description
                   "SA
                   "Security Association name.";
             }
           }
           case auth-trailer-key-chain {
             leaf key-chain {
               type key-chain:key-chain-ref;
                description
                 "key-chain name.";
               }
             }
           case auth-trailer-key {
             leaf key {
               type string;
               description
                 "Key string in ASCII format.";
             }
             container crypto-algorithm {
               uses key-chain:crypto-algorithm-types;
               description
                 "Cryptographic algorithm associated with key.";
             }
           }
         }
       }
     } // interface-common-config

     grouping interface-config {
       description "Configuration for real interfaces.";

       leaf network-type {
         type enumeration {
           enum "broadcast" {
             description
               "Specify OSPF broadcast multi-access network.";
           }
           enum "non-broadcast" {
             description
               "Specify OSPF Non-Broadcast Multi-Access
                (NBMA) network.";
           }
           enum "point-to-multipoint" {
             description
               "Specify OSPF point-to-multipoint network.";
           }
           enum "point-to-point" {
             description
               "Specify OSPF point-to-point network.";
           }
         }
         description
           "Network type.";
       }
       leaf passive {
         type boolean;
         description
           "Enable/Disable passive."; passive interface - a passive interface's
            prefix will be advertised but no neighbor adjacencies
            will be formed on the interface.";
       }

       leaf demand-circuit {
         if-feature demand-circuit;
         type boolean;
         description
           "Enable/Disable demand circuit.";
       }

       container multi-areas {
         description "Container for multi-area config.";
         list multi-area {
           if-feature multi-area-adj;
           key multi-area-id;
           description
             "Configure ospf multi-area."; OSPF multi-area adjacency.";
           leaf multi-area-id {
             type area-id-type;
             description
               "Multi-area ID"; adjacency area ID.";
           }
           leaf cost {
             type uint16;
             description
               "Interface cost for multi-area."; multi-area adjacency.";
           }
         }
       }

       container static-neighbors {
         description "Static "Statically configured neighbors.";

         list neighbor {
           key "address";
           description
             "Specify a neighbor router."; static OSPF neighbor.";

           leaf address {
             type inet:ip-address;
             description "Neighbor IP address.";
           }
           leaf cost {
             type uint16 {
               range "1..65535";
             }
             description "Neighbor cost.";
           }
           leaf poll-interval {
             type uint16 {
               range "1..65535";
             }
             units seconds;
             description "Neighbor poll interval."; interval in seconds.";
           }
           leaf priority {
             type uint8 {
               range "1..255";
             }
             description "Neighbor priority for DR election.";
           }
         }
       }

       leaf node-flag {
         if-feature node-flag;
         type boolean;
         default false;
         description
           "Set prefix as a segment routing (SR) node
            representative prefix.";
       }
       uses interface-fast-reroute-config;
       uses interface-common-config;
     } // grouping interface-config
     grouping tlv {
       description
         "TLV";
       leaf type {
         type uint16;
         description "TLV type.";
       }
       leaf length {
         type uint16;
         description "TLV length.";
       }
       leaf value {
         type yang:hex-string;
         description "TLV value.";
       }

     }

     grouping unknown-tlvs {
       description
         "Unknown TLVs grouping.
          Could be used grouping - Used for unknown TLVs or
          unknown sub-TLVs.";
       container unknown-tlvs {
         description "All unknown TLVs.";
         list unknown-tlv {
           description "Unknown TLV.";
           uses tlv;
         }
       }
     }

     grouping ospfv2-router-link {
       description "OSPFv2 router link.";
       leaf link-id {
         type union {
           type inet:ipv4-address;
           type yang:dotted-quad;
         }
         description "Link ID.";
       }
       leaf link-data {
         type union {
           type inet:ipv4-address;
           type uint32;
         }
         description "Link data.";
       }
       leaf type {
         type uint8;
         description "Link type.";
       }
     }

     grouping ospfv2-lsa-body {
       description "OSPFv2 LSA body.";
       container router {
         when "../../header/type = 1" {
           description
             "Only apply applies to Router-LSA."; Router LSAs.";
         }
         description
           "Router LSA.";
         leaf flags {
           type bits {
             bit V {
               description
                 "When set, the router is an endpoint of one or
                  more virtual links.";
             }
             bit E {
               description
                 "When set, the router is an AS Boundary Router
                  (ASBR).";
             }
             bit B {
               description
                 "When set, the router is an Area Border
                  Router (ABR).";
             }
           }
           description "Flags.";
         }
         leaf num-of-links {
           type uint16;
           description "Number of links.";
         }
         container links {
           description "All router Links.";
           list link {
             description "Router LSA link.";
             uses ospfv2-router-link;
             container topologies {
               description "All topologies for the link.";
               list topology {
                 description
                   "Topology specific information.";
                 leaf mt-id {
                   type uint8;
                   description
                     "The MT-ID for the topology enabled on
                      the link.";
                 }
                 leaf metric {
                   type uint16;
                   description "Metric for the topology.";
                 }
               }
             }
           }
         }
       }
       container network {
         when "../../header/type = 2" {
           description
             "Only apply applies to network LSA."; Network LSAs.";
         }
         description
           "Network LSA.";
         leaf network-mask {
           type inet:ipv4-address;
           description
             "The IP address mask for the network.";
         }
         container attached-routers {
           description "All attached routers.";
           leaf-list attached-router {
             type yang:dotted-quad;
             description
               "List of the routers attached to the network.";
           }
         }
       }
       container summary {
         when "../../header/type = 3 or "
            + "../../header/type = 4" {
           description
             "Only apply applies to Summary-LSA."; Summary LSAs.";
         }
         description
           "Summary LSA.";
         leaf network-mask {
           type inet:ipv4-address;
           description
             "The IP address mask for the network";
         }
         container topologies {
           description "All topologies for the summary."; summary LSA.";
           list topology {
             description
               "Topology specific information.";
             leaf mt-id {
               type uint8;
               description
                 "The MT-ID for the topology enabled on for
                  the link."; summary.";
             }
             leaf metric {
               type uint24;
               description "Metric for the topology.";
             }

           }
         }
       }
       container external {
         when "../../header/type = 5 or "
            + "../../header/type = 7" {
           description
             "Only apply applies to AS-external-LSA AS-external LSAs and NSSA-LSA."; NSSA LSAs.";
         }
         description
           "External LSA.";
         leaf network-mask {
           type inet:ipv4-address;
           description
             "The IP address mask for the network";
         }
         container topologies {
           description "All topologies for the external.";
           list topology {
             description
               "Topology specific information.";
             leaf mt-id {
               type uint8;
               description
                 "The MT-ID for the topology enabled on for the link.";
                  external or NSSA prefix.";
             }
             leaf flags {
               type bits {
                 bit E {
                   description
                     "When set, the metric specified is a Type 2
                      external metric.";
                 }
               }
               description "Flags.";
             }
             leaf metric {
               type uint24;
               description "Metric for the topology.";
             }
             leaf forwarding-address {
               type inet:ipv4-address;
               description
                 "Forwarding address.";
             }
             leaf external-route-tag {
               type uint32;
               description
                 "Route tag."; tag for the topology.";
             }
           }
         }
       }
       container opaque {
         when "../../header/type = 9 or "
            + "../../header/type = 10 or "
            + "../../header/type = 11" {
           description
             "Only apply applies to opaque LSA."; Opaque LSAs.";
         }
         description
           "Opaque LSA.";

         uses unknown-tlvs;

         container router-address-tlv {
           description
             "Router address TLV.";
           leaf router-address {
             type inet:ipv4-address;
             description
               "Router address.";
           }
         }

         container link-tlvs {
           description "All link TLVs in the LSA.";
           container link-tlv {
             description "Link TLV.";
             leaf link-type {
               type uint8;
               mandatory true;
               description "Link type.";
             }
             leaf link-id {
               type union {
                 type inet:ipv4-address;
                 type yang:dotted-quad;
               }
               mandatory true;
               description "Link ID.";
             }
             container local-if-ipv4-addrs {
               description "All local interface IPv4 addresses.";
               leaf-list local-if-ipv4-addr {
                 type inet:ipv4-address;
                 description
                   "List of local interface IPv4 addresses.";
               }
             }
             container remote-if-ipv4-addrs {
               description "All remote interface IPv4 addresses.";
               leaf-list remote-if-ipv4-addr {
                 type inet:ipv4-address;
                 description
                   "List of remote interface IPv4 addresses.";
               }
             }
             leaf te-metric {
               type uint32;
               description "TE metric.";
             }
             leaf max-bandwidth {
               type decimal64 {
                 fraction-digits 2;
               }
               description "Maximum bandwidth.";
             }
             leaf max-reservable-bandwidth {
               type decimal64 {
                 fraction-digits 2;
               }
               description "Maximum reservable bandwidth.";
             }
             container unreserved-bandwidths {
               description "All unreserved bandwidths.";
               list unreserved-bandwidth {
                 leaf priority {
                   type uint8 {
                     range "0 .. 7";
                   }
                   description "Priority from 0 to 7.";
                 }
                 leaf unreserved-bandwidth {
                   type decimal64 {
                     fraction-digits 2;
                   }
                   description "Unreserved bandwidth.";
                 }
                 description
                   "List of unreserved bandwidths for different
                    priorities.";
               }

             }
             leaf admin-group {
               type uint32;
               description
                 "Administrative group/Resource class/Color."; Class/Color.";
             }
             uses unknown-tlvs;
           }
         }

         container extended-prefix-tlvs {
           description "All extended prefix TLVs in the LSA.";
           list extended-prefix-tlv {
             description "Extended prefix TLV.";
             leaf route-type {
               type enumeration {
                 enum unspecified {
                   value "0";
                   description "Unspecified.";
                 }
                 enum intra-area {
                   value "1";
                   description "OSPF intra-area route.";
                 }
                 enum inter-area {
                   value "3";
                   description "OSPF inter-area route.";
                 }
                 enum external {
                   value "5";
                   description "OSPF External route.";
                 }
                 enum nssa {
                   value "7";
                   description "OSPF NSSA external route.";
                 }
               }
               description "Route type.";
             }
             leaf flags {
               type bits {
                 bit A {
                   description
                     "Attach flag.";
                 }
                 bit N {
                   description
                     "Node flag.";

                 }
               }
               description "Flags.";
             }
             leaf prefix {
               type inet:ip-prefix;
               description "Address prefix.";
             }
             uses unknown-tlvs;
           }
         }

         container extended-link-tlvs {
           description "All extended link TLVs in the LSA.";
           list extended-link-tlv {
             description "Extended link TLV.";
             uses ospfv2-router-link;
             uses unknown-tlvs;
           }
         }
       }
     }

     grouping ospfv3-lsa-options {
       description "OSPFv3 LSA options";
       leaf options {
         type bits {
           bit DC {
             description
               "When set, the router support supports demand circuits.";
           }
           bit R {
             description
               "When set, the originator is an active router.";
           }
           bit N {
             description
               "If set, the router is attached to an NSSA";
           }
           bit E {
             description
               "This bit describes the way AS-external-LSAs AS-external LSAs
                are flooded";
           }
           bit V6 {
             description
               "If clear, the router/link should be excluded
                from IPv6 routing calculaton";

           }
         }
         mandatory true;
         description "OSPFv3 LSA options.";
       }
     }

     grouping ospfv3-lsa-prefix {
       description
         "OSPFv3 LSA prefix.";

       leaf prefix {
         type inet:ip-prefix;
         description
           "Prefix.";
       }
       leaf prefix-options {
         type bits {
           bit NU {
             description
               "When set, the prefix should be excluded
                from IPv6 unicast calculations.";
           }
           bit LA {
             description
               "When set, the prefix is actually an IPv6 interface
                address of the Advertising Router.";
           }
           bit P {
             description
               "When set, the NSSA area prefix should be
                translated to an AS External LSA and readvertised
                by the translating NSSA area border."; Border Router.";
           }
           bit DN {
             description
               "When set, the inter-area-prefix-LSA inter-area-prefix LSA or
                AS-external-LSA
                AS-external LSA prefix has been advertised in a VPN
                environment."; as an
                L3VPN prefix.";
           }
         }
         mandatory true;
         description "Prefix options.";
       }
     }

     grouping ospfv3-lsa-external {
       description
         "AS-External and NSSA LSA.";
       leaf metric {
         type uint24;
         description "Metric";
       }

       leaf flags {
         type bits {
           bit E {
             description
               "When set, the metric specified is a Type 2
                external metric.";
           }
           bit F {
             description
               "When set, a Forwarding Address is included
                in the LSA.";
           }
           bit T {
             description
               "When set, an External Route Tag is included
                in the LSA.";
           }
         }
         description "Flags.";
       }

       leaf referenced-ls-type {
         type uint16;
         description "Referenced Link State type.";
       }

       uses ospfv3-lsa-prefix;

       leaf forwarding-address {
         type inet:ipv6-address;
         description
           "Forwarding address.";
       }

       leaf external-route-tag {
         type uint32;
         description
           "Route tag.";
       }
       leaf referenced-link-state-id {
         type uint32;
         description
           "Referenced Link State ID.";
       }
     }

     grouping ospfv3-lsa-body {
       description "OSPFv3 LSA body.";
       container router {
         when "../../header/type = 8193" { // 0x2001
           description
             "Only apply applies to Router-LSA."; Router LSAs.";
         }
         description "Router LSA.";
         leaf flags {
           type bits {
             bit V {
               description
                 "When set, the router is an endpoint of one or
                  more virtual links.";
             }
             bit E {
               description
                 "When set, the router is an AS Boundary Router
                  (ASBR).";
             }
             bit B {
               description
                 "When set, the router is an Area Border
                  Router (ABR).";
             }
             bit Nt {
               description
                 "When set, the router is an NSSA border router
                  that is unconditionally translating NSSA-LSAs NSSA LSAs
                  into AS-external-LSAs."; AS-external LSAs.";
             }
           }
           mandatory true;
           description "LSA option."; "Router LSA flags.";
         }

         uses ospfv3-lsa-options;

         container links {
           description "All router link.";
           list link {
             description "Router LSA link.";
             leaf interface-id {
               type uint32;
               description "Interface ID.";
             }
             leaf neighbor-interface-id {
               type uint32;
               description "Neighbor Interface ID.";
             }
             leaf neighbor-router-id {
               type yang:dotted-quad;
               description "Neighbor Router ID.";
             }
             leaf type {
               type uint8;
               description "Link type.";
             }
             leaf metric {
               type uint16;
                 description "Metric.";
             }
           }
         }
       }
       container network {
         when "../../header/type = 8194" { // 0x2002
           description
             "Only apply applies to network Network LSA.";
         }
         description "Network LSA.";

         uses ospfv3-lsa-options;

         container attached-routers {
           description "All attached routers.";
           leaf-list attached-router {
             type yang:dotted-quad;
             description
               "List of the routers attached to the network.";
           }
         }
       }
       container inter-area-prefix {
         when "../../header/type = 8195" { // 0x2003
           description
             "Only apply applies to inter-area-prefix LSA."; Inter-Area-Prefix LSAs.";
         }
         leaf metric {
           type uint24;
           description "Metric";
         }
         uses ospfv3-lsa-prefix;
         description "Inter-Area-Prefix LSA.";
       }
       container inter-area-router {
         when "../../header/type = 8196" { // 0x2004
           description
             "Only apply applies to inter-area-router LSA."; Inter-Area-Router LSAs.";
         }
         uses ospfv3-lsa-options;
         leaf metric {
           type uint24;
           description "Metric.";
         }
         leaf destination-router-id {
           type yang:dotted-quad;
           description
             "The Router ID of the router being described by the LSA.";
         }
         description "Inter-Area-Router LSA.";
       }
       container as-external {
         when "../../header/type = 16389" { // 0x4005
           description
             "Only apply applies to as-external LSA."; AS-external LSAs.";
         }

         uses ospfv3-lsa-external;

         description "AS-External LSA.";
       }
       container nssa {
         when "../../header/type = 8199" { // 0x2007
           description
             "Only apply applies to nssa LSA."; NSSA LSAs.";
         }
         uses ospfv3-lsa-external;

         description "NSSA LSA.";
       }
       container link {
         when "../../header/type = 8" { // 0x0008
           description
             "Only apply applies to link LSA."; Link LSAs.";
         }
         leaf rtr-priority {
           type uint8;
           description "Router Priority of for the interface.";
         }
         uses ospfv3-lsa-options;

         leaf link-local-interface-address {
           type inet:ipv6-address;
           description
             "The originating router's link-local
              interface address on for the link.";
         }

         leaf num-of-prefixes {
           type uint32;
           description "Number of prefixes.";
         }

         container prefixes {
           description "All prefixes for the link.";
           list prefix {
             description
               "List of prefixes associated with the link.";
             uses ospfv3-lsa-prefix;
           }
         }
         description "Link LSA.";
       }
       container intra-area-prefix {
         when "../../header/type = 8201" { // 0x2009
           description
             "Only apply applies to intra-area-prefix Intra-Area-Prefix LSA.";
         }
         description "Intra-Area-Prefix LSA.";

         leaf referenced-ls-type {
           type uint16;
           description "Referenced Link State type.";
         }
         leaf referenced-link-state-id {
           type uint32;
           description
             "Referenced Link State ID.";
         }
         leaf referenced-adv-router {
           type inet:ipv4-address;
           description
             "Referenced Advertising Router.";
         }

         leaf num-of-prefixes {
           type uint16;
           description "Number of prefixes.";
         }
         container prefixes {
           description "All prefixes in this LSA.";
           list prefix {
             description "List of prefixes in this LSA.";
             uses ospfv3-lsa-prefix;
             leaf metric {
               type uint24;
               description "Metric."; "Prefix Metric.";
             }
           }
         }
       }
     }

     grouping lsa-header {
       description
           "Common LSA for OSPFv2 and OSPFv3";
       leaf age {
         type uint16;
         mandatory true;
         description "LSA age.";
       }
       leaf type {
         type uint16;
         mandatory true;
         description "LSA type.";
       }
       leaf adv-router {
         type yang:dotted-quad;
         mandatory true;
         description "LSA advertising router.";
       }
       leaf seq-num {
         type uint32;
         mandatory true;
         description "LSA sequence number.";
       }
       leaf checksum {
         type uint16;
         mandatory true;
         description "LSA checksum.";
       }
       leaf length {
         type uint16;
         mandatory true;
         description "LSA length.";

       }
     }

     grouping ospfv2-lsa {
       description
           "OSPFv2 LSA.";
       container header {
         must "(type = 9 or type = 10 or type = 11) and "
            + "opaque-id and opaque-type "
            + "or (type != 9 and type != 10 and type != 11) "
            + "and not(opaque-id) and "
            + "not(opaque-type)" {
           description
             "Opaque type and id ID only apply to opaque LSA."; Opaque LSAs.";
         }
         description
           "Decoded OSPFv2 LSA header data.";
         leaf option {
           type bits {
             bit DC {
               description
                 "When set, the router support supports demand circuits.";
             }
             bit P {
               description
                 "Only used in type-7 LSA. When set, the an NSSA
                  border router should translate the type-7 LSA
                  to a type-5 LSA.";
             }
             bit MC {
               description
                 "When set, the router support supports MOSPF.";
             }
             bit E {
               description
                 "This bit describes the way AS-external-LSAs AS-external LSAs
                  are flooded";
             }
           }
           mandatory true;
           description "LSA option."; options.";
         }
         leaf lsa-id {
           type inet:ipv4-address;
           mandatory true;
           description "LSA ID.";
         }
         leaf opaque-type {
           type uint8;
           description "Opaque type.";
         }

         leaf opaque-id {
           type uint24;
           description "Opaque id."; ID.";
         }

         uses lsa-header;
       }
       container body {
         description
           "Decoded OSPFv2 LSA body data.";
         uses ospfv2-lsa-body;
       }
     }

     grouping ospfv3-lsa {
       description
           "Decoded OSPFv3 LSA.";
       container header {
         description
           "Decoded OSPFv3 LSA header data.";
         leaf lsa-id {
           type uint32;
           mandatory true;
           description "LSA ID.";
         }
         uses lsa-header;
       }
       container body {
         description
           "Decoded OSPF LSA body data.";
         uses ospfv3-lsa-body;
       }
     }
     grouping lsa-common {
       description
           "Common field for OSPF LSA represenation.";
       leaf decoded-completed {
         type boolean;
         description
           "The OSPF LSA body is fully decoded.";
       }
       leaf raw-data {
         type yang:hex-string;
         description
           "The complete LSA in network byte
            order hexadecimal as received/sent over the wire."; received or originated.";
       }
     }

     grouping lsa {
       description
           "OSPF LSA.";
       uses lsa-common;
       choice version {
         description
           "OSPFv2 or OSPFv3 LSA body.";
         container ospfv2 {
           description "OSPFv2 LSA";
           uses ospfv2-lsa;
         }
         container ospfv3 {
           description "OSPFv3 LSA";
           uses ospfv3-lsa;
         }
       }
     }

     grouping lsa-key {
       description
         "OSPF LSA key.";
       leaf lsa-id {
         type union {
           type inet:ipv4-address;
           type uint32;
         }
         description
           "LSA ID.";
       }
       leaf adv-router {
         type inet:ipv4-address;
         description
           "Advertising router.";
       }
     }

     grouping af-area-config {
       description
         "OSPF address-family specific area config state.";
       container ranges {
         description "Container for summary ranges";
         list range {
           key "prefix";
           description
             "Summarize routes matching address/mask (border
              routers
              (Area Border Routers (ABRs) only)";
           leaf prefix {
             type inet:ip-prefix;
             description
               "IPv4 or IPv6 prefix";
           }
           leaf advertise {
             type boolean;
             description
               "Advertise or hide.";
           }
           leaf cost {
             type uint24 {
               range "0..16777214";
             }
             description
               "Cost
               "Advertised cost of summary route.";
           }
         }
       }
     }

     grouping area-config {
       description
         "OSPF area config configuration state.";
       leaf area-type {
         type identityref {
           base area-type;
         }
         default normal;
         description
           "Area type.";
       }

       leaf summary {
         when "../area-type = 'stub' 'ospf:stub' or ../area-type "
            + "../area-type = 'nssa'" 'ospf:nssa'" {
           description
             "Summary generation valid for advertisement into the stub/NSSA area.";
         }
         type boolean;
         description
           "Enable/Disable summary generation to advertisement into the stub or
            NSSA area.";
       }
       leaf default-cost {
         when "../area-type = 'stub' 'ospf:stub' or ../area-type "
            + "../area-type = 'nssa'" 'ospf:nssa'" {
             description
               "Default cost
               "Cost for LSA default route advertised into the
                stub or NSSA area.";
         }
         type uint32 {
           range "1..16777215";
         }
         description
           "Set the summary default-cost default route cost for a
            stub or NSSA area.";
       }
     }

     grouping local-rib {
       description "Local-rib grouping.";
       container local-rib {
         description "Local-rib.";
         list route {
           key "prefix";
           description "Routes";
           leaf prefix {
             type inet:ip-prefix;
             description "Destination prefix.";
           }
           container next-hops {
             description "All next hops for the route.";
             list next-hop {
               key "next-hop";
               description "List of next hop for the route";
               leaf outgoing-interface {
                 type if:interface-ref;
                 description
                   "Name of the outgoing interface.";
               }
               leaf next-hop {
                type inet:ip-address;
                description "Nexthop address.";
               }
             }
           }
           leaf metric {
             type uint32;
             description "Metric for this route.";
           }
           leaf route-type {
             type route-type;
             description "Route type for this route.";
           }
           leaf route-tag {
             type uint32;
             description "Route tag for this route.";
           }
         }
       }
     }

     grouping instance-config {
       description
         "OSPF instance config state.";
       leaf router-id {
         if-feature router-id;
         type yang:dotted-quad;
         description
           "Defined in RFC 2328. A 32-bit number
            that uniquely identifies the router.";
       }

       container admin-distance {
         description "Admin distance config state.";
         choice scope {
           description
             "Options for expressing admin distance
              as single or multiple values.";
           case single-value {
             leaf all {
               type uint8;
               description
                 "Admin distance for intra-area, inter-area and
                  external route."; routes.";
             }
           }
           case multi-values {
             choice granularity {
               description
                 "Options for expressing admin distance
                  for intra-area and inter-area route."; routes.";
               case detail {
                 leaf intra-area {
                   type uint8;
                   description
                     "Admin distance for intra-area route."; routes.";
                 }
                 leaf inter-area {
                   type uint8;
                   description
                     "Admin distance for inter-area route."; routes.";
                 }
               }
               case coarse {
                 leaf internal {
                   type uint8;
                   description
                     "Admin distance for both intra-area and
                      inter-area route."; routes.";
                 }
               }
             }
             leaf external {
               type uint8;
               description
                 "Admin distance for both external route."; routes.";
             }
           }
         }
       }

       container nsr {
         if-feature nsr;
         description
           "NSR
           "Non-Stop Routing (NSR) config state.";
         leaf enable {
           type boolean;
           description
             "Enable/Disable NSR.";
         }
       }

       container graceful-restart {
         if-feature graceful-restart;
         description
           "Graceful restart config state.";
         leaf enable {
           type boolean;
           description
             "Enable/Disable graceful restart as defined in RFC 3623.";
         }
         leaf helper-enable {
           type boolean;
           description
             "Enable RestartHelperSupport in RFC graceful restart helper support for restarting
              routers (RFC 3623 Section B.2."; B.2).";

         }
         leaf restart-interval {
           type uint16 {
             range "1..1800";  // Range is defined in RFC 3623.
           }
           units seconds;
           default "120";  // Default is defined in RFC 3623.
           description
             "RestartInterval option
             "Interval in RFC seconds to attempt graceful restart prior
              to failing (RFC 3623 Section B.1."; B.1)";
         }
         leaf helper-strict-lsa-checking {
           type boolean;
           description
             "RestartHelperStrictLSAChecking option in RFC
             "Terminate graceful restart when an LSA topology change
              is detected (RFC 3623 Section B.2."; B.2).";
         }
       }

       leaf enable {
         if-feature admin-control;
         type boolean;
         default true;
         description
           "Enable/Disable the protocol.";
       }

       container auto-cost {
         if-feature auto-cost;
         description
           "Auto cost config
           "Interface Auto-cost configuration state.";
         leaf enable {
           type boolean;
           description
             "Enable/Disable auto cost."; interface auto-cost.";
         }
         leaf reference-bandwidth {
           when "../enable = 'true'" {
             description "Only when auto cost is enabled";
           }
           type uint32 {
             range "1..4294967";
           }
           units Mbits;
           description
             "Configure reference bandwidth in term of Mbits"; used to automatically
              determine interface cost (Mbits). The cost is the
              reference bandwidth divided by the interface speed
              with 1 being the minimum cost.";
         }
       }

       container spf-control {
         leaf paths {
           if-feature max-ecmp;
           type uint16 {
             range "1..32";
           }
           description
             "Maximum number of ECMP Equal-Cost Multi-Path (ECMP) paths.";
         }
         description "SPF calculation control.";
       }

       container database-control {
         leaf max-lsa {
           if-feature max-lsa;
           type uint32 {
             range "1..4294967294";
           }
           description
             "Maximum number of LSAs OSPF the router will receive."; accept.";
         }
         description "Database maintenance control.";
       }

       container stub-router {
         if-feature stub-router;
         description "Set maximum metric configuration";

         choice trigger {
           description
             "Specific different triggers to which will enable stub router.";
              router state.";
           container always {
             presence
               "Enables maximum metric for non-stub unconditional stub router link"; support";
             description "Set maximum metric always configuration";
               "Unconditional stub router state (advertise
                transit links with max metric";
           }
         }
       }

       container mpls {
         description
           "OSPF MPLS config state.";
         container te-rid {
           if-feature te-rid;
           description
             "Traffic Engineering stable
             "Stable OSPF Router IP address Address used for system."; Traffic
              Engineering (TE)";
           choice source {
             description
               "Different options for specifying TE router ID.";
             case interface {
               leaf interface {
                 type if:interface-ref;
                 description
                   "Take
                   "Use the interface's IPv4 address as TE
                    router ID.";
               }
             }
             case explicit {
               leaf router-id {
                 type inet:ipv4-address;
                 description
                   "Explicitly configure the TE router ID.";
               }
             }
           }
         }
         container ldp {
           description
             "OSPF MPLS LDP config state.";
           leaf igp-sync {
             if-feature ldp-igp-sync;
             type boolean;
             description
               "Enable LDP IGP synchronization.";
           }
           leaf autoconfig {
             if-feature ldp-igp-autoconfig;
             type boolean;
             description
               "Enable LDP IGP interface auto-configuration.";
           }
         }
       }
       uses instance-fast-reroute-config;
     }

     grouping interface-operation {
       description
         "OSPF interface operation state.";
       reference "RFC2328 Section 9";
       uses interface-config;

       leaf state {
         type if-state-type;
         description "Interface state.";
       }

       leaf hello-timer {
         type uint32;
         units "milliseconds";
         description "Hello timer.";
       }

       leaf wait-timer {
         type uint32;
         units "milliseconds";
         description "Wait timer.";
       }

       leaf dr {
         type inet:ipv4-address;
         description "DR."; "Designated Router (DR) IP address.";
       }

       leaf bdr {
         type inet:ipv4-address;
         description "BDR."; "Backup Designated Router (BDR) IP Address.";
       }

       container statistics {
         description "Per interface statistics";
         uses interface-stat;
       }
     } // interface-operation

     grouping neighbor-operation {
       description
         "OSPF neighbor operation data.";

       leaf address {
         type inet:ip-address;
         description
           "Neighbor address.";
       }
       leaf dr {
         type yang:dotted-quad;
         description
           "Designated Router.";
       }
       leaf bdr {
         type yang:dotted-quad;
         description
           "Backup Designated Router.";
       }
       leaf state {
         type nbr-state-type;
         description
           "OSPF neighbor state.";
       }
       container statistics {
         description "Per neighbor statistics";
         uses neighbor-stat;
       }
     }

     grouping instance-operation {
       description
         "OSPF Address Family operation state.";
       leaf router-id {
         type yang:dotted-quad;
         description
           "Defined in RFC 2328. A 32-bit number
            that uniquely identifies the router.";
       }

       uses local-rib;

       container statistics {
         description "Per instance statistics";
         uses instance-stat;
       }
     }

     augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "rt:routing-protocol" {
        when "rt:type = 'ospf:ospfv2' or rt:type = 'ospf:ospfv3'" {
         description
           "This augment augmentation is only valid for a routing protocol
            instance of OSPF (type 'ospfv2' or 'ospfv3').";
       }
       description "OSPF augmentation.";

       container ospf {
         description
           "OSPF.";
         container all-instances-inherit {
           if-feature instance-inheritance;
           description
             "Inheritance support to all instances.";
           container area {
             description
               "Area config to be inherited by all areas
                in all instances.";
           }
           container interface {
             description
               "Interface config to be inherited by all
                interfaces in all instances.";
           }
         }

         leaf operation-mode {
           type identityref {
             base operation-mode;
           }
           default ospf:ships-in-the-night;
           description
             "OSPF operation mode.";
         }

         list instance {
           key "af";
           description
             "An OSPF routing protocol instance.";

           leaf af {
             type identityref {
               base rt:address-family;
             }
             description
               "Address-family of the instance.";
           }

           uses instance-config;

           container all-areas-inherit {
             if-feature area-inheritance;
             description
               "Inheritance for all areas.";
             container area {
               description
                 "Area config to be inherited by all areas.";

             }
             container interface {
               description
                 "Interface config to be inherited by all interfaces
                  in all areas.";
             }
           }

           container areas {
             description "All areas.";
             list area {
               key "area-id";
               description
                 "List of ospf OSPF areas";
               leaf area-id {
                 type area-id-type;
                 description
                   "Area ID.";
               }

               uses area-config;
               uses af-area-config {
                 when "../../operation-mode = "
                    + "'ospf:ships-in-the-night'" {
                   description
                     "Ships in the night configuration.";
                 }
               }
               container all-interfaces-inherit {
                 if-feature interface-inheritance;
                 description
                   "Inheritance for all interfaces";
                 container interface {
                   description
                     "Interface config to be inherited by all
                      interfaces.";
                      interfaces in the area.";
                 }
               }

               container virtual-links {
                 description "All virtual links.";
                 list virtual-link {
                   when "../../area-id != '0' and "
                      + "../../area-type = 'normal'" 'ospf:normal'" {
                     description
                       "Transit area must be a non-backbone
                        normal area.";
                   }
                   key "router-id";
                   description
                     "OSPF virtual link";
                   leaf router-id {
                     type yang:dotted-quad;
                     description
                       "Virtual link Link remote endpoint router ID.";
                   }

                   uses interface-common-config;
                 }
               }
               container sham-links {
                 description "All sham links.";
                 list sham-link {
                   key "local-id remote-id";
                   description
                     "OSPF sham link";
                   leaf local-id {
                     type inet:ip-address;
                     description
                       "Address of the local end-point."; Sham Link endpoint.";
                   }
                   leaf remote-id {
                     type inet:ip-address;
                     description
                       "Address of the remote end-point."; Sham Link endpoint.";
                   }
                   uses interface-common-config;
                 }
               }
               container interfaces {
                 description "All interfaces.";
                 list interface {
                   key "interface";
                   description
                     "List of OSPF interfaces.";
                   leaf interface {
                     type if:interface-ref;
                     description
                       "Interface.";
                   }
                   uses interface-config;
                 } // list of interfaces
               }
             } // list of areas
           }
         } // list of instance

       } // container ospf
     }
     augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "rt:routing-protocol/ospf:ospf/ospf:instance" {
       when "../../rt:type = 'ospf:ospfv2' or
             ../../rt:type = 'ospf:ospfv3'" {
         description
           "This augment augmentation is only valid for OSPF
           (type 'ospfv2' or 'ospfv3').";
       }
       if-feature multi-topology;
       description
         "OSPF multi-topology routing-protocol augmentation.";
       container topologies {
         description "All topologies.";
         list topology {
           // Topology must be in the same routing-instance
           //  and of same AF as the container.
           key "name";
           description "OSPF topology.";
           leaf name {
             type leafref {
               path "../../../../../../../rt:ribs/rt:rib/rt:name";
             }
             description "RIB";
           }
           container areas {
             description "All areas of in the topology.";
             list area {
               key "area-id";
               description
                 "List of ospf OSPF areas";
               leaf area-id {
                 type area-id-type;
                 description
                   "Area ID.";
               }
               uses area-config;
               uses af-area-config {
                 when "../../../../operation-mode = "
                    + "'ospf:ships-in-the-night'" {
                   description
                     "Ships in the night configuration.";
                 }
               }
             }
           }
         }

       }
     }
     augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "rt:routing-protocol/ospf:ospf/ospf:instance/"
           + "ospf:areas/ospf:area/ospf:interfaces/ospf:interface" {
       when "../../../../../../rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       if-feature ospf:multi-topology;
       description "OSPF multi-topology interface augmentation.";
       container topologies {
         description "All topologies for the interface.";
         list topology {
           key "name";
           description "OSPF interface topology.";
           leaf name {
             type leafref {
               path "../../../../../../../../../../../"
                  + "rt:ribs/rt:rib/rt:name";
             }
             description
               "One of the topology topologies enabled on this interface.";
           }
           leaf cost {
              type uint32;
              description
                "Interface cost for this topology.";
           }
         }
       }
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol" {
       when "rt:type = 'ospf:ospfv2' or rt:type "
          + "rt:type = 'ospf:ospfv3'"  {
         description
           "This augment augmentation is only valid for a routing protocol
            instance of type 'ospfv2' or 'ospfv3'.";
       }
       description
            "OSPF operation operational state.";
       container ospf {
         description "OSPF";

         leaf operation-mode {
           type identityref {
             base operation-mode;
           }
           description
             "OSPF operation mode.";
         }

         list instance {
           key "af";
           description
             "An OSPF routing protocol instance.";

           leaf af {
             type identityref {
               base rt:address-family;
             }
             description
               "Address-family of the instance.";
           }

           uses instance-operation;

           container areas {
             description "All areas";
             list area {
               key "area-id";
               description "List of OSPF areas";
               leaf area-id {
                 type area-id-type;
                 description "Area ID.";
               }

               container statistics {
                 description "Per area statistics";
                 uses area-stat;
               }

               container virtual-links {
                 description "All virtual links.";
                 list virtual-link {
                   description
                     "OSPF virtual link";
                   leaf router-id {
                     type yang:dotted-quad;
                     description
                       "Virtual link router ID.";
                   }
                   uses interface-operation;
                 }
               }
               container sham-links {
                 description "All sham links.";
                 list sham-link {
                   description
                     "OSPF sham link";
                   leaf local-id {
                     type inet:ip-address;
                     description
                       "Address of the local end-point."; Sham Link endpoint.";
                   }
                   leaf remote-id {
                     type inet:ip-address;
                     description
                       "Address of the remote end-point."; Sham Link endpoint.";
                   }
                   uses interface-operation;
                 }
               }

               container interfaces {
                 description "All interfaces in the area.";
                 list interface {
                   key "interface";
                   description
                     "List of OSPF interfaces.";
                   leaf interface {
                     // Should it refer to config state leaf?
                     type if:interface-ref;
                     description "Interface.";
                   }

                   uses interface-operation;

                   container neighbors {
                     description "All neighbors on for the interface.";
                     list neighbor {
                       key "neighbor-router-id";
                       description
                         "List of OSPF neighbors.";
                       leaf neighbor-router-id {
                         type yang:dotted-quad;
                         description
                           "Neighbor router ID.";
                       }
                       uses neighbor-operation;
                     } // list of OSPF neighbors
                   }
                   container database {
                     description "Link scope LSA database.";
                     list link-scope-lsa-type {
                       key "lsa-type";
                       description
                         "List OSPF link scope LSA databases.";
                       leaf lsa-type {
                         type uint16;
                         description "OSPF link scope LSA type.";
                       }
                       container link-scope-lsas {
                         description
                           "All link scope LSAs of this LSA type.";
                         list link-scope-lsa {
                           key "lsa-id adv-router";
                           description "List of OSPF link scope LSAs";
                           uses lsa-key;
                           uses lsa {
                             refine "version/ospfv2/ospfv2" {
                               must "../../../../../../../../../../../"
                                  + "rt:type = 'ospfv2'" 'ospf:ospfv2'" {
                                 description "OSPFv2 LSA.";
                               }
                             }
                             refine "version/ospfv3/ospfv3" {
                               must "../../../../../../../../../../../"
                                  + "rt:type = 'ospfv3'" 'ospf:ospfv3'" {
                                 description "OSPFv3 LSA.";
                               }
                             }
                           }
                         }
                       }
                     } // list link-scope-lsas
                   }
                 } // list of OSPF interfaces
               }

               container database {
                 description "Area scope LSA database.";
                 list area-scope-lsa-type {
                   key "lsa-type";
                   description "List OSPF area scope LSA databases.";
                   leaf lsa-type {
                     type uint16;
                     description "OSPF area scope LSA type.";
                   }
                   container area-scope-lsas {
                     description
                       "All area scope LSA LSAs of this an area scope
                        LSA type.";
                     list area-scope-lsa {
                       key "lsa-id adv-router";
                       description "List of OSPF area scope LSAs";
                       uses lsa-key;
                       uses lsa {
                         refine "version/ospfv2/ospfv2" {
                           must "../../../../../../../../../"
                              + "rt:type = 'ospfv2'" 'ospf:ospfv2'" {
                             description "OSPFv2 LSA.";
                           }
                         }
                         refine "version/ospfv3/ospfv3" {
                           must "../../../../../../../../../"
                              + "rt:type = 'ospfv3'" 'ospf:ospfv3'" {
                             description "OSPFv3 LSA.";
                           }
                         }
                       }
                     }
                   }
                 } // list area-scope-lsas
               }
             } // list of OSPF areas
           }
           container database {
             description "AS scope LSA database.";
             list as-scope-lsa-type {
               key "lsa-type";
               description "List OSPF AS scope LSA databases.";
               leaf lsa-type {
                 type uint16;
                 description "OSPF AS scope LSA type.";
               }
               container as-scope-lsas {
                 description "All AS scope of LSA of this LSA type.";
                 list as-scope-lsa {
                   key "lsa-id adv-router";
                   description "List of OSPF area scope LSAs";
                   uses lsa-key;
                   uses lsa {
                     refine "version/ospfv2/ospfv2" {
                       must "../../../../../../../rt:type = 'ospfv2'" "
                          + "'ospf:ospfv2'" {
                         description "OSPFv2 LSA.";
                       }
                     }
                     refine "version/ospfv3/ospfv3" {
                       must "../../../../../../../rt:type = 'ospfv3'" "
                          + "'ospf:ospfv3'" {
                         description "OSPFv3 LSA.";
                       }
                     }
                   }
                 }
               }
             } // list as-scope-lsas
           }
         } // list of instances
       } // container ospf
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance" {
       when "../../rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       if-feature multi-topology;
       description
         "OSPF multi-topology routing-protocol augmentation.";
       container topologies {
         description "All topologies.";
         list topology {
           // Topology must be in the same routing-instance
           // and of same AF as the container.
           key "name";
           description "OSPF topology.";
           leaf name {
             type leafref {
               path "../../../../../../../"
                  + "rt:ribs/rt:rib/rt:name";
             }
             description "RIB";
           }

           uses local-rib;

           container areas {
             description "All areas in the topology.";
             list area {
               key "area-id";
               description
                 "List of ospf OSPF areas";
               leaf area-id {
                 type area-id-type;
                 description
                   "Area ID.";
               }
             }
           }
         }
       }
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:interfaces/ospf:interface" {
       when "../../../../../../rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       if-feature ospf:multi-topology;
       description "OSPF multi-topology interface augmentation.";
       container topologies {
         description "All topologies.";
         list topology {
           key "name";
           description "OSPF interface topology.";
           leaf name {
             type leafref {
               path "../../../../../../../../../../../"
                  + "rt:ribs/rt:rib/rt:name";
             }
             description
               "One of the topology topologies enabled on this interface.";
           }
         }
       }
     }

     grouping route-content {
       description
         "This grouping defines OSPF-specific route attributes.";
       leaf metric {
         type uint32;
         description "OSPF route metric.";

       }
       leaf tag {
         type uint32;
         default "0";
         description "OSPF route tag.";
       }
       leaf route-type {
         type route-type;
         description "OSPF route type";
       }
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:ribs/rt:rib/rt:routes/rt:route" {
       when "rt:source-protocol = 'ospf:ospfv2' or "
          + "rt:source-protocol = 'ospf:ospfv3'" {
         description
           "This augment augmentation is only valid for a routes whose
            source protocol is OSPF.";
       }
       description
         "OSPF-specific route attributes.";
       uses route-content;
     }

     identity if-link-type {
       description "Base identity for OSPF interface link type.";
     }

     identity if-link-type-normal {
       base if-link-type;
       description "OSPF interface link type normal.";
     }

     identity if-link-type-virtual-link {
       base if-link-type;
       description "OSPF interface link type virtual link.";
     }

     identity if-link-type-sham-link {
       base if-link-type;
       description "OSPF interface link type sham link.";
     }

     grouping notification-instance-hdr {
       description
        "This group describes common instance specific
         data for notifications.";

       leaf routing-instance {
         type rt:routing-instance-ref;
         description
           "Describe the routing instance.";
       }

       leaf routing-protocol-type {
         type leafref {
           path "/rt:routing/rt:routing-instance"
              + "[rt:name=current()/../routing-instance]/"
              + "rt:routing-protocols/rt:routing-protocol/"
              + "rt:type";
         }
         must ". = 'ospf:ospfv2' or . = 'ospf:ospfv3'" {
           description "Only interested in applies to the OSPF routing protocol"; protocol.";
         }
         description
          "Describes the type of the OSPF
          "OSPF routing protocol."; protocol type (OSPFv2 or OSPFv3).";

       }

       leaf routing-protocol-name {
         type leafref {
           path "/rt:routing/rt:routing-instance"
              + "[rt:name=current()/../routing-instance]/"
              + "rt:routing-protocols/rt:routing-protocol"
              + "[rt:type=current()/../routing-protocol-type]/"
              + "rt:name";
         }
         description
          "Describes the name of the OSPF
          "OSPF routing protocol."; protocol instance name.";
       }

       leaf af {
         type leafref {
           path "/rt:routing/rt:routing-instance"
              + "[rt:name=current()/../routing-instance]/"
              + "rt:routing-protocols/rt:routing-protocol"
              + "[rt:name=current()/../routing-protocol-name]"
              + "[rt:type=current()/../routing-protocol-type]/"
              + "ospf:ospf/ospf:instance/af";
         }
         description
           "Describes the address
           "Address family of the OSPF instance.";
       }
     }

     notification if-state-change {
       uses notification-instance-hdr;

       leaf link-type

     grouping notification-interface {
         type identityref
       description
         "This grouping provides the interface information
          for the notifications.";

       choice if-link-type-selection {
           base if-link-type;
         }
         description "Type of OSPF interface.";

       }
           "Options for link type.";
         container interface {
           description "Normal interface.";
           leaf interface {
             type if:interface-ref;
             description "Interface.";
           }
         }
         container virtual-link {
           description "virtual-link.";
           leaf area-id {
             type uint32; area-id-type;
             description "Area ID.";

           }
           leaf neighbor-router-id {
             type yang:dotted-quad;
             description "Neighbor router id."; Router ID.";
           }
         }
         container sham-link {
           description "sham-link.";
           leaf area-id {
             type uint32; area-id-type;
             description "Area ID.";
           }
           leaf local-ip-addr {
             type inet:ip-address;
             description "Sham link local address.";
           }
           leaf remote-ip-addr {
             type inet:ip-address;
             description "Sham link remote address.";
           }
         }
       }
     }

     grouping notification-neighbor {
       description
         "This grouping provides the neighbor information
          for the notifications.";

       leaf neighbor-router-id {
         type yang:dotted-quad;
         description "Neighbor Router ID.";
       }

       leaf neighbor-ip-addr {
         type yang:dotted-quad;
         description "Neighbor address.";
       }
     }

     notification if-state-change {
       uses notification-instance-hdr;
       uses notification-interface;

       leaf state {
         type if-state-type;
         description "Interface state.";
       }
       description
         "This notification is sent when an interface
         state change is detected.";
     }

     notification if-config-error {
       uses notification-instance-hdr;

       leaf link-type {
         type identityref {
           base if-link-type;
         }
         description "Type of OSPF interface.";
       }

       container interface {
         description "Normal interface.";
         leaf interface {
           type if:interface-ref;
           description "Interface.";
         }
       uses notification-interface;

       leaf packet-source {
         type yang:dotted-quad;
         description "Source address.";
       }
       }
       container virtual-link {
         description "virtual-link.";

       leaf area-id packet-type {
         type uint32; packet-type;
         description "Area ID."; "OSPF packet type.";
       }

       leaf neighbor-router-id error {
         type yang:dotted-quad; enumeration {
           enum "badVersion" {
             description "Neighbor router id.";
         } "Bad version.";
           }

       container sham-link {
         description "sham-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf local-ip-addr {
           type inet:ip-address;
           description "Sham link local address.";
         }

         leaf remote-ip-addr {
           type inet:ip-address;
           description "Sham link remote address.";
         }
       }
       leaf packet-type {
         type packet-type;
         description "OSPF packet type.";
       }

       leaf error {
         type enumeration {
           enum "badVersion" {
             description "Bad version.";
           }
           enum "areaMismatch"
           enum "areaMismatch" {
             description "Area mistmatch.";
           }
           enum "unknownNbmaNbr" {
             description "Unknown NBMA neighbor.";
           }
           enum "unknownVirtualNbr" {
             description "Unknown virtual link neighbor.";
           }
           enum "authTypeMismatch" {
             description "Auth type mismatch.";
           }
           enum "authFailure" {
             description "Auth failure.";
           }
           enum "netMaskMismatch" {
             description "Network mask mismatch.";
           }
           enum "helloIntervalMismatch" {
             description "Hello interval mismatch.";
           }
           enum "deadIntervalMismatch" {
             description "Dead interval mismatch.";
           }
           enum "optionMismatch" {
             description "Option mismatch.";
           }
           enum "mtuMismatch" {
             description "MTU mismatch.";
           }
           enum "duplicateRouterId" {
             description "Duplicate router ID.";
           }
           enum "noError" {
             description "No error.";
           }
         }
         description "Error code.";
       }
       description
         "This notification is sent when interface
          config error is detected.";
     }

     notification nbr-state-change {
       uses notification-instance-hdr;

       leaf link-type {
         type identityref {
           base if-link-type;
         }
         description "Type of OSPF interface.";
       }

       container interface {
         description "Normal interface.";
         leaf interface {
           type if:interface-ref;
           description "Interface.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
         leaf neighbor-ip-addr {
           type yang:dotted-quad;
           description "Neighbor address.";
         }
       }
       container virtual-link {
         description "virtual-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
       }
       container sham-link {
         description "sham-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf local-ip-addr {
           type inet:ip-address;
           description "Sham link local address.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
         leaf neighbor-ip-addr {
           type yang:dotted-quad;
           description "Neighbor address.";
         }
       }
       uses notification-interface;
       uses notification-neighbor;

       leaf state {
         type nbr-state-type;
         description "Neighbor state.";
       }

       description
         "This notification is sent when neighbor
          state change is detected.";
     }

     notification nbr-restart-helper-status-change {
       uses notification-instance-hdr;

       leaf link-type {
         type identityref {
           base if-link-type;
         }
         description "Type of OSPF interface.";
       }

       container interface {
         description "Normal interface.";
         leaf interface {
           type if:interface-ref;
           description "Interface.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
         leaf neighbor-ip-addr {
           type yang:dotted-quad;
           description "Neighbor address.";
         }

       }
       container virtual-link {
         description "virtual-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
       }
       uses notification-interface;
       uses notification-neighbor;

       leaf status {
         type restart-helper-status-type;
         description "Restart helper status.";
       }

       leaf age {
         type uint32;
         units seconds;
         description
           "Remaining time in current OSPF graceful restart
            interval, if the router is acting as a restart
            helper for the neighbor.";
       }

       leaf exit-reason {
         type restart-exit-reason-type;
         description
           "Restart helper exit reason.";
       }
       description
         "This notification is sent when a neighbor restart
          helper status change is detected.";
     }

     notification rx-bad-packet {
       uses notification-instance-hdr;
       uses notification-interface;

       leaf link-type {
         type identityref {
           base if-link-type;
         }
         description "Type of OSPF interface.";
       }

       container interface {
         description "Normal interface.";
         leaf interface {
           type if:interface-ref;
           description "Interface.";
         }
         leaf packet-source packet-source {
         type yang:dotted-quad;
         description "Source address.";
       }
       }
       container virtual-link {
         description "virtual-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf neighbor-router-id {
           type yang:dotted-quad;
           description "Neighbor router id.";
         }
       }

       container sham-link {
         description "sham-link.";
         leaf area-id {
           type uint32;
           description "Area ID.";
         }
         leaf local-ip-addr {
           type inet:ip-address;
           description "Sham link local address.";
         }

         leaf remote-ip-addr {
           type inet:ip-address;
           description "Sham link remote address.";
         }
       }

       leaf packet-type {
         type packet-type;
         description "OSPF packet type.";
       }

       description
         "This notification is sent when an OSPF packet
          has been received on a interface that
          cannot be parsed."; parsed is received on an OSPF interface.";
     }
     notification lsdb-approaching-overflow {
       uses notification-instance-hdr;

       leaf ext-lsdb-limit {
         type uint32;
         description
           "The maximum number of non-default AS-external LSAs
            entries that can be stored in the link state database.";
       }

       description
         "This notification is sent when the number of LSAs
          in the router's link state database has exceeded
          ninety percent of the ext-lsdb-limit.";

     }

     notification lsdb-overflow {
       uses notification-instance-hdr;

       leaf ext-lsdb-limit {
         type uint32;
         description
           "The maximum number of non-default AS-external LSAs
            entries that can be stored in the link state database.";
       }

       description
         "This notification is sent when the number of LSAs
          in the router's link state database has exceeded
          ext-lsdb-limit.";
     }

     notification nssa-translator-status-change {
       uses notification-instance-hdr;

       leaf area-id {
         type uint32; area-id-type;
         description "Area ID.";
       }

       leaf status {
         type nssa-translator-state-type;
         description
           "NSSA translator status.";
       }

       description
         "This notification is sent when there is a change
          in the router's ability to translate role in translating OSPF NSSA LSAs
          to OSPF AS-External LSAs.";
     }

     notification restart-status-change {
       uses notification-instance-hdr;

       leaf status {
         type restart-status-type;
         description
           "Restart status.";
       }

       leaf restart-interval {
         type uint16 {
           range "1..1800";
         }
         units seconds;
         default "120";
         description
           "Restart interval.";
       }

       leaf exit-reason {
         type restart-exit-reason-type;
         description
           "Restart exit reason.";
       }

       description
         "This notification is sent when the graceful restart
          state for the router has changed.";
     }
   }
   <CODE ENDS>
         ]]</artwork>
       </figure>
     </t>
     </section>

     <section title="OSPF

6.  OSPF Segment Routing Yang Module">
     <t>
       <figure>
         <artwork><![CDATA[ Module

   <CODE BEGINS> file "ietf-ospf-sr@2015-09-02.yang" "ietf-ospf-sr@2015-10-19.yang"
   module ietf-ospf-sr {
     namespace "urn:ietf:params:xml:ns:yang:ietf-ospf-sr";

     prefix ospf-sr;

     import ietf-inet-types {
       prefix "inet";
     }

     import ietf-yang-types {
       prefix "yang";
     }

     import ietf-routing {
       prefix "rt";
     }
     import ietf-segment-routing {
       prefix "sr";
     }
     import ietf-ospf {
       prefix "ospf";
     }
     organization
       "Cisco Systems
        170 West Tasman Drive
        San Jose, CA 95134-1706
        USA";

     contact
        "WG Web:   <http://tools.ietf.org/wg/ospf/>
         WG List:  <mailto:ospf@ietf.org>

         WG Chair: Acee Lindem
                   <mailto:acee@cisco.com>

         WG Chair: Abhay Roy
                   <mailto:akr@cisco.com>

         Editor:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Yingzhen Qu
                   <mailto:yiqu@cisco.com>
         Author:   Acee Lindem
                   <mailto:acee@cisco.com>
         Author:   Jeffrey Zhang
                   <mailto:zzhang@juniper.net>
         Author:   Ing-Wher Chen
                   <mailto:ing-wher.chen@ericsson.com>
         Author:   Greg Hankins
                   <mailto:greg.hankins@alcatel-lucent.com>";

     description
       "This YANG module defines the generic configuration
        data
        and operational state for OSPF, OSPF Segment Routing, which is
        common across all of the vendor
        implementations of the protocol. implementations. It is
        intended that the module will be extended by vendors to
        define vendor-specific OSPF Segment Routing configuration
        and operational parameters and policies,
        for example route maps or route policies.

        Terms and Acronyms

        OSPF (ospf): Open Shortest Path First

        IP (ip): Internet Protocol

        IPv4 (ipv4):Internet Protocol Version 4

        IPv6 (ipv6): Internet Protocol Version 6

        MTU (mtu) Maximum Transmission Unit

       ";

     revision 2015-10-19 {
       description
         "* Add per-protocol SRGB support.
          * Editorial changes.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF Segment Routing.";
     }

     revision 2015-09-02 {
       description
         "* Author list update.
          * Editorial changes.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF Segment Routing"; Routing.";
     }

     revision 2015-07-06 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF Segment Routing"; Routing.";
     }

     feature ti-lfa {
       description
         "Enhance IPFRR with ti-lfa support";
         "Topology-Independent Loop-Free Alternate (TI-LFA)
          computation using segment routing.";
     }

     /* Configuration */

     augment "/rt:routing/rt:routing-instance/rt:routing-protocols"
           + "/rt:routing-protocol/ospf:ospf/ospf:instance" {
       when "../../rt:type = 'ospf:ospfv2' or "
          + "../../rt:type = 'ospf:ospfv3'" {
         description
           "This augment augments the OSPF routing protocol when used"; used.";
       }
       description
         "This augments the OSPF protocol configuration
          with segment routing.";
       uses sr:controlplane-cfg;
       container protocol-srgb {
         if-feature sr:protocol-srgb;
         uses sr:srgb-cfg;
         description
           "Per-protocol SRGB.";
       }
     }

     augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "rt:routing-protocol/ospf:ospf/ospf:instance/"
           + "ospf:areas/ospf:area/ospf:interfaces/ospf:interface" {
       when "../../../../../../rt:type = 'ospf:ospfv2' or "
          + "../../../../../../rt:type = 'ospf:ospfv3'" {
         description
           "This augment augments the OSPF routing protocol interface configuration
            when used"; used.";
       }
       description
         "This augments the OSPF protocol interface
          configuration with segment routing.";

       uses sr:igp-interface-cfg;
     }

     augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "rt:routing-protocol/ospf:ospf/ospf:instance/"
           + "ospf:areas/ospf:area/ospf:interfaces/ospf:interface/"
           + "ospf:fast-reroute" {
       when "../../../../../../../rt:type = 'ospf:ospfv2' or "
          + "../../../../../../../rt:type = 'ospf:ospfv3'" {
         description
           "This augment augments the OSPF routing protocol when used"; used.";
       }
       description
         "This augments ISIS IP FRR the OSPF protocol IP-FRR with TILFA."; TI-LFA.";

       container ti-lfa {
         if-feature ti-lfa;
         leaf enable {
           type boolean;
           description
            "Enables TI-LFA computation.";
         }
         description
           "TILFA configuration.";
           "Topology Independent Loop Free Alternate
            (TI-LFA) support.";
       }
     }

     /* Operational states */

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance" {
       when "../../rt:type = 'ospf:ospfv2' or "
          + "../../rt:type = 'ospf:ospfv3'" {
         description
           "This augment augments the OSPF routing protocol when used"; used.";
       }
       description
        "This augments the OSPF protocol configuration operational state
         with segment routing.";

       uses sr:controlplane-cfg;
       container protocol-srgb {
         if-feature sr:protocol-srgb;
         uses sr:srgb-cfg;
         description
           "Per-protocol SRGB.";
       }
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:interfaces/ospf:interface" {
       when "../../../../../../rt:type = 'ospf:ospfv2' or "
          + "../../../../../../rt:type = 'ospf:ospfv3'" {
         description
         "This augment augments the OSPF routing protocol when used"; used.";
       }
       description
        "This augments the OSPF protocol configuration interface
         operational state with segment routing.";

       uses sr:igp-interface-cfg;
     }

     /* Database */

     grouping sid-sub-tlv {
       description "SID/Label sub-tlv sub-TLV grouping.";
       container sid-sub-tlv {
         description
           "Used to advertise the SID/Label associated with a
            prefix or adjacency.";
         leaf sid {
           type uint32;
           description "A
             "Segment Identifier (SID) - A 20 bit label or
              32 bit SID.";
         }
       }
     }

     grouping prefix-sid-sub-tlvs {
       description "Prefix SID sub-tlvs"; Segment ID (SID) sub-TLVs.";
       container perfix-sid-sub-tlvs{
         description "prefix sid sub-tlv."; "Prefix SID sub-TLV.";
         list prefix-sid-sub-tlv {
           description "prefix sid sub-tlv."; "Prefix SID sub-TLV.";
           leaf flags {
             type bits {
               bit NP {
                 description
                   "No-PHP flag.";
               }
               bit M {
                 description
                   "Mapping server flag.";
               }
               bit E {
                 description
                   "Explicit-NULL flag.";
               }
               bit V {
                 description
                   "Value/Index flag.";
               }
               bit L {
                 description
                   "Local flag.";
               }
             }
             description "Flags."; "Segment Identifier (SID) Flags.";
           }
           leaf mt-id {
             type uint8;
             description "Multi-topology ID.";
           }
           leaf algorithm {
             type uint8;
             description
               "The algorithm the prefix-sid is associated with."; with the prefix-SID.";
           }
           leaf sid {
             type uint32;
             description "An index or label.";

           }
         }
       }
     }

     grouping sid-binding-sub-tlvs {
       description "SID/Label binding sub-tlv sub-TLV grouping.";
       container sid-binding-sub-tlvs {
         description "sid "SID binding sub-tlvs."; sub-TLVs.";
         list sid-binding-sub-tlv {
           description "sid "SID binding sub-tlv."; sub-TLV.";
           leaf flags {
             type bits {
               bit M {
                 description
                   "Mirroring context flag.";
               }
             }
             description "Flags.";
           }
           leaf mt-id {
             type uint8;
             description "Multi-topology ID.";
           }
           leaf weight {
             type uint8;
             description "Weight for load-balancing purposes.";
           }

           uses sid-sub-tlv;

           container ero-metric-sub-tlv {
             description
               "The cost of an ERO Explicit Route Object (ERO) path.";
             leaf metric {
               type uint32;
               description "The aggregate IGP or TE path cost.";
             }
           }

           container ipv4-ero-sub-tlv {
             description
               "The ipv4 IPv4 ERO sub-tlv sub-TLV describes a path segment
                using ipv4 IPv4 address.";
             leaf flags {
               type bits {
                 bit L {
                   description
                     "If set, then the segment path is designated as
                      'loose'. Otherwise as Otherwise, the path is 'strict'.";
                 }
               }
               description "Flags."; "ERO Flags.";
             }
             leaf ipv4-address {
               type inet:ipv4-address;
               description "The address of the explicit route hop.";
             }
           }
           container unnumbered-ero-sub-tlv {
             description "The unnumbered interface ID ERO sub-tlv sub-TLV
                          describes a path segment that includes an
                          unnumbered interface.";
             leaf flags {
               type bits {
                 bit L {
                   description
                     "If set, then the segment path is designated as
                      'loose'. Otherwise as 'strict'.";
                 }
               }
               description "Flags."; "ERO Flags.";
             }
             leaf router-id {
               type yang:dotted-quad;
               description "Router-id of the next-hop.";
             }
             leaf interface-id {
               type uint32;
               description
                 "The identifier assigned to the link by the
                  router specified by the router-id.";
             }
           }
           container ipv4-backup-ero-sub-tlv {
             description
               "The ipv4 IPv4 backup ERO sub-tlv sub-TLV describes a path
                segment using ipv4 IPv4 address.";
             leaf flags {
               type bits {
                 bit L {
                   description
                     "If set, then the segment path is designated as
                      'loose'. Otherwise as 'strict'.";
                 }
               }
               description "Flags.";
             }
             leaf ipv4-address {
               type inet:ipv4-address;
               description "The address of the explicit route hop.";
             }
           }
           container unnumbered-backup-ero-sub-tlv {
             description
               "The unnumbered interface ID backup ERO sub-tlv sub-TLV
                describes a path segment that includes an
                unnumbered interface.";
             leaf flags {
               type bits {
                 bit L {
                   description
                     "If set, then the segment path is designated as
                      'loose'. Otherwise as Otherwise, the path is 'strict'.";
                 }
               }
               description "Flags.";
             }
             leaf router-id {
               type yang:dotted-quad;
               description "Router-id of the next-hop.";
             }
             leaf interface-id {
               type uint32;
               description
                 "The identifier assigned to the link by the
                 router specified by the router-id.";
             }
           }
         }
       }
     }

     grouping extended-prefix-range-tlvs {
       description "Extended prefix range TLV grouping.";

       container extended-prefix-range-tlvs {
         description "The list of range of prefixes.";
         list extended-prefix-range-tlv {    //type=2?
           description "The range of prefixes.";
           leaf range-size {
             type uint16;
             description "The number of prefixes covered by the
                          advertisement.";

           }
           leaf flags {
             type bits {
               bit IA {
                 description
                   "Inter-Area flag.";
               }
             }
             description "Flags.";
           }
           leaf prefix {
             type inet:ip-prefix;
             description "Address prefix.";
           }
           uses prefix-sid-sub-tlvs;
           uses sid-binding-sub-tlvs;
           uses ospf:unknown-tlvs;
         }
       }
     }

     grouping sr-algorithm-tlv {
       description "SR algorithm TLV grouping.";
       container sr-algorithm-tlv {
         description "All SR algorithm TLVs.";
         leaf-list sr-algorithm {
           type uint8;
           description
             "The Segment Routing (SR) algorithms that the router is
              currently using.";
         }
       }
     }

     grouping sid-range-tlvs {
       description "sid-range-tlvs grouping.";
       container "SID Range TLV grouping.";
       container sid-range-tlvs {
         description "List of SID range TLVs.";
         list sid-range-tlv {
           description "SID range TLV.";
           leaf range-size {
             type ospf:uint24;
             description "The SID range.";
           }
           uses sid-sub-tlv;
         }
       }
     }
     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:interfaces/ospf:interface/ospf:database/"
           + "ospf:link-scope-lsa-type/ospf:link-scope-lsas/"
           + "ospf:link-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque/"
           + "ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv" {
       when "../../../../../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       description
         "SR specific TLVs for OSPFv2 extended prefix TLV
          in type 9 opaque LSA.";
       uses prefix-sid-sub-tlvs;
       uses sid-binding-sub-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/"
           + "ospf:area/ospf:database/"
           + "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
           + "ospf:area-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque/"
           + "ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv" {
       when "../../../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       description
         "SR specific TLVs for OSPFv2 extended prefix TLV
          in type 10 opaque LSA.";
       uses prefix-sid-sub-tlvs;
       uses sid-binding-sub-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:database/"
           + "ospf:as-scope-lsa-type/ospf:as-scope-lsas/"
           + "ospf:as-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque/"
           + "ospf:extended-prefix-tlvs/ospf:extended-prefix-tlv" {
       when "../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       description
         "SR specific TLVs for OSPFv2 extended prefix TLV
          in type 11 opaque LSA.";
       uses prefix-sid-sub-tlvs;
       uses sid-binding-sub-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/"
           + "ospf:area/ospf:database/"
           + "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
           + "ospf:area-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque/"
           + "ospf:extended-link-tlvs/ospf:extended-link-tlv" {
       when "../../../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augment augmentation is only valid for OSPFv2.";
       }
       description
         "SR specific TLVs for OSPFv2 extended link TLV
          in type 10 opaque LSA.";

       container adj-sid-sub-tlvs {
         description "Adj-sid is "Adjacency SID optional sub-tlv."; sub-TLVs.";
         list adj-sid-sub-tlv {
           description "List of adj-sid sub-tlv."; Adjacency SID sub-TLVs.";
           leaf flags {
             type bits {
               bit B {
                 description
                   "Backup flag.";
               }
               bit V {
                 description
                   "Value/Index flag.";
               }
               bit L {
                 description
                   "Local/Global flag.";
               }
               bit S {
                 description
                   "Set flag.";
               }
             }
             description "Flags.";
           }
           leaf mt-id {
             type uint8;
             description "Multi-topology ID.";
           }
           leaf weight {
             type uint8;
             description "Weight used for load-balancing.";
           }
           leaf sid {
             type uint32;
             description "sid "Segment Identifier (SID) index/label.";
           }
         }
       }

       container lan-adj-sid-sub-tlvs {
         description "Lan adj-sid is "LAN Adjacency SID optional sub-tlv."; sub-TLVs.";
         list lan-adj-sid-sub-tlv {
           description "List of lan-adj-sid sub-tlv."; LAN adjacency SID sub-TLVs.";
           leaf flags {
             type bits {
               bit B {
                 description
                   "Backup flag.";
               }
               bit V {
                 description
                   "Value/Index flag.";
               }
               bit L {
                 description
                   "Local/Global flag.";
               }
               bit S {
                 description
                   "Set flag.";
               }
             }
             description "Flags.";
           }
           leaf mt-id {
             type uint8;
             description "Multi-topology ID.";

           }
           leaf weight {
             type uint8;
             description "Weight used for load-balancing.";
           }
           leaf neighbor-router-id {
             type yang:dotted-quad;
             description "Neighbor router ID."; "Neighbor router ID.";
           }
           leaf sid {
             type uint32;
             description "Segment Identifier (SID) index/label.";
           }
         }
       }
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:interfaces/ospf:interface/ospf:database/"
           + "ospf:link-scope-lsa-type/ospf:link-scope-lsas/"
           + "ospf:link-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque" {
       when "../../../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augmentation is only valid for OSPFv2.";
       }

       description
         "SR specific TLVs for OSPFv2 type 9 opaque LSA.";

       uses extended-prefix-range-tlvs;
       uses sr-algorithm-tlv;
       uses sid-range-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/"
           + "ospf:area/ospf:database/"
           + "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
           + "ospf:area-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque" {
       when "../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augmentation is only valid for OSPFv2.";
       }

       description
         "SR specific TLVs for OSPFv2 type 10 opaque LSA.";

       uses extended-prefix-range-tlvs;
       uses sr-algorithm-tlv;
       uses sid-range-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:database/"
           + "ospf:as-scope-lsa-type/ospf:as-scope-lsas/"
           + "ospf:as-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque" {
       when "../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'" {
         description
           "This augmentation is only valid for OSPFv2.";
       }
       description
         "SR specific TLVs for OSPFv2 type 11 opaque LSA.";

       uses extended-prefix-range-tlvs;
       uses sr-algorithm-tlv;
       uses sid-range-tlvs;
     }
   }
   <CODE ENDS>

7.  OSPF BFD Yang Module

   <CODE BEGINS> file "ietf-ospf-bfd@2015-10-19.yang"
   module ietf-ospf-bfd {
     namespace "urn:ietf:params:xml:ns:yang:ietf-ospf-bfd";

     prefix ospf-bfd;

     import ietf-routing {
       prefix "rt";
     }
     import ietf-bfd {
       prefix "bfd";
     }
     import ietf-ospf {
       prefix "ospf";

     }

     organization
       "Cisco Systems
        170 West Tasman Drive
        San Jose, CA 95134-1706
        USA";

     contact
        "WG Web:   <http://tools.ietf.org/wg/ospf/>
         WG List:  <mailto:ospf@ietf.org>

         WG Chair: Acee Lindem
                   <mailto:acee@cisco.com>

         WG Chair: Abhay Roy
                   <mailto:akr@cisco.com>

         Editor:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Derek Yeung
                   <mailto:myeung@cisco.com>
         Author:   Yingzhen Qu
                   <mailto:yiqu@cisco.com>
         Author:   Acee Lindem
                   <mailto:acee@cisco.com>
         Author:   Jeffrey Zhang
                   <mailto:zzhang@juniper.net>
         Author:   Ing-Wher Chen
                   <mailto:ing-wher.chen@ericsson.com>
         Author:   Greg Hankins
                   <mailto:greg.hankins@alcatel-lucent.com>";

     description
       "This YANG module defines the generic configuration
        and operational state for OSPF BFD, which is common
        across all of the vendor implementations. It is
        intended that the module will be extended by vendors to
        define vendor-specific OSPF BFD configuration
        and operational parameters and policies.

        Terms and Acronyms

        OSPF (ospf): Open Shortest Path First

        IP (ip): Internet Protocol

        IPv4 (ipv4):Internet Protocol Version 4
        IPv6 (ipv6): Internet Protocol Version 6
       ";

     revision 2015-10-19 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Data Model for OSPF BFD.";
     }
           leaf sid

     feature bfd-protocol-parms {
             type uint32;
       description "sid index/label.";
           }
         }
       }
         "OSPF BFD protocol specific parameters support.";
     }

     /* Configuration */

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:interfaces/ospf:interface/ospf:database/"
           + "ospf:link-scope-lsa-type/ospf:link-scope-lsas/" "/rt:routing/rt:routing-instance/rt:routing-protocols/"
           + "ospf:link-scope-lsa/ospf:version/ospf:ospfv2/" "rt:routing-protocol/ospf:ospf/ospf:instance/"
           + "ospf:ospfv2/ospf:body/ospf:opaque" "ospf:areas/ospf:area/ospf:interfaces/ospf:interface" {
       when "../../../../../../../../../../../../../../../" "../../../../../../rt:type = 'ospf:ospfv2' or "
          + "rt:type "../../../../../../rt:type = 'ospf:ospfv2'" 'ospf:ospfv3'" {
         description
         "This augment is only valid for OSPFv2."; augments the OSPF routing protocol when used";
       }
       description
         "SR specific TLVs for OSPFv2 type 9 opaque LSA.";

       uses extended-prefix-range-tlvs;
       uses sr-algorithm-tlv;
       uses sid-range-tlvs;
     }

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:areas/"
           + "ospf:area/ospf:database/"
           + "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
           + "ospf:area-scope-lsa/ospf:version/ospf:ospfv2/"
           + "ospf:ospfv2/ospf:body/ospf:opaque"
        "This augments OSPF protocol configuration
         with BFD.";

       container bfd {
       when "../../../../../../../../../../../../../"
          + "rt:type = 'ospf:ospfv2'"
         description "BFD configuration.";
         leaf enabled {
           type boolean;
           default false;
           description
           "This augment
             "True if BFD is only valid enabled for OSPFv2."; the OSPF interface.";
         }
       description
         "SR specific TLVs for OSPFv2 type 10 opaque LSA.";

       uses extended-prefix-range-tlvs;
         uses sr-algorithm-tlv;
       uses sid-range-tlvs; bfd:bfd-grouping-base-cfg-parms {
           if-feature bfd-protocol-parms;
         }
       }
     }

     /* Operational states */

     augment "/rt:routing-state/rt:routing-instance/"
           + "rt:routing-protocols/rt:routing-protocol/"
           + "ospf:ospf/ospf:instance/ospf:database/"
           + "ospf:as-scope-lsa-type/ospf:as-scope-lsas/"
           + "ospf:as-scope-lsa/ospf:version/ospf:ospfv2/" "ospf:ospf/ospf:instance/ospf:areas/ospf:area/"
           + "ospf:ospfv2/ospf:body/ospf:opaque" "ospf:interfaces/ospf:interface" {
       when "../../../../../../../../../../../" "../../../../../../rt:type = 'ospf:ospfv2' or "
          + "rt:type "../../../../../../rt:type = 'ospf:ospfv2'" 'ospf:ospfv3'" {
         description
         "This augment is only valid for OSPFv2."; augments the OSPF routing protocol when used";
       }
       description
         "SR specific TLVs for OSPFv2
        "This augments OSPF protocol operation
         with BFD.";

       container bfd {
         description "BFD operation.";
         leaf enabled {
           type 11 opaque LSA.";

       uses extended-prefix-range-tlvs;
       uses sr-algorithm-tlv; boolean;
           description
             "True if BFD is enabled for the OSPF interface.";
         }
         uses sid-range-tlvs; bfd:bfd-grouping-base-cfg-parms {
           if-feature bfd-protocol-parms;
         }
       }
     }
   }
   <CODE ENDS>

5.

8.  Security Considerations

   The data model defined does not create any security implications.

   This draft does not change any underlying security issues inherent in
   [I-D.ietf-netmod-routing-cfg].

6.

9.  Acknowledgements

   The authors wish to thank Acee Lindem, Yi Yang, Alexander Clemm,
   Gaurav Gupta, Ing-Wher Chen, Ladislav Lhotka, Stephane Litkowski,
   Greg Hankins and Manish Gupta for their thorough reviews and helpful
   comments.

   This document was produced using Marshall Rose's xml2rfc tool.

7.

10.  References

7.1.

10.1.  Normative References

   [RFC1793]  Moy, J., "Extending OSPF to Support Demand Circuits",
              RFC 1793, DOI 10.17487/RFC1793, April 1995,
              <http://www.rfc-editor.org/info/rfc1793>.

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

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328,
              DOI 10.17487/RFC2328, April 1998,
              <http://www.rfc-editor.org/info/rfc2328>.

   [RFC3101]  Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option",
              RFC 3101, DOI 10.17487/RFC3101, January 2003,
              <http://www.rfc-editor.org/info/rfc3101>.

   [RFC3623]  Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF
              Restart", RFC 3623, DOI 10.17487/RFC3623, November 2003,
              <http://www.rfc-editor.org/info/rfc3623>.

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

   [RFC4577]  Rosen, E., Psenak, P., and P. Pillay-Esnault, "OSPF as the
              Provider/Customer Edge Protocol for BGP/MPLS IP Virtual
              Private Networks (VPNs)", RFC 4577, DOI 10.17487/RFC4577,
              June 2006, <http://www.rfc-editor.org/info/rfc4577>.

   [RFC4750]  Joyal, D., Ed., Galecki, P., Ed., Giacalone, S., Ed.,
              Coltun, R., and F. Baker, "OSPF Version 2 Management
              Information Base", RFC 4750, DOI 10.17487/RFC4750,
              December 2006, <http://www.rfc-editor.org/info/rfc4750>.

   [RFC5187]  Pillay-Esnault, P. and A. Lindem, "OSPFv3 Graceful
              Restart", RFC 5187, DOI 10.17487/RFC5187, June 2008,
              <http://www.rfc-editor.org/info/rfc5187>.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
              <http://www.rfc-editor.org/info/rfc5340>.

   [RFC5643]  Joyal, D., Ed. and V. Manral, Ed., "Management Information
              Base for OSPFv3", RFC 5643, DOI 10.17487/RFC5643, August
              2009, <http://www.rfc-editor.org/info/rfc5643>.

   [RFC5838]  Lindem, A., Ed., Mirtorabi, S., Roy, A., Barnes, M., and
              R. Aggarwal, "Support of Address Families in OSPFv3",
              RFC 5838, DOI 10.17487/RFC5838, April 2010,
              <http://www.rfc-editor.org/info/rfc5838>.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
              <http://www.rfc-editor.org/info/rfc5880>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://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,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC7223]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 7223, DOI 10.17487/RFC7223, May 2014,
              <http://www.rfc-editor.org/info/rfc7223>.

7.2.

10.2.  Informative References

   [I-D.acee-rtg-yang-key-chain]
              Lindem, A., Qu, Y., Yeung, D., Chen, H., Zhang, J., and Y.
              Yang, "Key Chain YANG Data Model", draft-acee-rtg-yang-
              key-chain-07
              key-chain-09 (work in progress), July October 2015.

   [I-D.ietf-bfd-yang]
              Zheng, L., Rahman, R., Networks, J., Jethanandani, M., and
              G. Mirsky, "Yang Data Model for Bidirectional Forwarding
              Detection (BFD)", draft-ietf-bfd-yang-00 (work in
              progress), August 2015.

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", draft-ietf-netmod-routing-cfg-19 draft-ietf-netmod-routing-cfg-20 (work in
              progress), May October 2015.

   [I-D.ietf-spring-sr-yang]
              Litkowski, S., Qu, Y., Sarkar, P., and J. Tantsura, "YANG
              Data Model for Segment Routing", draft-ietf-spring-sr-
              yang-00 (work in progress), July 2015.

Authors' Addresses
   Derek Yeung
   Cisco Systems
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   EMail: myeung@cisco.com

   Yingzhen Qu
   Cisco Systems
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   EMail: yiqu@cisco.com

   Jeffrey Zhang
   Juniper Networks
   10 Technology Park Drive
   Westford, MA  01886
   USA

   EMail: zzhang@juniper.net

   Dean Bogdanovic

   EMail: ivandean@gmail.com

   Kiran Koushik Agrahara Sreenivasa
   Cisco Systems
   12515 Research Blvd, Bldg 4
   Austin, TX  78681
   USA

   EMail: kkoushik@cisco.com