DetNet                                                     B. Varga, Ed.
Internet-Draft                                                 J. Farkas
Intended status: Standards Track                                Ericsson
Expires: November 6, 2019 April 29, 2020                                         A. Malis
                                                             Independent
                                                               S. Bryant
                                                     Huawei
                                                  Futurewei Technologies
                                                             J. Korhonen
                                                             May 5,
                                                        October 27, 2019

DetNet Data Plane: MPLS over IEEE 802.1 Time Sensitive Networking (TSN)
                   draft-ietf-detnet-mpls-over-tsn-00
                   draft-ietf-detnet-mpls-over-tsn-01

Abstract

   This document specifies the Deterministic Networking MPLS data plane
   when operating over a TSN network. sub-network.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Terms Used in This Document . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   4
   3.   3
     2.3.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   4.   4
   3.  DetNet MPLS Data Plane Overview . . . . . . . . . . . . . . .   5
     4.1.  Layers of DetNet Data Plane . . . . . . . . . . . . . . .   5
     4.2.  DetNet MPLS Data Plane Scenarios  . . . . . . . . . . . .   6
     4.3.  Packet Flow Example with Service Protection . . . . . . .   9
   5.  DetNet MPLS Data Plane Considerations . . . . . . . . . . . .  11
     5.1.  Sub-Network Considerations  . . . . . . . . . . . . . . .  12
   6.   4
   4.  DetNet MPLS Operation Over IEEE 802.1 TSN Sub-Networks  . . .  12
     6.1.  Mapping of   5
     4.1.  Functions for DetNet Flow to TSN Stream ID and Sequence Number  . Mapping . . . . .  14
     6.2.   7
     4.2.  TSN Usage requirements of FRER . . . . . . . . . . . . . . . . . . . .  15
     6.3.  Procedures  . . . . . . . . . . . . . MPLS DetNet nodes . . . . . . . . . .  16
     6.4.  Layer 2 Addressing and QoS Considerations   7
     4.3.  Service protection within the TSN sub-network . . . . . .   9
     4.4.  Aggregation during DetNet flow to TSN Stream mapping  . .  16
   7.   9
   5.  Management and Control Considerations Implications . . . . . . . . . . . .  16
   8. .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   9.  11
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   10.  11
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  17
   11.  11
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     11.1.  11
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  17
     11.2.  11
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  19
   Appendix A.  Example of DetNet Data Plane Operation . . . . . . .  23  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23  13

1.  Introduction

   [Editor's note: Introduction to be made specific to DetNet MPLS over
   TSN scenario.  May be similar to intro of DetNet IP over TSN.].

   Deterministic Networking (DetNet) is a service that can be offered by
   a network to DetNet flows.  DetNet provides these flows with a low
   packet loss rates and assured maximum end-to-end delivery latency.
   General background and concepts of DetNet can be found in
   [I-D.ietf-detnet-architecture].

   The DetNet Architecture decomposes the DetNet related data plane
   functions into two sub-layers: a service sub-layer and a forwarding
   sub-layer.  The service sub-layer is used to provide DetNet service
   protection and reordering.  The forwarding sub-layer is used to
   provides congestion protection (low loss, assured latency, and
   limited reordering) leveraging MPLS Traffic Engineering mechanisms.

   This document

   [I-D.ietf-detnet-mpls] specifies the DetNet data plane operation and the on-
   wire encapsulation of DetNet flows over an for
   MPLS-based Packet Switched Network (PSN).  The specified encapsulation provides the building
   blocks to enable the DetNet service and forwarding sub-layer
   functions and supports flow identification as described in the DetNet
   Architecture.  As part of the service sub-layer functions, this
   document describes DetNet node data plane operation.  It also
   describes the function and operation of the Packet Replication (PRF)
   Packet Elimination (PEF) and Packet Ordering (POF) functions with an
   MPLS data plane.  It also describes an MPLS-based DetNet forwarding
   sub-layer that eliminates (or reduces) contention loss and provides
   bounded latency for DetNet flows.

   MPLS encapsulated  MPLS encapsulated DetNet
   flows can be carried over network technologies that can provide the
   DetNet required level of service.  This document defines examples of such, specifically carrying DetNet focuses on the
   scenario where MPLS flows over (DetNet) nodes are interconnected by a IEEE 802.1
   TSN sub-networks, and over DetNet IP PSN.

   The intent is for this document to support different traffic types
   being mapped over DetNet MPLS, but this is out side the scope of this
   document.  An example of such can be found in
   [I-D.ietf-detnet-dp-sol-ip].  This document also allows for, but does
   not define, associated controller plane and Operations,
   Administration, and Maintenance (OAM) functions. sub-network.

2.  Terminology

   [Editor's note: Needs clean up.].

2.1.  Terms Used in This Document

   This document uses the terminology established in the DetNet
   architecture [I-D.ietf-detnet-architecture], [I-D.ietf-detnet-architecture] and
   [I-D.ietf-detnet-mpls], and the reader is assumed to be familiar with
   that document and its terminology.

   The following terminology is introduced in this document:

   F-Label       A Detnet "forwarding" label that identifies the LSP
                 used to forward a DetNet flow across an MPLS PSN, e.g.,
                 a hop-by-hop label used between label switching routers
                 (LSR).

   S-Label       A DetNet "service" label that is used between DetNet
                 nodes that implement also the DetNet service sub-layer
                 functions.  An S-Label is also used to identify a
                 DetNet flow at DetNet service sub-layer.

   d-CW          A DetNet Control Word (d-CW) is used for sequencing and
                 identifying duplicate packets of a DetNet flow at the
                 DetNet service sub-layer.

2.2.  Abbreviations

   The following abbreviations are used in this document:

   AC            Attachment Circuit.

   CE            Customer Edge equipment.

   CoS           Class of Service.

   CW            Control Word.

   DetNet        Deterministic Networking.

   DF            DetNet Flow.

   DN-IWF        DetNet Inter-Working Function.

   FRER          Frame Replication and Elimination for Redundancy (TSN
                 function).

   L2            Layer 2.

   L2VPN         Layer 2 Virtual Private Network.

   L3            Layer 3.

   LSR           Label Switching Router.

   MPLS          Multiprotocol Label Switching.

   MPLS-TE       Multiprotocol Label Switching - Traffic Engineering.

   MPLS-TP       Multiprotocol Label Switching - Transport Profile.

   MS-PW         Multi-Segment PseudoWire (MS-PW).

   NSP           Native Service Processing.

   OAM           Operations, Administration, and Maintenance.

   PE            Provider Edge.

   PEF           Packet Elimination Function.

   PRF           Packet Replication Function.

   PREOF         Packet Replication, Elimination and Ordering Functions.

   POF           Packet Ordering Function.

   PSN           Packet Switched Network.

   PW            PseudoWire.

   QoS           Quality of Service.

   S-PE          Switching Provider Edge.

   T-PE          Terminating Provider Edge.

   TSN           Time-Sensitive Network.

3.

2.3.  Requirements Language

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

4.

3.  DetNet MPLS Data Plane Overview

   [Editor's note: simplify this section and highlight DetNet MPLS over
   subnets scenario being the focus

   The basic approach defined in the remaining part of the
   document.].

4.1.  Layers of DetNet Data Plane

   This document describes how DetNet flows are carried over MPLS
   networks.  The DetNet Architecture, [I-D.ietf-detnet-architecture],
   decomposes the DetNet data plane into two sub-layers: a service sub-
   layer and a forwarding sub-layer.  The basic approach defined in this
   document supports [I-D.ietf-detnet-mpls] supports the
   DetNet service sub-layer based on existing pseudowire (PW)
   encapsulations and mechanisms, and supports the DetNet forwarding
   sub-layer based on existing MPLS Traffic Engineering encapsulations
   and mechanisms.  Background on PWs can be
   found in [RFC3985] and [RFC3031].  Background on MPLS Traffic
   Engineering can be found in [RFC3272] and [RFC3209].

                         DetNet        MPLS
                           .
                           .
                       +------------+
                       |  Service   | d-CW, S-Label
                       +------------+
                       | Forwarding | F-Label(s)
                       +------------+
                           .
                           .

              Figure 1: DetNet Adaptation to MPLS Data Plane

   The DetNet MPLS data plane approach defined in this document is shown
   in Figure 1.  The service sub-layer is supported by a DetNet control
   word (d-CW) which conforms to the Generic PW MPLS Control Word
   (PWMCW) defined in [RFC4385].  A d-CW identifying service label
   (S-Label) is also used.

   A node operating on a DetNet flow in the Detnet service sub-layer,
   i.e.  a node processing a DetNet packet which has the S-Label as top
   of stack uses the local context associated with that S-Label, for
   example a received F-Label, to determine what local DetNet
   operation(s) are applied to that packet.  An S-Label may be unique
   when taken from the platform label space [RFC3031], which would
   enable correct DetNet flow identification regardless of which input
   interface or LSP the packet arrives on.  The service sub-layer
   functions (i.e., PREOF) use a DetNet control word (d-CW).

   The DetNet MPLS data plane builds on MPLS Traffic Engineering
   encapsulations and mechanisms to provide a forwarding sub-layer that
   is responsible for providing resource allocation and explicit routes.
   The forwarding sub-layer is supported by one or more forwarding
   labels (F-Labels).

4.2.  DetNet MPLS Data Plane Scenarios

   [Editor's note: simplify this section and highlight DetNet MPLS over
   subnets scenario being the focus in the remaining part of the
   document.].

   DetNet MPLS       Relay

         Edge          Transit        Relay       DetNet MPLS
   End System
         Node           Node           Node        End System
        (T-PE)        (S-PE)          (LSR)         (S-PE)         (T-PE)
   +----------+                                             +----------+
   |   Appl.  |<------------
      +---------+
   <--|Svc Proxy|-- End to End Service ----------->|   Appl.  |
   +----------+ ----------->
      +---------+                   +---------+   +----------+
      |IP | Service  |<--| Service |-- |Svc|<-- DetNet flow --| Service |-->| ---| Service  |
   +----------+ |--->
      +---+ +---+    +---------+  +----------+    +---------+   +----------+
   |Forwarding|
      |Fwd| |Fwd|  |Forwarding|    |   Fwd   |    |Fwd| |Fwd|   |Forwarding|
   +-------.--+
      +-.-+ +-.-+  +----.---.-+    +--.----.-+    +-.-+ +-.-+   +---.------+
           :  Link
        :    /  ,-----.  \   :  Link  :    /  ,-----.  \     :
   .....+    +-[TSN Sub]-+   +........+    +-[  Sub  ]-+   +......+    +-[  Sub  ]-+
                           [Network]     +.....
               [Network]
                `-----'                     `-----'
           |<- LSP -->| |<--------
           |<----------- LSP -----------| ---------->| |<--- LSP -->|

           |<-----------------
           |<------------- DetNet MPLS --------------------->| ------------

    Figure 2: A 1: Part of a Simple DetNet MPLS Network using a TSN sub-net

   Figure 2 1 illustrates a hypothetical DetNet MPLS-only network composed an extract of DetNet aware MPLS enabled end systems, operating over a DetNet
   aware enabled MPLS network.  In this figure, relay
   Edge/relay nodes sit at MPLS LSP boundaries and transit nodes are
   LSRs.

   DetNet end system  In this figure, two MPLS nodes (the edge node and relay the transit
   node) are interconnected by a TSN sub-network.

   DetNet edge/relay nodes are DetNet service sub-layer aware,
   understand the particular needs of DetNet flows and provide both
   DetNet service and forwarding sub-layer functions.  They add, remove
   and process d-CWs, S-Labels and F-labels as needed.  MPLS enabled end
   system and relay
   DetNet nodes can enhance the reliability of delivery by enabling the
   replication of packets where multiple copies, possibly over multiple
   paths, are forwarded through the DetNet domain.  They can also
   eliminate surplus previously replicated copies of DetNet packets.  DetNet
   MPLS (DetNet) nodes provide functionality similar to T-PEs
   when they sit at the edge of an MPLS domain, and functionality
   similar to S-PEs when they are in the middle of an MPLS domain, see
   [RFC6073].  End system and relay nodes also include DetNet forwarding
   sub-layer functions, support for notably explicit routes, also include DetNet forwarding sub-layer
   functions, support for notably explicit routes, and resources
   allocation to eliminate (or reduce) congestion loss and jitter.

   DetNet transit nodes reside wholly within a DetNet domain, and also
   provide DetNet forwarding sub-layer functions in accordance with the
   performance required by a DetNet flow carried over an LSP.  Unlike
   other DetNet node types, transit nodes provide no service sub-layer
   processing.  In a

4.  DetNet MPLS network, transit nodes may be Operation Over IEEE 802.1 TSN Sub-Networks

   The DetNet
   service aware or may be WG collaborates with IEEE 802.1 TSN in order to define a
   common architecture for both Layer 2 and Layer 3, what maintains
   consistency across diverse networks.  Both DetNet unaware MPLS Label Switching Routers
   (LSRs).  In this latter case, such LSRs would be unaware of the
   special requirements of the DetNet service sub-layer, but would still
   provide traffic engineering services and TSN use
   the QoS need same techniques to ensure that
   the (TE) LSPs meet the service requirements of provide their deterministic service:

   o  Service protection.

   o  Resource allocation.

   o  Explicit routes.

   As described in the carried DetNet
   flows.

   The LSPs may be provided by any architecture
   [I-D.ietf-detnet-architecture] and also illustrated here in Figure 1
   a sub-network provides from MPLS controller method.  For example
   they may be provisioned via perspective a management plane, RSVP-TE, MPLS-TP, or single hop connection
   between MPLS Segment Routing (when extended to support (DetNet) nodes.  Functions used for resource allocation).

   [Editor's note: Figure 3. and surrunding text are candidates to
   delete from this document.].

   Figure 3 illustrates how an end to end MPLS-based DetNet service is
   provided in a more detail.  In this figure, the end systems, CE1 allocation
   and
   CE2, explicit routes are able to send treated as domain internal functions and receive MPLS encapsulated does
   not require function interworking across the DetNet flows, and
   R1, R2 MPLS network and R3 are relay nodes as they sit in
   the middle TSN sub-network.

   In case of a DetNet
   network.  The 'X' in the end systems, and relay nodes represents
   potential DetNet compound flow packet replication and elimination
   points.  In this example, service protection is supported over four function due to the similarities of
   the DetNet member flows and TE LSPs.  For a unidirectional flow, R1
   supports PRF, R2 supports PREOF and R3 supports PEF and POF.  Note
   that the relay nodes may change the underlying forwarding sub-layer,
   for example tunneling MPLS over IEEE 802.1 TSN Section 6, or simply
   over interconnect network links.

         DetNet                                           DetNet
   MPLS  Service          Transit          Transit       Service MPLS
   DetNet  |             |<-Tnl->|        |<-Tnl->|            | DetNet
   End     |             V   1   V        V   2   V            | End
   System  |    +--------+       +--------+       +--------+   | System
   +---+   |    |   R1   |=======|   R2   |=======|   R3   |   |  +---+
   |  X...DFa...|._X_....|..DF1..|.__ ___.|..DF3..|...._X_.|.DFa..|.X |
   |CE1|========|    \   |       |   X    |       |   /    |======|CE2|
   |   |   |    |     \_.|..DF2..|._/ \__.|..DF4..|._/     |   |  |   |
   +---+        |        |=======|        |=======|        |      +---+
       ^        +--------+       +--------+       +--------+      ^
       |        Relay Node       Relay Node       Relay Node      |
       |          (S-PE)           (S-PE)           (S-PE)        |
       |                                                          |
       |<---------------------- DetNet MPLS --------------------->|
       |                                                          |
       |<--------------- End to End DetNet Service -------------->|

      -------------------------- Data Flow ------------------------->

       X   = Optional service protection (none, PRF, PREOF, PEF/POF)
       DFx = DetNet member flow x over a TE LSP

                    Figure 3: MPLS-Based Native DetNet

   As previously mentioned, this document specifies how MPLS is used to
   support DetNet flows using an MPLS data plane as well as how such can
   be mapped to IEEE 802.1 TSN and IP DetNet PSNs.  An equally import
   scenario is when IP is supported over DetNet MPLS and this is covered
   in [I-D.ietf-detnet-dp-sol-ip].  Another important scenario is where
   an Ethernet Layer 2 service is supported over DetNet MPLS and this is
   covered in [TBD-TSN-OVER-DETNET].

4.3.  Packet Flow Example with Service Protection

   [Editor's note: this text might be relevant for the discussion of
   FRER within the TSN sub-network.  Needs revision.].

   An example DetNet MPLS network fragment and packet flow is
   illustrated in Figure 4.

      1      1.1       1.1      1.2.1    1.2.1      1.2.2
   CE1----EN1--------R1-------R2-------R3--------EN2-----CE2
            \           1.2.1 /                   /
             \1.2     /-----+                   /
              +------R4------------------------+
                        1.2.2

       Figure 4: Example Packet Flow in DetNet Enabled MPLS Network

   In Figure 4 the numbers are used to identify the instance of a
   packet.  Packet 1 is the original packet, and packets 1.1, and 1.2
   are two first generation copies of packet 1.  Packet 1.2.1 is a
   second generation copy of packet 1.2 etc.  Note that these numbers
   never appear in the packet, and are not to be confused with sequence
   numbers, labels or any other identifier that appears in the packet.
   They simply indicate the generation number of the original packet so
   that its passage through the network fragment can be identified to
   the reader.

   Customer Equipment CE1 sends a packet into the DetNet enabled MPLS
   network.  This is packet (1).  Edge Node EN1 encapsulates the packet
   as a DetNet Packet and sends it to Relay node R1 (packet 1.1).  EN1
   makes a copy of the packet (1.2), encapsulates it and sends this copy
   to Relay node R4.

   Note that along the MPLS path from EN1 to R1 there may be zero or
   more LSRs which, for clarity, are not shown.  The same is true for
   any other path between two DetNet entities shown in Figure 4.

   Relay node R4 has been configured to send one copy of the packet to
   Relay Node R2 (packet 1.2.1) and one copy to Edge Node EN2 (packet
   1.2.2).

   R2 receives packet copy 1.2.1 before packet copy 1.1 arrives, and,
   having been configured to perform packet elimination on this DetNet
   flow, forwards packet 1.2.1 to Relay Node R3.  Packet copy 1.1 is of
   no further use and so is discarded by R2.

   Edge Node EN2 receives packet copy 1.2.2 from R4 before it receives
   packet copy 1.2.1 from R2 via relay Node R3.  EN2 therefore strips
   any DetNet encapsulation from packet copy 1.2.2 and forwards the
   packet to CE2.  When EN2 receives the later packet copy 1.2.1 this is
   discarded.

   The above is of course illustrative of many network scenarios that
   can be configured.  Between a pair of relay nodes there may be one or
   more transit nodes that simply forward the DetNet traffic, but these
   are omitted for clarity.

5.  DetNet MPLS Data Plane Considerations

   [Editor's note: Sort out what data plane considerations are relevant
   for sub-net scenarios.].

   This section provides informative considerations related to providing
   DetNet service to flows which are identified based on their header
   information.  At a high level, the following are provided on a per
   flow basis:

   Eliminating contention loss and jitter reduction:

      Use of allocated resources (queuing, policing, shaping) to ensure
      that the congestion-related loss and latency/jitter requirements
      of a DetNet flow are met.

   Explicit routes:

      Use of a specific path for a flow.  This limits misordering and
      bounds latency.

   Service protection:

      Which in the case of this document primarily relates to
      replication and elimination.  Changing the explicit path after a
      failure is detected in order to restore delivery of the required
      DetNet service characteristics is also possible.  Path changes,
      even in the case of failure recovery, can lead to the out of order
      delivery of data.

   Load sharing:

      Generally, distributing packets of the same DetNet flow over
      multiple paths is not recommended.  Such load sharing, e.g., via
      ECMP or UCMP, impacts ordering and possibly jitter.

   Troubleshooting:

      For example, to support identification of misbehaving flows.

   Recognize flow(s) for analytics:

      For example, increase counters.

   Correlate events with flows:

      For example, unexpected loss.

   The DetNet data plane also allows for the aggregation of DetNet
   flows, e.g., via MPLS hierarchical LSPs, to improved scaling.  When
   DetNet flows are aggregated, transit nodes provide service to the
   aggregate and not on a per-DetNet flow basis.  In this case, nodes
   performing aggregation will ensure that per-flow service requirements
   are achieved.

5.1.  Sub-Network Considerations

   As shown in Figure 2, MPLS nodes are interconnected by different sub-
   network technologies, which may include point-to-point links.  Each
   of these need to provide appropriate service to DetNet flows.  In FRER functions some cases, e.g., on dedicated point-to-point links or TDM
   technologies, all that is required is for a DetNet node to
   appropriately queue its output traffic.  In other cases, DetNet nodes
   will need to map DetNet flows to the flow semantics (i.e.,
   identifiers) and mechanisms used by an underlying sub-network
   technology.  Figure 5 shows several examples of header formats that
   can be used to carry DetNet MPLS flows over different sub-network
   technologies.  L2 represent a generic layer-2 encapsulation that
   might be used on a point-to-point link.  TSN represents the
   encapsulation used on an IEEE 802.1 TSN network, as described in
   Section 6.  UDP/IP represents the encapsulation used on a DetNet IP
   PSN.

                              +------+  +------+  +------+
           App-Flow           |  X   |  |  X   |  |  X   |
                        +-----+======+--+======+--+======+-----+
           DetNet-MPLS        | d-CW |  | d-CW |  | d-CW |
                              +------+  +------+  +------+
                              |Labels|  |Labels|  |Labels|
                        +-----+======+--+======+--+======+-----+
           Sub-Network        |  L2  |  | TSN  |  | UDP  |
                              +------+  +------+  +------+
                                                  |  IP  |
                                                  +------+
                                                  |  L2  |
                                                  +------+

             Figure 5: Example DetNet MPLS Sub-Network Formats

6.  DetNet MPLS Operation Over IEEE 802.1 TSN Sub-Networks

   [Editor's note: this level of interworking is a place holder section.  A standalone section
   on MPLS over IEEE 802.1 TSN.  Includes RFC2119 Language.]
   This section covers how DetNet MPLS flows operate over an IEEE 802.1
   TSN sub-network.
   possible.  However, such interworking is out-of-scope in this
   document and left for further study.

   Figure 6 2 illustrates such a scenario, where two MPLS (DetNet) nodes are
   interconnected by a TSN sub-network.  Node-1 is single homed and
   Node-2 is dual-homed.  MPLS nodes can be (1)
   DetNet MPLS End System, (2) DetNet MPLS Edge or Relay node or (3)
   MPLS Transit node.

   Note: in case of MPLS Transit node there is no DetNet Service sub-
   layer processing. dual-homed to the TSN sub-network.

      MPLS (DetNet)                 MPLS (DetNet)
         Node-1                        Node-2

      +----------+                  +----------+
   <--| Service* |-- DetNet flow ---| Service* |-->
      +----------+                  +----------+
      |Forwarding|                  |Forwarding|
      +--------.-+    <-TSN Str->   +-.-----.--+
                \      ,-------.     /     /
                 +----[ TSN-Sub ]---+     /
                      [ Network ]--------+
                       `-------'
   <---------------- DetNet MPLS --------------->

   Note: * no service sub-layer required for transit nodes

       Figure 6: 2: DetNet Enabled MPLS Network Over a TSN Sub-Network

   The Time-Sensitive Networking (TSN) Task Group of the IEEE 802.1
   Working Group have defined (and are defining) a number of amendments
   to IEEE 802.1Q [IEEE8021Q] that provide zero congestion loss and
   bounded latency in bridged networks.  Furthermore IEEE 802.1CB
   [IEEE8021CB] defines frame replication and elimination functions for
   reliability that should prove both compatible with and useful to,
   DetNet networks.  All these functions have to identify flows those
   require TSN treatment.

   As is the case for DetNet, a Layer 2 network node such as a bridge
   may need to identify the specific DetNet flow to which a packet
   belongs in order to provide the TSN/DetNet QoS for that packet.  It
   also may need a CoS marking, such as the priority field

   TSN capabilities of an IEEE
   Std 802.1Q VLAN tag, to give the packet proper service.

   The challange TSN sub-network are made available for MPLS DeNet
   (DetNet) flows is that via the protocol interworking function defined in IEEE
   802.1CB [IEEE8021CB] works only for IP
   flows.  The aim of [IEEE8021CB].  For example, applied on the protocol interworking function is to TSN edge port it
   can convert an ingress unicast MPLS (DetNet) flow to use a specific
   Layer-2 multicast destination MAC address and a VLAN, for example in order to
   direct the packets packet through a specific path inside the bridged network.
   A similar interworking function pair at the other end of the TSN sub-network sub-
   network would restore the packet to its original Layer-2 destination
   MAC address and VLAN.

   As protocol interworking function defined in [IEEE8021CB] does not
   work for MPLS labeled flows,

   Placement of TSN functions depends on the DetNet MPLS nodes MUST ensure proper TSN sub-network specific Ethernet encapsulation capabilities of the DetNet nodes.
   MPLS
   packets. (DetNet) Nodes may or may not support TSN functions.  For a
   given TSN Stream (i.e., DetNet flow) an MPLS (DetNet) node MUST behave is treated
   as a TSN-aware Talker or a Listener inside the TSN
   sub-network.

6.1.  Mapping of TSN Stream ID and Sequence Number

   TSN capable MPLS (DetNet) nodes are TSN-aware Talker/Listener as
   shown in Figure 7.  MPLS (DetNet) node MUST provide the TSN sub-
   network specific Ethernet encapsulation over the link(s) towards the
   sub-network.  An TSN-aware MPLS (DetNet) node MUST support Listener inside the
   following TSN components:

   1.  For recognizing flows:

       * sub-network.

4.1.  Functions for DetNet Flow to TSN Stream Identification (MPLS-flow-aware)

   2.  For FRER used inside the Mapping

   Mapping of a DetNet MPLS flow to a TSN domain, additonaly:

       *  Sequencing function (MPLS-flow-aware)

       *  Sequence encode/decode Stream is provided via the
   combination of a passive and an active stream identification function

   3.  For FRER when
   that operate at the node frame level.  The passive stream identification
   function is used to catch the MPLS label(s) of a DetNet MPLS flow and
   the active stream identification function is used to modify the
   Ethernet header according to the ID of the mapped TSN replication or elimination point,
       additionally:

       * Stream.

   IEEE P802.1CBdb [IEEEP8021CBdb] defines a Mask-and-Match Stream splitting
   identification function

       *  Individual recovery that can be used as a passive function

   [Editor's note: Should we added here requirements regarding for
   MPLS DetNet flows.

   IEEE
   802.1Q C-VLAN component?]

   The 802.1CB [IEEE8021CB] defines an Active Destination MAC and VLAN
   Stream Identification identification function, what can replace some Ethernet header
   fields namely (1) the destination MAC-address, (2) the VLAN-ID and The Sequencing functions are slightly
   modified
   (3) priority parameters with alternate values.  Replacement is
   provided for frames the frame passed down the protocol stack from the upper layers or
   up the stack from the lower layers.

   Stream Identification MUST pair MPLS flows

   Active Destination MAC and VLAN Stream identification can be used
   within a Talker to set flow identity or a Listener to recover the
   original addressing information.  It can be used also in a TSN Streams and encode bridge
   that in data plane formats is providing translation as well.  The packet's stream_handle
   subparameter (see IEEE 802.1CB [IEEE8021CB]) inside a proxy service for an End System.

4.2.  TSN requirements of MPLS DetNet nodes

   This section covers required behavior of a TSN-aware MPLS (DetNet)
   node using a TSN sub-network.

   From the TSN sub-network perspective MPLS (DetNet) nodes are treated
   as Talker or Listener, that may be (1) TSN-unaware or (2) TSN-aware.

   In cases of TSN-unaware MPLS DetNet nodes the TSN relay nodes within
   the Talker/
   Listener is defined based on TSN sub-network must modify the Flow-ID used in Ethernet encapsulation of the upper
   DetNet MPLS layer.  Stream Identification function MUST encode Ethernet
   header fields namely (1) the destination MAC-address, (2) the flow (e.g., MAC translation, VLAN-ID
   and (3) priority parameters with setting, Sequence
   number addition, etc.) to allow proper TSN sub-network specific values.
   Encoding is provided for the frame passed down the stack from handling inside
   the
   upper layers.

   The sequence generation function resides sub-network.  There are no requirements defined for TSN-unaware
   MPLS DetNet nodes in the Sequencing function.
   It generates this document.

   MPLS (DetNet) nodes being TSN-aware can be treated as a sequence_number subparameter for each packet combination
   of a
   Stream passed down to the lower layers.  Sequencing function MUST
   copy sequence information from TSN-unaware Talker/Listener and a TSN-Relay, as shown in
   Figure 3.  In such cases the MPLS d-CW of the packet to the
   sequence_number subparameter for (DetNet) node must provide the frame passed down TSN
   sub-network specific Ethernet encapsulation over the stack from link(s) towards
   the upper layers. sub-network.

                 MPLS (DetNet)
         Node-1
      <---------->
                     Node
      <---------------------------------->

      +----------+
   <--| Service Service* |-- DetNet flow ------------------
      +----------+
      |Forwarding|
      +----------+    +---------------+
      |    L2 with  |<---|    |    | L2 Relay with |---- |<--- TSN ---- ---
      |   TSN          |    | TSN function  |    Stream
      +-----.----+    +--.---------.--+    +--.------.---.-+
             \__________/        \   \______

       TSN-aware
                                  \_________
       TSN-unaware
        Talker /          TSN-Bridge
        Listener             Relay

            <---------
                                          <----- TSN sub-network ------------ Sub-network -----
      <------- TSN-aware Tlk/Lstn ------->

   Note: * no service sub-layer required for transit nodes

              Figure 7: 3: MPLS (DetNet) Node with TSN Functions

   A TSN-aware MPLS (DetNet) node impementations MUST support the Stream
   Identification TSN component for recognizing flows.

   A Stream identification component MUST be able to instantiate the
   following functions (1) Active Destination MAC and VLAN Stream
   identification function, (2) Mask-and-Match Stream identification
   function and (3) the related managed objects in Clause 9 of IEEE
   802.1CB [IEEE8021CB] and IEEE P802.1CBdb [IEEEP8021CBdb].

   A TSN-aware MPLS (DetNet) node implementations MUST support the
   Sequencing function and the Sequence encode/decode function as
   defined in IEEE 802.1CB [IEEE8021CB] if FRER is used inside the TSN
   sub-network.

   The Sequence encode/decode function MUST support the Redundancy tag
   (R-TAG) format as per Clause 7.8 of per Clause 7.8 of IEEE 802.1CB [IEEE8021CB].

   A TSN-aware MPLS (DetNet) node implementations MUST support the
   Stream splitting function and the Individual recovery function as
   defined in IEEE 802.1CB [IEEE8021CB].

6.2. [IEEE8021CB] when the node is a replication
   or elimination point for FRER.

4.3.  Service protection within the TSN Usage of FRER sub-network

   TSN Streams supporting DetNet flows may use Frame Replication and
   Elimination for Redundancy (FRER) [802.1CB] as defined in IEEE 802.1CB
   [IEEE8021CB] based on the loss service requirements of the TSN
   Stream, which is derived from the DetNet service requirements of the
   DetNet mapped flow.  The specific operation of FRER is not modified by FRER is not modified
   by the use of DetNet and follows IEEE 802.1CB [IEEE8021CB].

   FRER function and the provided service recovery is available only
   within the TSN sub-network as the TSN Stream-ID and the TSN sequence
   number are not valid outside the sub-network.  An MPLS (DetNet) node
   represents a L3 border and as such it terminates all related
   information elements encoded in the L2 frames.

   As the Stream-ID and the TSN sequence number are paired with the
   similar MPLS flow parameters, FRER can be combined with PREOF
   functions.  Such service protection interworking scenarios may
   require to move sequence number fields among TSN (L2) and PW (MPLS)
   encapsulations and they are left for further study.

4.4.  Aggregation during DetNet flow to TSN Stream mapping

   Implementations of this document SHALL use management and control
   information to map a DetNet flow to a TSN Stream.  N:1 mapping
   (aggregating DetNet flows in a single TSN Stream) SHALL be supported.
   The management or control function that provisions flow mapping SHALL
   ensure that adequate resources are allocated and configured to
   provide proper service requirements of the mapped flows.

5.  Management and Control Implications

   [Editor's note: This section covers management/control plane related
   implications of creation, mapping, removal of TSN Stream IDs, their
   related parameters and, when needed, the configuration of FRER.]
   DetNet flow and TSN Stream mapping related information are required
   only for TSN-aware MPLS (DetNet) nodes.  From the Data Plane
   perspective there is no practical difference based on the origin of
   flow mapping related information (management plane or control plane).

   TSN-aware MPLS DetNet nodes are member of both the use of DetNet domain and follows
   IEEE 802.1CB [IEEE8021CB].

   FRER function and the provided service recovery is available only
   within
   the TSN sub-network however as the Stream-ID and sub-network.  Within the TSN
   sequence number are paired with sub-network the MPLS flow parameters they can be
   combined with PREOF functions.

6.3.  Procedures

   [Editor's note: This section is TBD - covers required behavior of a TSN-aware DetNet MPLS
   (DetNet) node using has a TSN-aware Talker/Listener role, so TSN underlay.]

6.4.  Layer 2 Addressing and QoS Considerations

   [Editor's NOTE: review specific
   management and simplify this section.  May overlap with
   previous sections.]

   The Time-Sensitive Networking (TSN) Task Group of the IEEE 802.1
   Working Group have defined (and control plane functionalities must be implemented.
   There are defining) a number of amendments
   to IEEE 802.1Q [IEEE8021Q] that provide zero congestion loss and
   bounded latency many similarities in bridged networks.  IEEE 802.1CB [IEEE8021CB]
   defines packet replication the management plane techniques used
   in DetNet and elimination functions TSN, but that should
   prove both compatible with and useful to, DetNet networks.

   As is not the case for DetNet, a Layer 2 network node such as the control plane
   protocols.  For example, RSVP-TE and MSRP behaves differently.
   Therefore management and control plane design is an important aspect
   of scenarios, where mapping between DetNet and TSN is required.

   In order to use a bridge
   may need TSN sub-network between DetNet nodes, DetNet
   specific information must be converted to identify the TSN sub-network specific
   ones.  DetNet flow ID and flow related parameters/requirements must
   be converted to which a packet
   belongs in order to provide the TSN/DetNet QoS for that packet.  It
   also will likely need a CoS marking, such TSN Stream ID and stream related parameters/
   requirements.  Note that, as the priority field TSN sub-network is just a portion of an
   IEEE Std 802.1Q VLAN tag, to give the packet proper service.

   Although
   the flow identification methods described in IEEE 802.1CB
   [IEEE8021CB] are flexible, and in fact, include IP 5-tuple
   identification methods, end2end DetNet path (i.e., single hop from MPLS perspective),
   some parameters (e.g., delay) may differ significantly.  Other
   parameters (like bandwidth) also may have to be tuned due to the L2
   encapsulation used within the baseline TSN standards assume that every
   Ethernet frame belonging sub-network.

   In some case it may be challenging to a determine some TSN stream (i.e.  DetNet flow) carries Stream
   related information.  For example, on a multicast destination MAC address that is unique to TSN-aware MPLS (DetNet) node
   that flow
   within the bridged network over which acts as a Talker, it is carried.  Furthermore,
   IEEE 802.1CB [IEEE8021CB] describes three methods by quite obvious which a packet
   sequence number can DetNet node is the
   Listener of the mapped TSN stream (i.e., the MPLS Next-Hop).  However
   it may be encoded in an Ethernet frame.

   Ensuring not trivial to locate the point/interface where that
   Listener is connected to the proper Ethernet VLAN tag priority and destination
   MAC address are used on a DetNet/TSN packet TSN sub-network.  Such attributes may
   require further
   clarification of the customary L2/L3 transformations carried out by
   routers interaction between control and edge label switches.  Edge nodes may also have to move
   sequence number fields among Layer 2, PW, management plane functions
   and IP encapsulations.

7.  Management between DetNet and TSN domains.

   Mapping between DetNet flow identifiers and Control Considerations

   [Editor's note: This section is TBD Covers Creation, mapping, removal
   of TSN Stream IDs, related parameters and,when needed, configuration
   of FRER.  Supported identifiers,
   if not provided explicitly, can be done by management/control plane.  SEE sections in
   removed text file.]
   While management plane and control planes are traditionally
   considered separately, from the Data Plane perspective there is no
   practical difference a TSN-aware MPLS (DetNet)
   node locally based on the origin information provided for configuration of flow provisioning
   information, the
   TSN Stream identification functions (Mask-and-match Stream
   identification and active Stream identification function).

   Triggering the DetNet architecture
   [I-D.ietf-detnet-architecture] refers to these collectively as setup/modification of a TSN Stream in the
   'Controller Plane'.  This document therefore does not distinguish
   between information provided by distributed TSN sub-
   network is an example where management and/or control plane protocols,
   e.g., RSVP-TE [RFC3209]
   interactions are required between the DetNet and [RFC3473], or by centralized network
   management mechanisms, e.g., RestConf [RFC8040], YANG [RFC7950], TSN sub-network.
   TSN-unaware MPLS (DetNet) nodes make such a triggering even more
   complicated as they are fully unaware of the sub-network and run
   independently.

   Configuration of TSN specific functions (e.g., FRER) inside the Path Computation Element Communication Protocol (PCEP)
   [I-D.ietf-pce-pcep-extension-for-pce-controller] or any combination
   thereof.  Specific considerations TSN
   sub-network is a TSN domain specific decision and requirements for may not be visible
   in the DetNet
   Controller Plane domain.  Service protection interworking scenarios are discussed below.

8.
   left for further study.

6.  Security Considerations

   The security considerations of DetNet in general are discussed in
   [I-D.ietf-detnet-architecture] and [I-D.sdt-detnet-security].  Other
   security [I-D.ietf-detnet-security].
   DetNet IP data plane specific considerations will be added are summarized in a future version of this
   draft.

9.
   [I-D.ietf-detnet-ip].  Encryption may provided by an underlying sub-
   net using MACSec [IEEE802.1AE-2018] for DetNet IP over TSN flows.

7.  IANA Considerations

   This document makes no IANA requests.

10.

8.  Acknowledgements

   Thanks for

   The authors wish to thank Norman Finn and Finn, Lou Berger Berger, Craig Gunther,
   Christophe Mangin and Jouni Korhonen for their comments and
   contributions.

11. various contributions
   to this work.

9.  References

11.1.

9.1.  Normative References

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

   [RFC2211]  Wroclawski, J., "Specification of the Controlled-Load
              Network Element Service", RFC 2211, DOI 10.17487/RFC2211,
              September 1997, <https://www.rfc-editor.org/info/rfc2211>.

   [RFC2212]  Shenker, S., Partridge, C., and R. Guerin, "Specification
              of Guaranteed Quality of Service", RFC 2212,
              DOI 10.17487/RFC2212, September 1997,
              <https://www.rfc-editor.org/info/rfc2212>.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031,
              DOI 10.17487/RFC3031, January 2001,
              <https://www.rfc-editor.org/info/rfc3031>.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
              <https://www.rfc-editor.org/info/rfc3032>.

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

   [RFC3270]  Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
              P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
              Protocol Label Switching (MPLS) Support of Differentiated
              Services", RFC 3270, DOI 10.17487/RFC3270, May 2002,
              <https://www.rfc-editor.org/info/rfc3270>.

   [RFC3443]  Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing
              in Multi-Protocol Label Switching (MPLS) Networks",
              RFC 3443, DOI 10.17487/RFC3443, January 2003,
              <https://www.rfc-editor.org/info/rfc3443>.

   [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Signaling Resource ReserVation Protocol-
              Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
              DOI 10.17487/RFC3473, January 2003,
              <https://www.rfc-editor.org/info/rfc3473>.

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

   [RFC4385]  Bryant, S., Swallow, G., Martini, L., and D. McPherson,
              "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
              Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385,
              February 2006, <https://www.rfc-editor.org/info/rfc4385>.

   [RFC5085]  Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual
              Circuit Connectivity Verification (VCCV): A Control
              Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085,
              December 2007, <https://www.rfc-editor.org/info/rfc5085>.

   [RFC5129]  Davie, B., Briscoe, B., and J. Tay, "Explicit Congestion
              Marking in MPLS", RFC 5129, DOI 10.17487/RFC5129, January
              2008, <https://www.rfc-editor.org/info/rfc5129>.

   [RFC5462]  Andersson, L. and R. Asati, "Multiprotocol Label Switching
              (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
              Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
              2009, <https://www.rfc-editor.org/info/rfc5462>.

   [RFC7510]  Xu, X., Sheth, N., Yong, L., Callon, R., and D. Black,
              "Encapsulating MPLS in UDP", RFC 7510,
              DOI 10.17487/RFC7510, April 2015,
              <https://www.rfc-editor.org/info/rfc7510>.

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

11.2.

9.2.  Informative References

   [G.8275.1]
              International Telecommunication Union, "Precision time
              protocol telecom profile for phase/time synchronization
              with full timing support from the network", ITU-T
              G.8275.1/Y.1369.1 G.8275.1, June 2016,
              <https://www.itu.int/rec/T-REC-G.8275.1/en>.

   [G.8275.2]
              International Telecommunication Union, "Precision time
              protocol telecom profile for phase/time synchronization
              with partial timing support from the network", ITU-T
              G.8275.2/Y.1369.2 G.8275.2, June 2016,
              <https://www.itu.int/rec/T-REC-G.8275.2/en>.

   [I-D.ietf-detnet-architecture]
              Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", draft-ietf-
              detnet-architecture-12
              detnet-architecture-13 (work in progress), March May 2019.

   [I-D.ietf-detnet-dp-sol-ip]
              Korhonen, J.,

   [I-D.ietf-detnet-ip]
              Varga, B., "DetNet IP Data Plane
              Encapsulation", 2018.

   [I-D.ietf-detnet-flow-information-model] Farkas, J., Varga, B., Cummings, R., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and Y. Jiang, J. Korhonen, "DetNet
              Flow Information Model", draft-ietf-detnet-flow-
              information-model-03 (work in progress), March 2019.

   [I-D.ietf-pce-pcep-extension-for-pce-controller]
              Zhao, Q., Li, Z., Negi, M., and C. Zhou, "PCEP Procedures
              and Protocol Extensions for Using PCE as a Central
              Controller (PCECC) of LSPs", draft-ietf-pce-pcep-
              extension-for-pce-controller-01 Data Plane: IP",
              draft-ietf-detnet-ip-01 (work in progress),
              February July 2019.

   [I-D.ietf-spring-segment-routing-mpls]
              Bashandy, A., Filsfils, C., Previdi, S., Decraene,

   [I-D.ietf-detnet-mpls]
              Varga, B.,
              Litkowski, Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and R. Shakir, "Segment Routing with MPLS
              data plane", draft-ietf-spring-segment-routing-mpls-22 J. Korhonen, "DetNet Data Plane: MPLS",
              draft-ietf-detnet-mpls-01 (work in progress), May July 2019.

   [I-D.sdt-detnet-security]

   [I-D.ietf-detnet-security]
              Mizrahi, T., Grossman, E., Hacker, A., Das, S., Dowdell,
              J., Austad, H., Stanton, K., and N. Finn, "Deterministic
              Networking (DetNet) Security
              Considerations, draft-sdt-detnet-security, work Considerations", draft-ietf-
              detnet-security-05 (work in
              progress", 2017. progress), August 2019.

   [IEEE1588]
              IEEE, "IEEE 1588 Standard for a Precision Clock
              Synchronization Protocol for Networked Measurement and
              Control Systems Version 2", 2008.

   [IEEE802.1AE-2018]
              IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC
              Security (MACsec)", 2018,
              <https://ieeexplore.ieee.org/document/8585421>.

   [IEEE8021CB]
              Finn, N., "Draft Standard for Local and metropolitan area
              networks - Seamless Redundancy", IEEE P802.1CB
              /D2.1 P802.1CB, December 2015,
              <http://www.ieee802.org/1/files/private/cb-drafts/
              d2/802-1CB-d2-1.pdf>.
              <http://www.ieee802.org/1/files/private/cb-drafts/d2/802-
              1CB-d2-1.pdf>.

   [IEEE8021Q]
              IEEE 802.1, "Standard for Local and metropolitan area
              networks--Bridges and Bridged Networks (IEEE Std 802.1Q-
              2014)", 2014, <http://standards.ieee.org/about/get/>.

   [RFC2205]  Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
              September 1997, <https://www.rfc-editor.org/info/rfc2205>.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <https://www.rfc-editor.org/info/rfc2474>.

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

   [RFC3985]  Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation
              Edge-to-Edge (PWE3) Architecture", RFC 3985,
              DOI 10.17487/RFC3985, March 2005,
              <https://www.rfc-editor.org/info/rfc3985>.

   [RFC4448]  Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
              "Encapsulation Methods for Transport of Ethernet over MPLS
              Networks", RFC 4448, DOI 10.17487/RFC4448, April 2006,
              <https://www.rfc-editor.org/info/rfc4448>.

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

   [RFC4873]  Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
              "GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873,
              May 2007, <https://www.rfc-editor.org/info/rfc4873>.

   [RFC4875]  Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
              Yasukawa, Ed., "Extensions to Resource Reservation
              Protocol - Traffic Engineering (RSVP-TE) for Point-to-
              Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
              DOI 10.17487/RFC4875, May 2007,
              <https://www.rfc-editor.org/info/rfc4875>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC5586]  Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
              "MPLS Generic Associated Channel", RFC 5586,
              DOI 10.17487/RFC5586, June 2009,
              <https://www.rfc-editor.org/info/rfc5586>.

   [RFC5654]  Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
              Sprecher, N., and S. Ueno, "Requirements of an MPLS
              Transport Profile", RFC 5654, DOI 10.17487/RFC5654,
              September 2009, <https://www.rfc-editor.org/info/rfc5654>.

   [RFC5921]  Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
              L., and L. Berger, "A Framework for MPLS in Transport
              Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010,
              <https://www.rfc-editor.org/info/rfc5921>.

   [RFC6003]  Papadimitriou, D., "Ethernet Traffic Parameters",
              RFC 6003, DOI 10.17487/RFC6003, October 2010,
              <https://www.rfc-editor.org/info/rfc6003>.

   [RFC6006]  Zhao, Q., Ed., King, D., Ed., Verhaeghe, F., Takeda, T.,
              Ali, Z., and J. Meuric, "Extensions to the Path
              Computation Element Communication Protocol (PCEP) for
              Point-to-Multipoint Traffic Engineering Label Switched
              Paths", RFC 6006, DOI 10.17487/RFC6006, September 2010,
              <https://www.rfc-editor.org/info/rfc6006>.

   [RFC6073]  Martini, L., Metz,

   [IEEEP8021CBdb]
              Mangin, C., Nadeau, T., Bocci, M., and M.
              Aissaoui, "Segmented Pseudowire", RFC 6073,
              DOI 10.17487/RFC6073, January 2011,
              <https://www.rfc-editor.org/info/rfc6073>.

   [RFC6387]  Takacs, A., Berger, L., Caviglia, D., Fedyk, D., and J.
              Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
              Switched Paths (LSPs)", RFC 6387, DOI 10.17487/RFC6387,
              September 2011, <https://www.rfc-editor.org/info/rfc6387>.

   [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
              L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
              RFC 6790, DOI 10.17487/RFC6790, November 2012,
              <https://www.rfc-editor.org/info/rfc6790>.

   [RFC7551]  Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE
              Extensions for Associated Bidirectional Label Switched
              Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015,
              <https://www.rfc-editor.org/info/rfc7551>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, "Extended Stream identification functions",
              IEEE P802.1CBdb /D0.2 P802.1CBdb, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

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

   [RFC8169]  Mirsky, G., Ruffini, S., Gray, E., Drake, J., Bryant, S.,
              and A. Vainshtein, "Residence Time Measurement in MPLS
              Networks", RFC 8169, DOI 10.17487/RFC8169, May 2017,
              <https://www.rfc-editor.org/info/rfc8169>.

Appendix A.  Example of DetNet Data Plane Operation

   [Editor's note: Add a simplified example of DetNet data plane and how
   labels etc work in the case of MPLS-based PSN and utilizing PREOF.
   The figure is subject to change depending on the further DT decisions
   on the label handling..] 2019,
              <http://www.ieee802.org/1/files/private/cb-drafts/d2/802-
              1CB-d2-1.pdf>.

Authors' Addresses

   Balazs Varga (editor)
   Ericsson
   Magyar Tudosok krt. 11.
   Budapest  1117
   Hungary

   Email: balazs.a.varga@ericsson.com

   Janos Farkas
   Ericsson
   Magyar Tudosok krt. 11.
   Budapest  1117
   Hungary

   Email: janos.farkas@ericsson.com

   Andrew G. Malis
   Huawei Technologies
   Independent

   Email: agmalis@gmail.com

   Stewart Bryant
   Huawei
   Futurewei Technologies

   Email: stewart.bryant@gmail.com

   Jouni Korhonen

   Email: jouni.nospam@gmail.com