Internet DRAFT - draft-geng-detnet-dp-sol-srv6

draft-geng-detnet-dp-sol-srv6







Network Working Group                                            X. Geng
Internet-Draft                                                   M. Chen
Intended status: Experimental                                     Huawei
Expires: January 5, 2020                                          Y. Zhu
                                                           China Telecom
                                                           July 04, 2019


                  DetNet SRv6 Data Plane Encapsulation
                    draft-geng-detnet-dp-sol-srv6-01

Abstract

   This document specifies Deterministic Networking data plane operation
   for SRv6 encapsulated user data.

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 RFC 2119 [RFC2119].

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
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   This Internet-Draft will expire on January 5, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Conventions . . . . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Conventions . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  SRv6 DetNet Data Plane Overview . . . . . . . . . . . . . . .   4
     3.1.  SRv6 DetNet Data Plane Layers . . . . . . . . . . . . . .   5
     3.2.  SRv6 DetNet Data Plane Scenarios  . . . . . . . . . . . .   5
   4.  SRv6 DetNet Data Plane Solution Considerations  . . . . . . .   7
   5.  SRv6 DetNet Data Plane Solution for Service Sub-layer . . . .   8
     5.1.  TLV Based SRv6 Data Plane Solution  . . . . . . . . . . .   8
       5.1.1.  Encapsulation . . . . . . . . . . . . . . . . . . . .   8
       5.1.2.  SRv6 Network Programming new Functions  . . . . . . .  10
     5.2.  SID Based SRv6 Data Plane Solution  . . . . . . . . . . .  11
       5.2.1.  Encapsulation . . . . . . . . . . . . . . . . . . . .  11
       5.2.2.  Functions . . . . . . . . . . . . . . . . . . . . . .  12
     5.3.  DetNet SID Based SRv6 Data Plane Solution . . . . . . . .  13
       5.3.1.  Encapulation  . . . . . . . . . . . . . . . . . . . .  13
       5.3.2.  Functions . . . . . . . . . . . . . . . . . . . . . .  14
   6.  SRv6 DetNet Data Plane Solution for Transport Sub-layer . . .  14
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   10. Normative References  . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   Deterministic Networking (DetNet), as described in
   [I-D.ietf-detnet-architecture] provides a capability to carry
   specified data flows with extremely low data loss rates and bounded
   latency within a network domain.  DetNet is enabled by a group of
   technologies, such as resource allocation, service protection and
   explicit routes.

   Segment Routing(SR) leverages the source routing paradigm.  An
   ingress node steers a packet through an ordered list of instructions,
   called "segments".  SR can be applied over IPv6 data plane using the
   Segment Routing Extension Header
   (SRH,[I-D.ietf-6man-segment-routing-header]).  A segment in segment
   routing terminology is not limited to a routing/forwarding function.



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   A segment can be associated to an arbitrary processing of the packet
   in the node identified by the segment.  In other words, an SRv6
   Segment can indicate functions that are executed locally in the node
   where they are defined.  SRv6 network Programming
   [I-D.filsfils-spring-srv6-network-programming] describe the different
   segments and functions associated to them.

   This document describes how to implement DetNet in an SRv6 enabled
   domain, including :

   o Source routing, which steers the DetNet flows through the network
   according to an explicit path with allocated resources;

   o Network programming, which applies instructions (functions) to
   packets in some special nodes (or even all the nodes) along the path
   in order to guarantee, e.g., service protection and congestion
   protection.

   DetNet SRv6 encapsulation and new SRv6 functions
   ([I-D.filsfils-spring-srv6-network-programming]) for DetNet are
   defined in this document.  Control plane and OAM are not in the scope
   of this document.

   Control plane and OAM are not in the scope of this document.

2.  Terminology and Conventions

   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].

2.1.  Terminology

   Terminologies for DetNet go along with the definition in
   [I-D.ietf-detnet-architecture] and [RFC8402].  Other terminologies
   are defined as follows:

   o  NH: The IPv6 next-header field.

   o  SID: A Segment Identifier ([RFC8402]).

   o  SRH: The Segment Routing Header
      ([I-D.ietf-6man-segment-routing-header]).








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2.2.  Conventions

   Conventions in the document are defined as follows:

   o  NH=SRH means that NH is 43 with routing type 4 which is (as
      defined in [I-D.ietf-6man-segment-routing-header], the values
      representing the SRH.

   o  A SID list is represented as <S1, S2, S3> where S1 is the first
      SID to visit, S2 is the second SID to visit and S3 is the last SID
      to visit along the SR path.

   o  SRH[SL] represents the SID pointed by the SL field in the first
      SRH.  In our example, SRH[2] represents S1, SRH[1] represents S2
      and SRH[0] represents S3.  It has to be noted
      that[I-D.ietf-6man-segment-routing-header] defines the segment
      list encoding in the reverse order of the path.  A path
      represented by <S1,S2,S3>, will be encoded in the SRH as follows:

         SegmentList[0]=S3

         SegmentList[1]=S2

         SegmentList[2]=S1

      The reverse encoding has been defined in order to optimise the
      processing time of the segment list.  See [draft-ietf-6man-
      segment-routing-header] for more details.

   o  (SA,DA) (S3, S2, S1; SL) represents an IPv6 packet with:

         IPv6 header with source and destination addresses SA and DA
         respectively, and next-header set to SRH (i.e.: 43 with type 4)
         , with a list of segments(SIDs) <S1, S2, S3> with SegmentsLeft
         = SL

         The payload of the packet is not represented

         (S3, S2, S1; SL) represents the same SID list as <S1, S2, S3>,
         but encoded in the SRH format where the rightmost SID in the
         SRH is the first SID and the leftmost SID in the SRH is the
         last SID

3.  SRv6 DetNet Data Plane Overview







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3.1.  SRv6 DetNet Data Plane Layers

   [I-D.ietf-detnet-architecture]decomposes the DetNet data plane into
   two sub-layers: service sub-layer and transport sub-layer.  Different
   from DetNet MPLS data plane solution, which uses DetNet Control
   Word(d-CW) and S-Label to support service sub-layer and uses T-Label
   to support transport sub-layer, no explicit sub-layer division exists
   in SRv6 data plane.  A classical SRv6 DetNet data plane solution is
   showed in the picture below:

                                  +-------------------+
                                  | Outer Ipv6 Header |
                                  +-------------------+
                                  |        SRH        |
      +-------------------+       +-------------------+
      |     Ipv6 Header   | ----> |     Ipv6 Header   |
      +-------------------+       +-------------------+

   The outer IPv6 Header with the SRH is used for carrying DetNet flows.
   Traffic Engineering is instantiated in the segment list of SRH, and
   other functions and arguments for service protection (packet
   replication, elimination and ordering) and congestion control (packet
   queuing and forwarding) are also defined in the SRH.

3.2.  SRv6 DetNet Data Plane Scenarios

                |                                         |
    ----IPv6--->|<---------------SRv6 DetNet------------->|<----IPv6---
                |                                         |
                |             +------+T2+----+            |
      +---+    +---+        +-+-+          +-+-+        +---+    +---+
      | E1+----| In|--+T1+--+R1 |          |R2 |--+T4+--| Eg+----+ E2|
      +---+    +---+        +-+-+          +-+-+        +---+    +---+
                              +-----+T3+-----+

   The figure above shows that an IPv6 flow is sent out from the end
   station E1.  The packet of the flow is encapsulated in an outer
   IPv6+SRH header as a DetNet SRv6 packet in the Ingress(In) and
   transported through an SRv6 DetNet domain.  In the Egress(Eg), the
   outer IPv6 header+SRH of the packet is popped, and the packet is sent
   to the destination E2.

   The figure above shows that an IPv6 flow is sent our from the end
   station: E1.  The packet of the flow is encapsulated as a DetNet SRv6
   packet in the Ingress(In) and transported through an SRv6 DetNet
   domain.  In the Egress(Eg), the upper IPv6 header with SRH of the
   packet is popped, and the packet is transmitted to the
   destination(E2).



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   The DetNet packet processing is as follows:

   Ingress:

      Inserts the SRv6 Policy that will steer the packet from Ingress to
      the destination

      The methods and mechanisms used for defining, instantiating and
      applying the policy are outside of this document.  An example of
      policies are described in [I-D.ietf-spring-segment-routing-policy]

      Flow Identification and Sequence Number are carried in the SRH.

   Relay Node 1(Replication Node):

      Replicates the payload and IPv6 Header with the SRH.  This is a
      new function in the context of SRv6 Network Programming which will
      associate a given SID to a replication instruction in the node
      originating and advertising the SID.  The replication instruction
      includes:



      *  The removal of the existing IPv6+SRH header

      *  The encapsulation into a new outer IPv6+SRH header.  Each
         packet (the original and the duplicated) are encapsulated into
         respectively new outer IPv6+SRH headers.

      Binding two different SRv6 Policies respectively to the original
      packet and the replicated packet, which can steer the packets from
      Relay Node 1 to Relay Node 2 through two tunnels.

   Relay Node 2(Elimination Node):

      Eliminates the redundant packets.

      Binds a new SRv6 Policy to the survival packet, which steers the
      packet from Relay Node 2 to Egress.

   Egress:

      Decapsulates the outer Ipv6 header.

      Sends the inter packet to the End Station 2.

   The DetNet packet encapsulation is illustrated here below.  It has to
   be noted that, in the example below, the R2 address is a SRH SID



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   associated to a TBD function related to the packet replication the
   node R1 has to perform.  The same (or reverse) apply to node R2 which
   is in charge of the discard of the duplicated packet.  Here also a
   new function will have a new SID allocated to it and representing the
   delete of the duplication in R2.

      End Station1 output packet: (E1,E2)

      Ingress output packet: (In, T1)(R1,T1, SL=2)(E1,E2)

      Transit Node1 output packet: (In, R1)(R1,T1,SL=1)(E1,E2)

      Relay Node1 output packets : (R1,T2)(R2,T2,SL=2)(E1,E2),
      (R1,T3)(R2,T3,SL=2)(E1,E2)

      Transit Node2 output packet: (R1, R2)(R2,T2,SL=1)(E1,E2)

      Transit Node3 output packet: (R1, R2)(R2,T3,SL=1)(E1,E2)

      Relay Node2 output packet: (R2, T4)(Eg,T4,SL=2)(E1,E2)

      Transit Node4 output packet: (R2, Eg)(Eg,T4,SL=1)(E1,E2)

      Egress out : (E1,E2)

4.  SRv6 DetNet Data Plane Solution Considerations

   To carry DetNet over SRv6, the following elements are required:

   1.  A method of identifying the SRv6 payload type;

   2.  A suitable explicit path to deliver the DetNet flow ;

   3.  A method of indicating packet processing, such as PREOF(Packet
   Replication, Elimination and Ordering as defined in
   [I-D.ietf-detnet-architecture]);

   4.  A method of identifying the DetNet flow;

   5.  A method of carrying DetNet sequence number;

   6.  A method of carrying queuing and forwarding indication to do
   congestion protection;

   In this design, DetNet flows are encapsulated in an outer IPv6+SRH
   header at the Ingress Node.  The SR policy identified in the SRH
   steers the DetNet flow along a selected path.  The explicit path
   followed by a DetNet flow, which protect it from temporary



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   interruptions caused by the convergence of routing, is encoded within
   the SID list of the SR policy.  The network device inside the DetNet
   domain forwards the packet according to IPv6 Destination Address(DA),
   and the IPv6 DA is updated with the SID List according to SRv6
   forwarding procedures defined in
   [I-D.ietf-6man-segment-routing-header] and
   [I-D.filsfils-spring-srv6-network-programming]

   With SRv6 network programming, the SID list can also give instruments
   representing a function to be called at the node in the DetNet
   domain.  Therefore DetNet specific functions defined in
   [I-D.ietf-detnet-architecture], corresponding to local packet
   processing in the network, can also be implemented by SRv6.  New
   functions associated with SIDs for DetNet are defined in this
   document.

   This document describes how DetNet flows are encapsulated/identified,
   and how functions of Packet Replication/Elimination/Ordering are
   implemented in an SRv6 domain.  Congestion protection is also in the
   scope of this document.

   Editor: This version only covers the functions of service protection
   and the congestion protection considerations will be added in the
   following versions.

5.  SRv6 DetNet Data Plane Solution for Service Sub-layer

   This section defines options of SRv6 data plane solution to support
   DetNet Service Sub-layer.

5.1.  TLV Based SRv6 Data Plane Solution

5.1.1.  Encapsulation

   An SRv6 Segment is a 128-bit value.  SID is used as a shorter
   reference for "SRv6 Segment Identifier" or "SRV6 Segment".  SRv6 SID
   can also be represented as LOC:FUNCT, where:

      LOC, means "LOCATION" and defines the node associated with the SID
      (i.e.: represented by the SID).

      FUNCT, means "FUNCTION", and identifies the processing that the
      node specified in LOC applies to the packet.  See
      [I-D.filsfils-spring-srv6-network-programming] for details on SRV6
      Network Programming.






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   The SRH for DetNet in the outer IPv6 header is showed as follows,
   according to [I-D.ietf-6man-segment-routing-header] and
   [I-D.filsfils-spring-srv6-network-programming]:

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Next Header  |   Hdr Ext Len |  Routing Type |  Segment Left |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |   Last Entry  |     Flags     |              Tag              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                     Location & Function                       |
    |           (Segment List[0] for relay node or edge node)       |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                       Segment List[n]                         |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                          Optional TLVs                        |
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The SRH specification allows the use of optional TLVs.  Two new TLVs
   are defined to support DetNet service protection.  DetNet Flow
   Identification TLV is used to uniquely identify a DetNet flow in an
   SRv6 DetNet node.  DetNet sequence number is used to discriminate
   packets in the same DetNet flow.  They are defined as follows:

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Type      |    Length     |           RESERVED            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        RESERVED       |           Flow Identification         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   o  Type: 8bits, to be assigned by IANA.

   o  Length: 8 octets.





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   o  RESERVED: 28 bits, MUST be 0 on transmission and ignored on
      receipt.

   o  Flow Identification: 20 bits, which is used for identifying DetNet
      flow.

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Type      |    Length     |           RESERVED            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |RESERVD|                    Sequence Number                    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   o  Type: 8 bits, to be assigned by IANA.

   o  Length: 8.

   o  RESERVED: 20 bits.  MUST be 0 on transmission and ignored on
      receipt.

   o  Sequence Number: 28 bits, which is used for indicating sequence
      number of a DetNet flow.

5.1.2.  SRv6 Network Programming new Functions

   New SRv6 Network Programming functions are defined as follows:

5.1.2.1.  End. B.Replicatioreserve the value of argument field(Inherited
          argument)of segment[0] of SRH n: Packet Replication Function

   1.   IF NH=SRH & SL>0 THEN

   2.   extract the DetNet TLV values from the SRH

   3.   create two new outer IPv6+SRH headers: IPv6-SRH-1 and IPv6-SRH-2
        Insert the policy-instructed segment lists in each newly created
        SRH (SRH-1 and SRH-2).  Also, add the extracted DetNet TLVs into
        SRH-1 and SRH-2.

   4.   remove the incoming outer IPv6+SRH header.

   5.   create a duplication of the incoming packet.

   6.   encapsulate the original packet into the first outer IPv6+SRH
        header: (IPv6-SRH-1) (original packet)



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   7.   encapsulate the duplicate packet into the second outer IPv6+SRH
        header: (IPv6-SRH-2) (duplicate packet)

   8.   set the IPv6 SA as the local address of this node.

   9.   set the IPv6 DA of IPv6-SRH-1 to the first segment of the SRv6
        Policy in of SRH-1 segment list.

   10.  set the IPv6 DA of IPv6-SRH-2 to the first segment of the SRv6
        Policy in of SRH-2 segment list.

   11.  ELSE

   12.  drop the packet

5.1.2.2.  End. B.  Elimination: Packet Elimination Function

   1.  IF NH=SRH & SL>0 & "the packet is not a redundant packet" THEN

   2.  do not decrement SL nor update the IPv6 DA with SRH[SL]

   3.  extract the value of DetNet TLVs from the SRH

   4.  create a new outer IPv6+SRH header

   5.  insert the policy-instructed segment lists in the newly created
       SRH and add the retrieved DetNet TLVs in the newly created SRH

   6.  remove the incoming outer IPv6+SRH header.

   7.  set the IPv6 DA to the first segment of the SRv6 Policy in the
       newly created SRH

   8.  ELSE

   9.  drop the packet

5.2.  SID Based SRv6 Data Plane Solution

5.2.1.  Encapsulation

   SRv6 SID can be represented as LOC:FUNCT:ARG::, where:

   LOC, means "LOCATION" and defines the node associated with the SID
   (i.e.: represented by the SID).

   FUNCT, means "FUNCTION", and identifies the processing that the node
   specified in LOC applies to the packet.



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   ARG, means "ARGUMENTS" and provides the additional arguments for the
   function.  New SID functions for DetNet is defined in section 5.2.2.
   See [I-D.filsfils-spring-srv6-network-programming] for details on
   SRV6 Network Programming.  The SRH for DetNet in the outer IPv6
   header is illustrated as follows

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Next Header  |   Hdr Ext Len |  Routing Type |  Segment Left |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |   Last Entry  |     Flags     |              Tag              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     Location & Function                       |
    |         (Segment List[0] for relay node or edge node)         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Location & Function       |        Flow Identification    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |Flow ID|                 Sequence Number                       |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                      Segment List[n]                          |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                          Optional TLVS                        |
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   o  LOCATION&FUNCTION: the 80 most significant bits that are used for
      routing the packet towards the LOCATION (as defined in
      [I-D.filsfils-spring-srv6-network-programming]);

   o  FLOW IDENTIFICATION: 20 bits, in the DetNet TLVs in the SRH, used
      for DetNet flow identification in the DetNet relay node;

   o  SEQUENCE NUMBER : 28 bits, in the DetNet TLVs, used for dis crime
      packets in the same DetNet flow;

5.2.2.  Functions

   New SID functions are defined as follows:





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5.2.2.1.  End. B.Replication: Packet Replication Function

   The function is similar as that has been defined in section 5.1.2.1.
   The only difference is that instead of retrieving the TLV values,
   this function retrieves the argument.

5.2.2.2.  End. B.  Elimination: Packet Elimination Function

   The function is similar as that has been defined in section 5.1.2.2.
   The only difference is that instead of retrieving the TLV values,
   this function retrieves the argument.

5.3.  DetNet SID Based SRv6 Data Plane Solution

5.3.1.  Encapulation

   A non-forwarding DetNet SID is defined to carry Flow Identification
   and Sequence Number.

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Next Header  |   Hdr Ext Len |  Routing Type |  Segment Left |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |   Last Entry  |     Flags     |              Tag              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                     Location & Function                       |
    |           (Segment List[0] for relay node or edge node)       |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                       Segment List[n]                         |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                         DetNet SID                            |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        Optional TLVs                          |
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





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5.3.2.  Functions

   TBD

6.  SRv6 DetNet Data Plane Solution for Transport Sub-layer

   TBD

7.  IANA Considerations

   TBD

8.  Security Considerations

   TBD

9.  Acknowledgements

   Thank you for valuable comments from James Guichard and Andrew Mails.

10.  Normative References

   [I-D.filsfils-spring-srv6-network-programming]
              Filsfils, C., Camarillo, P., Leddy, J.,
              daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
              Network Programming", draft-filsfils-spring-srv6-network-
              programming-07 (work in progress), February 2019.

   [I-D.ietf-6man-segment-routing-header]
              Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
              Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
              Routing Header (SRH)", draft-ietf-6man-segment-routing-
              header-21 (work in progress), June 2019.

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

   [I-D.ietf-detnet-dp-sol-mpls]
              Korhonen, J. and B. Varga, "DetNet MPLS Data Plane
              Encapsulation", draft-ietf-detnet-dp-sol-mpls-02 (work in
              progress), March 2019.








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   [I-D.ietf-spring-segment-routing-policy]
              Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d.,
              bogdanov@google.com, b., and P. Mattes, "Segment Routing
              Policy Architecture", draft-ietf-spring-segment-routing-
              policy-03 (work in progress), May 2019.

   [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>.

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.

Authors' Addresses

   Xuesong Geng
   Huawei

   Email: gengxuesong@huawei.com


   Mach(Guoyi) Chen
   Huawei

   Email: mach.chen@huawei.com


   Yongqing Zhu
   China Telecom

   Email: zhuyq@gsta.com

















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