RIFT Working Group                                             W. Cheng
Internet Draft                                             China Mobile
Intended status: Standards Track                                 C. Lin
Expires: January 7, 2024                           New H3C Technologies
                                                                R. Wang
                                                           China Mobile
                                                           July 7, 2023


                         RIFT extensions for SRv6
                    draft-cheng-rift-srv6-extensions-01


Abstract

   The Segment Routing (SR) architecture allows a flexible definition
   of the end-to-end path by encoding it as a sequence of topological
   elements called segments.  It can be implemented over an MPLS or
   IPv6 data plane.  This document describes the RIFT extensions
   required to support Segment Routing over the IPv6 data plane (SRv6).



Status of this Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on January 7, 2024.

Copyright Notice

   Copyright (c) 2023 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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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
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   document must include Simplified BSD License text as described in

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   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...................................................3
   2. SRv6 Locator KV TIE............................................4
   3. SRV6 Locator Prefix TIE........................................7
   4. Advertise End.X SID in Node TIE................................9
   5. Example.......................................................11
   6. Security Considerations.......................................13
   7. IANA Considerations...........................................13
      7.1. SRv6 Locator KV TIE......................................13
      7.2. SRv6 Locator Prefix TIE..................................14
      7.3. SRv6 End.X SID...........................................14
   8. References....................................................15
      8.1. Normative References.....................................15
   Appendix A.  Thrift Models.......................................16
      A.1.  common.thrift...........................................16
      A.2.  encoding.thrift.........................................16
      A.3.  common_srv6.thrift......................................17
   Authors' Addresses...............................................19


























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1. Introduction

   The Segment Routing (SR) architecture [RFC8402] specifies how a node
   can steer a packet using an ordered list of instructions, called
   segments.  These segments are identified using Segment Identifiers
   (SIDs).

   Segment Routing can be instantiated on the IPv6 data plane through
   the use of the Segment Routing Header (SRH) defined in
   [RFC8754].Segment Routing instantiation on the IPv6 dataplane is
   referred to as SRv6.

   The network programming paradigm for SRv6 is specified in
   [RFC8986].It describes how any behavior can be bound to a SID and
   how any network program can be expressed as a combination of SIDs.
   It also describes several well-known behaviors that can be bound to
   SRv6 SIDs.

   Using SRv6 in data center networks brings several advantages:

   1) Improved Scalability: SRv6 simplifies the network architecture by
      reducing the amount of state that must be maintained in network
      devices, which leads to increased scale and reduced management
      overhead.

   2) Traffic Engineering: SRv6 enables more granular control over
      traffic paths within the network, allowing operators to direct
      traffic along specific paths to better utilize network resources
      and reduce congestion.

   3) Service Function Chaining: With SRv6, network operators can
      easily define paths that traverse multiple service functions,
      including firewalls, load balancers and other middleboxes. This
      enables the creation of more flexible and scalable service chains
      to support a wide range of applications.

   4) Path Segment Identification: SRv6 allows for the identification
      of specific path segments within the network, making
      troubleshooting and fault isolation simpler and faster.

   5) Simplified Tunneling: SRv6 supports tunneling for traffic across
      an IPv6 network without the need for an IP-in-IP or GRE
      encapsulation. This simplifies the network architecture and
      reduces complexity.

   This document describes the RIFT extensions required to support
   Segment Routing over the IPv6 data plane (SRv6).


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   At a high level, the extensions to RIFT are comprised of the
   following:

   1) Add new SRv6 Locator KV TIE using Well-Known KV TIE that is used
   to advertise an SRv6 Locator, its attributes, and SIDs.

   2) Add a new type of SRV6 Locator TIE, which is used to advertise
   the Locator prefix and End SID in southbound and northbound TIE.

   3) In the neighbor information of Node TIE, Add the new End.X SID
   information in the neighbor information of Node TIE to advertise the
   corresponding connection of End.X.



2. SRv6 Locator KV TIE

   For RIFT network, Each node is provisioned with a Locator. The
   Locator address are communicated to each node out-of-band and stored
   as configuration information.  Communication could be done via
   primitive pen and paper or via modern signaling (Netconf/YANG) from
   a configuration management system. Then the node can use his own
   locator address to generate End-SID, End.X-SID etc.

   To support Zero Touch Provisioning (ZTP), we can define a flexible
   Key-Value (K-V) format for transmitting Locator address information
   in RIFT SRv6 network, in order to enable TOF to pass the Locator
   address information to all nodes via KV-TIE. In this way, TOF can
   package the Locator address information into KV-TIE and transmit it
   to all nodes in the SRv6 network to support Zero Touch Provisioning.
   With this approach, all nodes in the network can obtain the Locator
   address information and use the addresses for path programming and
   other operations in the SRv6 network.

   This section requests an entry from the RIFT Well-Known Key-Type
   Registry for networks that use SRv6 along with suggested values
   inaccordance with RIFT-KV-REGISTRY [RIFT-KV-REGISTRY].











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   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Well-Known     |   Key-Type describing a SRv6 Locator Info   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     (System ID,                                               |
   |      SRv6 Locator Entry)                                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     Figure 1: SRv6 Locator Key/Value Pair

   where:

       System ID: A node's 64-bit RIFT System ID.
       SRv6 Locator Sub TLV: A node's SRv6 Locator address.

   The SRv6 Locator Entry has the following format:
   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Metric                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Loc Size     |                    Resv                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //              Locator (continued, variable)                  //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Sub-TLVs (variable) . . .             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                        Figure 2: SRv6 Locator Entry


   o Metric:  4 octets, as described in Section 4 of [RFC5305].

   o Loc-Size:  1 octet.  Number of bits in the SRv6 Locator field,
      which  MUST be from the range (1-128).  The entire TLV MUST
      beignored If the Loc-Size is outside this range.

   o Resv: 3 octets, Not defined.

   o Locator:  1-16 octets.  This field encodes the advertised SRv6
      Locator.  The SRv6 Locator is encoded in the minimal number of
      octets for the given number of bits.  Trailing bits MUST be set
      to zero and ignored when received.


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   o Optional Sub-TLVs: The SRv6 SID LBLN Information and SRv6 End SID
      Entry SHOULD be included in the Locator Entry.



   The SRv6 SID Structure Sub-Sub-TLV has the following format:

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    LB Length  |  LN Length    | Fun. Length   |  Arg. Length  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    Figure 3: SRv6 SID LBLN Information

   Where:

   o LB Length: 1-octet field.  SRv6 SID Locator Block length in bits.

   o LN Length: 1-octet bit field.  SRv6 SID Locator Node length in
      bits.

   o Function Length: 1-octet field.  SRv6 SID Function length in
      bits.

   o Argument Length: 1-octet field.  SRv6 SID Argument length in
      bits.



   The SRv6 End SID Entry has the following format:
















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   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Endpoint Behavior       |      Flags                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SID (128 bits) . . .                                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SID (cont . . .)                                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SID (cont . . .)                                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SID (cont . . .)                                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    Figure 4: SRv6 End SID Entry

   where:

   o Flags:  2 octet.  No flags are currently defined.  All bits are
      reserved for future use.  They MUST be set to zero on
      transmission and MUST be ignored on receipt.

   o Endpoint Behavior:  2 octets, as defined in [RFC8986].

   o SID:  16 octets.  This field encodes the advertised SRv6 SID.



3. SRV6 Locator Prefix TIE

   In the RIFT network, in order to support SRv6, a new type of TIE
   called SRv6 Locator Prefix TIE is introduced. The Locator address
   and End-SID is advertised in Locator TIE.

   When a neighbor node receives a Locator Address Advertisement in
   SRv6 Locator TIE, it adds a route for the Locator address to its
   routing table, just like a Prefix TIE.

   Similar to Prefix TIEs, northbound advertisement of the Locator
   Detailed Route and southbound advertisement of the Default Route are
   sent under normal circumstances in the RIFT protocol.


      +===================================+=====+=======+===========+
      |Name                               |Value| Schema|Description|
      |                                   |     |Version|           |
      +===================================+=====+=======+===========+

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      |Illegal                            |    0|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |TIETypeMinValue                    |    1|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |NodeTIEType                        |    2|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |PrefixTIEType                      |    3|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |PositiveDisaggregationPrefixTIEType|    4|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |NegativeDisaggregationPrefixTIEType|    5|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |PGPrefixTIEType                    |    6|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |KeyValueTIEType                    |    7|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |ExternalPrefixTIEType              |    8|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |PositiveExternalDisaggregation     |     |
      |PrefixTIEType                      |    9|    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |TIETypeMaxValue                    | TBD |    6.1|           |
      +-----------------------------------+-----+-------+-----------+
      |LocatorTIEType                     | TBD |   6.1 |This        |
      |                                   |     |       |Document    |
      +-----------------------------------+-----+-------+------------+
      |PositiveDisaggregation             | TBD |   6.1 |This        |
      |LocatorTIEType                     |     |       |Document    |
      +-----------------------------------+-----+-------+------------+
      |NegativeDisaggregation             | TBD |   6.1 |This        |
      |LocatorTIEType                     |     |       |Document    |
      +-----------------------------------+-----+-------+------------+
      |PGLocatorTIEType                   | TBD |   6.1 |This        |
      |                                   |     |       |Document    |
      +-----------------------------------+-----+-------+------------+
                Table 1: Requested TIEType Entries



   The format of the SRv6 Locator TLV is the same as TLV in SRv6
   Locator KV TIE described in Section 2 of the this document. Only the
   Type field of the Locator TLV changes with different TIE types.

   When supporting the compression mode, the SRv6 SID LBLN Information
   needs to be carried in the End-SID information. The format of SRv6
   SID LBLN Information is described in Figure 3.



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4. Advertise End.X SID in Node TIE

   End.X SID is advertised via Node TIE, where the Neighbor information
   is extended in the Expanded Neighbor section.

   In Registry RIFT_v6/encoding/NodeNeighborsTIEElement:

      +=========+======+=========+====================================+
      | Name    |Value |  Schema | Description                        |
      |         |      | Version |                                    |
      +=========+======+=========+====================================+
      | level   |    1 |     6.1 | Level of neighbor                  |
      +---------+------+---------+------------------------------------+
      | cost    |    3 |     6.1 | Cost to neighbor.  Ignore anything |
      |         |      |         | larger than `infinite_distance`    |
      |         |      |         | and `invalid_distance`             |
      +---------+------+---------+------------------------------------+
      |link_ids |    4 |     6.1 | Can carry description of multiple  |
      |         |      |         | parallel links in a TIE            |
      +---------+------+---------+------------------------------------+
      |bandwidth|    5 |     6.1 | Total bandwith to neighbor as sum  |
      |         |      |         | of all parallel links              |
      +---------+------+---------+------------------------------------+
      | End.X   |  TBD |     6.1 | SRv6 End.X SID                     |
      +---------+------+---------+------------------------------------+
                Table 2: Requested Neighbors TIE Element





   The Format of End.X SID:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Flags       |   Algorithm   |   Weight      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Endpoint Behavior      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+








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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SID (128 bits) . . .                                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SID (cont . . .)                                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SID (cont . . .)                                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SID (cont . . .)                                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | SRv6 SID LBLN Information (optional)                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    Figure 5: Format of End.X SID
     where:

         Flags:  1 octet.

          0 1 2 3 4 5 6 7
         +-+-+-+-+-+-+-+-+
         |B|S|P|Reserved |
         +-+-+-+-+-+-+-+-+


     where:

         B-Flag:  Backup flag.  If set, the SID is eligible for
                 protection, e.g., using IP Fast Reroute (IPFRR)
                 [RFC5286] as described in [RFC8355].
         S-Flag:  Set flag.  When set, the S-flag indicates that the
                 SID refers to a set of adjacencies (and therefore MAY
                 be assigned to other adjacencies as well).
         P-Flag:  Persistent flag.  When set, the P-flag indicates that
                 the SID is persistently allocated, i.e., the SID value
                 remains consistent across router restart and/or
                 interface            flap.
         Reserved bits:  Reserved bits MUST be zero when originated and
                 MUST be ignored when received.
         Algorithm:  1 octet, as defined in the "IGP Algorithm Types"
                 registry [RFC8665].
         Weight:  1 octet.  The value represents the weight of the SID
                 for the purpose of load balancing.  The use of the
                 weight is defined in [RFC8402].
         Endpoint Behavior:  2 octets, as defined in [RFC8986].
         SID:  16 octets.  This field encodes the advertised SRv6 SID.
         SRv6 SID LBLN Information: describe SRv6 SID LBLN Information.




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5. Example

   In a RIFT network, SRv6 is used to enable path computation and
   traffic engineering. The RIFT control plane uses SRv6 Segment
   Routing to program paths through the network. Each node in the
   network is assigned a unique IPv6 SID, which is used to represent
   the node and its attached topology. When a source node wants to send
   traffic to a destination node, it simply specifies a list of SIDs
   that correspond to the nodes that the traffic must traverse.
   Intermediate nodes forward the traffic based on the specified SIDs,
   ensuring that it follows the desired path. SRv6 is used in
   conjunction with RIFT's Topology Information Base (TIB) to enable
   efficient path computation and fast rerouting in the event of a
   topology change. With SRv6, RIFT networks can support end-to-end
   traffic engineering, service chaining, and other advanced network
   functions, while also providing fast and efficient routing within
   the network.



   Assuming the Locator Block is 2001:0db8::/32, denoted as LB; ToF1's
   Locator is 2001:0db8:1::/64, denoted as LB:1::/64, NodeSid is
   2001:0db8:1::1, denoted as LB:1::1; other nodes follow the similar
   pattern.
























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             +----------------+      +----------------+     Level 2
             |ToF 1           |      |ToF 2           |
             |NodeSid: LB:1:: |      |NodeSid: LB:2:: |
             |Loc: LB:1::/64  |      |Loc: LB:2::/64  |
             +---+--+--+--+---+      +-+--+---+--+--+--+
                 |  |  |  |            |  |   |  |
                 |  |  |  |            |  |   |  |
                 |  |  |  |            |  |   |  |
     +-----------+  |  +--)------------)--)-+ |  +------------+
     |              |     |            |  | | |               |
     |    +---------)-----)------------+  | | |               |
     |    |         |     |               | | |               |
     |    |         |     +-----------------)-- -----------+  |
     |    |         |                     | | |            |  |
     |    |         +--+     +------------+ | |            |  |
     |    |            |     |              | |  Level 1   |  |
   +-+----+-----+  +---+-----+---+  +-------+-+--+  +------+--+--+
   |Spin11      |  |Spin12       |  |Spin21      |  |Spin22      |
   |NodeSid:    |  |NodeSid:     |  |NodeSid:    |  |NodeSid:    |
   |  LB:3::    |  |   LB:4::    |  |     LB:5:: |  |    LB:6::  |
   |Loc:        |  |Loc:         |  |Loc:        |  |Loc:        |
   |  LB:3::/64 |  |   LB:4::/64 |  |   LB:5::/64|  |   LB:6::/64|
   +--+---+-----+  +---+-----+---+  +--+---+-----+  +---+-----+--+
      |   |            |      |        |   |            |       |
      |   +------------)-+    |        |   +------------)-+     |
      |                | |    |        |                | |     |
      |   +------------+ |    |        |    +-----------+ |     |
      |   |         |    |    |        |    |    Level 0  |     |
   +--+---+-----+   +----+----+--+   +-+----+-----+   +---+-----+----+
   |Leaf11      |   |Leaf12      |   |Leaf21      |   |Leaf22        |
   |NodeSid:    |   |NodeSid:    |   |NodeSid:    |   |NodeSid:      |
   |   LB:7::   |   |   LB:8::   |   |     LB:9:: |   |     LB:A::   |
   |Loc:        |   |Loc:        |   |Loc:        |   |Loc:          |
       LB:7::/64|   |   LB:8::/64|   |  LB:9::/64 |   |    LB:A::/64 |
   +--+---------+   +-+----------+   +-+----------+   ++-------------+
      +               +                +               +
      Prefix11        Prefix12         Prefix21        Prefix22

                  Figure 6: SRv6 information in RIFT network

   During network initialization, the controller distributes all SRv6
   Locator configurations to ToF. Then ToF generates SRv6 Locator KV
   TIE and extends it to all nodes by ZTP. After receiving this
   information, each node generates its own SRv6 Locator
   configurations.


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   Each node generates its Node SID based on its own SRv6 Locator and
   advertise its SRv6 Locator and Node SID information through SRv6
   Locator TIE.

   After establishing neighbor relationships with other adjacent nodes,
   the node uses the SRv6 Locator information to generate End.X SID and
   carries it in the Neighbors information of Node TIE to be
   transmitted out.

   Assuming Leaf11 sends a packet to Leaf21, when congestion occurs on
   the westward link of TOF1, the controller can specify the packet
   path NodeSid_Spin12, NodeSid_TOF2, NodeSid_Spin21, NodeSid_Leaf21,
   for Leaf11, Leaf11 add an SRv6 header with a Segment List of (SA,DA)
   (2001:0db8:9::, 2001:0db8:5::, 2001:0db8:2::, 2001:0db8:4::, SL=3),
   so that the packet will pass through Leaf11, Spin12, ToF2, Spin21,
   Leaf21 node in order.

   When compression mode is supported, it is not necessary to add the
   SRv6 header, and route can be arranged through the destination
   address. In the path mentioned above, using compression mode, the
   destination address is 2001:0db8:0004:0002:0005:0009:0000:0000 The
   destination address generated through this compression method is
   called C-SID.

   When there are multiple paths available, Controller can select a
   specific path by specifying the End.X SID.

6. Security Considerations

   TBD.

7. IANA Considerations

7.1. SRv6 Locator KV TIE

This document requests an entry from the RIFT Well-Known Key-Type
Registry for Locator TIE in accordance with RIFT-KV-REGISTRY [RIFT-KV-
REGISTRY]
            +=======+=======================+=====================+
            | Value | Description           | Reference           |
            +=======+=======================+=====================+
            | TBD   | SRv6 Locator KV TIE   | This Document       |
            +-------+-----------------------+---------------------+
                Table 3: Requested TIEType Entries



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7.2. SRv6 Locator Prefix TIE

   This document makes the following registration in the "TIETypeType"
   registry:

            +=======+=============================================+
            | Value | Name                                        |
            +=======+=============================================+
            | TBD   | LocatorTIEType                              |
            +-------+---------------------------------------------+
            | TBD   | PositiveDisaggregationLocatorTIEType        |
            +-------+---------------------------------------------+
            | TBD   | NegativeDisaggregationLocatorTIEType        |
            +-------+---------------------------------------------+
            | TBD   | PGLocatorTIEType                            |
            +-------+---------------------------------------------+
              Table 4: IANA Requested TIE Type


7.3. SRv6 End.X SID

   This document makes the following registration in
   the"NodeNeighborsTIEElement" registry of a Node TIE:

            +=======+=============================================+
            | Value | Name                                        |
            +=======+=============================================+
            | TBD   | SRv6 End.X SID                              |
            +-------+---------------------------------------------+
              Table 5: IANA Requested Neighbours TIE Element


















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8. References

8.1. Normative References

   [draft-ietf-rift-sr] Z. Zhang,"SRIFT: Segment Routing in Fat Trees",
             12 January 2023,<https://www.ietf.org/archive/id/draft-
             ietf-rift-sr-00.txt>.

   [draft-ietf-rift-rift] A. Przygienda, Ed., "RIFT: Routing in Fat
             Trees", 14 September 2023,
             <https://www.ietf.org/archive/id/draft-ietf-rift-rift-
             17.txt>

   [RFC8665], P. Psenak, Ed., "OSPF Extensions for Segment Routing",
             December 2019, <https://datatracker.ietf.org/doc/rfc8665>

   [RFC8402], C. Filsfils, Ed., "Segment Routing Architecture", July
             2018, <https://datatracker.ietf.org/doc/rfc8402/>

   [RFC8754], C. Filsfils, Ed., "IPv6 Segment Routing Header (SRH)",
             March 2020, <https://datatracker.ietf.org/doc/rfc8754/>

   [RFC8986], C. Filsfils, Ed., "Segment Routing over IPv6 (SRv6)
             Network Programming", February 2021,
             <https://datatracker.ietf.org/doc/rfc8986/>

   [RFC5305], T. Li., "SIS-IS Extensions for Traffic Engineering",
             October 2008, <https://datatracker.ietf.org/doc/rfc5305/>

   [RFC5286], A. Atlas, Ed., "Basic Specification for IP Fast Reroute:
             Loop-Free Alternates", September 2008,
             <https://datatracker.ietf.org/doc/rfc5286/>

   [RFC8355], C. Filsfils, Ed., "Resiliency Use Cases in Source Packet
             Routing in Networking (SPRING) Networks", March 2018,
             <https://datatracker.ietf.org/doc/rfc8355/>

   [draft-ietf-lsr-ospfv3-srv6-extensions], Z. Li, "OSPFv3 Extensions
             for SRv6", 8 June 2023, <
             https://datatracker.ietf.org/doc/draft-ietf-lsr-ospfv3-
             srv6-extensions/ >








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   Appendix A.  Thrift Models

   This section contains the normative Thrift models required to
   support SRv6. Per the main RIFT [RIFT] specification, all signed
   values MUST be interpreted as unsigned values.

   A.1.  common.thrift

   This section specifies extensions to RIFT common.thrift model.

   These extensions are REQUIRED in order to support SRv6.

   TBD.

   A.2.  encoding.thrift

   This section specifies extensions to RIFT encoding.thrift model.

   These extensions are REQUIRED in order to support SRv6.

   struct NodeCapabilities {

   ...

      /** indicates whether SRv6 feature is implemented on this node
             (but not necessarily enabled). */

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      21: optional bool

          srv6_support = false;

   }

/** Type of TIE.*/
enum TIETypeType {
    ...
    LocatorTIEType                       = 10,
    PositiveDisaggregationLocatorTIEType = 11,
    NegativeDisaggregationLocatorTIEType = 12,
    PGLocatorTIEType                     = 13,
    TIETypeMaxValue                              = 14,
}


/* neighbor of a node */
struct NodeNeighborsTIEElement {
   ...

   /* endx sid of neighbor */

   6: optional common_srv6.Srv6SidElement endx,

}



   A.3.  common_srv6.thrift

Struct Srv6LBLNElement {
    1: required i8 lb_len,
    2: required i8 ln_len,
    3: required i8 func_len,
    4: required i8 arg_len,
}


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struct Srv6SidElement {
   1: required i16 endpoint_behavior,
   2: required i16 flags,
   3: required common.Ipv6Addr sid_addr,
   4: optional Srv6LBLNElement lbln_attrib,
}

st     r      uct                 Srv6LocatorSubElement {
    /** metric */
    1: required   i32 metric,
    /** loc size*/
    2: require    i8  loc_size,
    /* locator address */
    3: required common.Ipv6Addr locator_addr,
}

struct SRv6LocatorSubTlv {
    /** locator */
    1: required   Srv6LocatorSubElement       srv6_locator,
    /*  lbln information of locator*/
    2: optional   Srv6LBLNElement             locator_lbln,
    /* node sid */
    3: optional   list<Srv6SidElement>     srv6_sid_list,
}

struct SRv6LocatorKV {
    /**system id
   1: required   set<common.SystemIDType> system_id,

    /* locator info */
    2: required   SRv6LocatorSubTlv          srv6_locator,
}


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Authors' Addresses



   Weiqiang Cheng
   China Mobile
   China

   Email: chengweiqiang@chinamobile.com

   Changwang Lin
   New H3C Technologies
   China

   Email: linchangwang.04414@h3c.com

   Ruixue Wang
   China Mobile
   China

   Email: wangruixue@chinamobile.com

































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