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Versions: 00                                                            
IDR                                                              R. Chen
Internet-Draft                                                   S. Peng
Intended status: Standards Track                         ZTE Corporation
Expires: 14 March 2022                                         P. Psenak
                                                           Cisco Systems
                                                       10 September 2021


   Updates to Algorithm Related Adjacency SID Advertisement in RF9085
           draft-chen-idr-bgp-ls-algorithm-related-adj-sid-00

Abstract

   This draft updates [RFC9085] to defines extensions to the Border
   Gateway Protocol-Link State (BGP-LS) address family in order to carry
   algorithm Related Adjacency SID.

Status of This Memo

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

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   This Internet-Draft will expire on 14 March 2022.

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   provided without warranty as described in the Simplified BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  BGP-LS Extensions for link Attribute  . . . . . . . . . . . .   2
     2.1.  Adjacency SID per Algorithm TLV . . . . . . . . . . . . .   2
     2.2.  LAN Adjacency SID per Algorithm TLV . . . . . . . . . . .   3
   3.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   [I-D.ietf-lsr-algorithm-related-adjacency-sid] defines the algorithm
   identifier can be included as part of an Adjacency-SID advertisement
   for SR-MPLS.

   [RFC9085] defines extensions to the Border Gateway Protocol-Link
   State (BGP-LS) address family in order to carry SR information via
   BGP, and an algorithm identifier is included as part of the Prefix-
   SID TLV advertisement.  This draft updates [RFC9085] and defines
   extensions to the Border Gateway Protocol-Link State (BGP-LS) address
   family in order to carry algorithm Related Adjacency SID.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  BGP-LS Extensions for link Attribute

2.1.  Adjacency SID per Algorithm TLV

   The Adjacency SID per Algorithm TLV is used in order to advertise
   information related to an algorithm Related Adjacency SID.  This
   information is derived from the Adjacency Segment Identifier (Adj-
   SID) per Algorithm Sub-TLV of ISIS/OSPFv2/OSPFv3(Section 4 of
   [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   The Adjacency SID per Algorithm TLV 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               Type            |              Length           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Flags         |     Weight    |   Algorithm   |   Reserved    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   SID/Label/Index (variable)                 //
      +---------------------------------------------------------------+

                                  Figure 1

   where:

   Type: TBD1 (Suggested value to be assigned by IANA)

   Length: variable.

   Flags: 1-octet value that should be set as:

   *  IS-IS Adj-SID per Algorithm flags as defined in Section 4.1.1 of
      [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   *  OSPFv2 Adj-SID per Algorithm Sub-TLV as defined in Section 4.2.1
      of [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   *  OSPFv3 Adj-SID per Algorithm Sub-TLV as defined in Section 4.3.1
      of [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   Weight: 1 octet carrying the weight used for load-balancing purposes.
   The use of weight is described in Section 3.4 of [RFC8402].

   Algorithm: Refer to ISIS/OSPFv2/OSPFv3 Adj-SID per
   Algorithm([I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   Reserved: 1-octet that MUST be set to 0 and ignored on receipt.

   SID/Label/Index:Refer to ISIS/OSPFv2/OSPFv3 Adj-SID per
   Algorithm([I-D.ietf-lsr-algorithm-related-adjacency-sid]).

2.2.  LAN Adjacency SID per Algorithm TLV

   This information is derived from LAN-Adj-SID per Algorithm Sub-TLV of
   ISIS/OSPFv2/OSPFv3(Section 4 of
   [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   The LAN Adjacency SID per Algorithm TLV 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Type             |            Length             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Flags     |     Weight    |  Algorithm    |  Reserved     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             OSPF Neighbor ID / IS-IS System ID                |
      +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    SID/Label/Index (variable)                //
      +---------------------------------------------------------------+

                                  Figure 2

   where:

   Type: TBD2 (Suggested value to be assigned by IANA)

   Length: variable.

   Flags: 1-octet value that should be set as:

   *  IS-IS LAN-Adj-SID per Algorithm flags as defined in Section 4.1.2
      of [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   *  OSPFv2 LAN-Adj-SID per Algorithm Sub-TLV as defined in
      Section 4.2.2 of [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   *  OSPFv3 LAN-Adj-SID per Algorithm Sub-TLV as defined in
      Section 4.3.2 of [I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   Weight: 1 octet carrying the weight used for load-balancing purposes.
   The use of weight is described in Section 3.4 of [RFC8402].

   Algorithm: Refer to ISIS/OSPFv2/OSPFv3 LAN-Adj-SID per
   Algorithm([I-D.ietf-lsr-algorithm-related-adjacency-sid]).

   Reserved: 1-octet that MUST be set to 0 and ignored on receipt.

   Neighbor ID/IS-IS System ID: Refer to ISIS/OSPFv2/OSPFv3 LAN-Adj-SID
   per Algorithm([I-D.ietf-lsr-algorithm-related-adjacency-sid]).




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   SID/Label/Index:Refer to ISIS/OSPFv2/OSPFv3 LAN-Adj-SID per
   Algorithm([I-D.ietf-lsr-algorithm-related-adjacency-sid]).

3.  Acknowledgements

   TBD.

4.  IANA Considerations

   This document makes the following Link Attribute TLVs registry under
   the "Border Gateway Protocol-Link State (BGP-LS) Parameter".


           +======+===========================================+
           | Type | Description                               |
           +======+===========================================+
           | TBD1 | Adjacency SID per Algorithm               |
           +------+-------------------------------------------+
           | TBD2 | LAN Adjacency SID per Algorithm           |
           +------+-------------------------------------------+

                                  Figure 3

5.  Security Considerations

   Procedures and protocol extensions defined in this document do not
   affect the BGP-LS security model.  See the "Security
   Considerations"section of [RFC9085] for a discussion of SR BGP-LS
   security.

6.  References

6.1.  Normative References

   [I-D.ietf-lsr-algorithm-related-adjacency-sid]
              Peng, S., "Algorithm Related IGP-Adjacency SID
              Advertisement", DOI 10.17487/I-D.ietf-lsr-algorithm-
              related-adjacency-sid, I-D. ietf-lsr-algorithm-related-
              adjacency-sid, June 2021,
              <https://www.ietf.org/archive/id/draft-ietf-lsr-algorithm-
              related-adjacency-sid-00.txt>.

   [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>.





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   [RFC8402]  Filsfils, C., "Key words for use in RFCs to Indicate
              Requirement Levels", RFC 8402, DOI 10.17487/RFC8402, July
              2018, <https://www.rfc-editor.org/info/rfc8402>.

   [RFC9085]  Previdi, S., "Border Gateway Protocol - Link State (BGP-
              LS) Extensions for Segment Routing", RFC 9085,
              DOI 10.17487/RFC9085, August 2021,
              <https://www.rfc-editor.org/info/rfc9085>.

Authors' Addresses

   Ran Chen
   ZTE Corporation
   Nanjing
   China

   Email: chen.ran@zte.com.cn


   Shaofu Peng
   ZTE Corporation
   Nanjing
   China

   Email: peng.shaofu@zte.com.cn


   Peter Psenak
   Cisco Systems
   Slovakia

   Email: ppsenak@cisco.com



















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