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SR Policies Extensions for NRP in BGP-LS
draft-chen-idr-bgp-ls-sr-policy-nrp-05

Document Type Active Internet-Draft (individual)
Authors Ran Chen , Jie Dong , Detao Zhao , Liyan Gong , Yongqing Zhu , Ran Pang
Last updated 2024-02-23
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draft-chen-idr-bgp-ls-sr-policy-nrp-05
IDR                                                              R. Chen
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                                 J. Dong
Expires: 26 August 2024                                           Huawei
                                                                 D. Zhao
                                                         ZTE Corporation
                                                                 L. Gong
                                                            China mobile
                                                                  Y. Zhu
                                                           China Telecom
                                                                 R. Pang
                                                            China Unicom
                                                        23 February 2024

                SR Policies Extensions for NRP in BGP-LS
                 draft-chen-idr-bgp-ls-sr-policy-nrp-05

Abstract

   This document defines a new TLV which enable the headend to report
   the configuration and the states of SR policies carrying NRP
   information by using BGP-LS.

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
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 August 2024.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Carrying NRP TLV in BGP-LS  . . . . . . . . . . . . . . . . .   3
   4.  Scalability Considerations  . . . . . . . . . . . . . . . . .   4
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   8.  Informative References  . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Segment Routing Policy [RFC9256] is an ordered list of segments (i.e.
   instructions) that represent a source-routed policy.  Packet flows
   are steered into a SR Policy on a node where it is instantiated
   called a headend node.  The packets steered into an SR Policy carry
   an ordered list of segments associated with that SR Policy.

   [I-D.ietf-teas-ietf-network-slices] provides the definition of IETF
   network slice for use within the IETF and discusses the general
   framework for requesting and operating IETF Network Slices, their
   characteristics, and the necessary system components and
   interfaces.It also introduces the concept Network Resource Partition
   (NRP), which is a subset of the resources and associated policies in
   the underlay network.

   [I-D.ietf-teas-ns-ip-mpls] introduces the notion of a Slice-Flow
   Aggregate which comprises of one or more IETF network slice traffic
   streams.  It also describes the Network Resource Partition (NRP) and
   the NRP Policy that can be used to instantiate control and data plane
   behaviors on select topological elements associated with the NRP that
   supports a Slice-Flow Aggregate.

   [I-D.ietf-idr-bgp-ls-sr-policy] describes a mechanism to distribute
   SR policy information to external components using BGP-LS.

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   [I-D.ietf-idr-sr-policy-nrp] defines the extensions to BGP SR policy
   to specify the NRP which the SR Policy candidate path is associated
   with.

   This document defines a new TLV which enable the headend to report
   the configuration and the states of an SR policy carrying the NRP
   information by using BPG-LS.

2.  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.

3.  Carrying NRP TLV in BGP-LS

   In order to collect configuration and states of the NRP SR policy,
   this document defines a new SR Policy state TLV which enable the
   headend to report the state at the SR Policy CP level.

   This TLV is carried in the optional non-transitive BGP Attribute
   "LINK_STATE Attribute" defined in [RFC7752]associated with the SR
   Policy CP NLRI type.

   This TLV is optional and only one this TLV is advertised for a given
   CP.  If multiple TLVs are present, then the first one is considered
   valid and the rest are ignored as describe in
   [I-D.ietf-idr-bgp-ls-sr-policy].

   The 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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Type      |   Length      |     Flags     |   RESERVED    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                         NRP ID (4 octets)                     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   Type: TBD1.

   Length: 6 octets.

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   Flags: 1 octet of flags.  None are defined at this stage.  Flags
   SHOULD be set to zero on transmission and MUST be ignored on receipt.

   RESERVED: 1 octet of reserved bits.  SHOULD be set to zero on
   transmission and MUST be ignored on receipt.

   NRP ID: 4-octet domain significant identifier of Network Resource
   Partition.

4.  Scalability Considerations

   The mechanism specified in this document defines the headend to
   report configuration and states of an SR policy carrying the NRP
   information by using BPG-LS.  BGP-LS SR Policy is used to report the
   SR Policy attributes and status.  As a new attribute of the SR
   Policy, NRP will not increase the number of the SR Policy reported by
   BGP-LS.

5.  Acknowledgements

   TBD.

6.  IANA Considerations

   IANA maintains a registry called "Border Gateway Protocol - Link
   State (BGP-LS) Parameters" with a sub-registry called "BGP-LS NLRI
   and Attribute TLVs".  The following TLV codepoints are suggested (for
   early allocation by IANA):

      Codepoint   Description                  Reference
    ----------------------------------------------------------
       TBD         NRP TLV                   This document

7.  Security Considerations

   Procedures and protocol extensions defined in this document do not
   affect the BGP security model.  See the "Security
   Considerations"section of [RFC4271] for a discussion of BGP
   security.Security considerations for acquiring and distributing BGP-
   LS information are discussed in [RFC7752].

8.  Informative References

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   [I-D.ietf-idr-bgp-ls-sr-policy]
              Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and J.
              Tantsura, "Advertisement of Segment Routing Policies using
              BGP Link-State", Work in Progress, Internet-Draft, draft-
              ietf-idr-bgp-ls-sr-policy-03, 5 November 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
              ls-sr-policy-03>.

   [I-D.ietf-idr-sr-policy-nrp]
              Dong, J., Hu, Z., and R. Pang, "BGP SR Policy Extensions
              for Network Resource Partition", Work in Progress,
              Internet-Draft, draft-ietf-idr-sr-policy-nrp-00, 17
              December 2023, <https://datatracker.ietf.org/doc/html/
              draft-ietf-idr-sr-policy-nrp-00>.

   [I-D.ietf-teas-ietf-network-slices]
              Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
              K., Contreras, L. M., and J. Tantsura, "A Framework for
              Network Slices in Networks Built from IETF Technologies",
              Work in Progress, Internet-Draft, draft-ietf-teas-ietf-
              network-slices-25, 14 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              ietf-network-slices-25>.

   [I-D.ietf-teas-ns-ip-mpls]
              Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli,
              D., Halpern, J. M., Peng, S., Chen, R., Liu, X.,
              Contreras, L. M., Rokui, R., and L. Jalil, "Realizing
              Network Slices in IP/MPLS Networks", Work in Progress,
              Internet-Draft, draft-ietf-teas-ns-ip-mpls-03, 26 November
              2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
              teas-ns-ip-mpls-03>.

   [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>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

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   [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>.

   [RFC9256]  Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
              A., and P. Mattes, "Segment Routing Policy Architecture",
              RFC 9256, DOI 10.17487/RFC9256, July 2022,
              <https://www.rfc-editor.org/info/rfc9256>.

Authors' Addresses

   Ran Chen
   ZTE Corporation
   Nanjing
   China
   Email: chen.ran@zte.com.cn

   Jie Dong
   Huawei
   Beijing
   China
   Email: jie.dong@huawei.com

   Detao Zhao
   ZTE Corporation
   Nanjing
   China
   Email: zhao.detao@zte.com.cn

   Liyan Gong
   China mobile
   Beijing
   China
   Email: gongliyan@chinamobile.com

   Yongqing Zhu
   China Telecom
   Guangzhou
   China
   Email: zhuyq8@chinatelecom.cn

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   Ran Pang
   China Unicom
   Beijing
   China
   Email: pangran@chinaunicom.cn

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