IDR Working Group C. Lin Internet Draft New H3C Technologies Intended status: Standards Track J. Li Expires: August 18, 2025 China Mobile Ran.Chen ZTE February 18, 2025 Advertisement of SR Policy Administative Flags using BGP Link-State draft-lin-idr-bgp-ls-sr-policy-admin-flag-00 Abstract This document defines the extension of BGP Link-State to advertise the administrative state of the candidate path or segment list, facilitating the operation and maintenance of the SR Policy. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on August 18, 2025. Copyright Notice Copyright (c) 2025 IETF Trust and the persons identified as the document authors. All rights reserved. Lin, et al. Expires August, 2025 [Page 1] Internet-Draft BGP-LS for SR Policy Admin Flags February 2025 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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 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....................................................3 3. Extension of SR Candidate Path State...........................3 4. Extension of SR Segment List TLV...............................3 5. Operations.....................................................3 6. IANA Considerations............................................3 7. Security Considerations........................................4 8. References.....................................................4 8.1. Normative References......................................4 8.2. Informative References....................................4 9. Acknowledgments................................................5 Authors' Addresses................................................6 1. Introduction Segment routing (SR) [RFC8402] is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. The ingress node steers packets into a specific path according to the Segment Routing Policy (SR Policy) as defined in [RFC9256]. An SR Policy may have multiple candidate paths that are provisioned or signaled [I-D.ietf-idr-sr-policy-safi] [RFC8664] from one of more sources. [I-D.lin-idr-sr-policy-admin-flags] proposes an extension to the BGP SR Policy that sets the management state of the candidate path or the segment list, facilitating the operation and maintenance of the SR Policy. This document defines extensions to BGP-LS to advertise defines the extension of BGP Link-State to advertise the administrative state of the candidate path or segment list. Lin, et al. Expires August, 2025 [Page 2] Internet-Draft BGP-LS for SR Policy Admin Flags February 2025 2. Terminology The definitions of the basic terms are identical to those found in Segment Routing Policy Architecture [RFC9256]. 3. Extension of SR Candidate Path State As defined in [I-D.ietf-idr-bgp-ls-sr-policy], the SR Candidate Path State TLV provides the operational status and attributes of the SR Policy at the candidate path level. New bits in Flags field of the SR Candidate Path State TLV are defined: - BI-Flag (Bit TBD): Indicates the CP is configured as "backup ineligible". - IS-Flag(Bit TBD): Indicates the CP is configured as "Ignore service route's Prefix SID". It allows traffic to a BGP service route to be steered over an SR policy without imposing the service route's prefix label or SRv6 Service SID. - N-Flag(Bit TBD): indicate the endpoint node SID is included in installing SID list(s) of the Candidate Path (CP) when set. 4. Extension of SR Segment List TLV As defined in [I-D.ietf-idr-bgp-ls-sr-policy],The SR Segment List TLV is used to report a single SID-List of a candidate path. Multiple instances of this TLV may be used to report multiple SID- Lists of a candidate path. A New bit in Flags field of the SR Segment List TLV is defined: - S-Flag(Bit TBD): Indicates the SR Segment is in an administrative shut state when set and not in administrative shut state when clear. 5. Operations The document does not bring new operation beyond the description of operations defined in Section 6 of [I-D.ietf-idr-bgp-ls-sr-policy]. The existing operations defined in [I-D.ietf-idr-bgp-ls-sr-policy] can apply to this document directly. 6. IANA Considerations TBD Lin, et al. Expires August, 2025 [Page 3] Internet-Draft BGP-LS for SR Policy Admin Flags February 2025 7. Security Considerations Procedures and protocol extensions defined in this document do not affect the BGP security model. 8. References 8.1. Normative References [I-D.ietf-idr-bgp-ls-sr-policy] Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and Tantsura, J., "Advertisement of Segment Routing Policies using BGP Link-State", draft- ietf-idr-bgp-ls-sr-policy-04 (work in progress), March 2024. [I-D.ietf-idr-sr-policy-safi] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., and Jain, D., "Advertising Segment Routing Policies in BGP", draft-ietf-idr-sr-policy-safi-02 (work in progress), March 2024. [I-D. lin-idr-sr-policy-admin-flags] Lin, C., Li, J., and Chen, R., "BGP SR Policy Extensions for Administrative Flags", draft-lin-idr-sr-policy-admin-flags (work in progress), February 2025. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [RFC9256] Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", RFC 9256, DOI 10.17487/RFC9256, July 2022, . 8.2. Informative References TBD Lin, et al. Expires August, 2025 [Page 4] Internet-Draft BGP-LS for SR Policy Admin Flags February 2025 9. Acknowledgments The authors would like to thank the following for their valuable contributions of this document: TBD Lin, et al. Expires August, 2025 [Page 5] Internet-Draft BGP-LS for SR Policy Admin Flags February 2025 Authors' Addresses Changwang Lin New H3C Technologies China Email: linchangwang.04414@h3c.com Jinming Li China Mobile 32 Xuanwumen West Street Beijing Xicheng District, 100053 China Email: lijinming@chinamobile.com Ran Chen ZTE Corporation Email: chen.ran@zte.com.cn Lin, et al. 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