Inter-Domain Routing K. Ananthamurthy Internet-Draft M. Mishra Intended status: Standards Track L. Krattiger Expires: 24 April 2025 Cisco K. Patel Arrcus 21 October 2024 BGP Route Type Capability draft-kriswamy-idr-route-type-capability-00 Abstract BGP supports different route types, which defines the encoding of Network Layer Reachability Information (NLRI) for a some of the Address Family Identifier (AFI)/Subsequent Address Family Identifier (SAFI) like Ethernet VPN (EVPN), Multicast VPN(MVPN) and so on. BGP speaker will reset the BGP session if a given route type is not supported. This document defines an Optional Capabilities to exchange the route types supported for a given AFI/SAFI such that session are not reset. 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. 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 24 April 2025. Ananthamurthy, et al. Expires 24 April 2025 [Page 1] Internet-Draft BGP Route Type Capability October 2024 Copyright Notice Copyright (c) 2024 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 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. Route Type Capability . . . . . . . . . . . . . . . . . . . . 3 4. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Normative References . . . . . . . . . . . . . . . . . . . . 4 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction BGP Ethernet VPN (EVPN), Multicast VPN(MVPN), and other address families support multiple route types. Different route types will have different key lengths consisting of multiple fields which are used as a BGP Route Key. If a particular route type is not supported on a BGP speaker then the session will be reset as there is no way to determine the key. When a new Route-type is added to EVPN, MVPN and any other address families that support route types, then all routers in the network to be updated to make sure that there is no session reset. Resetting a BGP session is expensive as we have seen from deployments that multiple AFI/SAFI are negotiated between the BGP neighbors and resetting a session will impact the network adversely. This document defines an optional capability exchange of route types per AFI/SAFI such that BGP speakers negotiate the route types and only if the neighbor has advertised a particular route-type capability support then only advertise the given route-type in MP_REACH_NLRI. Ananthamurthy, et al. Expires 24 April 2025 [Page 2] Internet-Draft BGP Route Type Capability October 2024 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. Route Type Capability The Rout type capability is a new BGP capability [[RFC5492] that can be used by BGP speaker to indicate the route types of a given AF/SAFI supported. This capability is defined as follows: * Capability code: To be assigned by IANA * Capability length: variable * Capability value: Consists of 0 to 63 of the tuples "AFI, SAFI, Route-Type length and Route-type values for address family" +----------------------------------------------------------+ | Address Family Identifier (2 octets) | +----------------------------------------------------------+ | Subsequent Address Family Identifier (1 octet) | +----------------------------------------------------------+ | Route-Type length (1 cotet) | +----------------------------------------------------------+ | Route-Types (variable length) | +----------------------------------------------------------+ * The AFI and SAFI, taken in combination, indicate that Route-types supported for routes that are advertised with the same AFI and SAFI. Route-types may be explicitly associated with a AFI and SAFI using the encoding of [BGP-MP] * Route-Type length: This field specifies the total length in octets, of Route-Types field. * Route-Type: This field specifies the Route-Types. A speaker that supports multiple "AFI, SAFI" tuples that requires route-type capability exchanges includes them as multiple Capabilities in the Capabilities Optional Parameter. Ananthamurthy, et al. Expires 24 April 2025 [Page 3] Internet-Draft BGP Route Type Capability October 2024 If route type capabilities are exchanged between BGP speakers for a specific AFI/SAFI, and the BGP peer does not support a particular route type, that route should not be advertised to the peer. 4. Error Handling TBD 5. Security Considerations TBD 6. IANA Considerations This document defines a new optional route type capability dnd request the BGP optional capability registry: 7. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [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, . [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, DOI 10.17487/RFC4760, January 2007, . [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Contributors In addition to the authors listed on the front page, the following coauthors have also contributed to this document: Satya Mohanty Ananthamurthy, et al. Expires 24 April 2025 [Page 4] Internet-Draft BGP Route Type Capability October 2024 Authors' Addresses Krishnaswamy Ananthamurthy Cisco 170 W. Tasman Drive San Jose, CA 95134 United States of America Email: kriswamy@cisco.com Mankamana Mishra Cisco 170 W. Tasman Drive San Jose, CA 95134 United States of America Email: mankamis@cisco.com Lukas Krattiger Cisco 170 W. Tasman Drive San Jose, CA 95134 United States of America Email: lkrattig@cisco.com Keyur Patel Arrcus Email: keyur@arrcus.com Ananthamurthy, et al. Expires 24 April 2025 [Page 5]