Session Date/Time: 24 Jul 2025 10:00

lsvr

Summary

The LSVR working group session at IETF 112 covered working group updates, discussion on BGP-SPF neighbor discovery mechanisms (L3DL and LDP-based), and an individual draft on the extension of applicability of SRv6 to BGP-SPF. Key discussions revolved around the comparison of L3DL and LDP for neighbor discovery and the level of detail needed in the SRv6 draft.

Key Discussion Points

Working Group Updates: Two new RFCs (base BGP-SPF and its data center applicability) were published. The BGP LS YANG document expired and is being updated. The L3DL draft has a recent update to address security directorate comments, and a response to the IEEE 802.1 liaison is needed.
BGP-SPF Peer Discovery Requirements: Requirements are outlined in RFC 9815 and 9816, with the need to discover the address of a single-hop peer and potentially additional information such as AS number, BGP ID, and security capabilities.
L3DL vs. LDP-based Neighbor Discovery:
- L3DL authors are considering using LLDP for layer 2 discovery and live checks.
- Discussion on the motivations behind L3DL and the advantages and disadvantages of each approach. Consideration of industry support for both proposals.
- There was a request to compare both approaches clearly on the mailing list.
LDP Presentation (Draft Plotorf):
- LDP uses a database exchange protocol with TLVs for information storage and advertisement.
- Reliability is achieved through multi-hello packets and unicast transmission of updated frames based on receiver requests.
- Discussion about standardizing the application interface to disseminate the LDP information to BGP.
SRv6 Extension Draft:
- Discussion on the need for more detailed explanation on how the SRv6 TLVs are used and what is installed in the RIB, referencing relevant IGP documents.
- Question on whether Flex-Algo functionality is implied by TLV definitions.

Decisions and Action Items

Action Item: Authors of L3DL and LDP-based neighbor discovery mechanisms to engage in detailed discussion on the mailing list to compare the approaches and address the IEEE 802.1 liaison.
Action Item: Author of draft on SRv6 extension to BGP-SPF to add additional details, potentially referencing IGP documents, about how the TLVs are used and what is installed in the IPv6 RIB.
Request: The Chairs would like to see a decision before the next IETF whether an interim meeting is required.

Next Steps

Intense discussion on the mailing list comparing L3DL and LDP-based neighbor discovery.
Address comments on SRv6 draft and possibly update it.