**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.