**Session Date/Time:** 27 Mar 2023 00:30

# lsr

## Summary
The LSR (Link State Routing) working group meeting covered a variety of topics including working group document status, updates on several drafts, and presentations on new proposals. Key discussions revolved around fast flooding, advertising offsets for flex algorithms, announcing unreachable prefixes, suppressing IS-IS adjacency, IGP extensions for link management and traffic engineering, and advertising service functions.

## Key Discussion Points

*   **Working Group Document Status:** Several drafts are in the RFC editor queue or have completed working group last call. Discussions on experimental drafts and maintenance drafts were also held.
*   **Fast Flooding:** Bruno presented updates on the fast flooding draft, focusing on improving the exchange rate between IS-IS and labels by getting rid of fixed timers and parameters, adapting to the speed of networks, and flow control mechanisms.
*   **Advertising Offset for Flex Algorithm:** Louis Chan presented a draft on advertising offsets for flex algorithms in IS-IS, addressing the problem of inefficient advertisement for each algorithm. Virtual flex algorithms were also discussed. There was disagreement if this was a scaling issue.
*   **Unreachable Prefix Announcement:** Peter provided an update on the unreachable prefix announcement draft, describing how to announce unreachable prefixes in IGP using existing protocol mechanisms for backward compatibility.
*   **IS-IS Adjacency Suppression:** Discussed a method for avoiding temporary black holes when a router restarts from an unplanned outage by suppressing adjacency advertisement.
*   **IGP Extensions for Link Management and Traffic Engineering (MT):** A proposal was made for IGP extensions to support link management and traffic engineering (MT) capabilities in SR networks, enabling the advertisement of SR policies for the PCEP and constructing paths for the non-establishment protocol.
*   **IGP Extensions for Extended TLVs (Type-Length-Value):** Jorge presented a proposal for a generalized way of handling large TLVs, splitting them into smaller containers for IS-IS. Concerns were raised regarding compatibility with existing implementations.
*   **Advertising Service Functions:** A proposal was discussed for IS-IS and OSPF extensions to advertise service functions and their attributes.

## Decisions and Action Items

*   **Fast Flooding Draft:** The working group agreed to proceed with a working group last call for the fast flooding draft.
*   **Unreachable Prefix Announcement Drafts:** The authors, Peter and , were asked to collaborate and come up with a subset of the two proposals to be merged in to a single draft.
*   **Interim Meeting:** An interim meeting may be scheduled to cover topics that were not fully discussed due to time constraints.

## Next Steps

*   Encourage participants to review the fast flooding draft for the working group last call.
*   Encourage Louis Chan to update virtual flex algorithm draft for scaling.
*   Peter and need to update the unreacheable prefix draft with proposed subset and combination.
*   Organize an interim meeting if there is enough interest from participants.
*   Further discussion on various topics on the mailing list.