Session Date/Time: 17 Mar 2025 06:00

pim

Summary

The PIM working group meeting covered a wide range of topics, including updates on existing drafts, discussions on new proposals, and problem statements for future work. Significant discussion revolved around the 1112 bis draft, multicast address allocation, multicast snooping, and applying multicast to distributed consensus systems. Several presentations were made on specific drafts and proposals, followed by discussions and feedback from the working group.

Key Discussion Points

RFC 1112 bis (Host Extensions for IP Multicast): Extensive discussion on the special treatment of 224.0.0.1, whether or not to call this RFC an update to IPv4 791, and the implications of changing the draft name.
PIM Multicast Protocols Overview Draft: Aiming to consolidate existing multicast protocols to a helpful document to the industry. Focus on reliable multicast history and future development.
IPv6 Multicast Group ID Allocation: Addressing the conflict between dynamic multicast group IDs and solicited node multicast addresses and proposing a new range allocation scheme.
Multicast Snooping Enhancements: Discussing enhancements to multicast snooping, including handling multicast meeting switches and optimizing multicast data distribution. Update to RFC 4541 and RFC 3810.
Multicast for Distributed Consensus: Exploring the potential benefits of multicast in distributed consensus systems, comparing iterative diffusion to a Stroman architecture, and discussing the impact on consensus latency and finality.
LISP Multicast Deployments: Documenting LISP multicast use cases and the experiences gained from deployments, including layer 2 BUM and layer 3 ASM/SSM/BIDER services.
SRV6 Multicast: Proposing to extend SRV6 architecture with stateless multicast replication and delivery, following the principles of RFC 8402 and aligning with SRV6 Unicast architecture.
IGMP/MLD Proxy Yang Model Extension: Proposing an extension to the IGMP/MLD proxy Yang data model to support multipath approaching and SDN controller based configuration.
IGMP/MLD Echo Mode Extension: Exploring an extension to IGMP/MLD messages to signal subscriber willingness to use "echo mode" for content delivery, potentially reducing bandwidth and enabling sleep modes.
Deterministic ECMP Selection in PIM: Describing a deterministic ECMP selection mechanism for PIM to improve traffic flow efficiency, especially in leaf-spine network topologies.

Decisions and Action Items

RFC 1112 bis:
- Discuss with AD and IESG on handling updates to very old documents.
- Consider changing the draft name to "PIM Multicast Protocols".
IPv6 Multicast Group ID Allocation:
- Proceed with working group last call on the problem statement draft.
- Review other problem statements to ensure the solutions actually fit.
Multicast Snooping Enhancements:
- Continue refining the document.
Multicast for Distributed Consensus:
- Contribute to the beer use case draft.
LISP Multicast Deployments:
- Review RFC 9739 (PIM Light) and incorporate relevant aspects into the draft.
Deterministic ECMP Selection in PIM:
- Ask the list working group for feedback.

Next Steps

Working group last calls to be initiated for the RFC 1112bis draft and the multicast group ID allocation problem statement.
Further development and refinement of various drafts based on the feedback received during the meeting.
Continued discussions on the mailing list to address specific technical issues and gather broader community input.
Prepare new versions for next IETF in Madrid.