Markdown Version | Session Recording

Session Date/Time: 23 Jul 2025 09:30

bier

Summary

The BIER working group meeting covered the status of existing drafts, a presentation on Halo Labels draft, and a presentation on the MOE multi-cost use case. A lively discussion ensued regarding the Halo Labels draft and its implications for interoperability, ultimately leading to a decision to adopt the draft and expand its scope. The MOE use case presentation sparked a discussion about the relevance of multicast in AI networks and potential deployment strategies.

Key Discussion Points

• Halo Labels Draft:
  • Clarification of the draft's purpose in resolving inconsistencies in MPLS payload type identification within the BIER header.
  • Discussion around the semantics of the protocol field and the distinction between global and context alphabets.
  • Debate regarding the implementation requirements for BIER routers supporting upstream and downstream labels, with concerns about interoperability and vendor choices.
  • Whether the draft should only address semantics, or attempt to enforce greater interoperability.
  • The use of downstream and upstream assigned service labels
• MOE Multi-Cost Use Case:
  • Introduction of MOE (Mixture of Experts) architecture in large language models (LLMs) and its potential benefits for training and inference.
  • Exploration of using multicast to reduce the pressure on source GPUs and alleviate latency/bandwidth issues in MOE deployments.
  • Discussion about the data volume transferred to experts and the trend of increasing context, prompting questions about the scalability and relevance of multicast.
  • Consideration of alternative approaches like broadcast and GMP, as well as the potential for leveraging switch-level adoption instead of NICs.
  • The importance of reliability in AI networks and the need for multicast solutions to integrate with existing reliable transmission functions.
  • Question of the charter scope of the BIER working group and whether the scope of the AI issues should be discussed in other IETF groups, or the IRTF

Decisions and Action Items

• Halo Labels Draft:
  • Decision to adopt the Halo Labels draft as a working group item.
  • Agreement to expand the scope of the draft to address interoperability concerns and define more specific behaviors for vendors implementing BIER with MPLS.
  • Take the updated draft to the mailing list for further discussion and refinement.
• MOE Multi-Cost Use Case:
  • Authors to connect with other IETF and IRTF groups working on data center AI to gather more data and explore potential solutions.

Next Steps

• Authors to revise the Halo Labels draft based on the meeting discussions and submit it to the mailing list for further review and potential refinements.
• Authors to investigate alternative solutions.
• Working group to explore the potential for switch-level adoption of BIER in data centers.
• Working group to consider how to balance solving AI multicast issues with the existing charter.