Session Date/Time: 22 Jul 2025 12:30

6man Session

Summary

The 6man working group session covered document status updates, hackathon results on IPv6 address selection rules, IPv6 node requirements updates, and several technical presentations. Key topics included IPv6 extension header limits, rule 5.5 implementation testing, node requirements for IPv6-only networks, and various protocol improvements. The session highlighted ongoing challenges with IPv6 deployment and multihoming, particularly around proper source address selection and routing behavior.

Key Discussion Points

Document Status Updates

Two RFCs published: DHCP prefix delegation to clients and deprecation of IPv6 route
Multiple documents in RFC Editor queue, including snack router alert and IPv6 zone identifiers
Extension header limits document (draft-ietf-6man-eh-limits) has five IESG discuss positions and may need to return to working group
ULA document (RFC 6724) close to approval with minor text fixes needed

IPv6 Address Selection Testing Results (Hackathon Report)

Comprehensive testing of RFC 3484 Rule 5.5 and RFC 8028 across multiple platforms
Apple and Windows implement Rule 5.5 correctly; Linux does not
Neither Apple nor Windows implement RFC 8028 properly for topology changes
Network Manager's ECMP behavior breaks IPv6 multihoming assumptions
Apple devices have a minor bug with router deprecation that self-corrects

IPv6 Node Requirements Updates (RFC 8504bis)

Adding mandatory support for both PMTU discovery and PLPMTU discovery
Removing extension header processing text, delegating to separate document
Considering mandatory RFC 8028 implementation for proper multihoming
Planning IPv6-only network section with requirements for local synthesis, PREF64 option
Discussion on router solicitation requirements vs RFC 4861 inconsistency

Technical Presentations

Reflection Utility: ICMP-based diagnostic tool in working group last call
Off-link Prefix Issues: Problems with redirect messages and neighbor discovery in isolated networks
IPv6 Aggregate Header Limits: Problem statement for handling large extension headers in SRv6 networks
ICMP Error Handling in SRv6: Uniform model for ICMP error propagation in service provider VPNs
WiFi Multicast Issues: Proposal to mandate IEEE 802.11 Flexible Multicast Service for IPv6

Decisions and Action Items

Extension Header Limits

Document will return to working group due to unresolvable IESG discusses
Need to separate node protection requirements from transmission limits
Authors to address discuss comments and potentially restructure document

IPv6 Node Requirements

Add PLPMTU discovery as mandatory requirement
Include DHCP-PD per client awareness
Consider RFC 8028 as mandatory for multihoming support
Create new draft to fix RFC 4861 router solicitation inconsistency
Develop IPv6-only network section for next revision

Implementation Issues

Network Manager developers to be contacted about ECMP routing problems
Apple bug report submitted for router deprecation issue
Linux Rule 5.5 patch needs cleanup and upstream submission

Next Steps

Continue extension header limits discussion on mailing list
RFC 6724bis final review and approval process
IPv6 node requirements working group last call preparation
Reflection utility working group last call completion
WiFi Alliance engagement regarding mandatory Flexible Multicast Service
Development of IPv6 multihoming deployment guidance document
Off-link prefix operational guidance document development
Cross-working group coordination for SRv6 ICMP error handling

The session demonstrated significant progress on IPv6 deployment challenges while identifying areas requiring continued standardization and implementation work, particularly around multihoming and IPv6-only network operations.