Session Date/Time: 21 Mar 2025 06:00

tcpm

Summary

The TCPM working group meeting covered the status of existing working group documents, discussed proposed updates to several drafts, and heard presentations on individual submissions related to TCP diagnostics and buffer management. Key topics included proportional rate reduction (PRR), accurate ECN rate request option (TAR), TCP reset diagnostic payloads, source buffer management, and the behavior of the close call for TCP sockets with a non-zero linger time.

Key Discussion Points

Accurate ECN: The draft is RFC editor queue and expected to be published soon.
6937bis (PRR): Discussion focused on the change from "pipe" to "in-flight" terminology. The change was well-received.
Generalized ECN: The working group is planning to initiate a working group last call soon, now that Accurate ECN is nearing completion.
TCP Accurate Request (TAR) Option: Updates were presented, addressing sparse ACK issues. Discussion involved the use of SYN cookies, middlebox issues, and the need for explicit reviews.
TCP Reset Diagnostic Payload: The presentation discussed adding diagnostic information to TCP RST packets. Concerns were raised regarding testing across diverse network paths, encoding methods, security considerations, and application access to the diagnostic payload.
Source Buffer Management: Presentation highlighting the impact of source buffer size on latency, particularly in scenarios like screen sharing and video streaming. Discussion involved APIs, a consistent behavior across platforms and the applicability to non-TCP protocols like QUIC.
Close Behavior with Linga Time: Discussed the expected behavior of the close call in BSD sockets when a reset is received or the connection terminates during the linger period. The consensus was that it should not return zero indicating success.

Decisions and Action Items

6937bis (PRR): The chair will make a final check on the mailing list before submitting the draft to the IESG.
TCP Accurate Request (TAR) Option: The authors will incorporate the feedback from the meeting into a new revision of the draft and then proceed to a working group last call.
- Volunteers for review: Join and Kores
TCP Reset Diagnostic Payload: Authors will revise the draft based on feedback regarding encoding, security considerations, testing, and application exposure of the diagnostic payload.
Source Buffer Management: Author will revise the document based on feedback.
Close Behavior with Linga Time: Michael will continue to seek input and look into behavior from different implementations.

Next Steps

Mailing list discussions for all drafts will continue.
6937bis will be submitted to the IESG after a final check on the mailing list.
A new revision of the Accurate Request draft is to be produced and a working group last call will commence.
Revised drafts for TCP Reset Diagnostic Payload and Source Buffer Management will be produced, reflecting the feedback received.
The group will revisit the topic of Source Buffer Management in Madrid in July to decide if this should continue as an independent effort or whether it maybe belongs in transport area.