**Session Date/Time:** 06 Nov 2023 16:30 # tsvwg ## Summary This meeting of the Transport Services Working Group (TSVWG) covered several key topics, including updates on GitHub status, RFC progress, and ongoing work items. Presentations were given on the DTLS over SCTP design team's progress, careful resumption of congestion control state, and multi-path DCCP. The DTLS over SCTP discussion focused on defining requirements and exploring implementation options, with a goal to propose a way forward for the working group. The careful resumption presentation highlighted recent hackathon activity and refinements to the draft. Multi-path DCCP status was also presented, focusing on language improvements and addressing open issues. ## Key Discussion Points * **GitHub Status:** 6 of 7 working group drafts have been moved to GitHub, allowing for issues and pull requests. * **RFC Status:** No new RFCs published. Two documents are with the IESG, and one is in first working group last call. * **DTLS over SCTP:** The design team presented its requirements analysis for securing SCTP-based communication, focusing on cloud deployments and 3GPP requirements. Key areas of discussion included message size limits, support for multiple streams, and security considerations against on-path attackers. The design team was tasked with developing a suggested way forward for the working group by the end of the year. * **Careful Resumption:** A hackathon project implemented careful resume in quiche. Refinements to the draft were discussed, including handling data-limited connections, splitting the unvalidated phase, and utilizing byte estimation for safe retreat. There was discussion regarding the storage time for RTT and BDP values. * **Multi-Path DCCP:** The draft has been updated with language improvements and guidance on sequence number space exhaustion. The goal is to address remaining issues and proceed to a working group last call. ## Decisions and Action Items * **DTLS over SCTP Design Team:** The design team will meet at the IETF to plan a way forward and will provide a suggestion on how to progress to the working group by the end of the year. This update will be published as an Internet Draft. * **Multi-Path DCCP:** Authors will address remaining issues and aim to publish version 12 by the end of the year. ## Next Steps * DTLS over SCTP design team to formulate a suggested way forward for the working group by the end of the year. * Multi-Path DCCP authors to address outstanding issues in the issue tracker and publish a new version of the draft, potentially leading to a working group last call. * Continue development and discussion on the careful resumption draft. --- **Session Date/Time:** 09 Nov 2023 08:30 # tsvwg Meeting Minutes ## Summary The TSVWG meeting covered several topics, including Happy Eyeballs version 3, an L4S field test update, L4S interoperability events, and updates on the NQB and L4S ops drafts. Discussions also included SDP extensions for checksums, DTLS for SCTP, and UDP options. Finally, there was a presentation of the media header extension draft, followed by discussion about its adoption as a working group item. ## Key Discussion Points * **Happy Eyeballs v3:** The update aims to incorporate ALPN information from DNS records (SVCB), and to generalize the notion of transport racing to include QUIC. Focus is on defining handshake completion for different transports. The discussion centered around which working group should adopt this draft (TSVWG vs. V6OPS). * **L4S Field Test Update (Comcast):** The first public trial, focused on DOCSIS networks, showed promising results. Cloud-native real-time applications demonstrated bigger benefits than legacy apps. Key challenges included fixing ECN bleaching and DSCP marking leaks. Testing mainly upstream, with downstream support coming. * **L4S Interoperability Events:** CableLabs is hosting interop events for L4S implementations, with upcoming opportunities in December and potentially March. Involved different congestion control implementations, DOCSIS equipment, and Wi-Fi access points. * **NQB (No Queueing Bloat) Draft:** Discussions centered on finalizing the draft and performing another working group last call. The addition of a co-author was noted. * **L4S Ops Draft:** Draft focuses on identifying and mitigating potential unfairness between L4S and classic ECN traffic. The draft has been migrated to a GitHub repository for easier contribution and issue tracking. * **SDP Extension for Zero Checksum:** Aims to reduce CPU overhead by allowing zero checksums in SDP when used over DTLS, which provides its own integrity protection. Updated based on working group last call. Discussed IANA registry and requirements. * **DTLS for SCTP:** Addressing security issues in RFC 4995 related to symmetric keys and HMAC algorithms. Proposes using a key vector based on random parameters to differentiate roles on both sides. * **UDP Options:** Discussions on outstanding issues, including fragmentation feedback mechanisms. Strong consensus against generating ICMP messages for UDP fragmentation, and instead letting the application deal with it. Authentication and encryption were also discussed. * **Media Header Extensions Draft:** Proposes sending metadata with media packets to assist wireless networks with short-term capacity changes. The metadata includes priority, burst size, and delay tolerance. There was discussion of encapsulation for the transport and the need for alignment with other standards and concerns from 3GPP. ## Decisions and Action Items * **Happy Eyeballs v3:** The ISG will discuss the adoption of this draft and potentially converge on a decision. * **NQB Draft:** Chairs to look for reviewers for the latest version of the NQB draft. If adequate review, initiate a final working group last call on the next revision. * **DTLS for SCTP:** Begin a formal adoption call on the list to confirm as work item in this working group. * **UDP Options:** Editors will incorporate feedback regarding fragmentation feedback mechanisms into the draft. * **Media Header Extensions Draft:** Discuss the draft further on the mailing list and continue discussion on the working group list. ## Next Steps * The ISG will discuss the adoption of Happy Eyeballs v3. * Chairs will seek reviewers for the NQB draft, and if reviews are sufficient, initiate another working group last call. * Formally start an adoption call on the list for DTLS for SCTP. * Editors will update the UDP Options draft based on meeting discussions. * Continue discussions regarding the Media Header Extensions draft on the mailing list,