IETF MOQ WG: Add Sender-Side Track Switching (SSTS) #1638

Message Snapshot

• List: moq@ietf.org
• Thread subject: Add Sender-Side Track Switching (SSTS) #1638
• Message subject: [Moq] Add Sender-Side Track Switching (SSTS) #1638
• Author: Law, Will
• Published: 2026-07-02T12:20:43.000Z
• Source tag: ietf-mailing-list
• Message URL: Open in IETF Mail Archive

Summary

Law, Will posted to the MOQ working group mailing list on July 2, 2026. For those interested in (the former) DTS, we had a number of action items<https://datatracker.ietf.org/doc/minutes-interim-2026-moq-17-202606221630…

Why It Matters

This message came from the public MOQ working group archive and captures active discussion, meeting coordination, or implementation feedback around Media over QUIC.

Message Excerpt

For those interested in (the former) DTS, we had a number of action itemshttps://datatracker.ietf.org/doc/minutes-interim-2026-moq-17-202606221630/ https://datatracker.ietf.org/doc/minutes-interim-2026-moq-17-202606221630/ arising for the moq interim on June 22nd. I have updated PR 1638<https://github.com/moq-wg/m…

Plain-Text Body

For those interested in (the former) DTS, we had a number of action itemshttps://datatracker.ietf.org/doc/minutes-interim-2026-moq-17-202606221630/ https://datatracker.ietf.org/doc/minutes-interim-2026-moq-17-202606221630/ arising for the moq interim on June 22nd. I have updated PR 1638https://github.com/moq-wg/moq-transport/pull/1638 with the following changes:

Dynamic Track Switching (DTS) has been renamed to Sender-Side Track Switching (SSTS) 2. We now allow SSTS to support multiple algorithms. The algorithms supported by the relay are advertised during setup by the new SSTS_ALGORITHMS setup option, which provides a list of supported algorithms. An empty list is an indication that the relay does not support, or has not implemented, SSTS. Algorithms are registered in a new IANA 'SSTS-Algorithms� registry. 3. The spec defines a base definition of the SWITCHING-SET-ASSIGNMENT parameter

SWITCHING-SET-ASSIGNMENT { Switching set ID (vi64), Algorithm (vi64) }

Each algorithm can then extend this to pass additional fields, as well as provide explicit rules for subscriber behavior and relay behavior. 2. The spec defines a default algorithm, which is registered as algorithm 0. This algorithm adds the following fields to the SWITCHING-SET-ASSIGNMENT parameter and also adds instructions for subscribers and relays in implementing this algorithm.

SWITCHING-SET-ASSIGNMENT { Switching set ID (vi64), Algorithm ID (vi64), Throughput threshold (vi64), Set throughput fraction (vi64), Activate switching (vi64), [Set rank (8)] }

We removed the setup options for MAX_DTS_CONCURRENT_TRACKS, per the decision at the interim.

Please review PR 1638 and approve if you find the changes acceptable. I also welcome someone writing their own algorithm, to test the extension mechanism.

Cheers Will

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