IETF MOQ WG: Knowing the start of a Subgroup

Message Snapshot

• List: moq@ietf.org
• Thread subject: Knowing the start of a Subgroup
• Message subject: [Moq] Re: Knowing the start of a Subgroup
• Author: Ian Swett
• Published: 2026-04-30T15:08:14.000Z
• Source tag: ietf-mailing-list
• Message URL: Open in IETF Mail Archive

Summary

Ian Swett posted to the MOQ working group mailing list on April 30, 2026. Thanks for clarifying. Using subgroup IDs in the catalog is an interesting usecase I hadn't considered. I'm not sure this would cause practical p…

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

Thanks for clarifying. Using subgroup IDs in the catalog is an interesting usecase I hadn't considered. I'm not sure this would cause practical problems, but I need more time to think about it.

Plain-Text Body

Thanks for clarifying. Using subgroup IDs in the catalog is an interesting usecase I hadn't considered. I'm not sure this would cause practical problems, but I need more time to think about it.

Regarding consistency, today we indicate the end of the Subgroup with a stream FIN, not a bitflag on the Object. So I actually think using Subgroup ID==Object ID is more consistent, but that's my opinion.

When we originally created Subgroups, we needed an ID to stitch them together in case they were split apart. I'm not sure anyone intended this be exposed to the application, but it sounds like you want to? QUIC doesn't expose Stream IDs as part of its API, which was an intentional choice and mostly a good one.

If we go with the bitflag approach (#1618), are people ok with requiring it be set on the first Object in the Subgroup? Requiring it gives the feature a lot more value IMO.

Also, do people want to resolve the undefined prioritization between Subgroups and datagrams in some way? "3. If two objects in response to the same request have the same subscriber

• and publisher priority and belong to the same group of the same track, the one with the lowest Subgroup ID (for objects with forwarding preference Subgroup), or the lowest Object ID (for objects with forwarding preference Datagram) is scheduled to be sent first. If the two objects have different Forwarding Preferences the order is implementation dependent."*

Thanks, Ian

On Thu, Apr 30, 2026 at 5:22 AM Magnus Westerlund <magnus.westerlund= 40ericsson.com@dmarc.ietf.org> wrote: