IETF MOQ WG: Support for Track Filters and Top-N

Message Snapshot

• List: moq@ietf.org
• Thread subject: Support for Track Filters and Top-N
• Message subject: [Moq] Re: Support for Track Filters and Top-N
• Author: Mo Zanaty (mzanaty)
• Published: 2026-05-12T14:22:13.000Z
• Source tag: ietf-mailing-list
• Message URL: Open in IETF Mail Archive

Summary

Mo Zanaty (mzanaty) posted to the MOQ working group mailing list on May 12, 2026. To avoid confusion, the current filter PR#1518 and interim slides define a track filter which always selects the top N tracks with the hi…

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

To avoid confusion, the current filter PR#1518 and interim slides define a track filter which always selects the top N tracks with the highest values of a specified property type. So a track filter is always​ top N. During the discussion, I think some may have used track filter to describe the general concept of filte…

Plain-Text Body

To avoid confusion, the current filter PR#1518 and interim slides define a track filter which always selects the top N tracks with the highest values of a specified property type. So a track filter is always​ top N.

During the discussion, I think some may have used track filter to describe the general concept of filtering some tracks in a namespace. The only other filter defined today which can do that is the Property Filter which is a Range Filter (aka Object Filter in the consensus call). It originally applied only to individual objects like all other Range Filters. But when we added Track Properties, it suddenly had new functionality to filter tracks in a namespace, filtering Publish messages in addition to objects. The other Range Filters (ObjectID, Subgroup, Priority) can't filter Publish messages.

Did anyone use track filter to mean anything other than this? (Track Property Filter which is a Range Filter in Subscribe Namespace aka Subscribe Tracks now.)

Thanks, Mo

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From: Magnus Westerlund magnus.westerlund=40ericsson.com@dmarc.ietf.org Sent: Tuesday, May 12, 2026 7:43 AM To: MOQ Mailing List moq@ietf.org Subject: [Moq] Support for Track Filters and Top-N

WG,

In yesterday’s meeting we discussed Fitlers (https://github.com/moq-wg/moq-transport/pull/1518) and the second poll indicated that there are both numerous support to include top-n track filters as well as equal amounts of opposition (7 vs 7). This leads me to see the need for some more discussion here. There was also an aspect that brought up, namely the track filters without Top-N functionality for SUBSCRIBE_NAMESPACE request. I don’t feel we got to the bottom if it is only the TOP-N functionality that people have problems or if there are concerns with Track filters without Top-N functionality.

I would like to encourage some continued discussion of the concerns here. As part of this discussion do please consider all of the following:

Fulfilling the use cases that the WG have been chartered to support * Impact on timeline for MOQT and if that is a concern * Security impact * Would there be impact in the splitting the filters into one MOQT core functionality and an extension

I would appreciate if you answer the following two questions from your perspective.

Do you support including track filters without Top-N functionality in the MOQT specification?

Do you support including track filters with Top-N functionality in the MOQT specification?

Cheers

Magnus Westerlund MOQ Chair