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Last Call Review of draft-ietf-tsvwg-aqm-dualq-coupled-24
review-ietf-tsvwg-aqm-dualq-coupled-24-opsdir-lc-jiang-2022-08-26-00

Request Review of draft-ietf-tsvwg-aqm-dualq-coupled
Requested revision No specific revision (document currently at 25)
Type Last Call Review
Team Ops Directorate (opsdir)
Deadline 2022-07-21
Requested 2022-07-07
Authors Koen De Schepper , Bob Briscoe , Greg White
Draft last updated 2022-08-26
Completed reviews Genart Last Call review of -24 by Christer Holmberg (diff)
Opsdir Last Call review of -24 by Sheng Jiang (diff)
Assignment Reviewer Sheng Jiang
State Completed
Review review-ietf-tsvwg-aqm-dualq-coupled-24-opsdir-lc-jiang-2022-08-26
Posted at https://mailarchive.ietf.org/arch/msg/ops-dir/Kf3BUnMVftuMEuclPlX8xLFmAtM
Reviewed revision 24 (document currently at 25)
Result Has Issues
Completed 2022-08-26
review-ietf-tsvwg-aqm-dualq-coupled-24-opsdir-lc-jiang-2022-08-26-00
Reviewer: Sheng Jiang
Review result: Has Issues
Document: draft-ietf-tsvwg-aqm-dualq-coupled-24
Review Date: 2022-08-26

I have reviewed this document as part of the Operational directorate's ongoing
effort to review all IETF documents being processed by the IESG. These comments
were written with the intent of improving the operational aspects of the IETF
drafts. Comments that are not addressed in last call may be included in AD
reviews during the IESG review. Document editors and WG chairs should treat
these comments just like any other last call comments.

This experimental document defines a framework for coupling the AQM algorithms
in two queues intended for flows with different responses to congestion. It is
the network part of the L4S architecture that enables both very low queuing
latency and high throughput at the same time.

I have concerns on the operational description in this document. This document
claims its mechanims can be deployed in the current network. But it lacks the
description on how and why it can works back-compatibly. I heard there were
intensive debate regarding to the usage of ECT (I did not participate it
myself), but the document has not introduced the reason or background why it is
allowed to use ECT from the urgement.

Another minor comments, there is another reason that can cause the result
mentioned in 4.2: if irresponsible terminals labels classic ect(0) flows into
l4s ect(1), it would overload l4s queue.

Regards,

Sheng