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Last Call Review of draft-ietf-rtgwg-qos-model-11

Request Review of draft-ietf-rtgwg-qos-model-11
Requested revision 11 (document currently at 12)
Type Last Call Review
Team Transport Area Review Team (tsvart)
Deadline 2023-12-01
Requested 2023-10-26
Requested by Jeff Tantsura
Authors Aseem Choudhary , Mahesh Jethanandani , Ebben Aries , Ing-Wher (Helen) Chen
I-D last updated 2023-12-06
Completed reviews Tsvart Last Call review of -11 by Colin Perkins (diff)
Intdir Last Call review of -11 by Dr. Joseph D. Touch (diff)
Rtgdir Last Call review of -11 by Adrian Farrel (diff)
Yangdoctors Last Call review of -03 by Jürgen Schönwälder (diff)
Yangdoctors Last Call review of -06 by Jürgen Schönwälder (diff)
Dear Directorate,

In preparation for the last call, we would like to request your review.

RTGWG chairs
Assignment Reviewer Colin Perkins
State Completed
Request Last Call review on draft-ietf-rtgwg-qos-model by Transport Area Review Team Assigned
Posted at
Reviewed revision 11 (document currently at 12)
Result Ready w/nits
Completed 2023-12-06
This document has been reviewed as part of the transport area review team's
ongoing effort to review key IETF documents. These comments were written
primarily for the transport area directors, but are copied to the document's
authors and WG to allow them to address any issues raised and also to the IETF
discussion list for information.

When done at the time of IETF Last Call, the authors should consider this
review as part of the last-call comments they receive. Please always CC if you reply to or forward this review.

I am not an expert on YANG or DiffServ, and I have not followed the development
and discussion related to this draft. This review is hence necessarily written
from a generalist transport perspective. Please accept my apologies if I touch
on topics that have been considered before in the working group.

The draft looks to be defining mechanisms to configure the use of existing QoS
mechanisms and to report on their effects. As such, any new transport protocol
impact would seem limited. The mechanisms described may make it easier to
deploy QoS, but the QoS techniques exist and can be used irrespective of
whether this draft is published.

For AQM, this draft specifies configuration parameters for RED and WRED. These
AQM algorithms have certainly been widely implemented and used, but there are
more modern alternatives that have been defined in IETF and that are also
starting to see use (e.g., PIE – RFC 8033, and several variants on CoDel – RFC
8289/8290). Has consideration been given to whether any other AQM algorithms
should be included? Is the mechanism extensible to support these and other
future AQM approaches? From a transport perspective I would not recommend use
of RED or WRED today, since the alternatives perform better and are harder to
misconfigure. Some discussion about extensibility and alternatives would be

Similarly there are only two traffic classifiers specified, which may warrant
an extension point.

Otherwise, this seems broadly ready.