Subject: [tsvwg] Major revision: draft-ietf-tsvwg-aqm-dualq-coupled-09

From: Bob Briscoe <[email-masked]>
Date: Thu, 4 Jul 2019 20:30:12 +0100

tsvwg folks,

In this major revision we've deleted the Open Issues Appendix having 
cleared all those listed, and all the minor 'ToDo' notes throughout:
https://tools.ietf.org/html/draft-ietf-tsvwg-aqm-dualq-coupled-09

If you follow the 'diff' link you will see a huge amount of altered 
text. Nonetheless, there are few technical changes (see below). Most of 
the re-write was clearing up text-rot 'cos this draft was the first we 
wrote about L4S, so over the years we've worked out better ways of 
introducing it. I believe it can now be considered in its final shape, 
but improvement suggestions are still welcome.

Also the author list got too long, so we've shifted some to a 
contributors section, with their permission.

Thanks to everyone who's been helping. Hopefully the main ones haven't 
been omitted from the acknowledgements...

      Technical changes:

* Added one new normative requirement (the example implementation in 
Appx A already did this, but it just wasn't called out as a MUST in the 
body):

    If the DualQ Coupled AQM has detected overload, it MUST signal
    congestion solely using drop, irrespective of the ECN field. 
    Switching to drop if ECN marking is persistently high is required by
    Section 7 of [RFC3168] and Section 4.2.1 of [RFC7567].

* Nice new abstracted out config API for the PI2 AQM (also being added 
to the reference Linux implementation). For the public Internet as 
always no config is needed. But for non-default settings, the API takes 
two parameters that will be well-known to operators (max and typical 
RTT) and calculates all five PI2 parameters from these.

* Completely re-written the Curvy RED appendix, which had got behind all 
the basic improvements added to the DualPI2 example (conditional 
priority scheduler, Classic ECN support, config in time units, etc. A 
couple of changes, including an explicit min threshold were based on 
recommendations from Gabi Bracha, for which thanks.

Cheers

Bob
for all the authors.

-- 
________________________________________________________________
Bob Briscoe                               http://bobbriscoe.net/