Hi Simon Very good point -- I also think this falls into the scope of draft-ietf-aqm-eval-guidelines aligned with my interpretation of your words. I believe Section 8.2.2 of https://tools.ietf.org/html/draft-ietf-aqm-eval-guidelines-08 somewhat implicitly covers that.
Cheers, Naeem On Tue, Oct 13, 2015 at 5:09 AM, Simon Barber <si...@superduper.net> wrote: > I was very interested to see this draft discusses a problem with AQMs > > AQM schemes like CoDel and PIE use congestion notifications to > constrain the queuing delays experienced by packets, rather than in > response to impending or actual bottleneck buffer exhaustion. With > current default delay targets, CoDel and PIE both effectively emulate > a shallow buffered bottleneck (section II, [ABE2015 > <https://tools.ietf.org/html/draft-khademi-alternativebackoff-ecn-01#ref-ABE2015>]). > This > interacts acceptably for TCP connections over low BDP paths, or > highly multiplexed scenarios (lmany concurrent TCP connections). > However, it interacts badly with lightly-multiplexed cases (few > concurrent connections) over high BDP paths. Conventional TCP > backoff in such cases leads to gaps in packet transmission and > underutilisation of the path. > > > I think it wold be good to add some discussion of this effect to the draft > on evaluating AQM algorithms. In many access network scenarios the paths > will be lightly loaded, and sometimes higher BDPs will be experienced. In > these cases it's good to know that the AQM is not hurting your experience. > > Simon > > _______________________________________________ > aqm mailing list > aqm@ietf.org > https://www.ietf.org/mailman/listinfo/aqm > >
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