Subject: [aqm] fq_codel, codel, and RRUL

From: Dave Taht <[email-masked]>
Date: Wed, 20 Mar 2013 09:43:25 -0400

The present state of the research (as opposed to what we've been able
to write down and publish), and some open questions
re codel were described and discussed at stanford a few weeks back.

http://www.youtube.com/watch?v=Mxoa5Si4Ubw
http://netseminar.stanford.edu/seminars/Inside_Codel_and_Fq_Codel.pdf

There was spirited discussion (kathie nichols, myself, eric dumazet,
and rong) of how codel and fq_codel actually works starting about 24
minutes in, and it ended up dominating the talk so much that I was
unable to talk about the "fq" part of fq_codel very much.

It certainly is my hope to spark further discussion of how these
algorithms work on this list, and I guess I should put together a talk
focusing on the sfq/fq portions of the algo in order to get traction
on it...

Earlier in the stanford and MIT talks I tried to describe how with
tests like the RRUL test how we were starting to look into the
behavior of mice and ants and congestion control of elephants with
aqm.  I also had wanted to talk about the three tier prioritization
scheme I've been fiddling with for over a year, some plots of the
results of that are in the slides.

There was a followup talk at MIT about the problems wireless and wifi
has, I don't have the link handy.

There is still a great deal of research needed on what the right
answers are for data centers, verses what we think is extra-ordinarily
promising on the edge. I note that sfqcodel is available now for ns2
under the bsd license, fq_codel is in ns3 also under the same license,
and the codel codel in linux presently is a bit behind and dual
bad/gpl licensed. fq_codel is GPL.

Please take a look at whatever versions you feel comfortable looking at.

I've been watching the ECN discussion go by and while have some
comments on that thread I'll make tomorrow or so, but I encourage
people to look at the ECN threads on the codel list as a starting
point for thinking about the problems of ECN on the wild and wooly
internet.

-- 
Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html