[Bloat] pie aqm finally landed in Linux

[Dave Taht <dave.taht@gmail.com>]

http://www.spinics.net/lists/netdev/msg264935.html

Hat off to vijay and the pie folk at cisco who shepherded the code
through 5 releases to get it upstream!

PIE is now mandated in DOCSIS3.1 cablemodems and the ECO for DOCSIS
3.0 went out a while ago.

I think the mandate differs from the Linux implementation. I don't
know the size of the recomended cablelabs target nor the size of the
estimation window (?)).

So that will improve going-upstream buffering problems dramatically.

The linux implementation supports ECN, the DOCSIS standard does not.
The ECN work in pie has some minor problems that fq_codel doesn't
have, we hope to discuss at ietf...

I will fold the v5 implementation of pie into cerowrt in the next release and
see what happens.

NOW:

The biggest problem remaining in cable is fixing excessive downstream
buffering. Surely something can be done to remove the 1.6 seconds of
buffering I observed yesterday (at some level without needing to AQM?
Some workaround that operators can use?). Some benchmarks I ran last
night (not against pie):

http://snapon.lab.bufferbloat.net/~d/bev/comcast_native_ipv6/

I sure hope the gpon, lte, and wifi folk are paying attention.

-- 
Dave Täht

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