[Cake] TCP ACK filtering

[Ryan Mounce]

Hi,

I'm seeking feedback from users of highly asymmetric internet
connections and TCP experts alike with respect to my work-in-progress
patch to add TCP ACK filtering (a.k.a. suppression / thinning) to
cake.

A preliminary version has been merged into the cobalt branch there is
an open PR for a revision with significantly reduced overhead (in
terms of CPU cycles).

https://github.com/dtaht/sch_cake/pull/63
https://github.com/dtaht/sch_cake/pull/64
https://github.com/dtaht/tc-adv/pull/17

There is still further research to be done on my part to extend this
filtering to SACKs in an intelligent manner (mostly of benefit to
flows with a large BDP).

Ironically I will be migrating from a 48:1 120/2.5 link to a more
balanced 5:2 100/40 link at home shortly so I won't have much of a
personal stake in this feature's performance from that point, however
I hope that it will be of benefit to others.

Regards,
Ryan Mounce