[Cake] best way at getting at tcp ack data?

Dave Taht dave.taht at gmail.com
Sun Oct 1 22:40:18 EDT 2017

The crux of my question was what would be the best way to incorporate
the FLOW_DISSECTOR_KEY_TCP into cake whilst retaining all the other
DPI. I would add a "ack_filter" parameter to the rate_flags?

On Sun, Oct 1, 2017 at 6:08 PM, Jonathan Morton <chromatix99 at gmail.com> wrote:
> Ah, so effectively you want to drop acks more aggressively than data packets
> when they become a saturating flow in themselves,

Well, no, what I envisioned would try to comprehensively "do the right
thing" when it came to dropping acks, and not actually wait til they
were saturating.

you have a good point though.

Where I see the most use for it is on very slow DSL, and on wifi
(where you have a small packet limit and reliable transfers).

I also don't know what will happen with extensive filtering in place
to the reverse path, reason tells me that the sparse packet priority
scheme when applied to filtered out acks will result in really bursty
throughput on the other side, and it would be better to defer a full
round between deliveries than leave the sparse packet priority scheme
in place, when doing ack filtering. But that's "reason", and that
fails me a lot whilst thinking about queues.

As I believe at least some level of ack filtering is widely
deployed... til now, I've largely been satisfied that the DRR would
deliver a ton of acks that would be filtered out by the device doing

>but without disturbing the
> cues that TCP relies on.  There is some logic behind that, since COBALT
> ramps up quite slowly with very small packets like acks.
> I think it's worth opening an issue to remind me to look into that.

Well, I might gather enough gumption to go after it, as well as try
and produce a cleaned up cake branch suitable for inclusion in 4.15.

At the moment I'm starting to prototype a bit with a bfifo, and
perhaps netem, 'cause grokking cake makes my head hurt.

> I still
> don't have a replacement for my MBP, which is complicating matters here.


> - Jonathan Morton


Dave Täht
CEO, TekLibre, LLC
Tel: 1-669-226-2619

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