[Cake] Getting Cake to work better with Steam and similar applications

[Andy Furniss]

Jonathan Morton wrote:
> 
>> On 29 Apr, 2017, at 18:11, Andy Furniss <adf.lists at gmail.com>
>> wrote:
>> 
>> With the ingress param shaping at 1mbit 5 tcps (cubic or bbr)
>> really destroys latency.
>> 
>> With the caveat that my test may be flawed, I am currently
>> suspecting that cake cobalt head + ingress param and a low rate is
>> buggy.
> 
> That’s odd, since I’m currently dogfooding it at 512Kbit, and it
> works fine like that.  Not to the point of wanting to play online
> games while torrenting and downloading Steam updates, but that sort
> of limitation comes with the territory.
> 
> With a game updater that uses *80* web-seeds simultaneously (a
> libtorrent quirk which should get patched in the next version), I can
> still reliably use my Web browser and e-mail on a second machine;
> these are things that start to fail intermittently over about 2
> seconds RTT, and I’ve measured this ISP at 45 seconds without
> modification.
> 
> The key thing to remember is that in ingress mode, you *must* reduce
> the shaped rate to some (large) fraction of the bottleneck link,
> otherwise it won’t control the queue at all.  For example, I’m
> reasonably sure my current link is dumb-shaped to 576Kbit at the ISP.
> The smaller the fraction, the better the control of latency Cake can
> achieve.
> 
> This is in contrast to egress mode, where you want to match the link
> capacity as closely as possible to get maximum performance; latency
> control remains ideal as long as you never actually *exceed* the true
> link capacity.

It was a rather artificial test with cake set at 1mbit behind hfsc at
18mbit - just trying to recreate one of Dendari's tests. With the
ingress parameter latency was hurt quite badly compared to without,
which was unexpected. There were a lot of drops - but it seemed like
they were hurting the ping flow. Putting ping into voice didn't help.