[Cake] Cake strange behaviour

Jonathan Morton chromatix99 at gmail.com
Sat Jul 16 12:25:10 EDT 2016

> Line is a 40/10 cake limited to 39000/9840.

I think you might be rather optimistic on your ingress shaping rate.  In order to control the queue effectively in the (less ideal) downstream position, the shaper needs to be set somewhat below the actual line rate.  I’m not yet sure exactly how far down it needs to be, but just 2.5% is probably not enough, especially in the face of a traffic type reputed to be “intensive".

> Without extensive testing I have no faith that the current aqm implementation in cake is actually working.

Meanwhile, I’ve been downloading a fresh copy of Star Citizen for the past 12+ hours, using the extremely intensive P2P method.  Cake reported 300-500 *bulk* flows at various times, all in the Best Effort tin.  Web browsing on the same machine is predictably slow, but actually works (aside from servers which automatically cut connections after a timeout, even if they aren’t idle).

But web browsing on a *different* machine is still responsive, even with fairly large images, thanks to triple-isolation.  That wouldn’t happen unless the upstream queue was being kept empty - a very difficult task under that sort of load.

All this is greatly helped by the fact that my 3G ISP has apparently just upgraded a nearby tower, so I am now able to set 4Mbps ingress without having to account for a lot of variability.  Previously I had to set 1Mbps ingress to be sure of low latencies.

I really should get on with migrating my firewall to a different box, to free up the one with two NICs.  Then I can run the sort of tests that might actually convince people.

 - Jonathan Morton

More information about the Cake mailing list