[Cake] Long-RTT broken again

Jonathan Morton chromatix99 at gmail.com
Sat Nov 7 00:02:13 EST 2015

> On 6 Nov, 2015, at 16:15, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
> Added a run with Reno to the same directory. Smoother, but worse overall
> throughput.

Yes, looks like it’s ramping up the slow way, and hasn’t reached the BDP by the time the test run ended.

However, it also looks like it’s properly ack-clocked, unlike CUBIC, so while it’s still bursty, it isn’t overflowing the buffer except during slow-start.

The fact that slow-start terminates (due to loss) after only a few RTTs is suspicious.  What parameters are you giving to netem?  I note that the default packet limit in netem is 1000, which is 1.5MB...

 - Jonathan Morton

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