[Cake] Running Cake at long RTTs

Toke Høiland-Jørgensen toke at toke.dk
Tue Oct 27 12:50:34 EDT 2015

Sebastian Moeller <moeller0 at gmx.de> writes:

>> - Turn the hard packet queue size into a lower bound rather than an
>>  upper bound.
> 	This seems dangerous for low memory configurations?

Well, yeah, the max packet count allowed can be higher this way, but I
guess the only sane answer to that is "don't configure cake for 100Mbit
and 1s+ of latency if you don't have the memory to spare".

Having the (now lower) bound be a bit lower than it is currently may be
a good idea, but not sure what it should be... The current 10240 matches

>> - Scale the target to be 1/16th of the interval.
> 	Codel theory claims 5-10%, so 1/20 to 1/10, so it seems you
> 	confirm the theory, not sure why cake did not do this as a
> 	default… rem, what actually was cake setting target to? Asked
> 	differently how sensitive to target being exactly 1/16th was the
> 	throughput?

Yup. 1/16th has the benefit of being implementable as a 4bit shift :)

Before, the target was hard-coded as 5 ms; so this was definitely an


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