Re: [Codel] [Cake] openwrt build available with latest cake and fq_pie

[Jonathan Morton <chromatix99@gmail.com>]

> On 14 Jun, 2015, at 21:24, Dave Taht <dave.taht@gmail.com> wrote:
> 
> Flows, btw, do end quite rapidly in the real world. What was it, 95%
> of all web flows ended inside of IW10?

It might be worth thinking about how heavily loaded a network needs to be for Codel to trigger on such a flow.  However, with perfect flow isolation, count will start at 1, making it less relevant to the present thread.

Cake will start triggering on a instantly-arrived burst (call it a packet salvo) after 35ms.  Thus, a ten-packet burst will not trigger provided at least 4.5 Mbps is available to that flow.  However, on many links that is still a tall order, since if the flows really are that short, there are probably lots of them in parallel.

A paced burst is much more friendly.  At a 100ms RTT, IW10 could be delivered at 100pps (1.5 Mbps), extending the range of link speeds on which congestion signalling will not occur by at least 3x (and generally more).  Since this greatly reduces the risk of packet loss, it might actually reduce the average time that the sender needs to maintain the connection’s buffers, despite the deliberate 1-RTT delay introduced.

 - Jonathan Morton