[j-nsp] Speed

[Saku Ytti]

On (2013-04-08 03:46 +0200), Johan Borch wrote:

> of a single session with a RTT of only 8ms? The performance is the same if
> I use 2 switches and the clients directly connected as if i use routers
> between. Any idea what it could be?

bw * delay = window

so 

window / delay = bw

64k*8 / 0.008 = 64000kbps = 64Mbps

To achieve 40Mbps, you'd need

40M*1000/8 * 0.008 = 48kB window

make sure with tshark what your actual window size is, don't trust iperf.
Best thing is to configure OS TCP stack to window scaling and dont touch
iperf window settings, I don't know why, but they just seem to break stuff.

Also never measure network with TCP, measure network with UDP, measure TCP
stack of hosts with TCP.

-- 
  ++ytti