[Netem] gigabit speeds

Aaron Brown brown at cis.udel.edu
Fri Jan 12 11:04:40 PST 2007


I've setup a network with a topology of a-b-c-d. The machines have 1 
Pentium 4 2.8GHz, 4 Gigs of RAM, e1000 NICs and are running Fedora Core 
4(2.6.17-1.2142_FC4smp). Without setting up delays, I get speeds of 
~945Mbit/s using iperf in UDP mode. However, once I add delays in, the 
speed starts dropping:

15ms delay in each direction between b-c: 775 Mbit/s
25ms delay in each direction between b-c: 462 Mbit/s
50ms delay in each direction between b-c: 226 Mbit/s

Are my machines not powerful enough to use netem at GigE speeds or have 
I simply misconfigured something? Thanks.

Cheers,
Aaron



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