Stress Testing LAN/WAN

I have the need to stress test a LAN and WAN. The primary concern is the WAN which is at most OC-3. The LAN would be an additional bonus if I could do that as well.
I am familiar with tools such as those from Spirent and IXIA which are very expensive. I was wondering if someone has had to do this and can recommend some open source
tools that would work well. I need to test a few different types of traffic, specifically trying to push traffic into various switch/router policies to make sure everything is performing as
expected. If anyone knows of some software that works well for this I would appreciate letting me know.




You can download a copy of the SolarWinds toolset from our website (the
eval is free).

There's a traffic generator in there called "WAN Killer". Give it a try.


I have used Solarwinds Wan Killer, but have yet to discover a method of
initiating round-trip traffic from a single generator, but Solarwinds
can stress a GiGE MAN link using a desktop PC with a GiGE card as the

To generate round-trip traffic you have to enable echo services on the
target host and then send to that port.

On a Windows box I think it's called "Simple TCP Services" and then you
send the traffic to TCP Echo.


With iperf, you can use the -d option to initiate a "real-time parallel" test (my term). You can also use the -r option to run a "trade-off parallel" test (again, my term).

To see the other options iperf offers:

Sounds like you might also be interested in the -B option. When coupled with multiple interfaces, you can pretty easily test QoS configs by sourcing from different interfaces / IPs (if that's your identifying characteristic).

KanREN uses iperf on Mac Minis running OSX 10.5 with great results. The newer Minis can pretty easily push 950+Mbps if you run 4 or more streams (-n option). Or at least that has been our experience.

I would also suggest doing some TCP buffer tuning if you anticipate round-trip latency to be >20ms. Here are some general guidelines for various platforms:

We use iperf running off of a bootable Linux CD
with a 2.4 Kernel and can push 960 to 980 Mbps
with no drops or errors on any pair of PCs with
Gig interfaces we have tried so far.

We usually 10 TCP streams, or tune the TCP stack
and use a single stream.

We also capture the traffic on both sides, run a
standard analysis, and plot the send and receive
per-second utilization and the re-transmit rate
from the send side.