Also, you might want to take a look at Anvil, from Mightnight Networks.
Its a very nice tool that runs on various Unix flavors and will test just
about any part of the RFC on what ever protocols you order...
To do some load testing, we need a "tool" (h/w device and/or s/w) to
a programmable amount of IP traffic on a segment (say 32Mbps on a fast
segment or fddi ring) and a way to measure it (w/ hopefully something
than a sniffer). Anyone have suggestions on what to use?
For the high end try Netcom Systems SmartBits.
Their systems can hold various interface cards (from 10-20 per chasis) and
you can run up to 4 chassis in a stack.
We are using them to fully stress test our Gigabit Bridge/Router and I've
been running tests with 24 gigabit cards into our device and we're also
using their 10/100mb cards to test our 10/100mb cards.
The software can generate various IP frames from templates or you can use
a raw packet editor.
NOT cheap! But it can generate and receive/trigger/count at full speed if
that's what you need.