[c-nsp] Open source QoS/stress test tools

[Netfortius]

We have recently implemented QoS on our Cisco lab equipment, with the purpose 
of testing and understanding what "form of deployment" could do us good, for 
the specific traffic prioritization we would like to address. Part of this 
process consisted in configuring two of our routers, and testing them with 
some applications (ftp, telnet, web, etc.), but this last part I think could 
be much better done with tools designed for such. So here comes the question: 
what open source tools have you used, and what for / how?

>From past usage, for other purposes, I became familiar with: iperf, netperf, 
pchar, ttcp, pathneck - but have used them exclusively as an immediate 
reaction, in cases where something needed to be evaluated right away, for 
some bad response time across WAN links, not for refinement and 
identification of QoS functionality (could they even be used as such?!?).

I have also googled around and came back with sites like:
http://www.deepspace6.net/docs/ar01s20.html
http://www.scl.ameslab.gov/netpipe/
http://www.caida.org/tools/taxonomy/perftaxonomy.xml ... etc.

Would anybody care to comment? What stress-test / traffic generators woudl you 
recommend?

TIA,
Stefan