iperf is a network performance testing tool hosted here

There ares patch for iperf here which adds support for DCCP and selecting the DCCP congestion control method and running continuously.

There is now a combined patch set based on the sources developed by Ian McDonald, which has support for DCCP, long unattended test runs, and TCP plug-able congestion control. Sources and information can be found here.

A UDP-Lite enabled clone of the above can be found in the UDP-Lite tarball.