ClusterGen is a trafficgenerator which uses pktgen Linux kernel module for packet generation. To reach high intensity of traffic, ClusterGen uses set of hosts that generate traffic at the same time.
Project was initially written and being developed by MERA
http://www.merasws.com/
This is a HTTP trafficgenerator for load testing web applications. It is very simple and fast and can simulate client activity on multiple servers at the same time. Supports almost all http methods such as GET, POST, HEAD