NetPerfMeter is a network performance meter for the UDP,
TCP, SCTP and DCCP transport protocols over IPv4 and IPv6.
It simultaneously transmits bidirectional flows to an endpoint
and measures the resulting flow bandwidths and QoS. The
results are written as vector and scalar files. The vector
files can e.g. be used to create plots of the results.

WWW: http://www.iem.uni-due.de/~dreibh/netperfmeter/