NetPIPE is a protocol independent performance tool that encapsulates
the best of ttcp and netperf and visually represents the network
performance under a variety of conditions. By taking the end-to-end
application view of a network, NetPIPE clearly shows the overhead
associated with different protocol layers. Netpipe answers such
questions as: how soon will a given data block of size k arrive at its
destination? Which network and protocol will transmit size k blocks
the fastest? What is a given network's effective maximum throughput
and saturation level?  Does there exist a block size k for which the
throughput is maximized? How much communication overhead is due to the
network communication protocol layer(s)? How quickly will a small (< 1
kbyte) control message arrive, and which network and protocol are best
for this purpose?

For a paper fully describing NetPIPE and sample investigation of
network performance issues using NetPIPE, see
http://www.scl.ameslab.gov/netpipe/paper/full.html.