TTCP is a benchmarking tool for determining TCP and UDP performance 
between 2 systems.

The program was created at the US Army Ballistics Research Lab (BRL)
and is in the public domain.  Feel free to distribute this program,
but please do leave the credit notices in the source and man page intact.

How to get TCP performance numbers:
receiver:  host1 $  ttcp -r -s
sender:    host2 $  ttcp -t -s host1

The -n and -l options change the number and size of the buffers.