[plug] Test program for Ethernet networks

[Lyndon Kroker]

Can someone suggest a(n open source) program that I could use to test the 
performance of Ethernet hubs, switches and routers, etc?  I am mostly looking 
to test the network bandwidth.  I would like to do this for (1) large single 
files and (2) groups of many small files.  A program that can run a series of 
tests automatically would be ideal.

Thanks,

Lyndon