Tuff Question

[XP_2600]

I think its something possible via using Network Monitor, and a software designed to capture packets and make some statistics, but anyway better than the whole of that why you dont use ISA 2000 Enterprise, if you have permission over all machines in the network, or you can use http://www.bandwidthcontroller.com/, i think TAiN Links have alot of better solutions so, but im just telling about the things which i know .