Ns is a discrete event simulator targeted at networking research. Ns provides substantial support for simulation of TCP, routing, and multicast protocols over wired and wireless (local and satellite) networks.
thats the links for that Great program and the Hjsplit program is inside to join the files and install it:
http://rapidshare.com/files/98799846/ns.rar.001.html
http://rapidshare.com/files/98811293/ns.rar.002.html
http://rapidshare.com/files/98821996/ns.rar.003.html
http://rapidshare.com/files/98904165/ns.rar.004.html
http://rapidshare.com/files/98809064/ns.rar.005.html
http://rapidshare.com/files/98905239/hjsplit.rar.html