Arturo Servin (arturo.servin) writes:
GNS3 http://www.gns3.net/
This is another network simulator, mainly for academic research.
NS-2 http://www.isi.edu/nsnam/ns/
And you can always setup some virtual machines with DNSs, hosts and routers with open-source software.
Also to add: http://warriors.eecs.umich.edu/viz_tools/nam.html (referenced from ISI.edu/nsnam above), and the Java version, JAVIS Also worth looking at: http://www.csse.uwa.edu.au/cnet/ (more for pure network simulation, not tied to any particular protocol). And of course, as suggested above, just using a virtual network using something like VirtualBox/KVM and some Linux/BSD boxes, and throw in maybe Dynamips / Dynagen / GNS3 (http://www.gns3.net/) if you want to simulate some IOS. Finally something like Quagga/BIRD for the routing protocol part. Cheers, Phil