Published at LXer:
The open source network simulation tool ns-2 is an invaluable tool for researchers working on wired or wireless networks. I came across ns-2 while working on my thesis. I needed a network simulator, and since my college lacked the brand-name heavyweights, I had to look for an alternative that was free but could do the job. While ns-2 is free, it's also pretty unfriendly.