This post will help you in installing Network Simulator 2 version NS2.35 in Ubuntu 11.10
Instructions
Install Ubuntu
Download NS-2.35 (http://sourceforge.net/projects/nsnam/files/allinone/ns-allinone-2.35/ns-allinone-2.35.tar.gz/download)
Unzip or untar it to any folder (recommended is /home/loginname) using the following commands one by one
sudo apt-get update
