Hi, I have already install ns-2.1b6,and ihave alraedy tested it with simple.tcl. Now i want to develop a Tcl script,but i can get Through.can you pls help me on how to develop a Tcl script for ns which simulatees a simple Topology. Thanks Adey. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/