There is an instproc init {} procedure each for Agent and for Agent/TCPAgent. I could not find the instproc init {} procedure of Agent/TCP/Reno or any of the other TCP Agents. Why? Is it because they inherit in a virtual way from class TCPAgent?, and so the instproc init {} procedure of the class TCPAgent is called only once for each of them. Then how do we differentiate between the creation of the different TCPAgents from only one instproc init {} procedure of class TCPAgent. My main objective is to pass arguments to the new Agent/TCP/Reno command which will pass the arguments to its respective init procedure (which I cannot find) and then the arguments will be passed to its static class constructor in the tcp-reno.cc file so i can choose whether or not to pass an argument to the constructor of the actual class RenoTcpAgent. The main idea is to add one more constructor to class RenoTcpAgent and then to be able to choose which constructor to call when creating the object from the tcl script like set tcpreno [new Agent/TCP/Reno]. So i thought i would do it by passing an argument like set tcpreno [new Agent/TCP/Reno arg1]. Any help, advice or suggestions for the above problem, or achieving a solution of some kind will be appreciated. Many thanks in advance. Pankaj _________________________________________________________________ See all the ways you can stay connected to friends and family http://www.microsoft.com/windows/windowslive/default.aspx