Hi, I wrote a new agent on TCP Reno which estimates congestion errors and does some congesion control. I tried to use the agent replacing the TCP in ~/ns/tcl/ex/simple.tcl with this agent, newTCP (new Agent/TCP/newTCP). It compiles and it runs. But out.tr shows no ack packet. I also traced that the Agent is only created but its member functions are not invoked. Any idea why ? -Dhiman