Hi , As a part of my MS project I proposed a 3-party authentication protocol which can be used in SIP too. for SIP. The proxy server utilizes this protocol to authenticate the UC's Invite,using the Registrar server. Now, I have to estimate the totoal overhead of the scheme on a normal SIP call. I searched dozens of SIP, UMTS, GSM related papers to find a simulator or emulator which could be used to to achive the goal but I couldn't get any solutions as I need to consider execution of the RSA,AES and SHA on the agent's processor, I also need the solution to answer me with not too much programming due to my time constraints. I browsed the Resirocate project docs but I don't think then can answer me in time. I am also not sure whether SIPp, MS LIve communication server and SERcan help me? Could you please suggest me any rapid solutions? Any simulation techniques?any piece of software or programmining interface? By the way I am a little familiar with opnet as I did a tiny project with it. Doest it help me? Thanks in advance. Samira. --------------------------------- Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.