Performance evaluation of SIP servers

Evaluating a SIP server's performance before being deployed is important for network design. Testing is the main way to fulfill this task. But different testing environment affects testing result greatly. This paper studies impact of end user's response delay on SIP server performance analytically and proposes the necessity to evaluate server's performance in real network environment. A distributed SIP performance testing tool, SIPPerformer that can simulate various traffic models as well as user response delay distributions is introduced. By employing a central test host and multiple distributed test agents, SIPPerformer can reach any needed traffic load by simply adding more test agents. Also SIPPerformer can simultaneously generate different types of traffic, such that various services in a SIP server can be invoked at the same time and performance interactions of these services can be studied. Some testing results of using SIPPerformer on an open source SIP proxy, SER, are reported.