Performance analysis of SIP signaling network using hierarchical modeling

The IP Multimedia Subsystem (IMS) is envisioned as a solution for the next generation multimedia rich communication. The 3^rd Generation Partnership Project (3GPP) has chosen Session Initiation Protocol (SIP) as signaling protocol for IMS. The main cause of performance degradation in SIP network is the overload. SIP does not provide sufficient mechanism to handle this problem. In this paper, we propose a hierarchical modeling for performance evaluation of the network for both normal and overload conditions. An analytical model is developed using cut-off priority queueing for a SIP server and the Generalized Stochastic Petri Nets (GSPN) technique is used to study the performance of the complete network. The proposed model is suitable for handling two different types of signaling traffic and protects them from overloading against each-other. Based on our performance analysis, it is observed that the system reduces retransmissions of SIP messages, thereby reducing congestion and increasing throughput.