Evaluation of SIP proxy server performance: Packet-level measurements and queuing model

The growing number of applications that use the Session Initiation Protocol (SIP) to manage media sessions over IP is placing increasing demands on the SIP proxy servers (SPS) that make up the core of the SIP network. In this work we investigate the performance of OpenSIPS, an open source SPS. We have collected a large set of experimental data to characterize the performance of the SPS under various call arrival rates and inter-arrival time distributions. Based on these measurements, we model the SPS as an M/G/1 queue. A key component of the model is a parameter that captures the cache-miss overhead, i.e., the impact of cache-misses on kernel service times.