SIP messages delay analysis in heterogeneous network

The performance of signaling protocols in circuit and packet switching networks is a significant parameter to evaluate the performance of any telecom operator. Today, users demand continuous high data rate, service availability, network reliability, mobility, QoS and minimum service initialization time. IP Multimedia Subsystem (IMS) standardized Session Initiation Protocol (SIP), which categorize as a signaling protocol for management and maintenance of new multimedia IP-based services. Session setup time for the interactive and real-time application has become major QoS parameter to assess the performance of these applications. In the context of this communication application, in this paper, we analyze the performance of session setup time of SIP protocol over IMS network with different access networks (GSM, WLAN and PSTN). We measure and compare mean delay of each SIP message during session setup over these access networks. We also measure the mean delay with respect to distance of nodes in the network. Our results show that SIP message size, processing, transmission, queuing delay, transition from packet to switched network, node mobility and wireless channel have a consequence on the reliability, performance and efficiency of the protocol.