A novel paralleling session setup mechanims in IMS

To reduce the session setup delay there have been many methods used widely in traditional 2G networks, as well as the IP Multimedia Subsystem (IMS). However, the existing approaches to solve the problem depend on optimization of Session Initiation Protocol (SIP) message transmitting and signaling flows. The article proposes a novel paralleling session setup mechanism (PSSM) based on the exploration of the performance of IMS session establishment. The scheme involves local routing policy and paralleling algorithm, which can decrease call setup delay. The analytical model is deduced, and then the delay and cost functions are formulated. By the mathematical analysis and performance simulation, the result shows that PSSM can reduce the call setup delay effectively comparing to the current session setup mechanism.