Performance evaluation of a SIP-based state-sharing mechanism

The Session Initiation Protocol (SIP) has been selected to manage sessions within the 3GPP IP-based multimedia subsystem (IMS). SIP sessions have to be highly available and reliable. This paper presents a performance evaluation of a novel state-sharing algorithm for providing reliable SIP services. The novelty is a result of sharing SIP (application-protocol) states as opposed to transport-protocol states. The most important performance parameters are evaluated in terms of the system variables such as server failure and repair time distributions, call arrival and call duration distributions, and link parameters, i.e., delay and bandwidth. The considered performance parameters are availability, reliability and dependability. Concerning the state transport mechanism, the results show that TFTP significantly outperforms FTP with respect to the overall performance.