Abstract: The session initiation protocol (SIP) is the main signaling protocol in the 3GPP IP multimedia subsystem (IMS). The SIP sessions in IMS have to be highly reliable. The developed fault-tolerant SIP call control concept includes state-sharing mechanism, failure-detection and fail-over management. The state-sharing mechanism representing the core entity in the overall system has been developed to meet the specific SIP functional features and requirements for reliability of SIP services. Theoretical analysis and measurements in a prototype implementation showed that TFTP outperforms FTP.
Keywords: Call control, fault-tolerance, session initiation protocol, reliability.