1. G. ITU-T Rec. H.323, “Packet based Multimedia Communications System,” Telecommunication Standardization Sector oflTV, July 2003.
2. 1. Rosenberg, H. Schulzrinne et aI. , “SIP: Session Initiation Protocol,” RFC 3261, IETF, June 2002.
3. 3GPP TS 23.228 V9.1.0, “IP Multimedia Subsystem (IMS); stage 2 (Release 9),” Sep. 2009.
4. 1. Rosenberg, “A Framework for Conferencing with the Session Initiation Protocol (SIP),” RFC 4353, IETF, Feb. 2006.