Interworking between SIP and MPEG-4 DMIF for heterogeneous IP video conferencing

This article discusses technical issues related to delivery and control of IP multimedia services, such as videoconferencing, involving heterogeneous end terminals. In particular, it describes the design and implementation of an experimental system for interworking between IETF SIP (session initiation protocol) and ISO MPEG-4 DMIF (delivery multimedia integration framework) session and call control signaling protocols. This IP videoconferencing interworking system is composed of two core units for supporting delivery of audio-video streams from a DMIF domain to a SIP domain (i.e. DMIF2SIP unit) and from a SIP domain to a DMIF domain (i.e. SIP2DMIF unit). These units perform various translation functions for transparent establishment and control of multimedia sessions across an IP networking environment, including, session protocol conversion, service gateway conversion and address translation.