Research And Development Of An H.323 Videoconferencing System Over IP Networks

ITU-T Recommendation H.323 is an international standard of videoconferencing systems over packet-based networks. This paper is addressed to Recommendation H.323 and its applications over IP networks, with an H.323 system developed by using object-oriented technology.First, the architecture of an H.323 videoconferencing system is analyzed in details, including the H.323 protocol stack, the entities, the communication procedures, the fast mechanism, and the conferencing management and control. Secondly, some key teconologies in the implementation of the H.323 system over IP networks, such as IP, codec, and real-time transport and control are investigated. In addition, based on the object-oriented technology, some rules and methods for an H.323 class library design are proposed, an H.323 class library is developed, and an H.323 system over IP networks is implemented. The experimental results show that the system agrees with Recommendation H.323, and can communicate with other kinds of H.323 systems.