Research And Implementation Of The SIP Videoconference Terminal And Interworking With The H.323 Terminal

The videoconference system is a sort of application that supports the real-time information exchange and cooperation among the people. At present, the protocols supporting videoconferences are H.323 of ITU and SIP of IETF. The H.323 protocol is relatively more consummate, which is applied broadly since it has been promulgated; the SIP provides prodigious conveniences for the development of all kinds of increment services and the conference calling, which attains increasing attention with the virtues such as simple, easy to be implemented and good expansibility. At present, videoconference system which based on the SIP and communicatied with the H.323 video conference system gradually have become the research hotspot.The paper studies SIP and H.323 protocol about how to initiate conversation and carry through video communication among participants, how to share the resources effectively and how to implement the communication with multi-protocols in the video terminal systems. We also compared the SIP with H.323 protocol in detail.The main framework of videoconference system terminal based on SIP is introduced; a conference terminal which is able to be connected by the SIP is implemented, and carry on bidirectional transmission of the audio and video; we implement the voice control in the SIP video conference system using the SIP_FC algorithm, which solves the accroach of shared resource resulted from the lack of floor control in SIP videoconference.At last, the theory of the communication between SIP videoconference terminal and H.323 videoconference terminal is analyzed, and the IWF of communication between SIP and H.323 defined in RFC4123 by IETF is studied. On Based on the analysis above, the core technology of IWF, the emphasis of which are on address conversion, message mapping, terminal media capacity and flow control of communication call, are farther studied. Based on the former H.323 videoconference system, an independent IWF is designed to achieve the connectedness of the terminals under the two protocols.。...