| So far, there are two types of architectures for IP_based conference systems, which are respectively named as H.323 and SIP. SIP service provider could build a new media system consisting of audio and video and chatting content. But SIP itself doesn' t support conference describing protocol nor does it provide conference control, which means it would not be used for the multipoint conference with centralized management. On the contrast, H. 323 is a mature_developed system, which is distinguished as centralized management to support multipoint conference. MCU is the center in the system with the endpoint transparent to the management mechanism. As a result, it is no need for the endpoints to maintenance any system control task. In this article we propose a compactness coupling conference system architecture, and at the same time we analysis the system key techniques, giving a part of flow chart and pseudocode as examples.Main content are given as below: how to use DirecShow technique to obtain multimedia data ; multimedia data transport over IP network ;multicast principal and application in the system; packing and unpacking RTP/RTCP packet so as to control network flow and In this part we introduce spillage arithmetic; As the core part of the system , conference control and management are the main concern in our design. In order to describe clearly about the whole flow of conference control we introduce Petri network to tell how the control unit works . In the end of this article we discuss some useful techniques to resolve security problem which are also very important in the system. |
