Research And Design Of Video Conferencing System Based On P2P

Video conferencing is a kind of communication network, in which participants of a meeting can transfer words, voice,video or other kinds of data through Internet or Intranet.With the improvement of communication technology,Video conferencing has been applied in many fields,such as economy,politics,education and so on. Most of existing video conferencing systems comply with H.323 protocol, and have a video server to receive and transfer the voice and video. Because of the limitation of CPU,memory and bandwidth resource of the server, the data which server transfer and process increases and the quality of video and voice in conferencing gets worse quickly when the number of client increases, so the video server becomes the bottleneck of existing video conferencing scale.In the first instance,we make the analysis about video conferencing system in the Japan. We found that the velocity of up and down is so fast in the net environment in the Japan. But in the China, we can onlu grarantee velocity of down if the net is so crowded. Becase the video quality will profect and the video will not lose easily if the system which is done in the China use in the Japan, so we choose developing environment in the China. Aiming at the problem that the video server becomes the bottleneck in the C/S structure, we combine P2P technology and B/S structure and put forward a P2P video conferencing structure with a core server and realize the sever in the paper. The server initializes between the clients, manages clients and meeting rooms, but do nothing for data transmission between clients. Using UPnP technology, we solve penetrable router by means of adding port mapping and make the clients conmunicate directly without the video server. On the same time it supply basic condition on P2P direct conjunction. Under the condition, we abundant the video conferencing system and rich the peer, and add cooperation browse, data white board, document share, chatting and so on. Because we adopt bandwidth selfadaptation technology and devise optimization of bandwidth, so the quanlity of video will increase great. At last we set up a prototype system in Visual C++ based above our ideas.