Reach And Design Of The P2P Audio And Video Communication System

With the development of computer technology, multimedia technology and broadband access technology, the traditional text communication and simple voice communication cannot have satisfied everyone's needs, multimedia communication becomes hot based on the audio and video, and becomes the development trend of future communications. Because of large amount of data which the audio and video have, the traditional design model bases on server and client needs to consume large amounts of network bandwidth, so this design model give a great load pressure to central server. P2P peer-to-peer technology has changed the traditional network state, terminal users can directly search and share resource between them, make full use of the computing capacity in network's computer nodes, reduce the burden of server, fully utilize the network bandwidth and improve the network's transmission environment.Realize the real-time audio and video transmission in the network needs related technical support, including rapid capture of audio and video data technology, code technology, data compression techniques and network transmission technology and so on. It's very important significance for the development of media application software, through the study of relevant technology.In the P2P network structure, how to locate node accurately and realize point-to-point communication is very important.Now multiple protocols can discovery equivalence node,such as Gnutella, BitTorrent and PNRP and etc.PNRP protocol is designed by Microsoft,which based on IPv4 and IPv6 point-to-point protocol, it's suitable for windows application.PNRP provides dynamic name registered and analytical protocol, PNRP is different from the traditional analytical system, it's provides new possible for P2P application.This paper use Microsoft company's PNRP protocl, realize the end-to-end communication in peer-to-peer network, it solves the obstacle which NAT technology bringh to P2P applications, and provides a new solution for developing P2P application software.Adopt DirectShow technology to realize audio and video communication module, use G.729, H.264 compression standard for compressing video and audio data, use IP multicast technology to share information between multicast group. This article is in Visual studio.net 2008 development environment, uses C# language to realize a system which based on LAN peer-to-peer network, including audio and video communications, text messages, file transfer ect.