Design And Implementation Of P2P File Sharing System Based On UDP

With the development of the Internet,the load and bandwidth pressure of the server under the traditional centralized C/S architecture are increasing.The use of distributed P2 P network technology can disperse the pressure on the server,and the peers in the network can communicate directly without the participation of the server.Although P2 P has many advantages compared to the C/S architecture,the establishment of connections between peers is limited by NAT devices.The peer without public IP has poor experience in traditional P2 P applications,and even cannot work properly in extreme cases.This paper refers to the mainstream file sharing systems of C/S architecture and P2 P architecture,and combines their advantages to design and implement a fully distributed P2 P file sharing system,which can simply download and share files.Replacing the TCP protocol used by traditional P2 P applications,based on reliable and connected UDP can better achieve NAT traversal,enabling more peers to connect with each other and effectively improving the download rate.In addition,the distributed hash table becomes more reliable in the presence of connections,peers can discover other peers faster through routing,and find their own related peers through rapid iteration,start sharing or downloading files.In addition,the P2 P network used by the P2 P file sharing system implemented in this paper is open,and other communications between different P2 P applications can be used normally except their own business.Even if they are not the same P2 P applications,they can also provide routing addressing for each other in the same P2 P network,assist one peer to establish connections with other peers,and find peers related to themselves.Based on the communication framework designed in this paper,various services such as P2 P instant messaging,P2 P multiplayer cooperative games or P2 P live broadcasting systems can also be realized,and various applications of decentralization can be realized by accessing the open P2P network.