The Study About P2P Distributed File Transportation System

This paper expounds the design and implement of a file transfer system based on BitTorrent, a P2P Protocol.Today, a new networKmodule, P2P(peers to peers) is more and more popular. Differ to traditional C/S network, in the P2P network, nodes are equal to each other, each node acts as both server and client. Compare to C/S network, P2P networKis more high-powered, more extensible and much stronger. P2P is a promising networKmodule.At the beginning, the appearance and actuality are introduced, and then there is a contrast between P2P and C/S.In the third chapter, one of the most popular P2P protocol, BitTorrent is researched. First, the basic networKarchitecture is introduced. And then NetworKAddress Transform (NAT) technology is discussed, which is used to help the peers in LAN communicate with other peers. At last, Distributed Hash Table(DHT), a new pure Distributed networKis discussed.The chapter four introduces the design of a file transfer system based on BitTorrent protocol. First, the frame of the system is introduced. Second, there is the coding format of the information in the protocol and the seeds. Third, tracker HTTP protocol is discussed. At last, the handshake protocol between peers is discussed.On the base of the discussion of last chapter, the implement is expounded in the fifth chapter. The system is written in C++ language, which recurs to the Module Dialog of MS MFC. In order to implement the program, the Object Oriented Programming and Multithreading technology are used. In the last chapter, there is a prospect of the P2P network. Today, the P2P networKis puzzled by it's own defects, including copyright dissension, security problem, bandwidth problem and so on.