BitTorrent传输协议的分析和实现

摘要

介绍了P2P技术现状的，以及比较了P2P模型和传统的C／S模型，及BitTorrent模型的区别。介绍了实现BitTorrent协议的相关的开发工具，Visual C++，MFC，STL，SOCKET。分析了P2P软件BitTorrent通信的工作原理，详细说明了BitTorrent协议的细节规范，描述了Bencoding编码的格式BT，种子文件的构造，BT的客户端和Tracker服务器通信的细节以及和P2P的通信规范。并用vc++ 开发出自己的BitTorent协议实现。具体的实现分为4个大的模块，Bencoding编码分析模块，BitTorrent种子（元信息文件）分析模块，BitTorrent客户端和Tracker服务器通信模块，BitTorrent客户端和BitTorrent客户端间的通信模块（Peer to Peer），详细说明了模块的架构和实现。

关健词：P2P；BitTorrent protocol；BT
 
Analysis and Implementation of the BitTorrent transport protocol
 
Abstract
This paper expounded present situation of the P2P technology, as well as has showed the difference among the P2P model,  the traditional C/S model and BitTorrent model. Expounded the development kit, Visual C++, MFC, STL, SOCKET.  It analyzed the communication working principle of P2P the software based on BitTorrent,  made a detailed description of BitTorrent protocol detail standard,  described detailes related to Bencoding code format,  the structure of the seed document,  the BT client side and the Tracker server correspondence detail as well as with the P2P transport protocol. And develops own Implementation with vc++.  The concrete Implementation is divided into 4 big modules: the Bencoding code analysis module,  the BitTorrent seed (source information file) analyzer,  the BitTorrent client side and the Tracker server connection module,  connection module between the BitTorrent client side and the BitTorrent client side (Peer to Peer),  which specify module construction and Implementation.

Key words: P2P; BitTorrent; BT

注释：不含源代码