【作者】 张勇；

【导师】 李昌华；

【作者基本信息】 西安建筑科技大学 ， 计算机应用技术， 2007， 硕士

【摘要】 最近几年来P2P文件共享已成为Internet中最为流行的应用，点对点技术(peer-to-peer，简称P2P)又称对等互联网络技术，是一种网络新技术，依赖网络中参与者的计算能力和带宽，而不是把依赖都聚集在较少的几台服务器上。点对点网络没有客户端或服务器的概念，只有平等的同级节点，这些节点同时对网络上的其它节点充当客户端和服务器，网络中的每个节点共享彼此的资源。本文首先介绍了P2P相关技术原理，对P2P与Client／Server模式进行了比较，简单介绍了P2P中的网络拓扑结构。接着对BitTorrent系统的工作原理和工作过程进行了详细研究，重点描述了BitTorrent中的两个核心算法：邻居选择算法和片选择算法。随后在对BitTorrent系统深入研究的基础上介绍了有关种子覆盖网的思想，对BitTorrent种子的文件片选择算法进行了一些改进，解决了BitTorrent系统中的文件传输效率及负载平衡问题。最后对研究工作进行了总结，并展望了下一步的研究方向。更多还原

【Abstract】 Along with the rapid development of Internet, more and more attentions have turned to the p2p technology. In recent years, the applications of the p2p file sharing become more and more popular on Internet. The technology of peer to peer is seemed as a new network technology, and it only depends the computing capability and bandwidth of the participant ,having no relation with the severs. The P2P network has no the notion of client and sever ,only has equal notes on the same lever, and the notes severs as the clients and severs to the others. The notes on the p2p network share their resource each other.This thesis introduces the theory with the p2p technology and the topological structures about the p2p network first, comparing the differences between the modes of p2p and client/sever. On the following parts, the thesis introduces the principle and work of the system of BitTorrent in details, emphasizing the two core algorithms in the system of BitTorrent: the neighbor selection and the pieces selection algorithms.And then on the foundation of researching on the system of BitTorrent, This thesis introduces the Idea of the overnet based on seeds. In order to solve the problems about load balance and transfer efficiency in the BitTorrent, the thesis introduces some improved methods on the seed’s piece selection strategy.Finally, this paper summarizes the research and looks forward to the next research direction.更多还原