P2P网络中自适应节点选择策略

以Bittorrent应用为背景,对P2P网络中传统的节点选择策略进行了研究分析,指出了传统节点选择策略中存在的随机选择节点连接与交互以及交互过程中节点带宽利用率偏低的问题.对Tracker以外的节点来源如DHT、PEX节点来源的情况进行分析,以自身上传带宽利用率和网络中各节点的空闲带宽为参考,以减少带宽资源浪费、提高带宽利用率为目的.针对节点选择各阶段特点,设计并实现自适应节点选择机制,实验表明在对原系统的公平性影响很小的情况下,自适应机制能有效的减少网络中带宽资源浪费并将自身上传节点带宽利用率提高8.45％.小规模节点环境下(100节点)平均缩短节点下载完成时间6.7％,大规模下载环境下(500节点)平均缩短下载完成时间36.3％.有效的提高了系统中文件的获得和分发效力.

Adaptive peer selection strategy in P2P

The traditional peer selection strategy of P2P network is analyzed with the background of BitTorrent application,and its existing problem in way of random selection node and low utilization of bandwidth in interaction process are pointed out.Kinds of node source are taken into account,including Tracker,DHT network and Peer exchange(PEX) source.A upload bandwidth utilization rate and peer’s free bandwidth as reference are used to reduce the waste of bandwidth and the bandwidth utilization rate of peer in network is improved.According to the characteristics of each stage in peer selection process,self-adapt peer selection mechanism is designed and implemented The experiment shows that the mechanism can effectively reduce the waste of bandwidth resources and increase the utilization rate of peers by 8.45%,within the circumstances of given a little impact to the fairness of the original system.The average download time is shorted by 6.7% in small node scale(100 node) and 36.3% in large node scale(500 node).The acquisition and distribution efficiency of files in whole system is enhanced.