BitTorrent系统中一种近似全局最少优先的文件块选择策略  

Approximate global rarest first strategy for block selection in BitTorrent system

作　　者：王利娥[1] 黄昆[2] 张大方[1] 

机构地区：[1]湖南大学软件学院可信系统与网络实验室,长沙410082 [2]湖南大学计算机与通信学院,长沙410082

出　　处：《计算机应用研究》2008年第5期1419-1421,共3页Application Research of Computers

基　　金：国防基础科研“十一五”规划项目(A1420060162)

摘　　要：提出了一种近似全局最优的文件块选择策略——种子覆盖网。在BitTorrent系统中,所有种子自组成一个应用层覆盖网,每个种子保存已上传文件块信息;种子响应请求时通过种子覆盖网查找下载者感兴趣且上传数目最少的文件块上传。模拟实验表明,与纯局部最少优先策略和SmartSeed策略相比较,在采用种子覆盖网策略的BT系统中,节点平均下载时间缩短了25%～35%,并且下载第一块和最后一块的平均等待时间缩短了40%～60%。This paper proposed an approximate global rarest first block selection strategy named by SeedOverlay ： in BitTorrent systems, seeds self-organized an application overlay, where each seed recorded the information of file blocks uploaded; when responding the downloader＇s request for a block, the seed retrievaled the approximate global information of file blocks uploaded through SeedOverlay, then uploaded the block that was global rarest and interested by the downloader. The simulation experience shows that compared to pure LRF and SmartSeed policy, SeedOverlay improves the expected average download time of file by more than 25% -35%, and decreases the average wait time of the first block and the last block by more than 40% - 60%.

关 键 词：对等网络 文件块选择 近似全局最少优先 局部最少优先 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]