P2P流媒体系统搭便车行为建模研究.pdf

42卷第6期山东大学学报(工学版) 2‘r JOURNAL OF SMANDONG UNI~'ERSiTY tENGINEERING SCIENCE) 11“‘.201 2 文章编号;1672-3961(2012)06-13031-06 DOI:.1672-, P2P流媒体系统搭便车行为建模研究刘琪,刘沂训,秦丰林(山东大学网络与信息中心,山东济南250100) 摘要:搭便车行为是指节点仅使用其它节点的资源而不作任何贡献,对P2P流媒体系统的服务质量会产生严重影响。基于两类流体模型对P2P流媒体系统的搭便车行为选行了建模研究,同时考虑了不存在种子节点和存在种子节点两类场景,并对稳态环境下搭便车行为对P2P流媒体系统性能的影响作了定量分析。结果发现,在存在种子节点场景下,诚实节点和搭便车节点的平均下载时间均远低于不存在种子节点场景,因此需要设计相应的激励机制以吸引种子节点留在系统中。而且,搭便车节点比诚实节点更容易从流媒体服务器和种子节点受益,因此需要在流媒体服务器和种子节点引入区分服务机制。关键词:P2P流媒体;搭便车行为;流体模型;激励机制中图分类号:TP393 文献标志码:A Modeling research offreeriding in P2P streaming systems LIU Qi,LIU Yi—xun,QIN Feng—lin (Network and Information Center,Shandong University,Jinan 250100,China) Abstract:Free riding peer—to—peer(p2p)systems means apeer utilizing work resources without con— will cause severe degradation ofthe service quality inP2P Ctreaming two~class fluid mod— was introduced model and analyze the free riding thismodel,tWO scenarios including without seed— ers and with seeders were aquantitative analysis oftheeffect offreeriding on theperformance ofP2P streanu‘ng systems particularly inthesteady state was put result showed thatbothhonestpeers andfleeriders couldachieve amuch lower download time inthe scenario with seedersthan thatwithout thus was essen— tointroduce themechanisms toincentivize t