抖动环境下文件复制节点选择算法  

FILE REPLICATION NODE SELECTION ALGORITHM IN WOBBLE CONDITION

作　　者：张敏[1] 冯烟利[2] 

机构地区：[1]山东师范大学信息与工程学院,山东济南250014 [2]山东工商学院计算机科学与技术学院,山东烟台264005

出　　处：《计算机应用与软件》2013年第2期74-77,97,共5页Computer Applications and Software

基　　金：国家自然科学基金项目(61070175)

摘　　要：文件复制技术是把负载分散在复制节点上,避免服务器超载,减少服务器响应延迟和查询路径的长度,以达到较高查询率的有效方法。因此文件复制节点的选择就成为了首要考虑的问题。P2P文件共享系统因为节点的加入和离开,甚至节点失效造成拓扑结构会不断地变换,选择一个文件处理性能好,抖动性弱的节点作为复制节点就显得非常重要。提出一种新的文件复制节点选择算法NDC(New Dynamic and Capacity Algorithm),通过在复制节点的选取上考虑抖动性因素,减少节点离开或者失效造成较长的通信延迟和用户体验的降级,提高文件击中率。由于网络的热点文件不断变化,会出现不同倾斜查询的情况,对NPC处理倾斜性查询文件的能力进行了分析。通过在P2Psim上进行的大量实验表明,NPC算法选出的节点处理文件性能好,抖动性弱,可以提供更精确的文件复制节点。File replication technique is an effective method to deal with server overload and to reduce server response delays and shorten query path by disperse the load onto replication nodes for achieving higher query efficiency.So the selection of file replication node becomes an issue to be primarily considered.In P2P file sharing system,the topology structure incessantly changes due to nodes joining and leaving and even getting failure,it will be very important to select a node with good file handling capacity and weak wobble property as the replication node.A new file replication node selection algorithm,new dynamic and capacity algorithm（NDC）,is proposed.The decrease in long time communication delay caused by node leaving or failure and the abatement in users＇ experience degradation as well as the improvement in file hit rate are achieved through considering the wobble factor when selecting the replication node.Since the constant change of hot files in internet,different skewed queries will occur,the ability of NPC in handling the skewed file queries is analysed.A great deal of experiments on P2Psim demonstrate that the node selected by NPC algorithm has good performance in dealing with the files,weak wobble property,and can provide more accurate file replication node.

关 键 词：失效函数 倾斜查询 抖动 WEIBULL分布 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]