基于改进的“三明治”时延差探测方法的网络拓扑推测算法研究  

Research on topology inference algorithm of improved sandwich probing mechanism

作　　者：王英[1] 阳小龙[2] 隆克平[2] 

机构地区：[1]重庆邮电大学光互联网及无线信息网络研究中心,重庆400065 [2]电子科技大学光互联网及移动信息网络研究中心,成都610054

出　　处：《重庆邮电大学学报（自然科学版）》2008年第5期568-572,585,共6页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：国家自然科学基金项目(60873263);国家"863"计划项目(2005AA122310)

摘　　要：在目前网络拓扑推测过程中"三明治"探测方法采用时延作为度量函数,在拓扑推测准确性和网络性能影响方面取得了很好的折衷,而且解决了时钟同步问题。但是由于"三明治"探测方法对网络的影响由其中的大包的流量所决定,发送过多的大包对网络流量影响较大。对"三明治"探测方法进行了改进,用背靠背的小包代替"三明治"探测包中的小包,共享其中的大包,从而可得到2倍于"三明治"探测方法测量所得到的信息量,达到了减少大包发送量的目的。基于分组方法的拓扑推测算法根据共享路径上度量函数非递减性和相关性进行拓扑推测,计算复杂度比最大似然估计算法小。采用基于分组的方法根据端到端测得的时延差进行拓扑推测。仿真结果表明,在重负载和轻负载2种情况下,探测方法改进后拓扑推测准确率都得到了提高。In current topology inference, the delay-based ＂sandwich＂ probe scheme balances the accuracy of topology inference and effects of the probe traffic without clock synchronization. For the effects of ＂sandwich＂ probe is mainly determined by the large packet of the probe, an improved ＂sandwich＂ probe is used by replacing the small packets with back-to-baek small packets and sharing the large packet. The measurements using the improved probe obtain as twice information as the original probe and thus reduce the number of probes. According to the monotonic non decrease of metric on the shared path and the correlation of packets, the grouping methods are used to infer topology of network with less computation overhead than MLE algorithm. Therefore, the delay differencebased grouping method is adopted to infer the topology of network. Simulation results show that the accuracy of topology inference is improved in beth lightly and high loaded network by using the improved ＂sandwich＂ probe.

关 键 词：拓扑推测 时延差 探测包 

分 类 号：TN915[电子电信—通信与信息系统] TP393[电子电信—信息与通信工程]