基于周期性对数流量模型的路由器性能分析

Router Performance Analysis Based on a Periodical Logarithmic Traffic Model

网络流量模型是网络规划设计和性能分析的基础问题 .该文在分析实际网络测试所得数据的基础上提出一个周期性对数突发流量模型 .不同于传统的基于概率统计模型 ,该模型主要考虑网络流量的周期性和突发特性 .在测试流量数据的基础上通过函数拟合的方法求解流量突发上界的时间特性 .应用该模型给出了在已知模型参数的条件下 ,网络互连的基本单元——路由器输入、输出接口的传输能力、缓存大小以及交换单元处理能力等必须满足的性能指标 .

Traffic modeling is fundamental for network design and performance analysis. Various traffic models have been proposed, but their applicability is challenging. A periodical logarithmic traffic model is proposed based on two collects of data from network test and measurement in this paper. One experimental traffic data is from the SUN Web server by analysis system log file,which has been widely used by many international authors, and another is collected from SNMP MIB(Management Information Base) polling on routers and packet capturing in the ICT(Institute of Computing Technology) network. Based on the experimental data, the traffic rate is supposed to be bounded by R(t)=αln(βt+1), where α and β are constant. Generally α indicates magnitude of traffic rate, while β shows some kind of traffic increasing. Obviously, the traffic model is very different from traditional statistical ones. Since the maximum traffic rate is considered, there is no statistical supposition assumed to the traffic model. Periodicity and burst of traffic are emphasized. The constants, α and β, are found from the time characterization of bound of burst by function fit on traffic profile by measurement on operating network.Designing issues for routers,as the basic unit for Internet, such as ability of transmission,input and output interfaces, buffer size and ability of processing of router fabric are discussed based on the traffic model.