基于排队论的级联交换机网络传输延迟分析
Analysis of the Transmission Delay in a Two-Stage Switch Network Based on Queuing Theory

针对车载信息系统中，级联交换机网络的数据包传输延迟时间计算缺乏形式化的建模和计算方法，为了分析跨交换机的数据传输对节点间数据传输延迟的影响，将级联交换机等效为排队系统，并在此基础上提出了一种级联M/M/1排队模型，该模型针对级联交换机网络，对传输负载和交换机服务率取不同比值时的数据包延迟时间进行分析，求出定性和定量解。仿真实验结果表明，当网络负载较重时数据包在第二个交换机中的延迟时间不会显著增加，其结果可以有效地支撑车载信息网络的开发。
It is not uncommon that a vehicle network consists of concatenation in switches. In order to analyze the impact of cross-switch packet transmission to the local packet exchange which is contained within a switch scope, this paper presented a discussion of the average packet delay in the second switch of a cascaded switch network. The analysis provided qualitative and quantitative calculation of the packet delay based on M/M/1 queuing model, which covered several combinations of transmission payload to service rate ratio. This paper concludes by reasoning and simulation that the queuing delay in the second switch does not increase remarkably when the utility rate of the network is high, and this can support the design of a vehicle network