Modeling And Simulation Of Train Communication Network Of Arcnet Based On Opnet

There are a lot of devices controlling information and passenger services information when the train is in motion, so a reliable, secure, high-speed, large-capacity transmission system is needed.In view of this situation, the train communication network came into being a key technology. As one type of train communication network, ARCNET based on token passing protocol,is used as the communication network of CRH2.It has such advantages as high transmission rate,huge traffic loads,simple operation of network nodes, supporting long haul transmission, excellent real-time property and extendibility.ARCNET network characteristics are analyzed. Because of using token passing protocol, when the individual nodes on the network need to transmit data, it must obtain a token to get access to the network first. The competitive is absent, and network traffic will not result in network congestion.It is the above advantages that make the ARCNET an ideal field bus and applied on train communication network.A physical bus and logical ring type communications network of CRH2is designed based on ARCNET protocol using OPNET network simulation platform.This design includes network model,node model and process model.A dual ring network without delay is also designed, and it makes the network reliability improved. Through the use of ARCNET protocol standards in the process model,the ARCNET Protocol finite state machine is achieved.Based on the model of this paper, from producing an order, to receiving and processing the command of a vehicle, a series of the process is simulated dynamically.Based on the communication network of CRH2,the end-to-end delay,the ARCNET network throughput, the token-passing time and the network switching delay are simulated. By analyzing the results of end-to-end delay, the design can verify the accuracy of the model established, and whether the network transfer rate is ideal is analyzed by the maximum end-to-end delay. Analysis of token passing time can help us to know about the real-time capacity of ARCNET network.On the other hand, simulation of network switching, whether the double-ring model of CRH2can achieve the performance without delay is verified. Network traffic situation which ARCNET can withstand is summarized by node throughput.