基于虚拟链路交换式以太网的列车通信网络可靠性分析

Analysis on Reliability of Train Communication Network Based on Virtual Link Switched Ethernet

随着轨道交通技术的不断发展,列车通信网络中需要传输的数据类型和数据量日益增大,传统列车通信网络的带宽难以满足要求。本文提出一种基于虚拟链路的环形交换式以太网解决方案,通过流量整形和虚拟链路调度技术可以保证每个BAG间隔内只有不超过一个帧在使用虚拟链路,可避免传统以太网对介质访问存在的碰撞问题,保证数据传输的确定性。为进一步探讨该网络的实时性,本文采用边扩张二元决策图EEBDD(Edge Expansion Binary Decision Diagram)算法分析该网络中的单条虚拟链路、多条虚拟链路以及全部虚拟链路的连通可靠性与及时可靠性,并通过网络仿真研究证实了本方案应用于列车通信网络的可行性。

Aiming at the problem that the bandwidth of the traditional train communication network （TCN ） cannot meet communication needs in the future , this paper presented an innovative solution for TCN based on virtual link switched Ethernet . This solution ensured that in each interval BAG there was no more than one frame transmitted in the virtual link by use of traffic shaping and scheduling techniques , w hich avoided colli-sions and ensured certainty of data transmission . To further evaluate the reliability of real-time performance of the network , this paper used the Edge Expansion Binary Decision Diagram （EEBDD） algorithm to analyze the connecting reliability and timely reliability of the single virtual link , multiple virtual links and all virtual links . Finally , network simulation confirms the feasibility of the application of the proposed alternative in train com-munication networks .