Research On Train Ethernet Network Performance Based On TRDP Protocol

In 2018,the "Fuxing" CRH was officially put into commercial operation,marking that the CRH technology of our country has reached the international advanced level with completely independent intellectual property rights.The train communication network with the computer network as its core realizes the functions of vehicle control,detection and diagnosis during train operation.Due to the delay of train network communication and network performance problems such as packet loss,the real-time and reliability of the train network control system will be affected,which will in turn affect the safety of the train.Therefore,to ensure the safe operation of trains,studying and improving the train network performance has become the focus of current train network control technology.First of all,the thesis analyzes and studies the train real-time Ethernet network system and communication mechanism,and theoretically analyzes the reasons for network delay,delay jitter and network packet loss.Secondly,a semi-physical simulation platform is built based on the TRDP protocol,and the experimental platform is dynamically networked according to the train topology discovery protocol and the DHCP service mechanism to complete the initial operation of the train and the dynamic acquisition of IP addresses by terminal devices.Then the software of VCU equipment,HMI equipment and traction simulation unit are designed according to the working conditions of the train traction process,and the train is simulated to transmit the traction control signal on the ETB backbone network through the experimental platform and transmit the speed signal within the ECN composition network,and then wireshark softwareis used online to monitor and capture message data.A special network performance analysis software has been developed to visually analyze the changing trend of train network performance data.The impacts of traction control command and speed signal packets on the network delay,delay jitter and network packet loss under different transmission cycles,message sizes and network load are analyzed.In view of the problem that increasing network load has a greater impact on network performance,the optimization of network performance by link aggregation technology and load balancing algorithm is studied.Meanwhile,having copmpaed the advantages and disadvantages of weighted polling algorithm and hash algorithm,the author chooses the hash algorithm as the network-loaded equalization algorithm,and uses OPNET simulation software for simulation optimization calculation.Finally,through experiments,under the condition of increased network loadt,he effectiveness of link aggregation and hash load balancing algorithms to optimize network performance are verified.