Design And Implementation Of ECN Switch Based On FPGA

With the development of high-speed rail and informatization and intelligent technology,train communication networks not only need to transmit real-time train control information and status information,but also transmit diagnostic data and multimedia data.With the increase in the demand for diversified services,the traditional stranded train bus WTB and the multifunctional vehicle bus MVB have low transmission rates and cannot continue to meet the real-time requirements of trains.Industrial Ethernet is currently widely used in train communication due to its high bandwidth and high speed,making high-performance train Ethernet switches a new technical hotspot.This paper aims to design an FPGA-based ECN switch prototype.The switch prototype designed in this paper provides four Gigabit Ethernet interfaces,is compatible with 100 M communications,and also supports frame filtering,frame relay,and support for quality of service functions.In this paper,the design of the ECN switch is carried out,the prototype of the ECN Layer2 switch is realized,the software and hardware design and implementation are completed,and the basic function test of the switch is carried out.First of all,this article fully analyzes the network composition of ECN,the hierarchical structure of Ethernet,Ethernet frame format and the structure of the switch;secondly,according to the functional requirements and technical indicators of ECN non-managed switches,it provides a FPGA-based The design scheme of the ECN switch prototype;again,according to the design scheme,the resources required for the scheme are evaluated and analyzed,and the system hardware is selected,and the circuit schematic diagram of the switch is designed,including the FPGA main control circuit and the switched Ethernet circuit,UART circuit,and FPGA configuration circuit.Then,use the FPGA development board of XC7Z020CLG484-2 chip of XILINX Company to design and realize the key modules of the switch,including MAC control module,look-up table module,receiving control module,switching structure module and sending control module.The functions of each module are independent,which is convenient for transplantation and development.The design is realized by using the VHDL language and Verilog language.The functional modules of the design are simulated by the simulation tool that comes with the Vivado software to verify the correctness of the functions of each module.The functions of each module of the switch designed in this article are independent,which is convenient for transplantation and development.Finally,the paper carried out overall functional simulation and basic functional boardlevel testing of the train switch to verify the correctness and feasibility of the scheme.