Design And Implementation Of The Middle Stage And Output Stage Switching Units Of Clos Switch

The performance of the entire space communication system is directly affected bynetwork technology, but the current use of the1553B, IEEE802.4and other informationsystem bus technology has been unable to meet the growing number of aerospaceelectronic equipment, so it is very necessary to find a new network technology.Laboratory research project-“Research on Network Switching Technology in X XX Information System ", uses new technology which is combination of switched andGigabit Ethernet and full-duplex Airlines Ethernet in space communication system. Thespecfic structure of the Clos switch is given, and the middle stage and the output stageswitching units are also designed and implemented using top-down approch in thepaper.Firstly, typical local area network technologys, switching network structures andenchange mechanism are showed, and advantages and disadvantages of them are alsogiven in the paper; secondlly a need analysis is made according to the program, and thespecific design of the switch is given, with C(24,4,8) network structure; then the functions,which are of the middle stage switching unit and key modules of the output stage, arediscribled, and the detalied design of them are given, at the same time, implementationof each module using Verilog code is realized; finally simulation tools are introdued,then simulation diagram of each module and borad_level test results are given, andanalysis according to them are made.Through the ModelSim simulation and board-level test of the middle stage andoutput stage switching units, based on this analysis, the internal logic of this twoswitching units are correct. And the input stage switching unit, the middle stageswtiching unit and output switching unit switching unit are integrated into the switch.Through the borad_level test, the logic function of a port switch is correct, up to Gigabitspeed. The result meets the requirement.