The Design And Implementation Of ATM Switch System Based On FPGA

ATM Switch system is the core in some communication network. at present , adoptive representative switching mode in communication network ways includes circuit switch , packet switch ,ATM switch and IP switch. First, this paper analyze the characteristic of these four switch technology then , considering the need of the task , ATM switch , the switch mode is decided . different types of switch fabrics and buffer strategies are also classified and compared with each other. Although , Crossbar switch fabric uses more resource than other switch fabric , it is applicable with the switch system of high speed and more capacity , because its speed of buffer and switch fabtic is equal to its port's speed . lately , more router and switch are realized with noblocked Crossbar switch fabric . moreover , Crossbar switch fabric is simple , it is realized with hardware easily. Virtual output queue set N FIFO queues corresponding N output ports in the middle of each input ports . this avoides with blocked of header of queue . so this paper selects Crossbar switch fabric based on Virtual output queue.After study on the three component: switch fabrics, buffer and strategies and schedule algorithms of the switch system, a high speed switch system model is finally confirmed according to the project demand, which is based on VOQ buffer strategy and Crossbar switch fabric and iDRM schedule algorithm. Then, this paper describes the detailed degign .each mduel of ATM Switch system.. An 8 8-port switch fabric with switch capacity of 1.2Gbps is accomplished in FPGA by VHDL. Not only does the design successfully break through three key technologies of switch system: VOQ buffer strategy and Crossbar switch fabric and iDRM schedule algorithm. but also has some reality meaning of changing the status that the key elements rely on buying overseas ASIC chips at large.