Design And Implementation Of Output Scheduling And Lookup Table In Crossbar Switch Unit

In the history of the development of network switch, the switch architecture and method have undergone three phases, the computer RAM switch architecture, the shared bus switch architecture and the crossbar switch architecture. As the traffic of exchange in the network grow, the capacity becomes a bottleneck of the shared bus switch architecture and it is necessary to use crossbar to meet the increasing requirement of exchange capacity.In this paper, which bases on the project “the design and implement of a dedicated network switch base on crossbar architecture” undertaken by our lab team, the base crossbar switch architecture is presented firstly, followed by a comparison in “input queue structure”, “output queue structure” and “input queue with cross point buffers structure”, then a discuss of the crossbar structure implementing detail in the project is given. Secondly, the implement of the output scheduling algorithm in a certain switch architecture is given. Thirdly, the design and implement of the lookup table in the crossbar switch is given, in which a hash pipelining look up algorithm base on multiple RAMs is discussed in detail, which uses less RAM resources while keeping low collision probability and fast look up speed, then a solution to solve the collision between multiple look up thread and self-study thread is given. finally, the validity of the system is verified by a functional verification of each module in the system using Modelsim software and a on board system testing, and the testing result is given.