Group-pipeline scheduler for input-buffer switch

This paper proposes a group-pipeline scheduler (GPS), a novel scheduling algorithm for high-speed cell based crossbar switches with virtual output queuing (VOQ). In the GPS, the number of input/output ports can easily he expanded using a pipeline technique. A new input port grouping technique makes the scheduling delay of the GPS much lower than that of conventional pipeline schedulers. Fair scheduling is achieved by two stage shuffling, module shuffle and phase shuffle, for randomization of input/output ports. Simulation results demonstrate that the scheduling delay is close to that of a centralized scheduler, and that perfect fairness is achieved.