Queue size arbitration method and apparatus to enhance performance of crossbar cell switch

摘要

The present invention provides a method and apparatus for arbitration among the inputs of a crossbar cell switch. The input cells of the crossbar cell switch are stored at their respective input ports in input queues prior to switching. The first cell of each input queue is known as the Head of Line (HoL) cell. For each set of HoL cells that may be directed to a specific output port, the HoL cell with the largest input port queue size is assigned to be switched during the current switching epoch. The method and apparatus for arbitration allows the crossbar cell switch to operate with smaller input queues, increasing the throughput of the switch and minimizing both the transit delay for the data cells through the switch and the buffer size needed to accommodate input queues.