Method and Apparatus for Operating Fast Switches Using Slow Schedulers

摘要

The invention includes an apparatus and method for switching packets through a switching fabric. The apparatus includes a plurality of input ports and output ports for receiving arriving packets and transmitting departing packets, a switching fabric for switching packets from the input ports to the output ports, and a plurality of schedulers controlling switching of packets through the switching fabric. The switching fabric includes a plurality of virtual output queues associated with a respective plurality of input-output port pairs. One of the schedulers is active during each of a plurality of timeslots. The one of the schedulers active during a current timeslot provides a packet schedule to the switching fabric for switching packets through the switching fabric during the current timeslot. The packet schedule is computed by the one of the schedulers active during the current timeslot using packet departure information for packets departing during previous timeslots during which the one of the schedulers was active and packet arrival information for packets arriving during previous timeslots during which the one of the schedulers was active.