Patent ID: 7710953

Claim:
An apparatus, comprising: a plurality of input ports for receiving arriving packets; a plurality of output ports for transmitting departing packets; a switching fabric for switching packets from the input ports to the output ports, the switching fabric comprising a plurality of virtual output queues for queuing packets based on the respective input ports on which the packets are received and the respective output ports for which the packets are destined; and a plurality of schedulers for computing packet schedules for use by the switching fabric in switching packets, wherein the schedulers are active during timeslots, wherein during a given timeslot only one of the schedulers is active for exchanging information with the switching fabric; wherein each of the schedulers is configured to, during a current timeslot in which the scheduler is active: receive, from the switching fabric, packet arrival information for packets arriving at the virtual output queues during the current timeslot; and provide, to the switching fabric, a packet schedule for use by the switching fabric in switching packets from selected ones of the virtual output queues to associated ones of the output ports during the current timeslot, wherein the packet schedule is computed by the scheduler using packet departure information for packets departing from the virtual output queues during at least one previous timeslot during which the scheduler was active and packet arrival information for packets arriving at the virtual output queues during at least one previous timeslot during which the scheduler was active.