Patent ID: 8081646
Filing Date: 2011-12-20
Classification: H04L

Abstract:
1. A packet switch, comprising: a plurality of output ports, each output port of the plurality of output ports configured to output data units of a data packet received by the output port; a plurality of input ports, each input port of the plurality of input ports comprising a plurality of virtual outputs queues corresponding to the plurality of output ports for mapping data units of data packets received by the input port to the plurality of output ports, each input port of the plurality of input ports configured to set an old age indicator for each of the virtual output queues in the plurality of virtual output queues of the input port to indicate the virtual output queue is old if an age of a data unit mapped by the virtual output queue has reached an old age threshold; an arbiter coupled to the plurality of input ports and configured to select virtual output queues based on the old age indicators of the virtual output queues and the availability of the output ports corresponding to the selected virtual output queues for storing a data unit, each output port corresponding to a selected virtual output queue being available to store a data unit from the selected virtual output queue; and a switch fabric coupled to the plurality of input ports and the plurality of output ports and configured to contemporaneously route data units mapped at heads of the selected virtual output queues to the output ports corresponding to the selected virtual output queues; and wherein, an input port of the plurality of input ports includes a counter configured to indicate the age of a virtual output queue in the input port by counting a number of arbitration cycles in which the virtual output queue is not empty and in which the arbiter does not select the virtual output queue.