Patent ID: 6519225
Filing Date: 2003-02-11
Classification: H04L

Abstract:
A network device comprising:a plurality of input ports and output ports residing on a plurality of line cards, the plurality of output ports configured to assert a backpressure signal when an associated output queue size exceeds a first predetermined threshold and de-assert the backpressure signal when the associated output queue size falls below a second predetermined threshold; a switch fabric coupled to the plurality of line cards allowing transfer of data among the plurality of input ports and output ports; and a fabric arbiter coupled to the switch fabric and the plurality of line cards, the fabric arbiter is configured to determine a fabric configuration for the switch fabric each-time slot and is further configured to operate in one of two modes of operation with respect to a backpressuring output port, in a first mode of operation, the fabric arbiter obeys the backpressure signal and does not include the backpressuring output port in the fabric configuration, in a second mode of operation, the fabric arbiter ignores the backpressure signal and causes head-of-line multicast cells destined for the backpressuring output port to be transferred to the backpressuring output port regardless of the backpressure signal.