Patent ID: 6920147

Claim:
A method of controlling buffering of a discrete information unit of digital data for use within a digital switch having multiple source input ports, multiple destination output ports, and a switch fabric for switching a discrete information unit received at any of the source input ports to any of the destination output ports, wherein each source input port is associated with an input unit including an input buffer having a plurality of logical output queues and wherein each destination output port is associated with an output unit, the method comprising: on an input unit, changing by one the number of discrete information units buffered in a logical output queue within an input buffer, the logical output queue reserved for buffering discrete information units received on the input unit and having a particular priority level; and transmitting a queue status message from the input unit to an output unit if the change was an incrementing of the number of discrete information units buffered in the logical output queue from zero to one, or the change was a decrementing of the number of discrete information units buffered in the logical output queue from one to zero.