Abstract: A method and apparatus for smoothing the rate of packet discards for random early detection (“RED”) in a communication device such as an ATM switch is described. The ATM switch includes a plurality of class of service queues. An accumulated discard probability is stored independently for each class of service queue. With the arrival of each packet (frame), an instantaneous discard probability is calculated. The sum of the instantaneous discard probability and the accumulated discard probability becomes the effective probability for discard. If the effective discard probability is greater than (or equal to) a random number, the cell is discarded, and the accumulated discard probability is cleared. Otherwise, the sum is stored back as the new value for the accumulated discard probability. The accumulated discard probability may optionally be cleared if a class of service queue's current cell count is zero.

Abstract: A method and apparatus for determining a percent utilization of shared resource and fine resolution scaling of a threshold based on the utilization is described. In one embodiment, the method includes detecting a cell that belongs to a VC queue where the VC queue includes a cell count, a minimum threshold cell count, and a maximum threshold cell count. The cell count is compared with the minimum threshold cell count. If the cell count is greater than (or equal to) the minimum threshold cell count, the method further includes determining a ratio between the cell count and the maximum threshold cell count, selecting a scaling factor responsive to the ratio, scaling the cell count by the scaling factor to provide a scaled cell count, comparing the scaled cell count with a maximum threshold cell count, and discarding the cell if the scaled cell count is greater than the maximum threshold cell count.