An apparatus and method for receiving a packet descriptor and a queue number that indicates a queue stored within a memory unit, determining a first amount of free memory in a group of packet descriptor queues, determining if the first amount of free memory is within a first range, applying a first drop probability to determine if the packet associated with the packet descriptor should be dropped when the first amount of free memory is within the first range, and applying a second drop probability to determine if the packet should be dropped when the first amount of free memory is within a second range. When it is determined that the packet is to be dropped, the packet descriptor is not stored in the queue. When it is determined that the packet is not to be dropped, the packet descriptor is stored in the queue.