Patent ID: 6556572
Filing Date: 2003-04-29
Classification: H04L,H04Q

Abstract:
An apparatus for scheduling cell forwarding for use in an asynchronous transfer mode (ATM) network for switching ATM cells, comprising:a plurality of queues each provided for one of a plurality of classes of transmission quality for queuing up an ATM cell in a corresponding one of the classes which is required by the ATM cell; a cell classifying circuit for receiving an ATM cell and classifying the ATM cell received to one of said plurality of queues in accordance with the class required by the ATM cell; a status circuit for detecting a status of said plurality of queues and storing status data representative of the status detected; a scheduling circuit operative in response to said status circuit for determining when the ATM cell queuing up in said plurality of queues is to be forwarded, wherein said scheduling circuit determines for each of the classes a weight on the basis of which the ATM cell queuing up in a corresponding one of said queues is to be forwarded, and causes said plurality of queues to forward the ATM cell in accordance with the weight determined, wherein said scheduling circuit resets the weight for each of said plurality of queues to a reset value when the status data represents a predetermined condition, wherein said scheduling circuit calculates the reset value for each of the classes, and wherein said scheduling circuit calculates the reset value on the basis of a ratio of a queue length of the ATM cells which queue up in each of said queues to an allowable delay of the ATM cells which queue up in corresponding one of said queues.