Patent ID: 6163528
Filing Date: 2000-12-19
Classification: H04L

Abstract:
A selective cell discard system in an asynchronous transfer mode (ATM) switch to exchange a cell input from a plurality of input ports to a plurality of output ports, for controlling the selective cell discard to guarantee quality of service (QOS) by controlling the order of cell discard or the read-out order of cells accumulated in a cell buffer when a number of cells exceeding the exchange capability of the switch is input, comprising:a selective cell discard controller connected to each of said plurality of input ports;a first-stage switch unit connected after said selective cell discard controller to receive an output from said selective cell discard controller, comprising:a first plurality of cell buffers corresponding to output port groups into which said plurality of output ports are divided; anda cell multiplexer which multiplexes cells input from said plurality of input ports through said selective cell discard controller according to routing information of said cells;a group of second-stage switch units corresponding to each of said first plurality of cell buffers for exchanging a cell in a concerned cell buffer in an output port group to any one of a second plurality of cell buffers corresponding to output ports belonging to a concerned output port group; andmeans for detecting a congestion in one of said cell buffers for an output port group, and discarding a cell to be input to the congested cell buffer for an output port group in said selective cell discard controller prior to said cell reaching said first-stage switch unit.