ATM switch controlling traffic congestion efficiently

摘要

In an ATM switch device having a plurality of input ports and a plurality of output ports, a port buffer is arranged for each of the output ports and is given a minimum guaranteed value which represents the minimum number of output cells sent to each output port even when traffic congestion takes place at the other output ports. A total queue monitoring buffer is also arranged to monitor a total number of output cells which is equal to a total sum of the minimum guaranteed values determined for the respective output ports and is counted up only when the counts of the port buffers exceed the minimum guaranteed values. With this structure, it is possible to detect traffic congestion all over the ATM switch device by the total queue monitoring buffer and to assure delivery of the output cells equal to the minimum guaranteed value. Each minimum guaranteed value may be determined for each service class and a multicast cell.