ATM switch and congestion control method

摘要

An ATM switch having a packet level discard function includes an upstream congestion detection circuit (127) for detecting a congestion state of an ATM switch provided in the upstream and a packet level discard control table (129) for holding at every connection a packet level discard priority (703-2j) indicating whether the ATM switch provided in the upstream has the packet level discard function or not, and wherein cells transmitted via an ATM switch not having a packet level discard function or an ATM switch which is not in the congestion state are packet-level-discarded with a priority to other cells. Thus, it is possible to improve a goodput of the ATM network in which ATM switches having a packet level discard function and ATM switches not having a packet level discard function are provided in a mixed state.