Abstract: An output buffer type ATM (Asynchronous Transfer Mode) exchange device and a multicast control method enable retrieval processing to bit map table for the sake of multicast control to delay, and which are capable of answering to be large capacity of the bit map table. The multicast control method of the output buffer type ATM exchange device multiplexes the cell inputted from a plurality of input ports during input cell period. The method accumulates unicast cell from among the cell distributed from a time division multiple bus into output buffer corresponding to the output port respectively. The method outputs the unicast cell to corresponding output port while synchronizing with output cell period.

Abstract: In traffic shaping apparatus including a plurality of cell buffers, a content addressable memory is provided to store times for addresses each designating one of the cell buffers, and a timer counter is provided to generate a time. When this time is transmitted to the content addressable memory, an address is read from the content addressable memory in accordance with this time, so that a cell output permission is given to one of the cell buffers.

Abstract: The input/output buffer type ATM switch capable of traffic control depending on the traffic type at the time of cell congestion is provided. There are provided an input buffer memory and an output buffer memory for storing cells at each of a plurality of input ports and a plurality of output ports. Each of the input buffer memories is provided with queues corresponding to each of the output ports, logically independent for traffic types and sharing a memory area. Each of the output buffer memories is provided with queues logically independent for traffic types and sharing a memory area, and outputs an overflow signal corresponding to a remaining memory capacity against each of the input buffer memories. Cell transmission from the input buffer memories is controled in response to a remaining memory capacity and the traffic type indicated by the overflow signal.