Abstract: A multicast connection control apparatus provided in a branching-and-consolidating node connecting a source terminal to a plurality of destination terminals for branching information over the forward connection or consolidating information over the backward connection in a multicast connection ATM network system includes a congested status management table for managing congested status in all RM cells and a controller. The controller transmits only an uncongested status RM cell transmitted thereto last over the backward connection when all the connections in a sequence are found to be in the uncongested state. The controller also transmits only a congested status RM cell over the backward connection when one of the connections is found to be in the congested state and cancels the subsequent transmission of the congested status RM cells in the same sequence over the backward connection.

Abstract: An asynchronous transfer mode (ATM) communication network system is constructed by connecting a plurality of ATM terminal communication devices to each other through connections. Each ATM terminal communication device has a transmission function to transmit an output ATM cell and a receiving function to receive an input ATM cell.