Mitsubishi Denki Kabushiki Kaisha

Keiichi Soda

Tatsuki Ichihashi

Tetsuya Yokotani

Kazuyuki Kashima

Koichi Hiramatsu

Yukio Ushisako

Toshiyuki Takahashi

Makoto Shibahara

Kazunori Kotaka

In a communication network in which one master device and a plurality of slave devices are connected via a multiplexer to each other in a tree form with the master device provided at the vertex, the master device specifies each of the slave devices via the multiplexer according to a round-robin. Then the slave device transmits specific information for starting used for matching the sampling time to the master device according to the specified order. Finally, the sampling time is adjusted by executing a prespecified operation according to the specific information for returning returned from the master device in response to the specific information for starting.

Communication network, and master device, slave device, multiplexer and switch constituting the communication network

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.

Multicast connection control method and apparatus

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. Each ATM terminal communication device includes memory including a connection control table having, for each ATM terminal communication device, an assigned virtual path identifier and an assigned virtual channel identifier; and an ATM cell transmission section for transmitting an output ATM cell including the virtual path identifier assigned to the ATM terminal communication device and the virtual channel identifier assigned to other ATM terminal communication devices, the virtual path identifier indicating the ATM terminal communication device as a transmitter of the output ATM cell, and the virtual channel identifier indicating the other ATM terminal communication device as a receiver of the output ATM cell. Each ATM terminal communication device further includes an ATM cell receiving section for comparing a virtual channel identifier of an input ATM cell with the virtual channel identifier assigned to the ATM terminal communication device, trapping the ATM cell when the virtual channel identifier of the input ATM cell matches the virtual channel identifier of the ATM terminal communication device, and discarding the input ATM cell when the virtual channel identifier of the input ATM cell does not match the virtual channel identifier of the ATM terminal communication device. The ATM terminal communication devices form a point to multipoint connection for a virtual path identified by the virtual path identifier of the output ATM cell transmitted from the ATM terminal communication device.

ATM communication device and ATM communication network system with

In an ATM communication network system comprising plural ATM terminals 1a to if respectively having individual real memories 38a to 38f to transmit and receive ATM cells and ATM switching apparatus 2a, 2c and 2e for switching the ATM cells transmitted and received among the ATM terminals 1a to if and setting a broadcast connection 4a designating the respective ATM terminals 1a to if as the transmitting ATM terminals, the virtual memory 3 may be realized on the real memories 38a to 38f of the ATM terminals 1a to if by periodically performing the broadcast cell communications using the broadcast connection 4a designating all the ATM terminals 1a to if in the present system as the transmitting apparatuses.

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Tokyo, Japan

Keiichi Soda