Abstract: A check-frame receiving unit receives a check frame containing bandwidth data of a bandwidth allocated to a communication between a transmitting side and a receiving side. A bandwidth-data extracting unit extracts bandwidth data in the check frame and outputs a received bandwidth with a MAC address in the check frame. A bandwidth comparing unit reads out preset bandwidth set in association with a destination MAC address from a bandwidth storing unit, and compares the received bandwidth with the preset bandwidth. A response-frame generating unit generates a response frame containing a result obtained by comparing the received bandwidth with the preset bandwidth, the received bandwidth, and the preset bandwidth. A response-frame transmitting unit transmits the response frame generated by the response-frame generating unit.

Abstract: A communication device capable of restraining the packet transmission efficiency from lowering. An address storing unit extracts, from uplink packets, the addresses of terminals connected to sub-units and registers the addresses in an address management table. An address extracting unit extracts the address of a destination terminal included in a downlink packet output from a layer 2 switch, and an address determining unit determines whether or not the address of the destination terminal is registered in the address management table. In accordance with the result of the determination, a packet output unit outputs the downlink packet to a corresponding coupler.

Abstract: The central apparatus obtains the destination information of a plurality of terminal devices, generates one request packet consolidating the obtained plural destination information, and transmits the generated one request packet. The relay unit receives one request packet, generates a plurality of request packets on the basis of the consolidated destination information, and transmits the generated request packet. The relay unit receives reply packets from a plurality of terminal devices, generates one reply packet consolidating the destination information of the transmission origins of the received plural reply packets, and transmits them to the central apparatus. The central apparatus receives the returned one reply packet and determines continuation and blockade of the network connection for each terminal device.

Abstract: A check-frame receiving unit receives a check frame containing bandwidth data of a bandwidth allocated to a communication between a transmitting side and a receiving side. A bandwidth-data extracting unit extracts bandwidth data in the check frame and outputs a received bandwidth with a MAC address in the check frame. A bandwidth comparing unit reads out preset bandwidth set in association with a destination MAC address from a bandwidth storing unit, and compares the received bandwidth with the preset bandwidth. A response-frame generating unit generates a response frame containing a result obtained by comparing the received bandwidth with the preset bandwidth, the received bandwidth, and the preset bandwidth. A response-frame transmitting unit transmits the response frame generated by the response-frame generating unit.

Abstract: The central apparatus obtains the destination information of a plurality of terminal devices, generates one request packet consolidating the obtained plural destination information, and transmits the generated one request packet. The relay unit receives one request packet, generates a plurality of request packets on the basis of the consolidated destination information, and transmits the generated request packet. The relay unit receives reply packets from a plurality of terminal devices, generates one reply packet consolidating the destination information of the transmission origins of the received plural reply packets, and transmits them to the central apparatus. The central apparatus receives the returned one reply packet and determines continuation and blockade of the network connection for each terminal device.

Abstract: A communication device capable of restraining the packet transmission efficiency from lowering. An address storing unit extracts, from uplink packets, the addresses of terminals connected to sub-units and registers the addresses in an address management table. An address extracting unit extracts the address of a destination terminal included in a downlink packet output from a layer 2 switch, and an address determining unit determines whether or not the address of the destination terminal is registered in the address management table. In accordance with the result of the determination, a packet output unit outputs the downlink packet to a corresponding coupler.