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 frame transmission device which does not require a separate supervisory line and enables supervisory frames to efficiently enter subscriber traffic for transmission without securing a fixed bandwidth. A supervisory token computing section gives supervisory frames supervisory tokens as permission to transmit within a minimum bandwidth. Subscriber token computing sections give subscriber frames subscriber tokens as permission to transmit within respective set transmission bandwidths. A best-effort token computing section gives the frames best-effort tokens as permission to transmit by using an extra bandwidth. The supervisory or subscriber tokens are given to read frames from a supervisory queue or subscriber queues, and if a frame queue length is smaller than or equal to the best-effort tokens remains in the queue, a queue read control section reads and outputs the remaining frames from the queue by using the extra bandwidth of best-effort tokens.

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 method of controlling the communication rate between a user terminal and an edge switch of a network is provided. This method includes the step of matching the transmission rate at which data is transmitted from the user terminal to the edge switch, with the communication rate of the edge switch that is determined under contract with a user.

Abstract: An uninterruptible transfer can be realized during a line failure in a transmission system performing a packet transmission between transmitting apparatuses connected via a plurality of lines. In a method for realizing the uninterruptible transfer, test packets including information of the number of packets received from the transmitting apparatus of a destination are periodically sent to the transmitting apparatus of a source. The transmitting apparatus of the source compares the received information of the number of packets included in the received test packets with the number of packets sent out to the transmitting apparatus of the destination via one line. When the comparison shows a disagreement between the number of the received packets and the number of the sent-out packets, packets corresponding to the disagreement are resent to the transmitting apparatus of the destination via another line.

Abstract: A frame transmission device which does not require a separate supervisory line and enables supervisory frames to efficiently enter subscriber traffic for transmission without securing a fixed bandwidth. A supervisory token computing section gives supervisory frames supervisory tokens as permission to transmit within a minimum bandwidth. Subscriber token computing sections give subscriber frames subscriber tokens as permission to transmit within respective set transmission bandwidths. A best-effort token computing section gives the frames best-effort tokens as permission to transmit by using an extra bandwidth. The supervisory or subscriber tokens are given to read frames from a supervisory queue or subscriber queues, and if a frame queue length is smaller than or equal to the best-effort tokens remains in the queue, a queue read control section reads and outputs the remaining frames from the queue by using the extra bandwidth of best-effort tokens.