Abstract: A repeater and method provides a technique to minimize congestion and packet loss, which may be generated when a fault is detected in a ring type packet network or when the network recovers from such a fault. A repeater having a plurality of ports for transmitting and receiving packets in a ring type network for transmitting the received packets on the basis of an address included in a received packet and a transmitting port database indicating an identifier of a port to transmit the packet having the address as the destination, comprises a control packet processing block to detect reception of a fault notifying packet transmitted from a repeater having detected a fault and a control block to update, upon reception of the fault notifying packet from an immediately adjacent repeater, a port identifier of the transmitting port database having a port identifier of the port having received said fault notifying packet into a port identifier of a port connected to another immediately adjacent repeater.

Abstract: The present invention provides a subscriber line terminal device, which enables identification of the cause of abnormality when abnormality is detected in remote monitoring of a subscriber line terminating device connected to the terminal device via an optical fiber. The terminal device receives a plurality of monitoring signals sent from the terminating device via the optical fiber, the plurality of monitoring signals indicating normality or abnormality of a plurality of monitored items in the terminating device respectively. When two or more among the plurality of monitoring signals indicates abnormality, the terminal device selects a monitoring signal with high order of priority from among the two or more monitoring signals indicating abnormality, based on a prescribed order of priority.

Abstract: A repeater and method provides a technique to minimize congestion and packet loss, which may be generated when a fault is detected in a ring type packet network or when the network recovers from such a fault. A repeater having a plurality of ports for transmitting and receiving packets in a ring type network for transmitting the received packets on the basis of an address included in a received packet and a transmitting port database indicating an identifier of a port to transmit the packet having the address as the destination, comprises a control packet processing block to detect reception of a fault notifying packet transmitted from a repeater having detected a fault and a control block to update, upon reception of the fault notifying packet from an immediately adjacent repeater, a port identifier of the transmitting port database having a port identifier of the port having received said fault notifying packet into a port identifier of a port connected to another immediately adjacent repeater.

Abstract: A data relay apparatus includes a storage unit that stores information generated based on contents of data, a determining unit that determines, based on the information, whether a communication path relating to the data is in a loop state when the data is received, and a limiting unit that limits relay of the data when the determining unit determines that the communication path is in the loop state.

Abstract: The present invention provides a subscriber line terminal device, which enables identification of the cause of abnormality when abnormality is detected in remote monitoring of a subscriber line terminating device connected to the terminal device via an optical fiber. The terminal device receives a plurality of monitoring signals sent from the terminating device via the optical fiber, the plurality of monitoring signals indicating normality or abnormality of a plurality of monitored items in the terminating device respectively. When two or more among the plurality of monitoring signals indicates abnormality, the terminal device selects a monitoring signal with high order of priority from among the two or more monitoring signals indicating abnormality, based on a prescribed order of priority.