Abstract: At a node, a first receiver receives ring information from a first adjacent node. A second receiver receives ring information from a second adjacent node. A first transmitter transmits ring information obtained by adding first local ring information attached between the node and the second adjacent node to the ring information received by the first receiver, to the second adjacent node. A second transmitter transmits ring information obtained by adding second local ring information attached between the node and the first adjacent node to the ring information received by the second receiver, to the first adjacent node.

Abstract: A transmission apparatus includes a processor configured to recognize a number of working failures and a number of protection failures on a network for transmission of wavelength-multiplexed signal light, the number of working failures being the number of failures in signal light in wavelengths at a working entity and the number of protection failures being the number of failures in signal light in wavelengths at a protection entity, configured to perform path switching for each group of signal light in wavelengths that are different from each other and configured to select, when multiple failures occur, restoration processing, on a basis of the number of working failures and the number of protection failures.

Abstract: A signal transmission method includes causing each of a plurality of nodes to transfer, using the actually used line, a second signal in a second layer, in which one or a plurality of first signals in a first layer are contained, to a node adjacent in the first or the second direction when each of the plurality of nodes transmits or receives the first signal, when no failure occurs in a transmission path in a network, and causing a first node, located at an end of a failure point, to switch a transmission direction of the second signal and to send out the second signal to the backup line, and causing a second node, which is a transmission source or a reception destination of the first signal, to select one of the first and second directions, when a failure occurs in the transmission path in the network.

Abstract: Transmitting a frame through a working path and a protection path is accomplished by detecting a failure occurring on the working path; changing a first destination address in the frame to a second destination address in accordance with the result of the detecting; and transmitting the frame after the changing to the protection path.

Abstract: A node apparatus in a ring network in which a protection path is provided that cycles around the ring network and transports a signal in a direction opposite to a signal transporting direction of the working path and in the event of a failure of the working path, a node apparatus adjacent to the failure loops back the signal flowing on the working path onto the protection path, the node apparatus comprising: allowable bandwidth storing unit which stores a maximum total bandwidth value, which represents the largest value among per-link total values of bandwidths that a plurality of working paths use on respective links connecting between the node apparatuses, as an allowable bandwidth for a shared path; and bandwidth control unit which controls the bandwidth of traffic flowing on the protection path, in accordance with the allowable bandwidth.

Abstract: A transmission device includes an ingress edge device that receives a frame, an egress edge device having a plurality of destination addresses, and a rewrite unit that rewrites a destination MAC address of the frame to another destination MAC address of the egress edge device when detecting a failure on a working path between the ingress edge device and the egress edge device.

Abstract: In an inter-ring connection method and device interconnecting a plurality of RPR rings, an inter-ring connecting device (interconnecting station) determines whether or not an RPR frame received from one ring is a broadcast frame; and resets, when the RPR frame determined to be the broadcast frame is relayed to another ring, a ttl of the frame so that a predetermined point between the inter-ring connection device itself and another identical inter-ring connection device opposed within a ring to be relayed is a cleave point. Also, topology information of the one ring is transmitted to another ring; topology information of each ring is held in a topology database; and an RPR frame is relayed (unicasted) between the rings by referring to the topology database based on a destination address of the RPR frame.

Abstract: A transmission apparatus arranged on one packet ring connects the packet ring and the other packet ring by performing an acquiring step for acquiring connection information of the other packet ring and the own apparatus and a notifying step for notifying other transmission apparatuses arranged on the packet ring of redundant configuration information indicating a status of the interconnection between the packet ring and the other packet ring, based on the connection information.

Abstract: In an inter-ring connection method and device interconnecting a plurality of RPR rings, an inter-ring connecting device (interconnecting station) determines whether or not an RPR frame received from one ring is a broadcast frame; and resets, when the RPR frame determined to be the broadcast frame is relayed to another ring, a ttl of the frame so that a predetermined point between the inter-ring connection device itself and another identical inter-ring connection device opposed within a ring to be relayed is a cleave point. Also, topology information of the one ring is transmitted to another ring; topology information of each ring is held in a topology database; and an RPR frame is relayed (unicasted) between the rings by referring to the topology database based on a destination address of the RPR frame.

Abstract: A loop frame detecting devise includes a frame receiving and transmitting unit and a loop detecting unit. The frame receiving and transmitting unit receives and transmits the Layer 2 frame. The loop detecting unit monitors contents of the frame that is received or to be transmitted by the frame receiving and transmitting unit, determines whether the frame is a loop frame that circulates in the Layer 2 network, detects the loop frame, and minimizes a loop failure.

Abstract: An abnormal traffic eliminating apparatus eliminates an abnormal traffic that is generated in a network through which frames including a MAC header part, an IP header part and an IP datagram part are transmitted. The apparatus is provided with a write part for writing an FCS field of an MAC frame that is received by a plurality of ports to a search engine part, and a loop monitoring and detecting part counting a number of received MAC frames having identical FCS values and judging that the network is in a loop state if the number of received MAC frames having the identical FCS values and received within a predetermined time exceeds a preset threshold value.