Abstract: In a multi-ring network with a plurality of rings to which RPR is applied connected, high-speed failure recovery is enabled when a failure occurs between the rings. The contact nodes 700-1 and 700-3 connected to the living inter-link 505 periodically transmit and receive a KeepAlive signal to/from each other. Then, when a KeepAlive signal fails to arrive for a fixed time period, determination is made that the inter-link 505 develops a fault to broadcast-transmit an inter-link failure notification RPR-MAC frame indicative of failure occurrence on the inter-link to each node. A contact node as a transmission source of the inter-link failure notification RPR-MAC frame and each node having received the inter-link failure notification RPR-MAC frame immediately flush learning contents of their own learning data bases. A contact node connected to the spare inter-link 506 switches the spare inter-link 506 to a forwarding state.

Abstract: A packet ring network system is disclosed which enables plurality of packet rings to perform packet transfer via a plurality of links while preventing multiple reception of packets and broadcast stream in a normal state where no failure has occurred. The packet ring network system includes a first packet ring and a second packet ring, each packet ring having a plurality of inter-ring connecting nodes, and each of the plurality of inter-ring connecting nodes in the first packet ring is connected with each of the plurality of inter-ring connecting nodes in the second packet ring in a one to one relationship so that the packet rings are connected with each other. When one of the inter-ring connecting nodes receives a packet to be broadcasted via a link connecting the first and second packet rings the node performs bidirectional flooding of the broadcast packet such that the packet arrives at a predetermined cleave point, and the node uses the source address of the other node so as to falsify the source.

Abstract: A topology database stores the number of RPR nodes which belong to an RPR network. A traffic rate measuring unit sends a variety of parameters for calculating a communication band available to a fairness controlled traffic packet to a fairness control unit. Upon detection of congestion, the fairness control unit calculates a communication band available for transmission of the fairness controlled traffic packet from the parameters sent from the traffic rate measuring unit, divides the communication band by the number of nodes to find an initial value for a fair rate.

Abstract: For eliminating a reduction in throughput in a network as a whole according to optimum path transfer technique which is the expansion of spanning tree protocol, a frame switching unit of the network has an STP control unit for, when a port state of a spanning tree is changed, notifying a table control unit of an identifier of the spanning tree and a port number of a predetermined port among the respective ports, the table control unit for setting, in a forwarding table storage unit, a received port number of a predetermined port as an output port in an entry in which a node ID is equivalent to a spanning tree identifier, and a table search unit for determining an output destination from among output ports obtained by acquisition of received frame information from a frame analysis unit.

Abstract: It is possible to increase the communication system transmission capacity flexibly and at low cost in accordance with a communication system traffic amount. A terminal connected to a plurality of networks distributes a plurality of frame segments generated by dividing a single frame to the plurality of networks connected to the local terminal transmits them. Further, the terminal reconstructs the original frame from the plurality of frame segments generated by dividing the single frame. It should be noted that each of the frame segments contains division configuration information indicating how the frame has been divided (the number of divisions and the order of the frame segments) and also contains information required for performing MAC address learning for determining the path to the destination terminal.

Abstract: In a communication system formed of two or more networks in which a part or all of nodes belonging to each said network form a plurality of combinations of nodes so as not to overlap with other node on the network to which each node belongs, the nodes belonging to the same combination are connected with each other and terminals are connected under the control of a part or all of the nodes belonging to the same combination, a node belonging to the combination transmits a frame received from a terminal under the control of the node itself to any of adjacent nodes on the network to which the node itself belongs and a node belonging to the same combination to which the node itself belongs and connected to the node itself. This obtains a highly reliable communication system whose desired transmission capacity can be realized at low costs and which can be restored from an abnormal state in a short time period.

Abstract: Nodes 901 and 902 have the same address. Upon reception of a broadcast packet whose TTL value is not zero from a ringlet 910a, a forwarding circuit 51 of each of the nodes 901 and 902 copies and transits the packet, and an address table 60 of each node learns the address based on the copied broadcast packet. Upon reception of a unicast packet whose destination is an address common to the two nodes from the ringlet 910a, the forwarding circuit 51 of one node 901 copies and transits the packet, while the forwarding circuit 51 of the other node 902 strips the packet, and each address tables learns the address. A filter circuit of the node 902 prohibits the passage of the packet from the ringlet 910a.

Abstract: In the case where a terminal under an RPR node (240) which does not belong to an interlink connection node group in an RPR network (20) transmits an Ethernet frame to a terminal under an RPR node of other RPR network (10), the RPR node (240) transmits an RPR frame in which the Ethernet frame is contained to any of interlink connection nodes (200, 230, and 270) in the same network.

Abstract: A topological information management frame is classified based on the contents stored in the topological information management frame, and information stored in a database is updated based on the contents stored in the topological information management frame depending on the classification of the topological information management frame.

Abstract: A network node including an FDB for registering a relationship between a destination MAC address and a port label, an input port table for registering a relationship between an input port and a port label, and a port label table for registering a relationship between a port label and an output port, at the reception of a frame, registers a relationship between a transmission source MAC address of a frame and a port label registered for an input port in the input port table at the FDB, at the time of transmission of a frame, transmits the frame to an output port registered at the port label table which port corresponds to a port label registered for the destination MAC address in the FDB and at the time of processing of flushing or updating the FDB unit, changes the contents of the input port table and the port label table.

Abstract: In a multi-ring network with a plurality of rings to which RPR is applied connected, high-speed failure recovery is enabled when a failure occurs between the rings. The contact nodes 700-1 and 700-3 connected to the living inter-link 505 periodically transmit and receive a KeepAlive signal to/from each other. Then, when a KeepAlive signal fails to arrive for a fixed time period, determination is made that the inter-link 505 develops a fault to broadcast-transmit an inter-link failure notification RPR-MAC frame indicative of failure occurrence on the inter-link to each node. A contact node as a transmission source of the inter-link failure notification RPR-MAC frame and each node having received the inter-link failure notification RPR-MAC frame immediately flush learning contents of their own learning data bases. A contact node connected to the spare inter-link 506 switches the spare inter-link 506 to a forwarding state.

Abstract: In a ring network to which a plurality of nodes are connected, even though a failure occurs in a link between a node and a client apparatus (a user terminal) or a node itself, communication between the node and the client apparatus can be achieved. Nodes (105a) and (105b) are provided, so that, even though a failure occurs at either one of the nodes in the link between the node and the client apparatus (102), communication can be done between the other node and the client apparatus (102) through the link. When the node (105a) has a failure, the node (105b) succeeds in operation of the node (105a) while the node (105a) holds a state of the node (105a) to avoid a steering operation or a lap protection operation, a packet disappearance in the packet ring caused by the operation, influence of traffics a packet route change, etc., consumption of CPU and memory resources, and a ring transfer band reduction.

Abstract: [Problems] To enable each of a plurality of links connecting rings to perform packet transfer while preventing multiple reception of packets and broadcast stream in a normal state where no failure has occurred. [Means for Solving Problems] An inter-ring connecting node 101a and an inter-ring connecting node 102a are connected, and similarly, an inter-ring connecting node 101b and the inter-ring connecting node 102b are connected. When each of the inter-ring connecting nodes 102a and 102b receives a packet to be broadcasted via a link 103 or 104, it performs bidirectional flooding of the broadcast packet such that the packet arrives at a predetermined cleave point. At this time, each of the inter-ring connecting nodes 102a and 102b uses the source address of the other node so as to falsify the source.

Abstract: The present invention provides a node capable of preventing the problems caused by switching between traffic communication paths when a link failure occurs. According to an embodiment of the invention, among ports of a node 10, ports P1 and P2 connected to a link between the node 10 and a node 20 are registered in a virtual port VP1, and ports P3 and P4 connected to a link between the node 10 and the node 30 are registered in a virtual port VP2. The virtual ports VP1 and VP2 are registered in a virtual port VP3 allocated to a virtual LAG group. When one link between the node 10 and the node 20 is disconnected, the node 10 transmits frames, which have been transmitted from a physical port connected to the link, from the virtual port including the physical port, among the virtual ports belonging to the virtual port VP3 allocated to the virtual LAG group.

Abstract: A topology database stores the number of RPR nodes which belong to an RPR network. A traffic rate measuring unit sends a variety of parameters for calculating a communication band available to a fairness controlled traffic packet to a fairness control unit. Upon detection of congestion, the fairness control unit calculates a communication band available for transmission of the fairness controlled traffic packet from the parameters sent from the traffic rate measuring unit, divides the communication band by the number of nodes to find an initial value for a fair rate.

Abstract: Provided in the EoE technique are the node, the network, the correspondence relationship generating method and the frame transfer program to avoid traffic concentration on a specific link to improve throughput of the network as a whole by realizing optimum path transfer. The frame switching unit includes the frame analysis unit for analyzing an input frame kind and the like, the table search unit for obtaining frame rewriting information and output port information, the forwarding table storage unit for managing an output port of a frame, the MAC learning unit for executing MAC address learning, the EoE-MAC learning unit for learning a relationship between a MAC address and an EoE-MAC address, the STP control unit for executing processing of a spanning tree, and the like.

Abstract: A base node (100) and a base node (101) transmit a keep alive frame broadcast by a relay node forming a communication medium (106) and a communication medium (107) from a port 1 and a port 2, monitor an arrival state of the keep alive frame at each port, and in normal operation, assume the two communication media connected to the port 1 and the port 2 as one node to expand a communication band and at failure detection, continue communication by using only a communication medium connected to a port at which no failure is detected.