Hitachi, Ltd.

Masato Tsukakoshi

Shigeki Morimoto

Yasuhiro Takahashi

Matsuaki Terada

Hidehiro Fukushima

Tohru Setoyama

Shinsuke Suzuki

Kenji Kusaka

Nobuyuki Takagishi

A highly-expandable router configuration technology which flexibly meets the need to increase lines as a network grows. A network information sharing unit is provided in a route calculation unit of each router in a clustered router. The network information sharing unit receives an update notification of network information collected by routing protocol units and sends this update information to all other routers in the clustered router as a network information notification packet. The network information sharing units in the receiving router notifies the routing protocol units of the contents of the received updated information. The routing protocol unit updates the network information thereof based on the notified contents, thereby allowing the network information obtained from all routers outside the clustered router to be shared and the clustered router to be recognized externally as a single router.

Method for sharing network information and a router apparatus

A router device is provided with a plurality of router node devices interconnected via internal transmission lines, in which each of the plurality of router node devices comprises a unit for connecting to a plurality of networks; a routing table describing paths via which packets are forwarded; a forwarding unit for forwarding a packet between one network and another, and for forwarding the packet between the network connected to the router node device and the network connected to some other router node device of the router device via some other router node device, according to the routing table; a routing information collection unit for collecting routing information from each router device connected to the network, not via other router node devices, to the router node device to create a routing table in each router device, the routing information being information to be exchanged among router devices, a distribution unit for distributing the collected routing information to other router node devices via the internal transmission lines; and a routing table generation unit for generating the routing table based on the collected routing information and the routing information distributed from the other router node devices.

Scalable cluster-type router device and configuring method thereof

A multiplex router device, having a multiplex configuration, is instrumental in reducing internal and external traffic flows for a routing protocol process that occurs at a time of system switchover. A data base integration module, in a route calculation unit in the active mode, stores network link-state information collected by a routing protocol packet transmission-reception module in a link-state data base, and at the same time sends the information to a route calculation unit, but does not send routing protocol information collected. In the route calculation unit in the standby mode, a data base integration module that received the network link-state information stores its contents into its own link-state data base. When a failure occurs in the route calculation unit in the active mode, the route calculation unit performs the routing protocol process by using the stored link-state data base.

System and method for using active and standby routers wherein both routers have the same ID even before a failure occurs

Multiplex router device comprising a function for controlling a traffic

In a network system comprising a plurality of secondary LAN's of different types operable at a relatively low speed, a single primary LAN accommodating the secondary LAN's and operable at a relatively high speed, and a plurality of bridges for connecting the primary LAN and the secondary LAN's, a communication frame transmitting on the primary LAN includes an identifier representative of the type of a secondary LAN to which a source terminal belongs and a bridge receiving the primary LAN frame carries out a protocol processing on the basis of the identifier representative of the type of the secondary LAN.

Communication network system having a plurality of different protocal LAN's

In a network system according to the hierarchical routing method, in which at least one main LAN and a plurality of sub-LANs are connected hierarchically through bridges, bridge IDs having the smallest values in the network are given to a plurality of bridges (first bridges) connected to the main LAN. Bridge IDs unique to each other having values greater than the bridge IDs of the first bridges are given to a plurality of bridges (second bridges) connecting sub-LANs. Each of the first bridges transmits periodically a control message (Hello message) for making the network in a tree structure by using some of the second bridges as backup bridges to the side of the sub-LANs. When a change takes place in the topology of the network, the reconstruction of the tree structure is effected in a localized part of the network including a position of hindrance, the root of the network being constituted by a particular first bridge.

Growing community of inventors

Sagamihara, Japan

Masato Tsukakoshi