Kabushiki Kaisha Toshiba

Takahiro Murono

Akihiro Horiguchi

Yoichiro Kutsukake

An inter-network relay unit is provided that is capable of simultaneously achieving guaranteed minimum bandwidth and priority control (including relay priority, discard priority, delay priority, etc.). A rate controller outputs relatively high priority packets from priority queues as guaranteed traffic based on guaranteed bandwidth for each link. Relatively low priority packets left in the priority queues are marked for preferential discard and output as best-effort traffic by an aging timer. When an output port is congested, an output queue portion discards only the marked packets. Thus, traffic having a plurality of relay priorities can use the guaranteed minimum bandwidth effectively and the guaranteed minimum bandwidth can be secured, irrespective of change in traffic volume for each relay priority level.

Inter-network relay system and method

A network connection device with improved processing speed for exchanging a frame including content addressable memories (CAMs), each having predetermined data stored in each of a plurality of entries in advance, for checking whether or not the predetermined data of each entry conforms to data of the frame transmitted from a sender network. The device also includes a table memory, provided to correspond to each entry of the CAM, for storing data of the other CAM to be searched next or an address of a destination sender network. The device further includes a data continuous search processing circuit for obtaining the address of the destination network of the frame from the sender network by use of data and the address stored in the table memory and a checking means when the CAM checks that the predetermined data conforms to data from the sender network, for setting the address of the frame from the sender network having the address of the frame from the sender network obtained, and for transmitting the frame having the address of the destination network set to the sender network. The checking means is continuously accessed based on data sent from the storing means, so that the address of the network can be obtained. The device achieves improved processing speed by use of the continuous search.

Network connection device

A multiplexed network connecting apparatus comprising, communication lines for connecting in parallel a pair of LANs, relay stations each interposed between each of the communication lines and each of the LANs, transmission means for transmitting a transmission frame from a first LAN of the LANs to a second LAN, and bypass transmission paths each for connecting the relay stations. One of the first relay stations connected to the first LAN, which is designated as an operation system relay station, receives the transmission frame from the first LAN, transfers the transmission frame to the second LAN through the communication line connected to the operation system relay station, and transfers the transmission frame to another of the first relay stations, which is designated as a standby system relay station, through the bypass transmission path when the communication line connected to the operation system relay station malfunctions.

Multiplexed network connecting apparatus

A connection apparatus connecting LANs includes LAN control sections, an address searching/registering section and a wiring network. The LAN control sections are respectively provided for LANs which transmit frames, and at least issue a request for address registering and a request for address searching. The address searching/registering section executes address searching/registering processing in accordance with the address searching/registering requests from the LAN control sections. The wiring network includes transmission lines for independently transmitting frames between the LAN control sections.

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Tokyo, Japan

Takahiro Murono