Hitachi, Ltd.

Alaxala Networks Corporation

Keiichiro Yamate

Makoto Kitani

Takahisa Miyamoto

Tatsuya Watanuki

Atsushi Kimoto

The network relay device of the invention makes a pair with at least a specific network device to relay data in a network. The network relay device includes: a control module that sends and receives a control frame signal to and from the specific network device, selects either of a master mode and a backup mode based on at least the control frame signal sent from the specific network device, and changes a working state according to a result of the selection; and a communication module that is under control of the control module to open a port and enable data transmission via a line linked to the port in the case of setting a master state to the working state, and to block off the port and disconnect the line linked to the port in the case of setting a backup state or another non-master state to the working state. The control module changes the working state from the backup state to a first intermediate state in response to selection of the master mode, determines whether the specific network device is in the backup state, based on the control frame signal sent from the specific network device, and changes the working state from the first intermediate state to the master state after confirmation that the specific network is in the backup state.

Network relay system and control method thereof

A handling address range is pre-assigned to each of switching devices consisting a network switching system. The switching device has a data receiving unit, an assigned data transport unit, an unassigned data transport unit, and a lower transport layer transport unit. The data receiving unit receives data including a destination address in a network layer and a destination identifier in a lower transport layer. If the destination identifier specifies the device itself, the assigned data transport unit and the unassigned data transport unit perform data transfer, whereas if the destination identifier specifies a device other than itself, the lower transport layer transport unit performs data transport. When the destination address is assigned address, the assigned data transport unit generates data including an identifier of a device corresponding to the destination address, and transports the generated data. When the destination address is not assigned address, the unassigned data transport unit transport the data to a switching device among the plurality of switching devices consisting the switching system to which the destination address is assigned.

Growing community of inventors

Hadano, Japan

Keiichiro Yamate