The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 2012
Filed:
Sep. 15, 2008
Makoto Kitani, Atsugi, JP;
Tatsuya Watanuki, Ebina, JP;
Keiichiro Yamate, Hadano, JP;
Atsushi Kimoto, Atsugi, JP;
Makoto Kitani, Atsugi, JP;
Tatsuya Watanuki, Ebina, JP;
Keiichiro Yamate, Hadano, JP;
Atsushi Kimoto, Atsugi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
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.