Patents by Inventor Nobuyuki Takagishi

Nobuyuki Takagishi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5018133
    Abstract: 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.
    Type: Grant
    Filed: September 6, 1990
    Date of Patent: May 21, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Masato Tsukakoshi, Yasuhiro Takahashi, Matsuaki Terada, Nobuyuki Takagishi