Fujitsu Corporation

Satsuki Norimatsu

Hiroshi Kinoshita

Atsuko Higashitaniguchi

Takashi Hatano

Akira Yamamoto

Yuichiro Sakane

Masami Doukai

Akihiro Horiuchi

Ayako Hashimoto

An optical pickup which has a failure prediction apparatus for predicting a failure of a laser diode has an input inputting a value of a current that flows through the laser diode and is measured at predetermined time intervals, a storage storing the current values inputted by said input, a detector detecting a current value that is a current value at any one of the measurement times of day stored in said storage and that has a change greater than or equal to a predetermined value relative to the current value at the preceding measurement time of day, and a generator generating a prediction curve that indicates a relationship between said elapsed time and the current value applicable at and after the measurement time of day of the current value detected by said detector.

Failure prediction apparatus and failure prediction method

The present invention provides a carrier network in which a spanning tree with no loops can be constructed even in a dual homing configuration, and a communication method for a control frame. By allocating an identical virtual network identifier to a plurality of user networks connected to the carrier network, a single virtual network is constituted. An ingress communication node connected to a first user network of the plurality of user networks attaches a tag including the virtual network identifier to a control frame transmitted from the first user network, and transmits the control frame attached with the tag to a transmission destination determined on the basis of the virtual network identifier. An egress communication node connected to a second user network of the plurality of user networks receives the control frame attached with the tag, which is to be transmitted to the second user network, removes the tag from the control frame attached with the tag, and transmits the control frame to the second user network.

Carrier network of virtual network system and communication node of carrier network

In a network providing a wide-area LAN service which allows communications to be performed between user networks () via a carrier network (), edge switches () each comprise: a tentative learning registration means () which, when a packet whose source MAC address and receiving port are not yet learned is received from the carrier network, registers the source MAC address and the receiving port in a tentatively learned state; a learned state changing means () which changes the learned state of the destination MAC address of a packet received from an associated one of the user networks to a permanently learned state; and a permanent learning registration means which, when a packet whose destination MAC address is registered in a learned state is received from the carrier network, registers the source MAC address and receiving port of the packet received from the carrier network in a permanently learned state. The invention thus provides a MAC address learning apparatus that improves the hit rate in a MAC address learning table maintained in each of the edge switches () provided in a wide-area VLAN carrier network.

MAC address learning apparatus

When setting up a working path, a protection path is automatically set up by taking each node on the working path as a start point. A working path setup request message carrying 'protection needed/not-needed' information is transmitted from an ingress node toward an egress node along the route of the working path. When transferring a path setup response message as a response to it, each node autonomously determines the route of the protection path and sends out a protection path setup request message along the route of the protection path.

Growing community of inventors

Fukuoka, Japan

Satsuki Norimatsu