Fujitsu Corporation

Masami Doukai

Kenichi Kawarai

Yasushi Sasagawa

Kou Takatori

Hiroshi Kinoshita

Ko Takatori

Atsuko Higashitaniguchi

Satsuki Norimatsu

A method of providing path protection includes setting a working path and a protection path by identifying, as a single path, a set of a control-purpose virtual network identifier and at least one virtual network identifier that are assigned to one or more users at a section defined as a point-to-point connection in a virtual network, and switching between the working path and the protection path.

Path protection method and layer-2 switch

A fault detection device capable of detecting network faults by itself with high accuracy in multi-vendor environments, without the need to interoperate with an associated device according to an identical protocol. A monitoring control packet transmitter generates a fault monitoring control packet and transmits the generated packet to the associated device with which the fault detection device need not interoperate to detect faults according to the same protocol. A transmit packet counter keeps count of the transmitted fault monitoring control packet. A receive packet counter receives a control packet transmitted from the associated device, and keeps count of the received control packet. A fault detector monitors the count of transmitted packets and the count of received packets and, if at least one of the counts remains unchanged for a fixed period of time, judges that a fault has occurred and sends a fault notification to outside.

Fault detection device

When a control packet is transmitted/received among devices that support a spanning tree protocol (STP), a receiving side device temporarily stores a received control packet in a buffer. When the transmission of a control packet from a transmitting side device is stopped, the control packet stored in the buffer is transferred to a STP processing unit in a specific cycle. Alternatively, the transmitting side device autonomously transmits a control packet for a specific period at specific intervals from when the STP processing unit stops its operation until it restarts the operation according to an instruction to start an automatic transmission.

Apparatus and method for processing control packet in spanning tree protocol

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

A label switching router (LSR) is disclosed in which a control label switched path (LSP) is set up on a route of LSRs, in the reverse direction of traffic, for restoration and protection. Link failure, node failure, etc., are signaled on the control LSP. Further, a process is carried out in units of LSPs (Bypass Tunnels), each of which bundles LSPs having the same switching point destination of traffic. A label is assigned to every Bypass Tunnel.

Restoration and protection method and an apparatus thereof

A WDM (Wavelength Divisional Multiplex) device is provided in which a client signal having a band that is greater than a band of a wavelength used for wavelength-division multiplexing is allocated a plurality of wavelengths and is transmitted as a wavelength-division multiplexed signal. The WDM device includes a used-band detecting part for detecting a used-band that is used by the client signal supplied from a client device. The used-band is detected from a path layer of the client signal using set-up information contained in the path layer of the client signal. The WDM device also includes a mapping part for mapping the detected used-band onto wavelengths used for wavelength-division multiplexing.

Growing community of inventors

Kawasaki, Japan

Masami Doukai