Fujitsu Corporation

Yasushi Sasagawa

Masami Doukai

Kou Takatori

Kenichi Kawarai

Kazunori Umezaki

Hiroomi Shinha

Yukiko Kudoh

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

A packet router in a label switching system includes a logical router configuring module for logically dividing a label switching router (LSR) into a plurality of LSRs each having a label switching function, and a module for specifying, when setting a label switched path on the basis of an explicit route specified, a port or a port group of an egress node. With this construction, a label switching architecture in an ATM network for actualizing MPLS (label switching) can be mapped to an ATM-Switch base system architecture, and a granularity or function (Constraint Base Routing) of specifying a variety of routes provided by MPLS can be attained.

Label switching system

In a packet relaying apparatus, a label distribution protocol processor performs a label assignment so that labels which a label management portion of its own processor manages and which the label management portion of an adjoining packet relaying apparatus manages are assigned in mutually reversed orders within a label available range when a directionality is determined to be unidirectional. In addition, an incoming label and an outgoing label assigned to a unidirectional FEC can be used as the outgoing label and the incoming label assigned to another FEC opposite in direction to the former FEC.

Packet relaying apparatus

An ATM network accommodates terminals having the version UNI 3.0 of signalling software installed and terminals having the version UNI 3.1 of the signalling software installed. A signalling device, when receiving a signalling message directed from a version UNI 3.0 terminal to a version UNI 3.1 terminal, translates the message created by the version UNI 3.0 signalling software into a format that the version UNI 3.1 signalling software can process, then sends it the version UNI 3.1 terminal.

Signalling device and signalling method

A LAN emulation system is capable of avoiding a fault without making a line dual by a local dual structure on the premise that a LAN emulation server is made dual. An ATM switch, to which a LAN emulation terminal is connected, is provided with a line fault detecting unit, a routing table in which to define a correspondence a specified address to a line, and a line status table rewritten based on a result of detection by the fault detecting unit. A LAN emulation configuration server (LECS) connected to the ATM switch is constructed to have a dual structure. If a fault occurs in a connection to the LAN emulation configuration server, it is feasible to easily implement a connection to the dual LAN emulation configuration server and, because of no necessity for making dual the line itself, to easily construct a fault avoiding system.

Lan emulation system and atm switch

According to a network system of the present invention, a protocol information requesting unit of call-out terminal requests, when setting a call between terminal devices having different signaling protocols, an ATM switch to supply signaling protocol information used by a call-in terminal. A protocol information supplying unit of the ATM switch reads protocol information corresponding to the protocol information of the call-in terminal from a first protocol information storage unit, and supplies the call-out terminal with this piece of protocol information. A protocol changing unit in the call-out terminal changes the signaling protocol used by the call-out terminal to the signaling protocol used by the call-in terminal. There comes a status wherein the two signaling protocols become coincident.

Network system

A device at the terminal unit and a device at the network support an interim local management (ILMI) protocol. When the power is applied to the device at the terminal unit, it notifies the device at the network of support range information about a VPI/VCI of the device at the terminal unit. The device at the network assigns a VPI/VCI to the device at the terminal unit according to the support range information about the VPI/VCI received in a cold start trap message from the device at the terminal unit when a signal is received from the device at the terminal unit.

Method and apparatus for negotiating connection identifier

ATM terminals are connected to an ATM network through a user network interface (UNI). When a connection is set between a calling side application and a called side application corresponding to an ATM signaling protocol performed by a signaling portion, and a unique sub-address that identifies an application is set to a call setting message along with a calling side terminal address and a terminating call terminal address, a plurality of connections can be securely set between a calling side application and a called side application.

Method for an ATM network which controls settings of a plurality of

A call processor performs call set-up/release processing based upon absence/presence of valid data from an SVC service terminal and either decreases or increases an idle band of the network by an amount equivalent to the assigned band of the SVC service terminal. Further, the call controller sends a network an OAM cell for band assignment or am OAM cell for canceling band assignment based upon absence/presence of valid data from a PVC service terminal and either decreases or increases an idle band of the network by an amount equivalent to the assigned band of the PVC service terminal. In a case where the transfer rate of data sent from terminal is high, a band assignment controller send the network an OAM cell for retesting band increase, increases the assigned band of the terminal by a prescribed amount and decreases the idle band by an amount equivalent to the increase in the assigned band. In a case where the transfer rate of data sent from terminal is low, the band assignment controller sends the network an OAM cell for requesting band decrease, decreases the assigned band of the terminal by a prescribed amount and increases the idle band by an amount equivalent to the decrease in the assigned band.

Growing community of inventors

Kawasaki, Japan

Yasushi Sasagawa