Abstract: A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.

Abstract: A data relay apparatus for data relay in a ring-type network for data including a path identifier which is transferred according to the path identifier, receives the data; stores the path identifier that is used to determine a data path in which the data is transferred in the ring-type communication network in association with a reception direction and a transmission direction of the data; compares the path identifier included in the received data and the path identifier stored by an information storing part to determine a path for receiving and transmitting the data and switches the transmission direction of the data based on a reception direction of a failure notification message notified when a communication failure occurs and whether a switching inhibition message transmitted concerning the communication failure is received; and transmits the data in the switched transmission direction.

Abstract: A plurality of nodes are connected to one another so as to form a ring network. A pseudo master node blocks relay of user data on one side, and transmits in the ring network a health packet that contains information about a priority order in which the pseudo master node is to be set as a master node. If the pseudo master node receives the health packet transmitted by it, or receives a health packet transmitted by another node, the pseudo master node judges whether the pseudo master node is to be set as a master node based on the priority order contained in the received health packet.

Abstract: A method provides a communication path in a ring network having a plurality of communication nodes. The method includes: setting transfer information of data in each of the plurality of communication nodes by making the transfer information correspond to connection information for identifying a connection within the ring network to provide a first communication path; determining whether to update the transfer information in each of the communication nodes according to the position where the fault occurs; and updating the transfer information according to the position where the fault occurs in one or more of communication nodes to provide a second communication path. Each of the plurality of communication nodes transfers input data by using the first or second communication path according to transfer information corresponding to connection information attached to the input data.

Abstract: The present invention provides a protection providing method in a network configuration having a customer edge apparatus redundantly connected to a first provider edge apparatus and a second provider edge apparatus for setting a primary provider edge apparatus and a secondary provider edge apparatus with the customer edge apparatus. The first provider edge apparatus transmits a first signaling message received when establishing a pseudowire to the customer edge apparatus. The second provider edge apparatus also transmits a second signaling message received when establishing a pseudowire to the customer edge apparatus. The customer edge apparatus compares the first and second signaling messages and sets the primary provider edge apparatus and the secondary provider edge apparatus.

Abstract: A node apparatus in a ring network in which a protection path is provided that cycles around the ring network and transports a signal in a direction opposite to a signal transporting direction of the working path and in the event of a failure of the working path, a node apparatus adjacent to the failure loops back the signal flowing on the working path onto the protection path, the node apparatus comprising: allowable bandwidth storing unit which stores a maximum total bandwidth value, which represents the largest value among per-link total values of bandwidths that a plurality of working paths use on respective links connecting between the node apparatuses, as an allowable bandwidth for a shared path; and bandwidth control unit which controls the bandwidth of traffic flowing on the protection path, in accordance with the allowable bandwidth.

Abstract: A transmission device includes an ingress edge device that receives a frame, an egress edge device having a plurality of destination addresses, and a rewrite unit that rewrites a destination MAC address of the frame to another destination MAC address of the egress edge device when detecting a failure on a working path between the ingress edge device and the egress edge device.

Abstract: A system that allows information of MPLS layers to be reported to PW layers by providing a function having a correlation between MPLS layers and PW layers. A transmission system uses MPLS (Multi-Protocol Label Switching) tunneling and label technology to map a communication service to MPLS, thereby providing bidirectional services on an end-to-end basis. The transmission system is a communication system comprising a means to perform label assignment control for bidirectional services; a means to transmit, after completion of assignment control, a message in which the LDP message used in assignment control is a payload and a tunnel-directed label (L2) used by bidirectional services is a header; and a means to associate, on the basis of the received LDP message used in assignment control, a service-directed label (P1) included in the LDP message with the received tunnel-directed label (L2) in the part where the message is terminated.

Abstract: According to the transmission method, labels to be used at the failure occurrence are previously and individually set to links in respective directions among all nodes on the one directional link connecting between adjacent nodes basis, and when a failure occurs, a failure notifying message is sent out onto a same directional ring from a termination node of a failed block, to be sequentially transferred to each downstream node, and a label table for connecting the links in cooperative with the reception of the failure notifying message is created in each node, and also, a bypassing path is formed by turning back the rings at both end nodes of the failed block. Thus, in a ring network of label switching system, it becomes possible to easily perform the label table management and also to set a bypassing path in a short time at the failure occurrence.

Abstract: A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.

Abstract: A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.

Abstract: A transmitting apparatus in a network constituted of a plurality of rings connected via a plurality of routes includes a node type determining unit and a backup path setting message transmitting unit. The node type determining unit determines, on receipt of a working path setting message requesting to set a working path, whether the transmitting apparatus is any one of a branch node at which a backup path is branched off from the working path or a merge node at which the backup path merges into the working path. The backup path setting message transmitting unit transmits, when the transmitting apparatus is determined to be a branch node or a merge node, a backup path setting message specifying a route from a ring including the transmitting apparatus to a connection node connecting the ring and a neighboring ring.

Abstract: A switch that performs packet forwarding processing based on a label for a connection in which a communication path is specified by the label, includes a receiving unit that receives loopback information with a label of a first layer used for packet forwarding for a first connection, and a packet processing unit that transmits a first loopback packet having a packet including the loopback information, a label of the first layer, and a label of a second layer used for packet forwarding for a second connection layered on the label of the first layer, and also transmits a second loopback packet having the packet including the loopback information and the label of the second layer.

Abstract: The present invention provides a protection providing method in a network configuration having a customer edge apparatus redundantly connected to a first provider edge apparatus and a second provider edge apparatus for setting a primary provider edge apparatus and a secondary provider edge apparatus with the customer edge apparatus. The first provider edge apparatus transmits a first signaling message received when establishing a pseudowire to the customer edge apparatus. The second provider edge apparatus also transmits a second signaling message received when establishing a pseudowire to the customer edge apparatus. The customer edge apparatus compares the first and second signaling messages and sets the primary provider edge apparatus and the secondary provider edge apparatus.

Abstract: In a digital filter device which filters a plurality of signals by a single digital filter, an input data memory stores the input data strings generated by computing processors, and a digital filter reads the input data strings in a predetermined sequence to be filtered and generates output data strings. An output data memory stores the output data strings, and a data processor reads the output data strings in a predetermined sequence to be processed. Furthermore, a filter memory and coefficient memories respectively store data-under-calculation and a filter coefficient in a delay circuit included in the digital filter.

Abstract: An object of the invention is to provide a control apparatus and a control method having a simple constitution, which can stably perform switching of optical path in an optical signal exchanger, while suppressing an influence on a control due to the mechanical resonance of tilt mirrors. To this end, the control apparatus of the optical signal exchanger is constituted such that in an optical signal exchanger of three-dimensional type using one set of MEMS mirror arrays, each having a plurality of tilt mirrors arranged on a plane, each tilt mirror having a reflecting surface an angle of which is controllable, when the angle of the MEMS mirror on the optical path is feedback controlled by detecting power of an optical signal output from a specific position, a resonance component removing section that removes a resonance frequency component included in a control signal is shared corresponding to a pair of driving electrodes arranged in a coaxial direction of the MEMS mirror.

Abstract: In a known 1:1 redundant communication method, if traffic passes through a working communication path, there is no traffic in a backup communication path other than a switching control packet for instructing control of switching between the working communication path and the backup communication path. This is a problem for the efficiency of the communication bandwidth of the backup communication path. In a 1:1 redundant communication system, the present invention enables flexible communication in the backup communication path and the effective use of communication bandwidth of the backup communication path by controlling traffic in the backup communication path on the basis of information on the condition of the working communication path included in the switching control packet that is transmitted via the backup communication path.

Abstract: A plurality of nodes are connected to one another so as to form a ring network. A pseudo master node blocks relay of user data on one side, and transmits in the ring network a health packet that contains information about a priority order in which the pseudo master node is to be set as a master node. If the pseudo master node receives the health packet transmitted by it, or receives a health packet transmitted by another node, the pseudo master node judges whether the pseudo master node is to be set as a master node based on the priority order contained in the received health packet.

Abstract: A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.

Abstract: A light source supplies optical signal to an optical switch and a detector detects light receiving level. A control unit changes a deflection control amount for changing an angle of a tilt mirror, and outputs the deflection control amount to a driving unit. When an input and an output ports are same, optical offset of the tilt mirror is calculated based on optimal angle at which the light detector detects an optimal point of the light receiving level. Whenever the input and the output port are different, a structure parameter of the tilt mirror is calculated based on the optical offset and the optimal angle. The optical offset and the structure parameter are stored in a memory as a test result.