Abstract: An optical transmission path characteristic estimation device that estimates a polarization characteristic value of an optical path in which first sections that are in service operation of an optical communication service that uses a plurality of wavelengths and second sections that are out of the service operation are mixed, the optical transmission path characteristic estimation device includes a memory, and a processor coupled to the memory and configured to acquire first polarization characteristic values for each of the plurality of wavelengths in the first sections, and acquires second polarization characteristic values for each of the plurality of wavelengths in the second sections, based on information that represent an operation state of the optical communication service, and calculate wavelength-specific polarization characteristic values of the optical path for each of the plurality of wavelengths, based on the first polarization characteristic values and the second polarization characteristic valu

Abstract: An apparatus stores information identifying unallocated channels for each of spans, where a span indicates a section between adjacent nodes of a plurality of nodes in a communication network. The apparatus extracts unallocated channels for each of all spans provided between a start point node and an end point node of a path in the communication network, by referring to the information, and determines a channel including consecutive unallocated spans which are arranged on routes including the path and spans outside the path, and whose number is minimum among the extracted unallocated channels, as a channel to be set to the path.

Abstract: A transmission apparatus includes a plurality of output units and a detector. The plurality of output units is configured to couple to a plurality of transmission paths, respectively, branched from one transmission path. The plurality of output units includes at least one first output unit configured to transmit signal light selectively to one of the branched transmission paths, and at least one second output unit configured to transmit test light with a wavelength different from a wavelength of the signal light to another of the branched transmission paths. The detector is configured to decide a failure in the branched transmission paths, based on a result of detection of a reflected light of the test light received through at least one of the branched transmission paths.

Abstract: An apparatus stores information identifying unallocated channels for each of spans, where a span indicates a section between adjacent nodes of a plurality of nodes in a communication network. The apparatus extracts unallocated channels for each of all spans provided between a start point node and an end point node of a path in the communication network, by referring to the information, and determines a channel including consecutive unallocated spans which are arranged on routes including the path and spans outside the path, and whose number is minimum among the extracted unallocated channels, as a channel to be set to the path.

Abstract: A noise suppression method is used in an optical transmission system which includes node equipments transmitting a WDM optical signal. First node equipment drops a first optical signal from the WDM optical signal. The method includes: transmitting a failure signal that specifies the first optical signal from second node equipment to the first node equipment via a first route when the second node equipment arranged on the first route for transmitting the first optical signal to the first node equipment has detected a failure of the first optical signal; transmitting a shutoff signal that specifies the first optical signal from the first node equipment toward the second node equipment via the first route; and shutting off an optical output of a wavelength corresponding to the first optical signal in third node equipment that has relayed the failure signal and has received the shutoff signal.

Abstract: An optical transport network system includes a plurality of NEs, each transmitting wavelength-multiplexed optical signals. Each NE includes a routing information DB that is used to store reachable area information, which contains identifiers of other NEs in a range within which the optical signals can be transmitted from the own NE without using an REG. A FROM NE includes a path candidate searching unit that searches for a plurality of path candidates for transmitting optical signals from the FROM NE to a TO NE. The TO NE includes a path selecting unit that selects a path for transmitting optical signals from among a plurality of path candidates. The path selecting unit obtains the number of times for which the REG is used for each of the plurality of path candidates; and, based on each number of times that is obtained, selects a path for transmitting the optical signals.

Abstract: An optical cross-connect apparatus includes: a plurality of switch units connected to each other via input ports and output ports; a storage unit to store a setting table in which output port information and corresponding input port information are associated together and registered for each optical signal such that the output port information identifies a specific output port, in the output ports, that outputs the optical signal and the input port information identifies a specific input port, in the input ports, that inputs the optical signal; a setting processor to set each switch unit in the plurality of switch units according to the setting table so as to set a wavelength for each optical signal that is input via the input ports or output via the output ports; and an update processor to update the content of the setting table in response to external input.

Abstract: A network design method includes an input step for inputting a network condition at each of plural timings in advance, an acceptance step for accepting restricting conditions concerning respective costs at the plural timings, a design step for designing a network satisfying a restricting condition accepted in the acceptance step under the network condition input in the input step, and an output step for outputting a design result of the design step.

Abstract: A transmission apparatus includes a plurality of output units and a detector. The plurality of output units is configured to couple to a plurality of transmission paths, respectively, branched from one transmission path. The plurality of output units includes at least one first output unit configured to transmit signal light selectively to one of the branched transmission paths, and at least one second output unit configured to transmit test light with a wavelength different from a wavelength of the signal light to another of the branched transmission paths. The detector is configured to decide a failure in the branched transmission paths, based on a result of detection of a reflected light of the test light received through at least one of the branched transmission paths.

Abstract: An optical cross-connect apparatus includes: a plurality of switch units connected to each other via input ports and output ports; a storage unit to store a setting table in which output port information and corresponding input port information are associated together and registered for each optical signal such that the output port information identifies a specific output port, in the output ports, that outputs the optical signal and the input port information identifies a specific input port, in the input ports, that inputs the optical signal; a setting processor to set each switch unit in the plurality of switch units according to the setting table so as to set a wavelength for each optical signal that is input via the input ports or output via the output ports; and an update processor to update the content of the setting table in response to external input.

Abstract: A noise suppression method is used in an optical transmission system which includes node equipments transmitting a WDM optical signal. First node equipment drops a first optical signal from the WDM optical signal. The method includes: transmitting a failure signal that specifies the first optical signal from second node equipment to the first node equipment via a first route when the second node equipment arranged on the first route for transmitting the first optical signal to the first node equipment has detected a failure of the first optical signal; transmitting a shutoff signal that specifies the first optical signal from the first node equipment toward the second node equipment via the first route; and shutting off an optical output of a wavelength corresponding to the first optical signal in third node equipment that has relayed the failure signal and has received the shutoff signal.

Abstract: There is provided a communication device including a score information storage unit to store score information indicating a score as an evaluated value of a communication path; a receiver unit to receive a route connection notice including current score information; a routing unit to acquire the score information stored in the score information storage unit, and select the communication path next to the communication path based on the acquired score information of the communication path; a score updating unit to add a score of the communication path selected by the routing unit to the current score of the partial communication route indicated by the current score information, and update the current score information to the added score as a new current score; and a transmission unit to transmit the route connection notice including the current score information.

Abstract: There is provided a communication device including a score information storage unit to store score information indicating a score as an evaluated value of a communication path; a receiver unit to receive a route connection notice including current score information; a routing unit to acquire the score information stored in the score information storage unit, and select the communication path next to the communication path based on the acquired score information of the communication path; a score updating unit to add a score of the communication path selected by the routing unit to the current score of the partial communication route indicated by the current score information, and update the current score information to the added score as a new current score; and a transmission unit to transmit the route connection notice including the current score information.

Abstract: A network design method includes an input step for inputting a network condition at each of plural timings in advance, an acceptance step for accepting restricting conditions concerning respective costs at the plural timings, a design step for designing a network satisfying a restricting condition accepted in the acceptance step under the network condition input in the input step, and an output step for outputting a design result of the design step.

Abstract: Span information (information about conditions of a path between a node of interest and another, adjacent node connected thereto) retained in respective nodes is cumulatively transmitted from a add-drop node, which is to become a starting-point node of a certain wavelength path, toward a add-drop node, which is to become an end-point node of the wavelength path. The end-point node autonomously determines a path satisfying predetermined transmission conditions as an optimal pathway of said wavelength path, on the basis of cumulative span information transmitted over the respective plural pathways from the starting-point node to the node of interest. As a result, a load imposed on line design to be performed by a client can be mitigated, and an optimization design for each path (wavelength) matching a mesh-type optical network can be performed.

Abstract: Span information (information about conditions of a path between a node of interest and another, adjacent node connected thereto) retained in respective nodes is cumulatively transmitted from a add-drop node, which is to become a starting-point node of a certain wavelength path, toward a add-drop node, which is to become an end-point node of the wavelength path. The end-point node autonomously determines a path satisfying predetermined transmission conditions as an optimal pathway of said wavelength path, on the basis of cumulative span information transmitted over the respective plural pathways from the starting-point node to the node of interest. As a result, a load imposed on line design to be performed by a client can be mitigated, and an optimization design for each path (wavelength) matching a mesh-type optical network can be performed.

Abstract: There is provided a circuit board cabinet which is capable of more reliably preventing flames of a fire in a shelf from spreading to external devices, without degrading cooling capability thereof. Flames of the fire occurring in the shelf rise within a slot, pass through a shield plate, and then enter a heat shield unit. In the heat shield unit, the flames are first blocked by a heat shield plate and substantially reduced in force while passing through holes formed through the heat shield plate. Portions of the flames which were not blocked by the heat shield plate reach a top board of the unit after passing through the holes, where they are reduced. Since there is a predetermined distance between the heat shield plate and the top board, the flames having passed through the heat shield plate spread horizontally to some extent and then reach the top board. Therefore, it is possible to reduce the force of the flames sufficiently by the top board.