Abstract: A transmission apparatus exercises insertion control for inserting a client signal and a stuff byte into a payload area in a frame into which the client signal is to be mapped, and sends the frame after the insertion control. In addition, the transmission apparatus inserts the client signal or the stuff byte in columns of the frame into the payload area except a leading column.

Abstract: A signal transmission method includes causing each of a plurality of nodes to transfer, using the actually used line, a second signal in a second layer, in which one or a plurality of first signals in a first layer are contained, to a node adjacent in the first or the second direction when each of the plurality of nodes transmits or receives the first signal, when no failure occurs in a transmission path in a network, and causing a first node, located at an end of a failure point, to switch a transmission direction of the second signal and to send out the second signal to the backup line, and causing a second node, which is a transmission source or a reception destination of the first signal, to select one of the first and second directions, when a failure occurs in the transmission path in the network.

Abstract: A node device receives supervisory control information on a dedicated wavelength different from a wavelength of signal light, which is input from an input port together with the signal light, and extracts, from signal light to be output from an output port, information superposed on an optical main signal of the signal light. Then, it is confirmed whether or not the signal light to be output and the supervisory control information correspond by using the extracted information, and supervisory control information corresponding to the signal light to be output is transmitted on the dedicated wavelength from the output port.

Abstract: A network design apparatus includes an input unit configured to receive network information that indicates nodes connected by optical transmission paths and path information that indicates paths between the nodes; an design unit configured to perform, based on the network information and the path information, wavelength dispersion compensation design using a constraint condition that a path whose span count is larger than a span count of another path that does not satisfy a transmission condition does not satisfy the transmission condition; and an output unit configured to output a result obtained by the design unit.

Abstract: There is provided topology information including connection states among nodes in a network, and port information including restriction conditions on connectivity among ports within a restricted node. A path search apparatus finds a first path having the minimum total link-cost among a plurality of paths. The topology information is changed so that the first path is not searched for as a path having the minimum total link-cost among the plurality of paths, and the port information is changed based on a port connectivity change rule. Then, the path search apparatus finds a second path different from the first path, based on the changed port information and the changed topology information, and reconfigures a pair of link-disjoint paths satisfying the restriction conditions imposed on the restricted node, by removing a link shared by both the first and second paths from the original topology information.

Abstract: A network design device includes a bypass number setting unit setting the number of bypass node; a loss calculating unit calculating a reference loss; a graph generating unit generating a graph having a variation value obtained based on a difference between a transmission loss of a link coupling nodes to each other and the reference loss; a path detecting unit detecting a minimum-variation-path in which sum of each variation value from a start point to an end point of the graph is minimum; and a comparing unit comparing a calculation OSNR and a reference OSNR, the calculation OSNR being obtained by a calculation from a start point to an end point assuming that an optical amplifier is located on a node other than a bypass node on the minimum-variation-path, wherein the bypass number setting unit changes the number of bypass node based on a result of the comparing unit.

Abstract: An apparatus for designing an optical network having nodes, includes: a parameter holding unit which holds values of one or more optical-transmission parameters corresponding to one or more components constituting the optical network; a part generation unit which generates design candidates for a part to be arranged in each of one or more spans between the nodes so that each of the design candidates contains at least one of the one or more components; a part selection unit which makes a selection, for each of the one or more spans, of one of the design candidates which has at least one value of at least one of the one or more optical-transmission parameters satisfying a design condition; and a construction control unit which constructs the optical network by combining one or more parts each of which is selected by the part selection unit.

Abstract: A receiving/processing unit receives signals parallelized by a parallelizing unit, and executes a frame process including frame synchronization process on the signals. A phase comparing circuit and a phase judging circuit judge whether a bit delay is present based on a phase difference between a phase of a clock signal at a clock/data recovering unit and a phase of a clock signal at the parallelizing unit. The receiving/processing unit includes a logic processing circuit that executes a bit delay process based on a result of judgment by the phase comparing circuit and the phase judging circuit.

Abstract: According an aspect of the embodiment, there is provided a method for accommodating signal paths to a ring network. A demand chain is defined as a series of traffic demands in which each traffic demand shares one of the pair of terminal nodes pointed thereby with at least one adjacent traffic demand and the number of pairs of terminal nodes pointed by traffic demands in the series of traffic demands is maximized. Each traffic demand of the demand chain is corresponded to a demand accommodating route which is defined as a route between the pair of terminal nodes on the ring network pointed by the each traffic demand and arranged in a predetermined rotation direction on the ring network. Then, signal paths required by traffic demands each pointing a pair of terminal nodes both included in the demand accommodating route chain are accommodated to the demand accommodating route chain.

Abstract: An optical transponder includes a mapping unit mapping, out of multiple types of signals including a first client signal and a second client signal that transmission rates are different from each other, the first client signal having a lower transmission rate to a Generic Framing Procedure (GFP) frame defined in ITU-T Recommendations; a coding unit applying 64B/66B coding to the first client signal mapped to the GFP frame; and a multiplexing unit multiplexing the first client signal to which the 64B/66B coding has been applied and the second client signal in a frame conforming to an Optical Transport Network (OTN) defined in ITU-T Recommendations; in which the first client signal and the second client signal are accommodated in an identical frame in a mixed manner and transmitted as an optical signal having one wavelength.

Abstract: An optical connection switching according to the present invention comprises an optical connection switching facility capable of making a connection between any one of optical input ports and any one of optical output ports, one or more optical transmitting/receiving units connected to a portion of the optical input/output ports, and management control units for controlling the optical connection switching facility to make a connection between the optical input/output port connected to the optical transmitting/receiving unit and the optical input/output port connected to equipment for acquiring and managing information on the equipment by making a communication with the equipment through the use of the optical transmitting/receiving unit. This enables acquiring the information on the equipment having an optical communication interface to be optically connected, thereby automating the connection management of the equipment.

Abstract: A frame generating apparatus accommodating a client signal in an optical data transfer unit frame with a higher bit rate than the client signal includes a deserializer, a plurality of generic mapping procedure circuits, and a serializer. The deserializer deserializes the client signal into parallel signals, the number of parallel signals corresponding to the number of tributary slots used in the optical data transfer unit frame. The plurality of generic mapping procedure circuits inserts data and stuff into a frame accommodating portion of the optical data transfer unit frame based on a difference in the bit rate between the client signal and the optical data transfer unit frame. The serializer serializes the parallel signals output from the plurality of generic mapping procedure circuits.

Abstract: In an optical network design apparatus, a constraint setter sets a first constraint that one of alternative values given beforehand is selected as the dispersion compensation amount of each node, sets a first margin value that assumes a nonnegative value, sets a second constraint that the first margin value is equal to or greater than the difference between the residual dispersion and the lower bound of an allowable range, sets a second margin value that assumes a nonnegative value, and sets a third constraint that the second margin value is equal to or greater than the difference between the upper bound of the allowable range and the residual dispersion. A calculation controller generates an objective function including the first, second and third constraints and including a summation of the first and second margin values for all paths, and derives a solution that minimizes the objective function.

Abstract: An appropriate ring topology is selected by searching network topology information on the basis of given information about client signal paths on a predetermined condition, and a wavelength ring accommodating the client signal paths and having an optimal transmission characteristic is designed on the basis of the selected ring topology. Accordingly, accommodation of client signal paths in an optical network is efficiently designed.

Abstract: If exists a client signal of a bandwidth larger than “optical signal bandwidth BW” divided by “the number of utilizable ports P”, extracted is a combination(s) of signals including one or more of a signal of a maximum bandwidth, of signals of which a total bandwidth is within the BW and of signals of which the number of total ports required in correspondence with a protection type of each client signal is equal to P, and selected is a combination of which the total bandwidth is a maximum from among the extracted combinations.

Abstract: In a network design apparatus, a full channel evaluator determines whether all wavelength channels for main signals can deliver the main signals of an existing optical network. When it is found that one or more wavelength channels cannot deliver main signals, a chromatic dispersion evaluator determines whether there are a specified number of wavelength channels that satisfy a specified chromatic dispersion condition. An optical signal-to-noise ratio (SNR) evaluator extracts a specified number of wavelength channels out of those satisfying the chromatic dispersion condition in descending order of optical SNRs thereof, and determines whether the extracted wavelength channels satisfy a specified optical SNR condition.

Abstract: An optical signal reception device that receives and demodulates an optical signal modulated by DQPSK and performs logical inversion and other controls to transit to the object reception state.

Abstract: A method for determining a value of chromatic dispersion compensation in an optical network including a plurality of nodes connected by at least one transmission line, the plurality of nodes including a plurality of dispersion compensators, the optical network including a plurality of wavelength paths between the optional nodes, the method includes determining a compensation value of the dispersion compensators in the optical network by the computer, the compensation value selecting that an error between the object value of the residual chromatic dispersion in accordance with of the first end node of the first path and the permissible value of the residual chromatic dispersion of the first end node of the first path is least, and the value of the residual chromatic dispersion of the first end is in the permissible value of the residual chromatic dispersion of the second end node of the second path.

Abstract: A chromatic dispersion compensation design system includes: an input unit that inputs information of an optical network having a plurality of nodes optically coupled to each other via an optical transmission path; an allowable range determining unit that determines an allowable range of a residual chromatic dispersion with respect to every wavelength path of a plurality of signals from a starting node to a terminal node, based on the information of the optical network; and a calculation unit that calculates a wavelength path capacity in the allowable range of the residual chromatic dispersion, in view of a chromatic dispersion variability of each optical element in the optical network.

Abstract: An optical signal reception device is disclosed that receives and demodulates an optical signal modulated by DQPSK and performs logical inversion and other controls to transit to the object reception state.