Information processing device, information processing method, program, and optical communication system

Abstract

To provide an information processing device, an information processing method, a program, and an optical communication system that improve the reachability of a path of the optical communication system which converts the wavelength of a light signal at a relay node in the path.SOLUTION: An information processing device 10 has: a specification part 11 which specifies, based upon use states of wavelengths at a first node, a second node and a third node performing communication using a light signal, a path reaching the third node from the first node via the second node and transferring the light signal through conversion of the wavelength at the second node from a first wavelength to a second wavelength; a determination part 12 which determines whether reaching is possible through the path based upon deterioration characteristics of the SN ratio of a wavelength converter converting the wavelength of the light signal at the second node from the first wavelength to the second wavelength; and a control part 13 which controls the first node, second node and third node to perform the communication using the light signal through the path when the determination part determines that the reaching is possible through the path.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an information processing apparatus, an information processing method, a program, and an optical communication system.

Background Art

[0002] In recent years, with the rapid spread of mobile terminals represented by smartphones and the high-capacity data communication such as high-definition images due to the sophistication of the terminals, the traffic flowing through the network has been continuously growing rapidly. According to a certain survey, the total download traffic of broadband contract users in Japan in 2020 was about 19 Tbps and has been increasing at an annual rate of about 57%, and further traffic growth is expected in the future. On the other hand, in the core network that supports high-capacity communication, technologies such as wavelength division multiplexing (WDM) that multiplexes optical signals of multiple different wavelengths and transmits them on a single optical fiber, advanced modulation methods such as DP-QPSK (Dual Polarization Differential Quadrature Phase Shift Keying), and 16-QAM (16-Quadrature Amplitude Modulation) have been developed to meet the needs of increasing capacity.

[0003] With the progress of 5G (5th Generation) services in wireless communication, not only the need for increasing capacity but also the need for reducing network latency has been increasing. In response to these needs, in recent years, in the IWON (Innovative Optical and Wireless Network) concept and the like, an all-optical network that realizes a high-capacity and low-latency NW has been proposed. The all-optical network transmits as much as possible in the form of light without converting to an electrical signal in the path. Therefore, not only can high-capacity communication be achieved without being restricted by the communication capacity of the switch (relay device) that performs the conversion to an electrical signal, but also low latency can be achieved because the latency associated with the electrical conversion is reduced.

[0004] In optical communication systems, the same wavelength cannot be used within an optical fiber. Therefore, optical signals arriving at a relay node with the same wavelength but different paths cannot be accommodated in the same optical fiber. For this reason, the relay node converts the wavelength of the optical signal in one path so that the optical signal in that path and the optical signal in the other path can be accommodated in the same optical fiber. As a technology related to this, for example, Patent Document 1 is known. Patent Document 1 discloses a wavelength converter that converts the wavelength of an optical signal between the receiving end and the transmitting end using a coherent method. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 2017-511036 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in related technologies, for example, when the wavelength of an optical signal is converted at a relay node along the path, it can be difficult to guarantee its arrival along that path.

[0007] In light of the aforementioned problems, the purpose of this disclosure is to provide a technology that can improve the reachability of an optical communication system in which the wavelength of an optical signal is converted at relay nodes along the path. [Means for solving the problem]

[0008] In a first aspect of the present disclosure, an information processing device is provided, comprising: an identification unit that identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, the path which converts the wavelength of the optical signal from a first wavelength to a second wavelength at the second node and transmits it; a determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of the wavelength converter that converts the wavelength of the optical signal from a first wavelength to a second wavelength at the second node; and a control unit that controls the first node, second node, and third node to perform optical signal communication along the path if the determination unit determines that the path is reachable.

[0009] Furthermore, in a second aspect of the present disclosure, an information processing method is provided which, based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, identifies a path from the first node to the third node via the second node, where the wavelength of the optical signal is converted from a first wavelength to a second wavelength at the second node before transmission; determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of the wavelength converter that converts the wavelength of the optical signal from a first wavelength to a second wavelength at the second node; and, if it is determined that the path is reachable, controls the first, second, and third nodes to perform optical signal communication along the path.

[0010] Furthermore, in a third aspect of the present disclosure, a program is provided that causes a computer to execute a process that, based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, identifies a path from the first node to the third node via the second node, where the wavelength of the optical signal is converted from the first wavelength to the second wavelength at the second node before transmission; determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of the wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node; and, if it is determined that the path is reachable, controls the first, second, and third nodes to perform optical signal communication along the path.

[0011] Furthermore, in a fourth aspect of the present disclosure, an optical communication system is provided, comprising: a first node, a second node, and a third node that perform optical signal communication; and an information processing device, wherein the information processing device includes: an identification unit that identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first node, the second node, and the second node converts the wavelength of the optical signal from a first wavelength to a second wavelength and transmits it; a determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of a wavelength converter that converts the wavelength of the optical signal from a first wavelength to a second wavelength at the second node; and a control unit that controls the first node, the second node, and the third node to perform optical signal communication along the path if the determination unit determines that the path is reachable. [Effects of the Invention]

[0012] From one perspective, in an optical communication system where the wavelength of the optical signal is converted at relay nodes along the path, the reachability of the path can be improved. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of the configuration of an information processing device according to the embodiment. [Figure 2] This figure shows an example of the configuration of an optical communication system according to the embodiment. [Figure 3] This figure shows an example of the node configuration according to the embodiment. [Figure 4] This figure shows an example of the configuration of a wavelength converter according to the embodiment. [Figure 5] This figure shows a more detailed example of the configuration of the wavelength converter according to the embodiment. [Figure 6] This figure shows an example of the configuration of a coherent receiving front-end unit according to the embodiment. [Figure 7] This figure shows an example of the configuration of the coherent transmission front end according to the embodiment. [Figure 8] A flowchart showing an example of processing performed by the information processing apparatus according to the present invention. [Figure 9] This figure shows an example of information recorded in the node DB (database) according to this embodiment. [Figure 10] This figure shows an example of information recorded in the degradation characteristics database according to this embodiment. [Figure 11] This figure shows an example of the noise figure (NF) of the optical amplifier of a node according to the embodiment. [Figure 12] This figure shows an example of the hardware configuration of an information processing device according to the embodiment. [Modes for carrying out the invention]

[0014] The principles of this disclosure will be described with reference to several exemplary embodiments. These embodiments are described for illustrative purposes only and should be understood as helping those skilled in the art to understand and implement this disclosure without implying any limitation on the scope of this disclosure. The disclosures described herein may be implemented in various ways other than those described below. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this disclosure belongs. Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0015] (Embodiment 1) <Configuration> Referring to FIG. 1, the configuration of the information processing apparatus 10 according to the embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of the information processing apparatus 10 according to the embodiment. Note that the information processing apparatus 10 can also be referred to as, for example, an NMS (Network Management System) or the like. The information processing apparatus 10 includes a specifying unit 11, a determination unit 12, and a control unit 13.

[0016] The specifying unit 11 specifies a path that reaches the third node via the second node from the first node, based on the usage status of wavelengths at each of the first node (starting node), the second node (one or more relay nodes), and the third node (ending node) that perform communication by optical signals, and that converts and transfers the wavelength of the optical signal at the second node. In an optical communication system, a node that is the start point of data transmission is also referred to as a starting node, a node that relays data is also referred to as a relay node, and a node that is the end point of data transmission is also referred to as an ending node.

[0017] The determination unit 12 determines the reachability of the path based on the degradation characteristics of the signal-to-noise ratio (SN ratio) of the wavelength converter at the second node. When the determination unit 12 determines that communication by optical signals on the path is possible, the control unit 13 controls the first node, the second node, and the third node to perform communication by optical signals on the path.

[0018] (Embodiment 2) <System Configuration> Next, with reference to Figure 2, the configuration of the optical communication system 1 according to the embodiment will be described. The optical communication system 1 may be, for example, an all-photonics network using OAO (Optical to Analog to Optical) wavelength conversion, which converts the wavelength of optical signals by analog signal processing without performing digital signal processing. Figure 2 is a diagram showing an example of the configuration of the optical communication system 1 according to the embodiment. In the example of Figure 2, the optical communication system 1 has an information processing device 10. The optical communication system 1 also has nodes 20A, 20B, 20C, 20D, 20E, 20F, and 20G (hereinafter, when there is no need to distinguish between them, they will simply be referred to as "node 20"). Note that the number of information processing devices 10 and nodes 20 is not limited to the example in Figure 2.

[0019] The information processing device 10 is connected to one or more nodes 20 via optical transmission lines (e.g., optical fibers). Each node 20 is also connected to two or more other nodes 20 via optical transmission lines. The connection configuration (network topology) of the information processing device 10 and the nodes 20 may be, for example, a mesh shape or a ring shape.

[0020] Route P1 is an example of a route where node 20A is the starting node, nodes 20B through 20D are relay nodes in that order, and node 20E is the ending node 20. Note that the starting node 20 may be a computer such as a server or a switch device that has a circuit to convert electrical signals into optical signals and transmit them. Similarly, the ending node may be a computer such as a server or a switch device that has a circuit to convert received optical signals into electrical signals.

[0021] <Configuration of Node 20> Next, with reference to Figure 3, the configuration of node 20 according to the embodiment will be described. Figure 3 is a diagram showing an example of the configuration of node 20 according to the embodiment. In the example of Figure 3, node 20, which is a relay node, has one or more optical fibers 201, optical amplifiers (optical amplifiers, optical AMPs) 202A, optical amplifiers 202B, optical switches (WSS, Wavelength Selective Switch) 203, optical amplifiers 204A, optical amplifiers 204B, optical switches 205A, optical switches 205B, one or more wavelength converters 206, one or more optical fibers 207, and a controller 208.

[0022] The optical amplifier 202 compensates for the transmission loss of the optical signal input from the optical fiber 201 on a fiber-by-fiber basis at node 20. The optical switch 203 switches the optical signal from the optical amplifier 202 on a wavelength-by-wavelength basis and outputs it to, for example, the optical amplifier 204A.

[0023] The optical amplifier 204 compensates for the loss of the optical signal from the wavelength conversion port of the optical switch 203 and outputs it to the optical switch 205A. The optical switch 205A separates the fiber-based optical signal from the optical amplifier 204A into wavelength units and outputs them to the wavelength converter 206.

[0024] The wavelength converter 206 converts the first wavelength optical signal from the optical switch 205A into an electrical signal, performs analog signal processing such as analog compensation on the electrical signal, and then converts it back into a second wavelength optical signal before outputting it to the optical switch 205B. The wavelength converter 206 converts the optical signal into an electrical signal, performs only analog signal processing on it, and then converts it back into an optical signal of a different wavelength for relaying. Physically, there is an analog delay in the electrical circuit, but it is at most a few nanoseconds or less and is negligibly small. Therefore, compared to cases where wavelength conversion is performed by digital signal processing, a low-latency wavelength conversion function can be realized on a channel-by-channel basis.

[0025] Here, the wavelength converter 206 may perform analog compensation such as bandwidth compensation, PDL compensation (polarization-dependent loss compensation), and dispersion compensation. However, since the same wavelength cannot be used within an optical fiber, optical signals arriving at node 20 with the same wavelength but different paths cannot be accommodated in the same optical fiber. Therefore, node 20 uses the wavelength converter 206 to convert the wavelength of the optical signal in one path from the first wavelength to the second wavelength, so that the optical signal in that path converted to the second wavelength and the optical signal of the first wavelength in the other path can be accommodated in the same optical fiber.

[0026] The optical switch 205B bundles the wavelength-based optical signals from the wavelength converter 206 into fiber units and outputs them to the optical amplifier 204B.

[0027] Optical amplifier 204B compensates for the loss of optical signal from optical switch 205B and outputs it to optical switch 203. Optical switch 203 receives optical signals on a fiber-by-fiber basis from optical amplifier 204B, performs wavelength-by-wavelength switching, and outputs it to optical amplifier 202B. Optical amplifier 202B compensates for the transmission loss of optical signal from optical switch 203 on a fiber-by-fiber basis and outputs it to optical fiber 207. Optical fiber 207 outputs optical signals on a fiber-by-fiber basis from optical amplifier 202B to other nodes 20. Controller 208 controls each device within node 20 (e.g., optical switch 203).

[0028] <<Configuration of Wavelength Converter 206>> Next, the configuration of the wavelength converter 206 according to the embodiment will be described with reference to Figures 4 to 7. Figure 4 is a diagram showing an example of the configuration of the wavelength converter 206 according to the embodiment. Figure 5 is a diagram showing a more detailed example of the configuration of the wavelength converter 206 according to the embodiment. Figure 6 is a diagram showing an example of the configuration of the coherent receiving front end unit 110 according to the embodiment. Figure 7 is a diagram showing an example of the configuration of the coherent transmitting front end unit 120 according to the embodiment.

[0029] In the example shown in Figure 4, the wavelength converter 206 includes a coherent receiving front end 110, a coherent transmitting front end 120, and an analog compensation unit 130.

[0030] The coherent receiving front-end unit 110 converts the optical signal into an electrical signal and performs coherent detection. The coherent receiving front-end unit 110 coherently detects the input optical signal SO1 based on the local light emission r1 and outputs the generated analog electrical signal SA1.

[0031] The coherent transmission front-end unit 120 converts electrical signals into optical signals and performs coherent modulation. The coherent transmission front-end unit 120 coherently modulates the analog electrical signal SA2, which is obtained by folding back the analog electrical signal SA1, based on the transmitted optical light r2, and outputs the generated output optical signal SO2.

[0032] The input optical signal SO1 and the output optical signal SO2 are phase-modulated and polarization-multiplexed optical signals. The analog electrical signals SA1 and SA2 are 4-lane (4ch) signals containing the XI signal (common-phase component) of the X-polarization, the XQ signal (orthogonal component) of the X-polarization, the YI signal (common-phase component) of the Y-polarization, and the YQ signal (common-phase component) of the Y-polarization.

[0033] The frequency of the local light emission r1 is the frequency (carrier frequency) of the received input optical signal SO1, and the frequency of the transmitted light r2 is the frequency of the transmitted output optical signal SO2. For example, the local light emission r1 and the transmitted light r2 have different frequencies, but they can also be the same frequency. By changing the frequencies of the local light emission r1 and the transmitted light r2, the wavelength of the aliased optical signal can be switched. In other words, the input optical signal SO1 can be converted into an output optical signal SO2 of a different wavelength.

[0034] The analog compensation unit 130 is a circuit that performs predetermined analog signal processing on the analog electrical signal SA1 between the coherent receiving front end unit 110 and the coherent transmitting front end unit 120 to generate the analog electrical signal SA2. The analog compensation unit 130 performs analog signal processing on the analog electrical signal SA1 to compensate for the signal quality according to the signal characteristics between the input of the coherent receiving front end unit 110 and the output of the coherent transmitting front end unit 120, thereby generating the analog electrical signal SA2.

[0035] Note that optical signals, analog electrical signals, or both may be simply referred to as "signals." Signal quality compensation in this disclosure includes compensation for degradation of the optical signal that occurs each time it passes through node 20, and compensation for degradation of the analog electrical signal that occurs within node 20. For example, the degradation of the optical signal to be compensated includes pass band narrowing (PBN) that occurs when passing through optical multiplexers, optical filters, etc., at each node 20, amplitude variations in the four lanes due to variations in O / E or E / O conversion efficiency, optical frequency offset, etc. The degradation of the analog electrical signal to be compensated includes bandwidth degradation due to characteristic degradation and characteristic variations of the analog electrical circuits in each of the four lanes, amplitude variations in the four lanes, skew in the four lanes, etc. In other words, signal quality compensation includes bandwidth compensation to compensate for signal bandwidth degradation, frequency offset compensation to compensate for frequency shifts of local emission, skew compensation to compensate for timing variations of each signal component contained in the signal, and amplitude compensation to compensate for amplitude variations of each signal component contained in the signal.

[0036] As shown in Figure 5, the analog compensation unit 130 may include an analog signal processing unit 131, a control unit 132, and a monitor unit 133. The wavelength converter 206 may also include a reference light source 140 that generates local light emission r1 and a transmitting light source 150 that generates transmitted light r2. The reference light source 140 may be located inside the coherent receiving front end unit 110, and the transmitting light source 150 may be located inside the coherent transmitting front end unit 120.

[0037] The analog signal processing unit 131 is an analog circuit that performs predetermined analog signal processing to compensate for signal quality. The analog signal processing unit 131 processes the analog electrical signal SA1 while it remains an analog signal and outputs the analog electrical signal SA2. The analog signal processing unit 131 performs only analog signal processing and does not perform digital signal processing which causes large delays. As a result, the physical delay can be reduced to, for example, a few nanoseconds or less.

[0038] The monitor unit 133 monitors the signal characteristics of one of the following: the input optical signal SO1, the analog electrical signal SA1, the analog electrical signal SA2, or the output optical signal SO2, between the input of the coherent receiving front-end unit 110 and the output of the coherent transmitting front-end unit 120. The signal characteristics to be monitored include, for example, the characteristics of the polarization signal (polarization multiplexed X-polarization and Y-polarization) contained in the optical signal or the characteristics of the complex signal (phase-modulated I-component and Q-component) contained in the analog electrical signal.

[0039] The control unit 132 controls the operation of the analog signal processing unit 131 based on the monitoring results from the monitor unit 133. By optimizing the analog signal processing according to the monitored signal characteristics, it performs bandwidth compensation, skew compensation, etc., to suppress degradation of signal quality. Since the signal processing speed of the control unit 132 and the monitor unit 133 does not affect the latency of the main signal, the time constants of the control unit 132 and the monitor unit 133 may be low. The control unit 132 and the monitor unit 133 may be analog circuits or digital circuits.

[0040] As shown in Figure 6, the coherent receiving front-end section 110 includes a polarization separation section 111, 90-degree hybrid circuits 112-1 to 112-2, O / E conversion sections 113-1 to 113-4, and amplifiers 114-1 to 114-4.

[0041] The polarization separation unit 111 separates the input optical signal SO1, which is a polarization-combined signal, into X-polarized and Y-polarized signals. The 90-degree hybrid circuits (coherent photodetectors) 112-1 to 112-2 perform coherent detection by interfering the optical signal separated by the polarization separation unit 111 with the local light emission r1 of the reference light source 140, and the O / E conversion units 113-1 to 113-4, which consist of photodiodes and the like, convert the detected signal into a 4-lane analog electrical signal. The 90-degree hybrid circuit 112-1 separates the X-polarized input optical signal SO1 into I and Q components, and then the O / E conversion units 113-1 to 113-2 perform photoelectric conversion to generate XI and XQ signals. The 90-degree hybrid circuit 112-2 separates the Y-polarized input optical signal SO1 into I and Q components, then performs photoelectric conversion by O / E conversion units 113-3 to 113-4 to generate YI and YQ signals. Amplifiers 114-1 to 114-4 amplify the generated XI, XQ, YI, and YQ signals respectively and output them to the analog compensation unit 130 as a 4-lane analog electrical signal SA1. The analog compensation unit 130 performs analog signal processing on all or part (X-polarized or Y-polarized) of the XI, XQ, YI, and YQ signals.

[0042] As shown in Figure 7, the coherent transmission front-end section 120 includes amplifiers 121-1 to 121-4, MZ modulators (MZM: Mach-Zehnder Modulator) 122-1 to 122-4, and a polarization combining section 123.

[0043] Amplifiers 121-1 to 121-4 amplify the XI, XQ, YI, and YQ signals of the analog electrical signal SA2 output from the analog compensation unit 130, respectively, and drive the MZ modulators 122-1 to 122-4. The MZ modulators (IQ optical modulators) 122-1 to 122-4 apply IQ modulation to the transmitted light r2 of the transmitting light source 150 according to the applied XI, XQ, YI, and YQ signals, respectively. MZ modulators 122-1 to 122-2 generate X-polarized IQ-modulated optical signals based on the XI and XQ signals via amplifiers 121-1 to 121-2. MZ modulators 122-3 to 122-4 generate Y-polarized IQ-modulated optical signals based on the YI and YQ signals via amplifiers 121-3 to 121-4. The polarization combining unit 123 polarization combines the generated X-polarized IQ-modulated optical signal and the Y-polarized IQ-modulated optical signal, and outputs the combined optical signal as the output optical signal SO2.

[0044] <Processing> Next, an example of processing by the information processing device 10 according to the embodiment will be described with reference to Figures 8 to 11. Figure 8 is a flowchart showing an example of processing by the information processing device 10 according to the embodiment. Figure 9 is a diagram showing an example of information recorded in the node DB (database) 901 according to the embodiment. Figure 10 is a diagram showing an example of information recorded in the degradation characteristics DB 1001 according to the embodiment. Figure 11 is a diagram showing an example of the NF (Noise Figure) of the optical amplifier of node 20 according to the embodiment.

[0045] The information processing device 10 may, for example, execute the processing shown in Figure 8 when it receives a route setting request (route setting request, path request). The path request may include identification information of the starting node 20 and identification information of the ending node 20. The path request may be sent from, for example, the starting node 20. Alternatively, the path request may be issued (sent) from, for example, a communication device that initiates data communication using node 20. In this case, the communication device may be an optical media converter or the like that converts the received electrical signal into an optical signal and relays it.

[0046] In step S101, the identification unit 11 determines, based on the path request and the information recorded in the node DB 901, whether there is a wavelength and path (hereinafter also referred to as the "first path") that meets the conditions and allows communication at any of the relay nodes 20 along the path without wavelength conversion.

[0047] Here, the identification unit 11 may identify, for example, the shortest path from the starting node 20 to the ending node 20 that minimizes the transmission delay, passing through one or more nodes 20, as the first path. In this case, the identification unit 11 may identify, for example, the path from the starting node 20 to the ending node 20 that passes through one or more nodes 20, where the wavelength is not in use at the relay node 20 (no wavelength collision) and the number of hops (for example, the number of relay nodes 20 in the path) is minimized. The identification unit 11 may, for example, not identify paths where the number of hops is greater than or equal to a threshold. Also, the identification unit 11 may, for example, not identify paths where the communication speed in the path is less than or equal to a threshold.

[0048] In the example in Figure 9, node DB901 records usage status and communication speed, associated with combinations of source node ID, destination node ID, and wavelength ID. The source node ID is the identification information of the source node 20. The destination node ID is the node ID of another node 20 (destination node 20) that a certain node 20 (source node 20) can transmit optical signals to. The usage status may also be information indicating whether communication at each wavelength is currently being used in communication from node 20 to destination node 20. The communication speed may also be information indicating the communication speed (communication bandwidth) at each wavelength from source node 20 to destination node 20.

[0049] The node ID, destination node ID, wavelength ID, and communication speed may be pre-set by the administrator of the information processing device 10. The usage status may be set (updated) by the information processing device 10. The node DB 901 may be recorded in the internal storage device of the information processing device 10 or in an external storage device of the information processing device 10.

[0050] If a first path exists (YES in step S101), the control unit 13 sends a first setting command for each node 20 on the first path (step S102). Here, the first setting command for each node 20 may include information indicating the wavelength of the optical signal to be forwarded by the node 20 that received the first setting command, and the node ID of the destination node 20. The node 20 that received the first setting command then configures the optical switch 203, etc., to forward (relay) the optical signal of the wavelength specified in the first setting command to the destination node 20 specified in the first setting command. This makes it possible, for example, to transfer data from the starting node 20 to the ending node 20 in the optical communication system 1.

[0051] On the other hand, if there is no first route (NO in step S101), the identification unit 11 and the determination unit 12 determine, based on the path request and the information recorded in the node DB 901, whether there is a route that meets the conditions (hereinafter also referred to as the "second route" as appropriate) that can be reached by performing wavelength conversion at one or more relay nodes 20 along the route (step S103).

[0052] Here, the identification unit 11 may identify candidate routes for the second route, and the determination unit 12 may determine whether each of the one or more routes identified by the identification unit 11 is reachable or not. The identification unit 11 may then identify the route that the determination unit 12 has determined to be reachable from among the candidate routes for the second route as the second route.

[0053] In this case, first, the identification unit 11 may, for example, identify a route from the starting node 20 to the ending node 20 that passes through one or more nodes 20, where if a relay node 20 is transmitting to the destination node 20 (the next relay node 20 or the ending node 20) at the first wavelength (i.e., the first wavelength is in use), the relay node 20 converts the wavelength to the second wavelength. The identification unit 11 may, for example, not identify a route with a hop count of more than or equal to a threshold as a candidate for the second route. The identification unit 11 may also, for example, not identify a route with a communication speed of less than or equal to a threshold as a candidate for the second route.

[0054] The determination unit 12 may then determine, for each path included in the candidate second path, whether or not it is possible to reach the final node 20 along that path, based on at least one of the following: the degradation characteristics of the signal-to-noise ratio (SNR) at the wavelength converters 206 of one or more nodes 20 that perform wavelength conversion along that path; the degradation characteristics of the SNR at the optical amplifiers of each node 20 along that path; and the degradation characteristics (degree of degradation) of the SNR due to the link length of that path.

[0055] In this case, the determination unit 12 may refer to the degradation characteristics DB1001 shown in Figure 10 and acquire the degradation characteristics of the signal-to-noise ratio (SNR) at the wavelength converters 206 of one or more nodes 20 that perform wavelength conversion in the path, and the degradation characteristics of the SNR at each optical amplifier of each node 20 in the path. In the example in Figure 10, the degradation characteristics DB1001 records the SNR degradation characteristics at the wavelength converter 206 and the SNR degradation characteristics at the optical amplifiers, associated with combinations of node ID, input wavelength ID, and output wavelength ID. Note that if the input wavelength ID and output wavelength ID are the same, it indicates that no wavelength conversion is performed.

[0056] The input wavelength ID is the wavelength ID of the optical signal input to node 20 in the path. The output wavelength ID is the wavelength ID of the optical signal output from node 20 in the path. The signal-to-noise ratio (SNR) degradation characteristics at the wavelength converter 206 are an indicator of the degree to which the SNR of the optical signal is degraded by the wavelength converter 206 when the wavelength converter 206 converts the input wavelength to the output wavelength. The SNR degradation characteristics at the optical amplifiers are an indicator of the degree to which the SNR of the optical signal is degraded by each optical amplifier at node 20.

[0057] The information in the degradation characteristics DB1001 may be pre-set by the administrator of the information processing device 10. In this case, the values ​​for the degradation characteristics of the signal-to-noise ratio in the wavelength converter 206 and the degradation characteristics of the signal-to-noise ratio in the optical amplifier may be values ​​determined by the administrator based on measured values ​​or design values. The degradation characteristics DB1001 may be recorded in the internal storage device of the information processing device 10 or in an external storage device of the information processing device 10.

[0058] Furthermore, the determination unit 12 may determine the link length of the route based on, for example, the number of hops in the route and the total length of the optical fiber cable in the route, or at least one of the two. The determination unit 12 may also estimate the degradation characteristics of the signal-to-noise ratio (SNR) due to the link length of the route. In this case, the determination unit 12 may calculate the value (estimated value) of the SNR degradation characteristics due to the link length of the route by multiplying the value of the link length of the route by, for example, the value of a coefficient determined by the administrator or the like based on measured values ​​or design values.

[0059] Furthermore, the determination unit 12 may determine that it is not possible to reach the final node 20 along the path if the product of the value of the signal-to-noise ratio degradation characteristic at the wavelength converter 206 of one or more nodes 20 that perform wavelength conversion along the path, the value of the signal-to-noise ratio degradation characteristic at each optical amplifier of each node 20 along the path, and the value of the signal-to-noise ratio degradation characteristic due to the link length of the path is less than or equal to a threshold. This makes it possible to better guarantee arrival along the path, even in systems where the signal-to-noise ratio of the transmitted signal is degraded by wavelength conversion using the wavelength converter 206.

[0060] If there is no second path (NO in step S103), the control unit 13 sends a response (reply) indicating that routing is not possible in response to the path request (step S104), and terminates the process. On the other hand, if there is a second path (YES in step S103), the control unit 13 sends a first setting command for each node 20 among the nodes 20 in the second path that do not perform wavelength conversion (step S105). Note that the process in step S105 may be the same as the process in step S102.

[0061] Next, the control unit 13 sends a second setting command for each node 20 that performs wavelength conversion among the nodes 20 in the second path (step S106). Here, the second setting command for each node 20 may include information indicating the wavelength of the optical signal received by the node 20 that received the second setting command, information indicating the wavelength of the optical signal to be converted and forwarded by the node 20, and the node ID of the destination node 20. The node 20 that received the second setting command then configures the optical switch 203, optical switch 205A, wavelength converter 206, etc. to convert the optical signal of the first wavelength specified in the second setting command into an optical signal of the specified second wavelength and forward (relay) it to the destination node 20. This makes it possible, for example, to transfer data from the starting node 20 to the ending node 20 in the optical communication system 1.

[0062] (An example of determining whether or not to perform wavelength conversion along the communication path based on communication priority) The specific unit 11 may determine whether or not to perform wavelength conversion along the path according to the communication priority. This makes it possible, for example, to set (assign) a path that results in relatively little degradation of the signal-to-noise ratio due to wavelength conversion along the path for communications with relatively high priority.

[0063] In this case, the identification unit 11 may determine the priority of each of the multiple path requests received within a specified period (for example, one minute). The identification unit 11 may also determine the priority of each path request for each route that has already been configured and is currently in use, and each path request received within the specified period for which no route has been configured.

[0064] In this case, the identification unit 11 may first determine the priority of the received path request based on at least one of the communication speed requested in the path request and the importance level specified in the path request. Here, the identification unit 11 may determine a higher priority the higher the communication speed requested by the user or the application performing the communication. The identification unit 11 may also determine a higher priority the higher the importance level specified by the user or the application performing the communication.

[0065] Furthermore, the identification unit 11 may identify a first path for a first-priority path request, based on the first priority, in which the optical signal is transferred at the second node while maintaining its first wavelength. Alternatively, the identification unit 11 may identify a path for a second-priority path request, which is lower than the first priority, in which the optical signal is converted from the first wavelength to the second wavelength at the second node before transfer, based on the second priority. In this case, the identification unit 11 may, for example, execute the processing shown in Figure 8 for each path request in order of decreasing priority. This allows for the preferential allocation of the first path, which does not perform wavelength conversion at any of the relay nodes 20 along the path, to relatively high-priority path requests.

[0066] (An example of determining the converted wavelength along the path according to the communication priority) The specific unit 11 may determine the converted wavelength along the path according to the communication priority. This allows, for example, a path to be set (assigned) with a wavelength that results in relatively little degradation of the signal-to-noise ratio due to wavelength conversion along the path for communications with relatively high priority.

[0067] As shown in Figure 11, the NF of the optical amplifier at node 20 deteriorates as the wavelength decreases. Therefore, for example, when converting to a relatively short wavelength, the deterioration characteristics worsen compared to when converting to a relatively long wavelength.

[0068] In this case, the identification unit 11 may first determine the priority of the received pass request based on at least one of the communication speed requested in the received pass request and the importance level specified in the pass request, similar to the example described above.

[0069] Furthermore, the identification unit 11 may identify a path for a third-priority path request in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength at the second node based on the third priority and then transmitted. Alternatively, for a fourth-priority path request, which is lower than the third priority, the identification unit 11 may identify a path for a fourth-priority path in which the wavelength of the optical signal is converted from the first wavelength to a third wavelength shorter than the second wavelength at the second node based on the fourth priority and then transmitted. In this case, the identification unit 11 may, for example, execute the processing shown in Figure 8 for each path request in order of decreasing priority. Furthermore, in the processing of step S103 in Figure 8, the identification unit 11 may divide the wavelength band of the node 20 that converts the wavelength along the path into a specific number (for example, 10 as shown in Figure 11), and set (assign) paths in the wavelength band of the relatively longer wavelengths among the available wavelength bands in order of decreasing priority. This makes it possible to preferentially assign a second path to a relatively high-priority path request, where the signal-to-noise ratio degradation is relatively reduced at the relay node 20 along the path.

[0070] <Hardware Configuration> Figure 12 shows an example of the hardware configuration of an information processing device 10 according to an embodiment. In the example in Figure 12, the information processing device 10 (computer 100) includes a processor 101, memory 102, and a communication interface 103. These parts may be connected by a bus or the like. The memory 102 stores at least a portion of the program 104. The communication interface 103 includes an interface necessary for communication with other network elements.

[0071] When program 104 is executed in cooperation with the processor 101 and memory 102, etc., the computer 100 performs at least some of the processing of embodiments of this disclosure. Memory 102 may be any type suitable for a local technology network. Memory 102 may, in non-limiting examples, be a non-temporary computer-readable storage medium. Memory 102 may also be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 102 is shown for computer 100, computer 100 may have several physically different memory modules. Processor 101 may be any type. Processor 101 may include one or more general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), and, in non-limiting examples, processors based on multicore processor architectures. Computer 100 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent to a clock that synchronizes the main processor.

[0072] Embodiments of the present disclosure may be implemented in hardware or in dedicated circuitry, software, logic, or any combination thereof. Some embodiments may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device.

[0073] This disclosure also provides at least one computer program product tangibly stored on a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions contained in a program module, and is executed on a device on a target real or virtual processor to perform the processes or methods of this disclosure. The program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a specific task or implement a specific abstract data type. The functionality of the program module may be combined or divided among the program module as desired in various embodiments. The machine-executable instructions of the program module can be executed on a local or distributed device. On a distributed device, the program module can reside on both local and remote storage media.

[0074] Program code for performing the methods of this disclosure may be written in any combination of one or more programming languages. These program codes are provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device. When the program code is executed by the processor or controller, the functions / operations in the flowchart and / or block diagrams it implements are performed. The program code may run entirely on a machine, partially on a machine, partially as a standalone software package, partially on a machine, partially on a remote machine, or entirely on a remote machine or server.

[0075] Programs can be stored and supplied to a computer using various types of non-temporary computer-readable media. Non-temporary computer-readable media include various types of tangible recording media. Examples of non-temporary computer-readable media include magnetic recording media, magneto-optical recording media, optical disc media, and semiconductor memory. Magnetic recording media include, for example, flexible disks, magnetic tapes, and hard disk drives. Magneto-optical recording media include, for example, magneto-optical disks. Optical disc media include, for example, Blu-ray discs, CD (Compact Disc)-ROM (Read Only Memory), CD-R (Recordable), and CD-RW (ReWritable). Semiconductor memory includes, for example, solid-state drives, mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory). Programs may also be supplied to a computer using various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. Temporary computer-readable media can supply programs to a computer via wired communication channels such as electric wires and optical fibers, or via wireless communication channels. <Variation>

[0076] The information processing device 10 may be a device contained in a single enclosure, but the information processing device 10 of this disclosure is not limited to this. The information processing device 10 may be implemented by cloud computing, for example, consisting of one or more computers. Alternatively, the information processing device 10 and the node 20 may be configured as an integrated device. Furthermore, the node 20 may perform at least some of the processing of each functional unit of the information processing device 10. Such information processing devices 10 are also included as examples of the "information processing device" of this disclosure.

[0077] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention.

[0078] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) A identifying unit identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, and the path in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength at the second node before transmission. A determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of a wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, If the determination unit determines that the route is reachable, the control unit controls the first node, the second node, and the third node to perform optical signal communication along the route. An information processing device having (Note 2) The determination unit determines whether the path is reachable based on the degradation characteristics of the signal-to-noise ratio at the wavelength converter at the second node and the degradation characteristics of the signal-to-noise ratio at the optical amplifier at the third node with respect to the second wavelength. The information processing device described in Appendix 1. (Note 3) The specified part is, Based on the communication speed requested in the received routing request and at least one of the importance levels specified in the routing request, the priority of the routing request is determined. In response to a routing request of first priority, the second node identifies a first route that transmits the optical signal at the first wavelength based on the first priority, For routing requests with a second priority lower than the first priority, the system identifies a route at the second node to convert the wavelength of the optical signal from the first wavelength to the second wavelength and transmit it based on the second priority. The information processing device described in Appendix 1 or 2. (Note 4) The specified part is, Based on the communication speed requested in the received routing request and at least one of the importance levels specified in the routing request, the priority of the routing request is determined. In response to a third-priority routing request, the second node identifies a route for converting the wavelength of the optical signal from the first wavelength to the second wavelength and transferring it based on the third priority. For a routing request with a fourth priority lower than the third priority, the system identifies a route at the second node to convert the wavelength of the optical signal from the first wavelength to a third wavelength shorter than the second wavelength, based on the fourth priority, and then transmit the signal. The information processing device described in Appendix 1 or 2. (Note 5) The wavelength converter converts the optical signal of the first wavelength into an electrical signal, performs analog signal processing on the electrical signal, and then converts it into an optical signal of the second wavelength. The information processing device described in Appendix 1 or 2. (Note 6) If the determination unit determines that the route is not reachable, the control unit transmits a response indicating that the route cannot be set. The information processing device described in Appendix 1 or 2. (Note 7) Based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, a path is identified that reaches the third node from the first node through the second node, and in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength and transmitted at the second node. Based on the degradation characteristics of the signal-to-noise ratio in the wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, it is determined whether the path is reachable. If it is determined that the path is reachable, the first node, the second node, and the third node are controlled to perform optical signal communication along the path. Information processing methods. (Note 8) Based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, a path is identified that reaches the third node from the first node through the second node, and in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength and transmitted at the second node. Based on the degradation characteristics of the signal-to-noise ratio in the wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, it is determined whether the path is reachable. If it is determined that the path is reachable, the first node, the second node, and the third node are controlled to perform optical signal communication along the path. A program that instructs a computer to perform a process. (Note 9) It has a first node, a second node, and a third node that perform communication using optical signals, and an information processing device. The aforementioned information processing device is A identifying unit identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first node, the second node, and the third node, the path in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength at the second node and then transmitted; A determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of a wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, The system includes a control unit that controls the first node, the second node, and the third node to perform optical signal communication along the path if the determination unit determines that the path is reachable. Optical communication system. (Note 10) The wavelength converter converts the optical signal of the first wavelength into an electrical signal, performs analog signal processing on the electrical signal, and then converts it into an optical signal of the second wavelength. The optical communication system described in Appendix 9. [Explanation of symbols]

[0079] 1. Optical communication system 10 Information Processing Devices 11 Specific section 12 Judgment section 13 Control Unit 20 nodes

Claims

1. A identifying unit identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, and the path in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength at the second node before transmission. A determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of a wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, If the determination unit determines that the route is reachable, the control unit controls the first node, the second node, and the third node to perform optical signal communication along the route. An information processing device having

2. The determination unit determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of the wavelength converter at the second node and the signal-to-noise ratio degradation characteristics of the optical amplifier at the third node with respect to the second wavelength. The information processing apparatus according to claim 1.

3. The specified part is, Based on the communication speed requested in the received routing request and at least one of the importance levels specified in the routing request, the priority of the routing request is determined. In response to a first-priority routing request, the second node identifies a first route that transmits the optical signal at the first wavelength based on the first priority, For a routing request with a second priority lower than the first priority, the system identifies a route at the second node to convert the wavelength of the optical signal from the first wavelength to the second wavelength and transmit it, based on the second priority. The information processing apparatus according to claim 1 or 2.

4. The specified part is, Based on the communication speed requested in the received routing request and at least one of the importance levels specified in the routing request, the priority of the routing request is determined. In response to a third-priority routing request, the second node identifies a route for converting the wavelength of the optical signal from the first wavelength to the second wavelength and transmitting it based on the third priority. For a routing request with a fourth priority lower than the third priority, the system identifies a route at the second node to convert the wavelength of the optical signal from the first wavelength to a third wavelength shorter than the second wavelength, based on the fourth priority, and then transmit the signal. The information processing apparatus according to claim 1 or 2.

5. The wavelength converter converts the optical signal of the first wavelength into an electrical signal, performs analog signal processing on the electrical signal, and then converts it into an optical signal of the second wavelength. The information processing apparatus according to claim 1 or 2.

6. If the determination unit determines that the route is not reachable, the control unit transmits a response indicating that the route cannot be set. The information processing apparatus according to claim 1 or 2.

7. Based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, a path is identified that reaches the third node from the first node through the second node, and in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength and transmitted at the second node. Based on the signal-to-noise ratio degradation characteristics of the wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, the feasibility of reaching the destination along the path is determined. If it is determined that the path is reachable, the first node, the second node, and the third node are controlled to perform optical signal communication along the path. Information processing methods.

8. Based on the wavelength utilization status at each of the first, second, and third nodes that perform optical signal communication, a path is identified that reaches the third node from the first node through the second node, and in which the wavelength of the optical signal is converted from the first wavelength to the second wavelength and transmitted at the second node. Based on the signal-to-noise ratio degradation characteristics of the wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, the feasibility of reaching the destination along the path is determined. If it is determined that the path is reachable, the first node, the second node, and the third node are controlled to perform optical signal communication along the path. A program that instructs a computer to perform a process.

9. It has a first node, a second node, and a third node that perform communication using optical signals, and an information processing device. The aforementioned information processing device is A identifying unit identifies a path from the first node to the third node via the second node, based on the wavelength utilization status at each of the first node, the second node, and the third node, which converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node and transmits it. A determination unit that determines whether the path is reachable based on the signal-to-noise ratio degradation characteristics of a wavelength converter that converts the wavelength of the optical signal from the first wavelength to the second wavelength at the second node, The system includes a control unit that controls the first node, the second node, and the third node to perform optical signal communication along the path if the determination unit determines that the path is reachable. Optical communication system.

10. The wavelength converter converts the optical signal of the first wavelength into an electrical signal, performs analog signal processing on the electrical signal, and then converts it into an optical signal of the second wavelength. The optical communication system according to claim 9.

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