Optical Network Path Control Device, Optical Network System, Path Control Method, and Path Control Program

Abstract

A path control device (100) according to an aspect of the present invention comprises a control unit (10) that aggregates paths for the same reception node into the same core of the same multi-core optical transmission line.

Description

Technical Field

[0001] The present invention relates to a path control device for an optical network, an optical network system, a path control method, and a path control program.

Background Art

[0002] In recent years, due to the rapid spread of mobile terminals typified 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 subscribers 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, wavelength division multiplexing technology (Wavelength Division Multiplexing: WDM) that multiplexes optical signals of a plurality of different wavelengths onto a single optical fiber for transmission, advanced modulation methods such as DP-QPSK (Dual Polarization Differential Quadrature Phase Shift Keying), 16-QAM (16-Quadrature Amplitude Modulation), etc., the development of high-capacity technologies has been promoted. However, since the number of wavelengths available for WDM is limited, it is expected that the increase in communication capacity by WDM will peak in the near future. Also, even with advanced modulation methods, the reach is limited due to strict signal S / N requirements, and the limits are approaching. In contrast, in recent years, for the purpose of expanding the transmission capacity per optical fiber, research and development of multi-core optical fiber (Multi Core Optical Fiber: MCF) that fills a plurality of cores in one cladding has been promoted instead of the conventional single-mode optical fiber (Single Mode Optical Fiber: SMF).

[0003] In this way, the technological development for increasing the capacity is steadily progressing. On the other hand, the technological development for effectively utilizing the limited frequency resources is also underway. For example, in the elastic accommodation technology, the conventional WDM wavelength interval is shortened to improve the frequency utilization efficiency. Furthermore, from the perspective of network control, for example, there are also efforts to reduce path blocking and improve the frequency utilization efficiency by allocating paths according to the signal quality of the optical transmission path, the bandwidth of the communication signal, and the communication distance.

[0004] In recent years, the study of a heterogeneous environment network using the above-mentioned MCF and mixed with the conventional SMF has been conducted.

[0005] Next, the network configuration using MCF is shown in FIG. 17. The network is composed of a plurality of nodes that switch the traffic path, and the connection forms include point-to-point, ring, mesh, etc. Next, an example of the node configuration is shown in FIG. 18. The node is composed of a fan-out that separates the input MCF into single-core units (SMF), an optical amplifier that compensates for the transmission loss, a switch element (Wavelength Selectable Switch: WSS) that uses the SMF as an input and performs path switching in wavelength units, a fan-in that bundles the SMF output from the WSS back into the MCF, a plurality of transceivers (Transponder: TRPD) that receive traffic from the WSS or transmit it to the WSS at the node, a monitor that partially branches the optical signal passing through the SMF and measures the power, etc., and a control system that controls each component of the node.

[0006] In addition, to quickly recover from a failure such as a fiber break, there is a network with two paths, a working system and a protection system. At the node before the failure point, the Network Management System (NMS) instructs the node's switch to switch from the working system to the protection system so as to bypass the failure point and continue communication. For example, in the case of a network configuration with 4 cores of MCF as 4 working systems, the number of fibers in terms of SMF input to the node is 4 (number of cores) × 4 (number of fibers) × 2 (working system, protection system) = 32 fibers, which increases dramatically compared to the conventional network configuration using SMF.

[0007] Next, in the case of a network with 4 cores of MCF as 4 working systems used in the above calculation, if the node has non-blocking switching where all wavelengths within a core can be switched to all cores and all paths, and one Add (insertion) / Drop (branching) port to the TRPD is prepared for each, then 32 units of 1×18WSS, 32 units of single-core optical amplifiers, and 16 units of protection switches are required for the working system only. Furthermore, considering the protection system, components twice as many are required, and the enlargement and high cost of the node become very problematic.

[0008] In prior art examples, for example, Patent Document 1, Patent Document 2, and Patent Document 3 disclose cross-connect devices with reduced device scale in a network using MCF. However, in these prior art examples, although switching of each core of MCF is possible, the configuration is such that switching in terms of wavelengths within each core is not possible.

[0009] Also, Patent Document 4 discloses a method of improving the accommodation efficiency of paths by considering path attributes (transmitting node, receiving node, relay node, distance, bandwidth, etc.) in an MCF network.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0011] From the above, there is a demand for the development of a technology that can switch by wavelength unit while suppressing the enlargement of the node scale and improving the accommodation efficiency of paths.

[0012] One aspect of the present invention has been made in view of the above problems, and an example of its object is to provide a technology that can further improve the accommodation efficiency of paths while reducing the node scale in an optical network including a multi-core fiber.

Means for Solving the Problems

[0013] A path control device according to one aspect of the present invention is a path control device that controls a path from a transmission node to a reception node in an optical network including a multi-core optical transmission line having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission line, wherein the node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and switches paths in core units, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit, and the path control device includes a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line.

[0014] An optical network system according to an aspect of the present invention includes a plurality of nodes connected by a multi-core optical transmission line having a plurality of cores, and a path control device that controls a path from a transmission node to a reception node in an optical network including the multi-core optical transmission line and the plurality of nodes. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and switches paths in units of cores, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit. The path control device includes a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line.

[0015] A path control method according to an aspect of the present invention is a path control method for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission line having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission line. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and switches paths in units of cores, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit. The path control method includes aggregating paths for the same reception node to the same core of the same multi-core optical transmission line.

[0016] A path control method according to an aspect of the present invention is a path control program for causing a computer to function as a path control device that controls a path from a transmission node to a reception node in an optical network including a multi-core optical transmission line having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission line. The computer functions as a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and switches paths in units of cores, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit.

Advantages of the Invention

[0017] According to one aspect of the present invention, it is possible to provide a technique for enhancing the accommodation efficiency of paths while reducing the node scale.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Mode for Carrying Out the Invention

[0019] 〔Exemplary Embodiment 1〕 <Configuration of System and Apparatus> The configurations of the optical network system 1, the path control device 100, and the node 101 according to this exemplary embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram schematically showing an example of the configuration of the optical network system 1. FIG. 2 is a block diagram showing an example of the configuration of the path control device 100. FIG. 3 is a block diagram showing an example of the configuration of the node 101.

[0020] The optical network system 1 is an optical network system including a multi-core optical fiber. In one aspect, the optical network system 1 may be a heterogeneous optical network system in which multi-core optical fibers and single-core optical fibers are mixed.

[0021] As shown in FIG. 1, the optical network system 1 includes a path control device 100, a node 101, and an optical transmission line 102.

[0022] The path control device 100, also referred to as an NMS (Network Management System), controls the optical network system 1. In one aspect, the path control device 100 controls each node 101 to allocate a path from a transmitting node to a receiving node.

[0023] The optical transmission path 102 is composed of a ring 103 connecting a plurality of nodes 101 and a connection link 104 connecting a plurality of rings 103. The optical transmission path 102 includes a multi-core optical transmission path. The optical transmission path 102 may be partially composed of a multi-core optical transmission path and partially composed of a single-core optical transmission path, or may be entirely composed of a multi-core optical fiber.

[0024] As shown in FIG. 2, the path control device 100 includes a control unit 10.

[0025] The control unit 10 aggregates paths for the same receiving node to the same core of the same multi-core optical transmission path.

[0026] As shown in FIG. 3, the node 101 includes a transceiver unit 101A, a wavelength selection switch unit 101B, and an optical switch unit 101C.

[0027] The transceiver unit 101A transmits and receives optical signals.

[0028] The optical switch unit 101C is connected to a plurality of multi-core optical transmission paths and performs path switching on a core-by-core basis.

[0029] The wavelength selection switch unit 101B selectively connects between the transceiver unit 101A and the optical switch unit 101C in terms of wavelength.

[0030] <Flow of the path control method> The flow of the path control method according to this exemplary embodiment will be described with reference to FIG. 4. FIG. 4 is a flowchart showing an example of the flow of the path control method according to this exemplary embodiment. As shown in FIG. 4, the path control method according to this exemplary embodiment includes at least step S1.

[0031] In step S1, the control unit 10 controls the paths connecting from the transmitting node to the receiving node among the cores included in each optical transmission path 102 in the optical network system 1, and aggregates paths for the same receiving node to the same core of the same multi-core optical transmission path.

[0032] <Effects achieved by the present exemplary embodiment> As described above, the optical path control device 100 according to the present exemplary embodiment is a path control device that controls a path from a transmission node to a reception node in an optical network including a multi-core optical transmission line having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission line. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and performs path switching on a core-by-core basis, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit. The path control device employs a configuration including a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line.

[0033] Further, the optical network system according to the present exemplary embodiment includes a plurality of nodes connected by a multi-core optical transmission line having a plurality of cores, and a path control device that controls a path from a transmission node to a reception node in the optical network including the multi-core optical transmission line and the plurality of nodes. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to a plurality of the multi-core optical transmission lines and performs path switching on a core-by-core basis, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit. The path control device employs a configuration including a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line.

[0034] Also, the path control method according to this exemplary embodiment is a path control method for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path. The node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit that is connected to the plurality of multi-core optical transmission paths and switches paths in core units, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit. The path control method can adopt a configuration including aggregating paths for the same reception node to the same core of the same multi-core optical transmission path.

[0035] Therefore, according to the path control apparatus 100, the optical network system 1, and the path control method according to this exemplary embodiment, paths for the same reception node are aggregated to the same core of the same multi-core optical transmission path. Therefore, the number of cores that need to be branched (dropped) to receive optical signals at the reception node can be minimized. Thus, even if the reception node has a non-blocking configuration, blocking can be suppressed. Thereby, while reducing the node scale, the accommodation efficiency of paths can be further enhanced. As a result, it becomes possible to reduce the cost of the entire optical network system.

[0036] Here, aggregating to the same core of the same multi-core optical transmission path means that when it fits into one core, it is assigned to one core, and when the number of paths to be aggregated is large and does not fit into one core, it can also be assigned to a plurality of cores.

[0037] 〔Exemplary Embodiment 2〕 A second exemplary embodiment of the present invention will be described in detail with reference to the drawings. Note that components having the same functions as those described in the above exemplary embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0038] <Configuration of System and Apparatus> The exemplary embodiment will be described in detail with reference to FIG. 5 and the like. FIG. 5 shows the configuration of a heterogeneous optical network using MCF.

[0039] The configurations of the optical network system 1 and the path control device 100 according to this exemplary embodiment are the same as those of the above-described exemplary embodiment 1, and the detailed configurations will be described in this exemplary embodiment.

[0040] The optical network system 1 is an optical network system including a multi-core optical fiber which is a multi-core optical transmission path. In one aspect, the optical network system 1 may be a heterogeneous optical network system in which a multi-core optical fiber which is a multi-core optical transmission path and a single-core optical fiber which is a single-core optical transmission path are mixed. As an example, a non-coupled multi-core optical fiber may be used as the multi-core optical fiber.

[0041] As shown in FIG. 5, in the optical network system 1, a path control device 100 and a plurality of nodes 101 are connected via an optical transmission path 102.

[0042] In this exemplary embodiment, the optical transmission path 102 is in a ring shape. However, it is not limited thereto, and it may be in another form such as a multi-ring or a mesh shape. Further, two paths, a working system and a protection system, are provided for the optical transmission path 102.

[0043] Note that a plurality of nodes and an optical amplifier (not shown) for compensating for optical transmission loss may be connected to each ring.

[0044] (Multi-core optical fiber) FIG. 6 shows the structure of a 7-core multi-core optical fiber as an example of the structure of the multi-core optical fiber. In the multi-core optical fiber 50 shown in FIG. 6, seven cores 51 are included in one cladding 52. Note that multi-core optical fibers are roughly classified into non-coupled multi-core optical fibers and coupled multi-core optical fibers which have been developed.

[0045] FIG. 7 shows the structure of a 4-core uncoupled multi-core optical fiber as an example of the structure of an uncoupled multi-core optical fiber. The uncoupled multi-core optical fiber 50 is an optical fiber that separates the intervals between the cores 51 and suppresses crosstalk between the cores 51. In the uncoupled multi-core optical fiber 50, since each core 51 can be used as an independent optical transmission path, it is possible to directly utilize the optical communication technology developed for conventional single-core optical fibers.

[0046] FIG. 8 shows the structure of a 4-core coupled multi-core optical fiber as an example of the structure of a coupled multi-core optical fiber. The coupled multi-core optical fiber is an optical fiber that realizes a high core density by reducing the interval between the cores 51. In the coupled multi-core optical fiber, crosstalk occurs between the respective cores 51, so MIMO (Multi Input Multi Output) processing using a DIP (Digital Signal Processor) or the like is required in the optical receiver.

[0047] In the present exemplary embodiment, the 4-core uncoupled multi-core optical fiber shown in FIG. 7 is used as the multi-core optical fiber constituting the optical transmission path 102. However, the number of cores is not limited to 4 (4 cores).

[0048] (Node) FIG. 9 is a block diagram showing an example of the configuration of the node 101 used in the present exemplary embodiment. Each node 101 includes, in one example, an input MCF 201, a transmission loss compensation multi-core optical amplifier 202, a multi-core optical switch 203, a node loss compensation multi-core optical amplifier 204, a fanout 205, a TRPD 206, a WSS 207, a fanin 208, an output MCF 209, and a node controller 210.

[0049] The node 101, in the order of the flow of the optical signal, · A transmission loss compensation multi-core optical amplifier 202 that compensates for the transmission loss of the input MCF 201 in units of multi-core fibers, · A multi-core optical switch 203 that performs core-to-core switching of MCF from the multi-core optical amplifier 202, · A node loss compensation multi-core optical amplifier 204 that compensates for the loss of an optical signal from the Drop (branch) port of the multi-core optical switch 203, · A fanout 205 that separates an optical signal in units of MCF from the node loss compensation multi-core optical amplifier 204 into units of SMF (single-core unit), · A WSS 207 that switches an optical signal in units of SMF (single-core unit) from the fanout 205 by wavelength and performs Add (insertion) / Drop (branch) to the TRPD 206 that transmits and receives the optical signal, · A fanin 208 that bundles an optical signal in units of SMF (single-core unit) from the WSS 207 into MCF, · A node loss compensation multi-core optical amplifier 204 that compensates for the loss of an optical signal in units of MCF from the fanin 208, · A multi-core optical switch 203 that receives an optical signal from the node loss compensation multi-core optical amplifier 204 at the Add port and performs core-to-core switching, · A transmission loss compensation multi-core optical amplifier 202 that compensates for the loss of an optical signal from the multi-core optical switch 203, · An output MCF 209 that transmits an optical signal from the transmission loss compensation multi-core optical amplifier 202, · A node controller 210 that controls each device within the node including. Note that the TRPD 206, the multi-core optical switch 203, and the WSS 207 are specific examples of the transmission and reception unit, the optical switch unit, and the wavelength selection switch unit in the claims.

[0050] The multi-core optical switch 203 is connected to a plurality of multi-core optical fibers and performs path switching in units of cores. As an example, the multi-core optical switch 203 is configured to directly accommodate multi-core optical fibers.

[0051] The WSS 207 selectively connects between the TRPD 206 and the multi-core optical switch 203 by wavelength.

[0052] As an example, when the number of cores of the input MCF201 and the output MCF209 is 4 and the number of MCFs is 4, the transmission loss compensation multi-core optical amplifier 202 becomes an optical amplifier that compensates for 19 cores. Also, when the number of Add (insertion) / Drop (branching) ports is 1 port each (the Add / Drop rate corresponds to 25%) and the number of protection ports is 1 port, the multi-core optical switch 203 becomes a 6×6 switch. Further, since the node loss compensation multi-core optical amplifier 204 only needs to compensate for one MCF with 4 cores, it becomes an optical amplifier that compensates for 4 cores.

[0053] A tap coupler (not shown) for branching a part of the optical signals is attached to the SMF, and the optical signals branched from the tap coupler are input to a monitor (not shown). The node controller 210 controls the multi-core optical switch 203 and the WSS207 according to the monitor information received from the monitor.

[0054] Note that, in this exemplary embodiment, the WSS207 is a multi-core optical switch to which a plurality of multi-core optical fibers are directly connected. However, it is not limited thereto, and the WSS207 may have a configuration in which it is indirectly connected to the multi-core optical fiber (that is, via a fan-out and a single-core fiber).

[0055] (Path control device) FIG. 10 is a block diagram showing an example of the configuration of the path control device in this exemplary embodiment. The path control device has the configuration described in the above-described first exemplary embodiment as a basic configuration, but the control unit 10 further includes a path calculation unit 11. Also, the storage unit 20 stores a path information database (path information DB).

[0056] The path calculation unit 11 performs path calculation with reference to the path information database. As an example, the path calculation unit 11 extracts unused cores from among a plurality of available MCFs from the transmission node to the reception node.

[0057] <Flow of path control method> The path control method of the present exemplary embodiment will be described. This method is performed by the path control device 100 of the present exemplary embodiment. In this method, the case where there is a direct path from the transmission node to the reception node will be described.

[0058] FIG. 11 is a conceptual diagram of wavelength assignment, and FIG. 12 is a flowchart of the operation.

[0059] First, when a path request is issued, the path calculation unit 11 in the control unit 10 of the path control device 100 refers to the path information database (path information DB) stored in the storage unit 20, and extracts unused cores from among a plurality of MCFs that can be used from the transmission node to the reception node (step S1).

[0060] Next, from the unused cores extracted in step S1, the control unit 10 extracts cores that can be connected from the transmission node to the reception node (step S2).

[0061] Next, in the connectable cores extracted in step S2, the control unit 10 extracts free wavelengths of the same wavelength from the transmission node to the reception node (step S3).

[0062] Next, the control unit 10 assigns a path to the free wavelength extracted in step S3 (step S4). At this time, for example, as shown in FIG. 11, the same reception node (path No. 1 and path No. 2, and path No. 3 and path No. 4) is assigned to the same core of the same fiber.

[0063] Next, under the control of the control unit 10, the node controller 210 in the node 101 (transmission node) controls the transponder 206 to match the selected wavelength (step S5).

[0064] Next, the node controller 210 controls the WSS 207 to accommodate the set path in the desired single-mode optical fiber (step S6).

[0065] Next, it is accommodated in a desired SDM fiber by fan-in 208 (step S7).

[0066] Next, node controller 210 controls multi-core optical switch 203 and switches the path so as to be the allocation in step S4 described above (step S8).

[0067] Next, signaling is performed to confirm the conduction of the path (step S9). If signal passage is impossible, it is performed again from allocating another wavelength (step S4). If signal passage is confirmed, the operation is completed (END).

[0068] <Effects of this exemplary embodiment> In this way, since paths to the same receiving node are aggregated into one core of one fiber, the number of cores that need to be branched (dropped) to receive an optical signal at the receiving node can be minimized. Therefore, even in node 101 having a small number of drop ports, it is possible to reduce the probability of causing blocking, and the accommodation efficiency of the path can be improved. As a result, it is possible to reduce the cost of the entire optical network system.

[0069] 〔Exemplary Embodiment 3〕 The third exemplary embodiment of the present invention will be described in detail with reference to the drawings. Note that components having the same functions as those described in the above exemplary embodiments are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0070] The configurations of the system and the apparatus are basically the same as those of the above-described exemplary embodiment 2. However, as the transponder 206 in the present embodiment, a wavelength-variable transponder that can selectively output different wavelengths is used.

[0071] <Flow of path control method> The path control method of this exemplary embodiment will be described. In this method, the case where there is no direct path from the transmitting node to the receiving node will be described.

[0072] FIG. 13 is a conceptual diagram of wavelength allocation, and FIG. 14 is a flowchart of operations.

[0073] First, when a path request is issued, a path calculation unit 11 in a control unit 10 of a path control device 100 refers to a path information database (path information DB) stored in a storage unit 20, and extracts unused cores from among a plurality of MCFs available from a transmission node to a reception node (step S1 in FIG. 14).

[0074] Next, from the unused cores extracted in step S1, the control unit 10 extracts cores that can be connected from the transmission node to the reception node (step S2).

[0075] Next, in the connectable cores extracted in step S2, the control unit 10 extracts a wavelength with an available wavelength having as long a hop count as possible and the same wavelength from the transmission node to the reception node (step S3).

[0076] Next, the control unit 10 allocates a path to the available wavelength extracted in step S3 (step S4). At this time, the control unit 10 may allocate a path including wavelength switching at a relay node.

[0077] Next, under the control of the control unit 10, a node controller 210 in a node 101 (transmission node) controls a transponder 206 to match the selected wavelength (step S5).

[0078] Next, the node controller 210 controls a WSS 207 to accommodate the set path in a desired single-mode optical fiber (step S6).

[0079] Next, it is accommodated in a desired SDM fiber by a fan-in 208 (step S7).

[0080] Next, the node controller 210 controls a multi-core optical switch 203 to switch the path so as to be the allocation of step S4 described above (step S8).

[0081] Next, the operation at the relay node (aggregating paths to the same receiving node on the same fiber: step S9) will be described with reference to FIG. 13. FIG. 13 shows the numbers of SMF fibers (single core) to be dropped (branched) and added (inserted) at each node 101 (SMF fiber No.), and the numbers of receiving nodes of the respective paths assigned to the respective SMF fibers (single core) to be added (inserted) at each node 101 (receiving node No.).

[0082] First, at node No. 1 (transmitting node), since four SMF units (single core units) of links can be accommodated, paths to receiving nodes No. 2, 6, 10, 14 are assigned to SMF (single core) No. 1, paths to receiving nodes No. 3, 7, 11, 15 are assigned to SMF (single core) No. 2, paths to receiving nodes No. 4, 8, 12, 16 are assigned to SMF (single core) No. 3, and paths to receiving nodes 4, 9, 12 are assigned to SMF (single core) No. 4. Note that the respective paths assigned to the same SMF (single core) are assigned different wavelengths from each other.

[0083] Similarly, at node No. 2 (relay node), since the path to node No. 2 is included in SMF (single core) No. 1, it is dropped at node No. 2, and another path (here, the path to receiving node 1) is inserted in place of the path to node No. 2, and paths to receiving nodes No. 1, 6, 10, 14 are assigned to SMF (single core) No. 5, paths to receiving nodes No. 3, 7, 11, 15 are assigned to SMF (single core) No. 6, paths to receiving nodes No. 4, 8, 12, 16 are assigned to SMF (single core) No. 7, and paths to receiving nodes 4, 9, 12 are assigned. In the above, the paths to receiving node No. 7 are separated between SMF No. 2 and SMF No. 5.

[0084] Next, at node No. 3 (relay node), fiber No. 2 and fiber No. 5 are dropped (branched) to WSS207, and the paths to receiving node No. 7 added at nodes 1 and 2 in WSS207 are aggregated to fiber No. 5. For example, the path to node No. 3 assigned to fiber No. 5 is dropped (branched) at node No. 3, and instead, the path to node No. 7 assigned to fiber No. 2 is added (inserted) to fiber No. 5 after the wavelength is switched in TRPD206. The above operations are executed by the node controller 210 of each node 101 controlled by the control unit 10 of the path control device 100 by controlling the multi-core optical switch 203, TRPD206, and WSS207.

[0085] In this way, the paths to the same receiving node added at other nodes are selectively aggregated (the paths to the same receiving node are assigned to the same core) every time they pass through a node. As a result, since the paths to the same receiving node are aggregated to one fiber, the number of cores that need to be branched (dropped) to receive an optical signal at the receiving node can be minimized. Therefore, even in a node configuration with a small number of drop ports, it is possible to reduce the probability of causing blocking and improve the accommodation efficiency of paths. As a result, it is possible to reduce the cost of the entire optical network system.

[0086] Next, for the purpose of confirming the conduction of the path, signaling is performed (step S10). If signal conduction is not possible, it is performed again from allocating another wavelength (step S4). If signal conduction is confirmed, the operation is completed (END).

[0087] 〔Exemplary Embodiment 4〕 The fourth exemplary embodiment of the present invention will be described in detail with reference to the drawings. Note that components having the same functions as those described in the above exemplary embodiments are denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0088] In the present exemplary embodiment, the configuration of the node is different from that of other exemplary embodiments. Therefore, only the configuration of the node will be described. Note that the configuration of the path control device 100 and the path control method are the same as the operation flows described in the above-described exemplary embodiment 2 or exemplary embodiment 3.

[0089] FIG. 15 is a block diagram showing an example of a node 101 used in the present exemplary embodiment. Each node 101 includes, in one example, · an input MCF 201, · a transmission loss compensation multi-core optical amplifier 202 that compensates for the transmission loss of the input MCF 201 in multi-core fiber units, · a fanout 205 that separates the optical signal in MCF units from the transmission loss compensation multi-core optical amplifier 202 into SMF units, · a fiber switch 301 that switches the optical signal in SMF units from the fanout 205, · a node loss compensation single-core optical amplifier 302 that compensates for the loss of the optical signal from the Drop (branch) port of the fiber switch 301, · a WSS 207 that switches the optical signal in SMF units from the node loss compensation single-core optical amplifier 302 in wavelength units and performs Add (insertion) / Drop (branch) to the TRPD 206, · a node loss compensation single-core optical amplifier 302 that compensates for the loss of the optical signal in SMF units from the WSS 207, · a fan-in 208 that bundles the optical signal in SMF units from the fiber switch 301 into an MCF, · a transmission loss compensation multi-core optical amplifier 202 that compensates for the loss of the optical signal in MCF units from the fan-in 208, · an output MCF 209 that transmits the optical signal from the transmission loss compensation multi-core optical amplifier 202, · a TRPD 206, · a node controller 210 that controls each device within the node and includes.

[0090] Note that the fan-out 205 is a specific example of the separation unit in the claims. The fiber switch 301 accommodates the input MCF 201 after separating it into single-core units by the fan-out 205.

[0091] Even in an optical network system having a node configuration in which the multi-core optical switch 203 is replaced with the fiber switch 301 as in this exemplary embodiment, by aggregating the paths to the same receiving node into one core by the path control device, it is possible to reduce the probability of causing blocking and improve the accommodation efficiency of the paths. However, the node configuration using the multi-core optical switch 203 can reduce the number of optical amplifiers, fan-ins, fan-outs, etc. compared to the node configuration using the fiber switch 301.

[0092] 〔Example of Realization by Software〕 Some or all of the functions of the path control device 100 may be realized by hardware such as an integrated circuit (IC chip), or may be realized by software.

[0093] In the latter case, the path control device 100 is realized by, for example, a computer that executes the instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as computer C) is shown in FIG. 16. The computer C includes at least one processor C1 and at least one memory C2. A program P for operating the computer C as the path control device 100 is recorded in the memory C2. In the computer C, the processor C1 reads and executes the program P from the memory C2, whereby each function of the path control device 100 is realized.

[0094] As the processor C1, for example, a CPU (Central Processing Unit), GPU (Graphic Processing Unit), DSP (Digital Signal Processor), MPU (Micro Processing Unit), FPU (Floating point number Processing Unit), PPU (Physics Processing Unit), a microcontroller, or a combination thereof can be used. As the memory C2, for example, a flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof can be used.

[0095] Note that the computer C may further include a RAM (Random Access Memory) for expanding the program P during execution and temporarily storing various data. Also, the computer C may further include a communication interface for transmitting and receiving data to and from other devices. Also, the computer C may further include an input / output interface for connecting input / output devices such as a keyboard, mouse, display, and printer.

[0096] Also, the program P can be recorded on a non-transitory tangible recording medium M readable by the computer C. As such a recording medium M, for example, a tape, disk, card, semiconductor memory, or programmable logic circuit can be used. The computer C can obtain the program P via such a recording medium M. Also, the program P can be transmitted via a transmission medium. As such a transmission medium, for example, a communication network or broadcast wave can be used. The computer C can also obtain the program P via such a transmission medium.

[0097] 〔Supplementary Note 1〕 The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. For example, embodiments obtained by appropriately combining the technical means disclosed in the above-described embodiments are also included in the technical scope of the present invention.

[0098] 〔Supplementary Note 2〕 Some or all of the above-described embodiments may also be described as follows. However, the present invention is not limited to the embodiments described below.

[0099] (Supplementary Note 1) A path control device for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission line having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission line, wherein the node includes a transmission / reception unit that transmits and receives optical signals, an optical switch unit connected to a plurality of the multi-core optical transmission lines and performing path switching in units of cores, and a wavelength selection switch unit that selectively connects between the transmission / reception unit and the optical switch unit, and is provided with wherein the path control device includes a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission line, and is characterized by being such a path control device.

[0100] According to the above configuration, it is possible to increase the accommodation efficiency of paths while reducing the node scale. As a result, it is possible to reduce the cost of the entire optical network system.

[0101] (Supplementary Note 2) The control unit aggregates paths for the same reception node to the same core of the same multi-core optical transmission line at the transmission node, and is characterized by being such a path control device according to Supplementary Note 1.

[0102] According to the above configuration, while reducing the node scale of the transmission node, the accommodation efficiency of the path can be further improved. As a result, it becomes possible to reduce the cost of the entire optical network system.

[0103] (Appendix 3) In the relay node that relays the transmission node and the reception node, the control unit aggregates the paths destined for the same reception node to the same core of the same multi-core optical transmission path via the wavelength selection switch unit. The path control device according to Appendix 1 or 2, characterized in that.

[0104] According to the above configuration, while reducing the node scale of the relay node, the accommodation efficiency of the path can be further improved. As a result, it becomes possible to reduce the cost of the entire optical network system.

[0105] (Appendix 4) The optical switch unit directly accommodates the multi-core optical transmission path. The path control device according to any one of Appendices 1 to 3, characterized in that.

[0106] According to the above configuration, even in the mode where the optical switch unit directly accommodates the multi-core optical transmission path, since the control unit aggregates the paths destined for the same reception node to the same core of the same multi-core optical transmission path, the node scale can be reduced while further improving the accommodation efficiency of the path.

[0107] (Appendix 5) The node includes a separation unit that separates the multi-core optical transmission path into single-core units, and the optical switch unit accommodates the multi-core optical transmission path after separating it into single-core units by the separation unit. The path control device according to any one of Appendices 1 to 3, characterized in that.

[0108] According to the above configuration, even in the mode where the optical switch unit accommodates the multi-core optical transmission path after separating it into single-core units by the separation unit, the control unit aggregates the paths for the same receiving node to the same core of the same multi-core optical transmission path, so that while reducing the node scale, the accommodation efficiency of the paths can be further improved.

[0109] (Appendix 6) It includes a storage unit for storing a path information database. The control unit performs path calculation by referring to the path information database. The path control device according to any one of Appendices 1 to 5, characterized in that.

[0110] According to the above configuration, the control unit refers to the path information database and aggregates the paths for the same receiving node to the same core of the same multi-core optical transmission path.

[0111] (Appendix 7) A plurality of nodes connected by a multi-core optical transmission path having a plurality of cores, A path control device for controlling a path from a transmitting node to a receiving node in an optical network including the multi-core optical transmission path and the plurality of nodes, Comprising, The node is A transmission / reception unit for transmitting and receiving optical signals, An optical switch unit connected to a plurality of the multi-core optical transmission paths and performing path switching in core units, A wavelength selection switch unit for wavelength-selectively connecting between the transmission / reception unit and the optical switch unit, Comprising, The path control device is Provided with a control unit that aggregates paths for the same receiving node to the same core of the same multi-core optical transmission path. An optical network system, characterized in that.

[0112] According to the above method, the same effect as that of Appendix 1 can be achieved.

[0113] (Appendix 8) A path control method for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path, wherein the node includes a transceiver for transmitting and receiving optical signals, an optical switch unit connected to a plurality of the multi-core optical transmission paths and performing path switching on a core-by-core basis, and a wavelength selection switch unit that selectively connects between the transceiver and the optical switch unit, and the path control method includes aggregating paths for the same reception node to the same core of the same multi-core optical transmission path, and is characterized by the above.

[0114] According to the above method, the same effect as that of Appendix 1 is achieved.

[0115] (Appendix 9) A path control program for causing a computer to function as a path control device for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path, the program causing the computer to function as a control unit that aggregates paths for the same reception node to the same core of the same multi-core optical transmission path, wherein the node includes a transceiver for transmitting and receiving optical signals, an optical switch unit connected to a plurality of the multi-core optical transmission paths and performing path switching on a core-by-core basis, and a wavelength selection switch unit that selectively connects between the transceiver and the optical switch unit, and is characterized by the above.

[0116] According to the above program, the same effect as that of Appendix 1 is achieved.

[0117] 〔Supplementary Note 3〕 This application claims priority based on Japanese Patent Application No. 2021-079303 filed on May 7, 2021, and incorporates the entire disclosure thereof herein.

Explanation of Reference Numerals

[0118] 1 Optical network system 10 Control unit 20 Storage unit 100 Path control device 101 Node 203 Multicore optical switch (optical switch unit) 205 Fanout (separation unit) 206 TRPD (transmission / reception) 207 WSS (wavelength selection switch unit)

Claims

1. A path control device for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path, wherein the node includes: a transceiver unit for transmitting and receiving optical signals; an optical switch unit connected to a plurality of the multi-core optical transmission paths and performing path switching on a core-by-core basis; a wavelength selective switch unit for selectively connecting between the transceiver unit and the optical switch unit; and is provided with: the path control device includes: a control unit for aggregating paths for the same reception node to the same core of the same multi-core optical transmission path; the control unit aggregates paths for the same reception node inserted at different nodes to the same core every time passing through a node; A path control device characterized by the above.

2. The control unit aggregates paths for the same reception node to the same core of the same multi-core optical transmission path at the transmission node. The path control device according to claim 1, characterized by the above.

3. The control unit aggregates paths for the same reception node to the same core of the same multi-core optical transmission path via the wavelength selective switch unit at a relay node that relays between the transmission node and the reception node. The path control device according to claim 1 or 2, characterized by the above.

4. The optical switch unit directly accommodates the multi-core optical transmission path. The path control device according to any one of claims 1 to 3, characterized by the above.

5. The node includes: a separation unit for separating the multi-core optical transmission path into single-core units; the optical switch unit accommodates the multi-core optical transmission path after separating it into single-core units by the separation unit. The path control device according to any one of claims 1 to 3, characterized by the above.

6. It is provided with a storage unit for storing path information databases, the control unit performs path calculation with reference to the path information databases. The path control device according to any one of claims 1 to 5, characterized by the above.

7. A plurality of nodes connected by a multi-core optical transmission path having a plurality of cores, a path control device for controlling a path from a transmission node to a reception node in an optical network including the multi-core optical transmission path and the plurality of nodes, and is provided with: wherein the node includes: a transceiver unit for transmitting and receiving optical signals; An optical switch unit connected to the plurality of multi-core optical transmission paths and performing path switching on a core-by-core basis, A wavelength selection switch unit that wavelength-selectively connects between the transmission / reception unit and the optical switch unit, Comprising, The path control device, Comprises a control unit that aggregates paths for the same receiving node to the same core of the same multi-core optical transmission path, The control unit aggregates paths for the same receiving node inserted at different nodes to the same core each time passing through a node, An optical network system characterized by this.

8. A path control method for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path, The node, A transmission / reception unit that transmits and receives optical signals, An optical switch unit connected to the plurality of multi-core optical transmission paths and performing path switching on a core-by-core basis, A wavelength selection switch unit that wavelength-selectively connects between the transmission / reception unit and the optical switch unit, Comprising, The path control method, Aggregating paths for the same receiving node to the same core of the same multi-core optical transmission path, Including, Aggregating paths for the same receiving node to the same core of the same multi-core optical transmission path, Aggregating paths for the same receiving node inserted at different nodes to the same core each time passing through a node Including, A path control method characterized by this.

9. A path control program for causing a computer to function as a path control device for controlling a path from a transmission node to a reception node in an optical network including a multi-core optical transmission path having a plurality of cores and a plurality of nodes connected by the multi-core optical transmission path, causing the computer to function as a control unit that aggregates paths for the same receiving node to the same core of the same multi-core optical transmission path, The node, A transmission / reception unit that transmits and receives optical signals, An optical switch unit connected to the plurality of multi-core optical transmission paths and performing path switching on a core-by-core basis, A wavelength selection switch unit that wavelength-selectively connects between the transmission / reception unit and the optical switch unit, Comprising, The control unit aggregates paths for the same receiving node inserted at different nodes to the same core each time passing through a node, A path control program characterized by this.

Images