Control device, control system, path design method, and program

Abstract

A control device for designing a path for connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, said control device comprising: a storage unit for holding information regarding the carrier network; a reception unit for receiving first information which is information regarding an access line for a first user network in which the first optical user terminal is provided and second information which is information regarding an access line for a second user network in which the second optical user terminal is provided; and a path calculation unit that designs the path on the basis of the first information, the second information, and the information regarding the carrier network.

Description

Control device, control system, path design method, and program

[0001] The present invention relates to a technique for designing paths in an optical transmission system that transmits optical signals.

[0002] In a conventional optical transmission system, a plurality of optical transmission devices are provided as carrier facilities, and the optical transmission devices are connected to user terminals via Ethernet (registered trademark) or the like.

[0003] Each optical transmission device includes a transponder and an optical signal multiplexing unit, and a carrier (telecommunications operator) sets up an optical wavelength path between a transponder of an optical transmission device at one location and a transponder of an optical transmission device at another location. When the transponder of the optical transmission device at one location receives a signal such as Ethernet (registered trademark) as an optical signal from a user terminal, it converts the optical signal into an electrical signal, adds error correction codes and the like for long-distance transmission, converts the electrical signal back into an optical signal, and transmits the optical signal through the optical wavelength path.

[0004] Hideki Nishizawa, et. al., "Open whitebox architecture for smart integration of optical networking and data center technology," Vol. 13, No. 1 / January 2021 / Journal of Optical Communications and Networking. Kazuo Takagi and Osamu Matsuda, "Transport SDN Solution for Telecommunications Carriers," NEC Technical Journal, Vol. 68, No. 3, pp. 42-46, 2016.

[0005] For example, in an APN (All Photonics Network), it is assumed that the optical transmission equipment will be configured so that transponders are incorporated into user terminals. It is also assumed that users will own their own optical transmission networks. Hereinafter, user terminals incorporating transponders will be referred to as optical user terminals, and the optical transmission networks owned by users will be referred to as user networks. In this configuration, optical user terminals are directly connected to each other via optical wavelength paths, which is expected to enable low-latency, wide-bandwidth communications.

[0006] When users own user networks and optical user terminals, it is expected that a network service will be provided in which optical user terminals deployed in user networks at multiple locations are optically connected to each other. To realize interconnection between any optical user terminals, it is necessary to design a path across the carrier network, which is the carrier's network. Note that the path design includes at least one of route design, wavelength design, and transmission design.

[0007] However, the conventional technology has a problem in that it is not possible to appropriately design the optical wavelength paths that pass through the user network and the carrier network.

[0008] The present invention has been made in view of the above points, and has an object to provide a technique for appropriately designing optical wavelength paths that pass through a user network and a carrier network.

[0009] According to the disclosed technology, there is provided a control device for designing a path connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, the control device comprising: a storage unit for storing information about the carrier network; a receiving unit for receiving first information which is information about an access line of the first user network in which the first optical user terminal is equipped, and second information which is information about an access line of the second user network in which the second optical user terminal is equipped; and a path calculation unit for designing the path based on the first information, the second information, and the information about the carrier network.

[0010] The disclosed technology provides a technology for appropriately designing optical wavelength paths that pass through user networks and carrier networks.

[0011] FIG. 1 is a diagram illustrating an example of the overall configuration of an optical transmission system. FIG. 2 is a diagram for explaining an overview of processing. FIG. 3 is a diagram for explaining a processing procedure for designing and opening an optical wavelength path. FIG. 4 is a diagram for explaining Example 1. FIG. 5 is a diagram for explaining Example 2. FIG. 6 is a diagram for explaining Example 3. FIG. 7 is a diagram illustrating an example of the configuration of a controller 100. FIG. 8 is a diagram illustrating an example of the configuration of a controller 200. FIG. 9 is a diagram illustrating an example of the hardware configuration of an apparatus.

[0012] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. Below, first, the problem will be described in detail, and then the technology related to the present embodiment will be described.

[0013] (About the Issues) As mentioned above, in the future, when users own user networks and optical user terminals, it is expected that NW (network) services will be provided in which optical user terminals deployed in user networks at multiple locations are optically connected to each other. In order to realize interconnection between arbitrary optical user terminals, it is necessary to perform path design (e.g., route design, wavelength design, transmission design) across the carrier network, which is the carrier's NW.

[0014] Conventional techniques related to path design in optical transmission networks include, for example, the technique (AOPP) disclosed in Non-Patent Document 1 and the technique disclosed in Non-Patent Document 2. In AOPP, the transmission quality of each route is measured after the route and wavelength are determined, and the results are summed up to determine whether transmission is possible.

[0015] In addition, in the transmission SDN disclosed in Non-Patent Document 2, the SDN controller performs path design on the premise that it holds the topology and device configuration information of the user network.

[0016] However, in the AOPP disclosed in Non-Patent Document 1, transmission quality cannot be included as an indicator when selecting a route, so as a result of route selection, a route with poor transmission quality may be selected, which may result in the need to deploy regenerative repeater equipment that is not actually necessary.

[0017] Furthermore, when using the transmission SDN disclosed in Non-Patent Document 2, users are required to provide all of the topology and device configuration information of their user networks to the carrier, which forces the carrier to manage user equipment information that it does not need to manage.

[0018] That is, the conventional technology has a problem in that it is not possible to appropriately design optical wavelength paths that pass through user networks and carrier networks.

[0019] The system configuration and operation for solving the above problems will be described below.

[0020] (System Configuration) Fig. 1 shows an example of the overall configuration of an optical transmission system according to this embodiment. In the optical transmission system shown in Fig. 1, a user network A and a user network Z are connected to a carrier network. The user network A includes an optical user terminal 20A and an OXC (Optical Cross-Connect) 30A. The OXC may also be called an optical transmission device.

[0021] The optical user terminal 20A has a transponder, and the transponder is equipped with an optical transceiver 21A. That is, the optical user terminal 20A is equipped with the optical transceiver 21A. The user network Z is equipped with an optical user terminal 20Z and an OXC 30A. The optical user terminal 20Z is equipped with the optical transceiver 21Z.

[0022] The provider network includes multiple OXCs, which are connected to each other via transmission paths. A controller 100 on the user network side and a controller 200 on the provider network side are also included. A system including the controllers 100 and 200 may be called a control system. The controller 100 can communicate with the user network via a control line, and the controller 200 can communicate with the provider network via a control line. The controllers may also be called control devices. A controller 100 on the user network side may be provided for each user network, or one controller 100 may be provided for multiple user networks. In the following, it is assumed that a controller 100 is provided for each user network.

[0023] The boundary between the user network and the carrier network in the path connecting the optical transceivers 21A is called an NNI (Network-Network Interface). In the example of Figure 1, NNIs t11, t12, t21, and t22 are shown.

[0024] (Overview of Technology Relating to Embodiment) In this embodiment, the controller 100 of each user network calculates the route and transmission quality from the path endpoint to the NNI, and provides route information (e.g., route ID, destination NNI, available wavelengths on the route, transmission quality, distance, etc.) to the operator's controller 200. The operator's controller 100 designs a path based on the route information provided by the controller 100 of each user network and facility configuration information within its own network.

[0025] This allows the user to design paths that take into account end-to-end transmission quality without disclosing the facility configuration information of the user network to the carrier.

[0026] For example, in the example shown in Figure 2, focusing on the calculation of transmission quality, the controller 100 of user network A transmits the transmission quality A11 of access line 1 and the transmission quality A12 of access line 2 to the controller 200, and the controller 100 of user network Z transmits the transmission quality A21 of access line 1 and the transmission quality A22 of access line 2 to the controller 200.

[0027] The carrier network controller 200 can calculate the transmission quality of route 1 as A11+R1+A21 using the transmission quality R1 within the carrier network, and can calculate the transmission quality of route 2 as A12+R2+A22 using R2. Note that, for convenience of explanation, it is assumed here that the end-to-end transmission quality can be calculated as the sum of the transmission qualities of the sections.

[0028] (Example of Processing Procedure) With reference to FIG. 3, an outline example of the processing procedure for designing and opening an optical wavelength path in cooperation between a user network and a provider network will be described.

[0029] In the example of Fig. 3, it is assumed that user network A is the requestor and user network Z is the connection destination. User network A is provided with a controller 100A, and user network Z is provided with a controller 100Z. The carrier network is provided with a controller 200. The controllers 100A and 100Z can collect information from each device in user networks A and Z, and the controller 200 can collect information from each device in the carrier network.

[0030] In S1 (step 1), the controller 100A presents (transmits) information about the user network A (request source) to the controller 200. The controller 200 acquires the information.

[0031] The information about user network A (requestor) includes, for example, information about the optical transceiver and transponder of the optical user terminal 20A, fiber information about the access line, desired transmission quality (e.g., OSNR), connection conditions (required bandwidth, etc.), etc.

[0032] In S2, the controller 100Z transmits information about the user network Z (connection destination) to the controller 100. The content of the information may be the same as above. The controller 200 acquires the information.

[0033] In S3, the controller 100 determines whether or not a connection is possible and performs end-to-end path design using information on the capabilities of the optical user terminals in the user networks A and Z (e.g., available wavelengths and transmission modes) and parameters related to the transmission quality of the user networks A and Z. The determination of whether or not a connection is possible is, for example, determining whether or not each optical transceiver in the optical user terminals in the user networks A and Z is an optical transceiver that can be connected to the carrier network.

[0034] With regard to end-to-end path design, the controller 100 determines the route and wavelength that satisfy the desired transmission quality, and if there are multiple selectable transmission modes, selects the optimum transmission mode.

[0035] In S4, based on the results of the path design, the controller 200 notifies the controllers 100A and 100Z of the parameters (wavelength, etc.) to be set in the optical transceivers in the user networks A and Z. Upon receiving the notification, each controller 100 sets the parameters in the optical user terminal.

[0036] Below, examples 1 to 3 will be described as more specific examples of processing procedures.

[0037] (First embodiment) A first embodiment will be described with reference to Fig. 4. The first embodiment is an example in which a required bandwidth is specified as a connection condition. In the first embodiment, as shown in Fig. 4, there is only one boundary between each user network and the provider network. The provider network is, for example, an APN.

[0038] <S1> In S1, the controller 100A transmits information about the optical transceiver 21A, information about the optical transceiver 21Z, the end-to-end required quality Q, the required bandwidth, the transmission capacity (C1) of the optical user terminal 20A, and information about the access line (transmission quality A1) to the controller 100. The controller 200 acquires this information. The optical transceiver information includes, for example, the model number. The model number of the optical transceiver can be used to determine whether the optical transceiver can be connected to the carrier network.

[0039] <S2> In S2, the controller 100Z transmits the transmission capacity (C2) of the optical user terminal 20Z and information on the access line (transmission quality A2) to the controller 200. The controller 200 acquires this information.

[0040] <S3> In S3, the controller 200 selects a transmission mode M that matches the requested bandwidth, and confirms that both the transmission capabilities C1 and C2 include M. Here, it is assumed that the confirmation result is OK.

[0041] The controller 200 calculates the required quality Q_N within the carrier network for each combination of connection points (boundaries between the user network and the carrier network) based on the required quality Q, transmission quality A1, and transmission quality A2. In the example of Figure 4, there is one combination of connection points, so there is one required quality Q_N. Q_N is a quality that satisfies, for example, "Q - (A1 + A2)."

[0042] The controller 200 determines a route that satisfies Q_N and allows wavelengths to be secured. In the example of Fig. 4, it is assumed that Route 1 and Route 2 are determined as the routes.

[0043] The controller 200 selects one route and one wavelength according to KPIs (for example, wavelength utilization efficiency (maximum wavelength number), distance).

[0044] <S4> In S4, the controller 200 notifies the selected wavelength and transmission mode M to each of the controller 100A and the controller 100Z.

[0045] (Example 2) Example 2 will be described with reference to Fig. 5. Example 2 is also an example in which a required bandwidth is specified as a connection condition. In Example 2, as shown in Fig. 5, there are two boundaries between each user network and the provider network.

[0046] <S1> In S1, the controller 100A transmits information about the optical transceiver 21A, information about the optical transceiver 21Z, the end-to-end required quality Q, the required bandwidth, the transmission capability (C1) of the optical user terminal A, and information about the access line (transmission qualities A11 and A12) to the controller 200. The controller 200 acquires this information.

[0047] <S2> In S2, the controller 100Z transmits the transmission capability (C2) of the optical user terminal Z and information on the access line (transmission qualities A21 and A22) to the controller 200. The controller 200 acquires this information.

[0048] <S3> In S3, the controller 200 selects a transmission mode M that matches the requested bandwidth, and confirms that both the transmission capabilities C1 and C2 include M. Here, it is assumed that the confirmation result is OK.

[0049] The controller 200 calculates the required quality Q_Nij (i=1, 2 and j=1, 2) in the carrier network for each combination of connection points (boundaries between the user network and the carrier network) based on the required quality Q and transmission qualities A11, A12, A21, and A22. In the example of Fig. 5, there are four combinations of connection points: t11-t21, t11-t22, t12-t21, and t12-t22.

[0050] The controller 200 determines a route that satisfies Q_Nij and allows wavelengths to be secured. In the example of Fig. 5, it is assumed that Route 1, Route 2, and Route 3 are determined as the routes.

[0051] The controller 200 selects a route, a connection point, and a wavelength according to KPIs (for example, wavelength utilization efficiency (maximum wavelength number), distance). Here, it is assumed that route 2 and wavelength 1 are selected.

[0052] <S4> In S4, the controller 200 notifies the controller 100A of wavelength 1, transmission mode M, and connection point t11 ​​as parameters, and notifies the controller 100Z of wavelength 1, transmission mode M, and connection point t22.

[0053] (Third Embodiment) A third embodiment will be described with reference to Fig. 6. The third embodiment is an example in which a required bandwidth and a redundancy condition are specified as connection conditions. In the third embodiment, as shown in Fig. 6, there are two boundaries between each user network and the carrier network. In the third embodiment, the optical user terminal 20A includes an optical transceiver 21A and an optical transceiver 22A, and the optical user terminal 20Z includes an optical transceiver 21Z and an optical transceiver 22Z.

[0054] <S1> In S1, the controller 100A transmits information on the optical transceivers 21A and 22A, information on the optical transceivers 21Z and 22Z, the end-to-end required quality Q, the required bandwidth, the transmission capabilities (C11, C12) of the optical user terminal 20A, and information on the access line (transmission qualities A11, A12) to the controller 200. The controller 200 acquires this information. Note that C11 is the transmission capability of the optical transceiver 21A, and C12 is the transmission capability of the optical transceiver 22A.

[0055] <S2> In S2, the controller 100Z transmits the transmission capabilities (C21, C22) of the optical user terminal 20Z and access line information (transmission qualities A21, A22) to the controller 200. The controller 200 acquires this information. Note that C21 is the transmission capability of the optical transceiver 21Z, and C22 is the transmission capability of the optical transceiver 22Z.

[0056] <S3> In S3, the controller 200 selects a transmission mode M that matches the requested bandwidth and confirms that all of the transmission capabilities C11, C12, C21, and C22 include M. Here, it is assumed that the confirmation result is OK.

[0057] The controller 200 calculates the required quality Q_Nij (i=1, 2 and j=1, 2) in the carrier network for each combination of connection points (boundaries between the user network and the carrier network) based on the required quality Q and transmission qualities A11, A12, A21, and A22. In the example of Fig. 6, there are four combinations of connection points: t11-t21, t11-t22, t12-t21, and t12-t22.

[0058] The controller 100 determines a route that satisfies Q_Nij and that can secure a wavelength. In the example of Fig. 6, it is assumed that Route 1, Route 2, and Route 3 are determined as the routes.

[0059] The controller 200 selects two routes with no overlapping nodes and fibers, connection points for each of the two routes, and wavelengths for each of the two routes, according to KPIs (for example, wavelength utilization efficiency (maximum wavelength number), sum of distances, etc.). Here, it is assumed that Route 1 and Route 3 are selected.

[0060] <S4> In S4, the controller 200 notifies each of the controllers 100A and 100Z of the wavelength of each route and the transmission mode M as parameters.

[0061] (Device Configuration Example) Fig. 7 shows an example of the functional configuration of the controller 100 on the user network side. As shown in Fig. 7, the controller 100 has a topology management unit 110, a device management unit 120, a path management unit 130, a path calculation unit 140, and a carrier controller communication unit 150. The "user network" below is a user network under the control of the controller 100.

[0062] The topology management unit 110 manages the topology of the user network. "Management" includes storing information. In other words, the "management unit" includes a "storage unit." The same applies to each management unit described below.

[0063] The device management unit 120 manages information about each device (e.g., optical user terminal) in the user network. This information includes information about the optical transceiver of each optical user terminal (e.g., model number). The path management unit 130 manages paths in the user network. The path calculation unit 140 calculates paths in the user network. The operator controller communication unit 150 communicates with the controller 200.

[0064] For example, the "optical transceiver information and optical user terminal transmission capability" managed by the device management unit 120 is transmitted to the controller 200 by the operator controller communication unit 150. Also, access line information managed by the path management unit 130 (or the topology management unit 110) is transmitted to the controller 200 by the operator controller communication unit 150. Also, for example, the end-to-end required quality and required bandwidth input to the controller 100 by a user are transmitted to the controller 200 by the operator controller communication unit 150.

[0065] 8 shows an example of the functional configuration of the carrier network-side controller 200. As shown in FIG. 8, the controller 200 includes a user network path management unit 210, a user network controller communication unit 220, a connection request reception unit 230, a topology management unit 240, a device management unit 250, a path management unit 260, and a path calculation unit 270.

[0066] The user network path management unit 210 manages paths in each user network. The user network controller communication unit 220 communicates with the controller 100 of each user network. The connection request reception unit 230 receives, for example, information from the user network controller 100 (for example, information on S1 and S2 in Examples 1 to 3) as a connection request.

[0067] The topology management unit 240 manages the topology of the provider network. The device management unit 120 manages information about each device in the provider network. The device management unit 120 also manages device information received from the controller of each user network.

[0068] The path management unit 130 manages paths at the provider. The path management unit 130 also manages end-to-end paths obtained by path design. The path calculation unit 140 designs (calculates) end-to-end paths. For example, the process of S3 in the first to third embodiments is performed by the path calculation unit 140.

[0069] The configuration of the controller 200 is not limited to the configuration shown in Fig. 8. The controller 200 may have the configuration shown in Fig. 9. The controller 200 shown in Fig. 9 includes a receiving unit 201, a path calculation unit 202, a transmitting unit 203, and a storage unit 204.

[0070] The controller 200 shown in FIG. 9 designs a path that connects a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network.

[0071] The storage unit 204 stores information about the carrier networks. The receiving unit 201 receives first information, which is information about an access line of a first user network in which a first optical user terminal is provided, and second information, which is information about an access line of a second user network in which a second optical user terminal is provided.

[0072] The path calculation unit 203 designs the above-mentioned path based on the first information, the second information, and the information of the carrier network. The transmission unit 203 transmits parameters obtained by the path design to each of the first user network side and the second user network side.

[0073] (Hardware Configuration Example) Any of the devices (controller 100, controller 200) described in this embodiment can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0074] That is, the device can be realized by executing a program corresponding to the processing performed by the device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0075] Fig. 10 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 10 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected by a bus BS. The computer may further include a GPU.

[0076] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0077] The memory device 1003 reads and stores a program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the device in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0078] (Summary, Effects, etc. of the Embodiments) As described above, the technology described in the present embodiments makes it possible to appropriately design optical wavelength paths that pass through a user network and a carrier network. More specifically, it becomes possible to design paths that include end-to-end transmission quality as an index, without disclosing facility configuration information of the user network to the carrier.

[0079] The following additional notes are provided regarding the above-described embodiments.

[0080] <Additional Notes> (Additional Item 1) A control device for designing a path connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, comprising: a memory; and at least one processor connected to the memory, wherein the memory holds information of the carrier network, and the processor receives first information that is information about an access line of a first user network in which the first optical user terminal is equipped and second information that is information about an access line of a second user network in which the second optical user terminal is equipped, and designs the path based on the first information, the second information, and the information of the carrier network. (Additional Item 2) The control device according to Additional Item 1, wherein the first information includes transmission quality of an access line of the first user network, the second information includes transmission quality of an access line of the second user network, and the information of the carrier network includes the transmission quality of each route in the carrier network. (Supplementary Item 3) The control device according to Supplementary Item 1 or 2, wherein the processor determines a required quality in the provider network for each combination of a connection point between the first user network and the provider network and a connection point between the second user network and the provider network based on the first information, the second information, and information about the provider network, and designs the path based on the required quality for each combination. (Supplementary Item 4) The control device according to any one of Supplementary Items 1 to 3, further comprising: the processor transmits parameters obtained by designing the path to each of the first user network side and the second user network side. (Supplementary Item 5) A control system comprising: the control device according to any one of Supplementary Items 1 to 4; and a user network side control device, provided for each user network, that acquires information of an access line and transmits the information to the control device.(Supplementary Item 6) A path design method executed by a control device for designing a path connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, the path design method comprising: receiving first information that is information about an access line of a first user network in which the first optical user terminal is equipped, and second information that is information about an access line of a second user network in which the second optical user terminal is equipped, and designing the path based on the first information, the second information, and information about the carrier network stored in a storage unit of the control device. (Supplementary Item 7) A non-transitory storage medium storing a program for causing a computer to function as each unit in a control device according to any one of Supplementary Items 1 to 4.

[0081] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0082] 11 to 18, 30 OXC 20 Optical user terminal 21, 22 Optical transceiver 100 Controller 110 Topology management unit 120 Device management unit 130 Path management unit 140 Path calculation unit 150 Operator controller communication unit 200 Controller 201 Receiving unit 202 Path calculation unit 203 Transmitting unit 204 Storage unit 210 User network path management unit 220 User network controller communication unit 230 Connection request receiving unit 240 Topology management unit 250 Device management unit 260 Path management unit 270 Path calculation unit 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

1. A control device for designing a path connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, the control device comprising: a memory unit for retaining information of the carrier network; a receiving unit for receiving first information which is information of an access line of a first user network in which the first optical user terminal is equipped, and second information which is information of an access line of a second user network in which the second optical user terminal is equipped; and a path calculation unit for designing the path based on the first information, the second information, and the information of the carrier network.

2. The control device according to claim 1, wherein the first information includes the transmission quality of an access line of the first user network, the second information includes the transmission quality of an access line of the second user network, and the information of the operator network includes the transmission quality of each route in the operator network.

3. The control device according to claim 1, wherein the path calculation unit determines the required quality in the operator network for each combination of a connection point between the first user network and the operator network and a connection point between the second user network and the operator network based on the first information, the second information, and information about the operator network, and designs the path based on the required quality for each combination.

4. The control device according to claim 1, further comprising a transmission unit that transmits parameters obtained by designing the path to both the first user network side and the second user network side.

5. A control system comprising: a control device according to any one of claims 1 to 4; and a user network side control device provided for each user network, for acquiring information on access lines and transmitting said information to said control device.

6. A path design method executed by a control device for designing a path connecting a first optical user terminal equipped with an optical transceiver and a second optical user terminal equipped with an optical transceiver via a carrier network, the method comprising: receiving first information which is information on an access line of a first user network in which the first optical user terminal is equipped, and second information which is information on an access line of a second user network in which the second optical user terminal is equipped; and designing the path based on the first information, the second information, and information on the carrier network stored in a memory unit of the control device.

7. A program for causing a computer to function as each unit in the control device according to any one of claims 1 to 4.

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