Control device, communication system, and switching method

Abstract

This control device comprises: an information collection unit that collects cloud information items pertaining to a plurality of cloud resources from the respective cloud resources; and a switching instruction unit that, in the case where there is a need for switching the cloud resources and a cloud resource that satisfies the quality upper limit obtained from a higher-level device exists, instructs the cloud resource that satisfies the quality upper limit so as to switch to the cloud resource that satisfies the quality upper limit on the basis of the collected cloud information and the quality upper limit.　

Description

Control device, communication system, and switching method

[0001] The present invention relates to a control device, a communication system, and a switching method.

[0002] Conventionally, when edge computing is performed using cloud resources and communication facilities, a communication system has been proposed in which a cloud controller that controls the cloud resources and a network controller that controls the communication facilities work together under the control of an integrated controller, enabling optimal resource selection and route selection for the entire system (see, for example, Patent Document 1).

[0003] FIG. 10 is a diagram showing an example configuration of a conventional communication system 1. The communication system 1 includes a terminal device 2, multiple communication devices 3-1 to 3-4, multiple cloud resources 4-1 to 4-2, a cloud controller 5, a network controller 6, and an integrated controller 7. The terminal device 2 is a user terminal used by a user. The multiple communication devices 3-1 to 3-4 are relay devices that transfer signals between the terminal device 2 and the cloud resources 4-1 to 4-2. The cloud resource 4-1 is a resource for providing cloud services. The cloud resource 4-2 is a spare resource that is used when the cloud resource 4-1 is unavailable due to a failure or the like. The cloud resources 4-1 and 4-2 may be, for example, servers, databases, or storage.

[0004] The cloud controller 5 is a control device that configures and monitors the cloud resources 4-1 to 4-2. When the cloud controller 5 receives an instruction from the integrated controller 7 to change the cloud resources 4 to be used by a user, the cloud controller 5 instructs the cloud resources 4 to change the settings. For example, when an instruction to change the cloud resources 4 to be used by the terminal device 2 is received, the cloud controller 5 configures the resources to be allocated to the terminal device 2 for the cloud resources 4 to be used by the terminal device 2.

[0005] The network controller 6 configures and monitors the communication devices 3 and monitors the network. When a path switching instruction is received from the integrated controller 7, the network controller 6 instructs the communication devices 3 that require path switching to switch their paths. The integrated controller 7 determines the optimal cloud resource allocation and network path in accordance with the information obtained from the cloud controller 5 and the network controller 6, taking into account the usage status of the cloud resources 4 and the usage status of the network. The integrated controller 7 instructs at least one of the cloud controller 5 or the network controller 6 to switch in accordance with the determined cloud resource allocation and network path.

[0006] International Publication No. WO / 2023 / 157399

[0007] In the communication system 1 described in the cited document 1, as described above, the integrated controller 7 is configured to perform centralized management of route control. Therefore, the amount of information sent and received between the controllers tends to increase, which increases the load on the network and the processing load on the controller. As a result, there is a problem in that it takes a long time to process.

[0008] In view of the above circumstances, an object of the present invention is to provide a technique that can reduce processing time.

[0009] One aspect of the present invention is a control device that includes an information collection unit that collects cloud information regarding multiple cloud resources from each of the multiple cloud resources, and a switching instruction unit that instructs the cloud resource that satisfies the quality upper limit to switch to a cloud resource that satisfies the quality upper limit when switching of the cloud resource is necessary and there is a cloud resource that satisfies the quality upper limit based on the collected cloud information and a quality upper limit obtained from a higher-level device.

[0010] One aspect of the present invention is a control device comprising: an information collection unit that collects network information regarding a plurality of communication devices and a network formed by the plurality of communication devices from each of the plurality of communication devices; and a switching instruction unit that, based on the collected network information and a quality upper limit obtained from a higher-level device, instructs a communication device related to a network path that satisfies the quality upper limit to switch to a network path that satisfies the quality upper limit when a network path switching is necessary and the network path satisfies the quality upper limit.

[0011] One aspect of the present invention is a communication system comprising a plurality of cloud resources, a plurality of communication devices provided on a path for using any of the plurality of cloud resources, a cloud controller that controls the plurality of cloud resources, a network controller that controls the plurality of communication devices, and an integrated controller that controls the cloud controller and the network controller, wherein the cloud controller includes a first information collection unit that collects cloud information related to the plurality of cloud resources from each of the plurality of cloud resources, and based on the collected cloud information and a quality upper limit obtained from the integrated controller, determines whether switching of the cloud resource is necessary and whether there is a cloud resource that satisfies the quality upper limit. and a first switching instruction unit that instructs the cloud resource that satisfies the quality upper limit to switch to a cloud resource that satisfies the quality upper limit when a network route needs to be switched to another cloud resource that satisfies the quality upper limit, and the network controller comprises a second information collection unit that collects network information regarding the plurality of communication devices and the network formed by the plurality of communication devices from each of the plurality of communication devices, and a second switching instruction unit that instructs the communication devices related to the network route that satisfies the quality upper limit to switch to a network route that satisfies the quality upper limit when a network route needs to be switched to a cloud resource that satisfies the quality upper limit based on the collected network information and the quality upper limit obtained from the integrated controller.

[0012] One aspect of the present invention is a switching method that collects cloud information regarding multiple cloud resources from each of the multiple cloud resources, and based on the collected cloud information and a quality upper limit obtained from a higher-level device, if it is necessary to switch the cloud resources and there is a cloud resource that satisfies the quality upper limit, instructs the cloud resource that satisfies the quality upper limit to switch to a cloud resource that satisfies the quality upper limit.

[0013] One aspect of the present invention is a switching method that collects network information regarding a plurality of communication devices and a network formed by the plurality of communication devices from each of the plurality of communication devices, and, based on the collected network information and a quality upper limit obtained from a higher-level device, if a network route switching is necessary and there is a network route that satisfies the quality upper limit, instructs a communication device related to the network route that satisfies the quality upper limit to switch to the network route that satisfies the quality upper limit.

[0014] The present invention makes it possible to reduce processing time.

[0015] 1 is a diagram illustrating an example of the configuration of a communication system in an embodiment. FIG. 2 is a diagram illustrating an example of the functional configuration of a cloud controller, a network controller, and an integrated controller in an embodiment. FIG. 3 is a diagram illustrating an example of a quality requirement DB in an embodiment. FIG. 4 is a sequence diagram illustrating a processing flow (part 1) performed by a communication system in an embodiment. FIG. 5 is a sequence diagram illustrating a processing flow (part 2) performed by a communication system in an embodiment. FIG. 6 is a sequence diagram illustrating a processing flow (part 3) performed by a communication system in an embodiment. FIG. 7 is a diagram illustrating an example of the functional configuration of a cloud controller, a network controller, and an integrated controller in a first modified example. FIG. 8 is a diagram illustrating an example of the configuration of a communication system in a second modified example of an embodiment. FIG. 9 is a diagram illustrating an example of the configuration of a conventional communication system.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] FIG. 1 is a diagram illustrating an example configuration of a communication system 100 according to an embodiment. The communication system 100 includes one or more termination devices 10, a plurality of communication devices 20-1 to 20-4, a plurality of cloud resources 30-1 to 30-3, a cloud controller 40, a network controller 50, and an integrated controller 60. In the following description, the communication devices 20-1 to 20-4 will be referred to as communication devices 20 unless otherwise specified, and the cloud resources 30-1 to 30-3 will be referred to as cloud resources 30 unless otherwise specified. The number of termination devices 10, communication devices 20, and cloud resources 30 included in the communication system 100 is not limited to the number shown in FIG. 1 .

[0018] 1 shows an example in which communication devices 20-1 to 20-4 form a ring network, a termination device 10 is connected to communication device 20-1, cloud resources 30-1 and 30-2 are connected to communication device 20-2, and a cloud resource 30-3 is connected to communication device 20-4. In FIG. 1, as an example, a configuration is shown in which communication devices 20-1 and 20-2 are connected by lines R1 and R2 with different distances, but other communication devices 20 may also be connected by multiple lines with different distances.

[0019] Furthermore, in the communication system 100, each cloud resource 30 is connected to a cloud controller 40, a network controller 50 is connected to each communication device 20, and the cloud controller 40 and the network controller 50 are connected to an integrated controller 60. In the following description, it is assumed that each communication device 20 is located at a different base.

[0020] The terminal device 10 is a user terminal used by a user, and is, for example, a device that receives services provided by the cloud resource 30. As an example, it is assumed that the terminal device 10 uses the cloud resource 30-1 via a line R1 between the communication device 20-1 and the communication device 20-2.

[0021] The communication device 20 is a relay device that transfers signals between the terminal device 10 and the cloud resource 30. The communication device 20 changes settings such as a signal transfer path in response to an instruction from the network controller 50. Changing the settings of a signal transfer path means, for example, switching the signal transfer path.

[0022] The cloud resources 30 are resources for providing cloud services. The cloud resources 30 may be, for example, a server configured with at least one of a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), etc., or may be a database or storage with memory. The cloud resources 30 may be any resource for performing signal processing on user communication data. The cloud resources 30 change the settings of resources allocated to users in response to instructions from the cloud controller 40. Changing the resource allocation settings means, for example, changing the amount of resource allocation.

[0023] Cloud resources 30-1 and 30-2 are installed at the same location. Cloud resource 30-3 is installed at a different location from cloud resources 30-1 and 30-2. Cloud resources 30-2 and 30-3 are spare resources that are used when cloud resource 30-1 is unavailable due to a failure or other reason.

[0024] The cloud controller 40 is a control device that configures and monitors the cloud resources 30. The cloud controller 40 collects information about the cloud resources 30 (hereinafter referred to as "cloud information"). The cloud controller 40 notifies the integrated controller 60 of the collected cloud information. The cloud controller 40 may notify the integrated controller 60 of the cloud information periodically, or only when a predetermined condition is met.

[0025] The cloud information includes information such as the usage status of the cloud resource 30 for each user in each cloud resource 30, CPU usage rate, amount of free resources, and processing delay time.

[0026] The usage status indicates whether each cloud resource 30 is being used. If the cloud resource 30 is being used, the usage status includes information indicating which user is using it. The CPU usage rate indicates the proportion of the processing volume that the CPU of each cloud resource 30 can handle at one time that is being used for processing. The amount of free resources indicates the amount of resources that each cloud resource 30 has that are not being used for processing (are available). The processing delay time indicates the delay time required for processing by each cloud resource 30.

[0027] The cloud controller 40 determines, based on the collected cloud information, whether or not switching of the cloud resources 30 is necessary. If switching of the cloud resources 30 is necessary and the cloud controller 40 can handle the switching by itself, the cloud controller 40 controls the switching of the cloud resources 30 without receiving control from the integrated controller 60.

[0028] A case where the cloud controller 40 alone can handle the switching is a case where the quality upper limit notified by the integrated controller 60 can be satisfied by simply changing the settings of the cloud resources 30, without switching the network path used by the user. The quality upper limit notified by the integrated controller 60 is a threshold calculated by the integrated controller 60 based on the quality requirements requested by the user. The quality upper limit notified by the integrated controller 60 is a different value between the cloud controller 40 and the network controller 50. The quality requirements requested by the user include delay and CPU usage rate, for example, an upper limit value for end-to-end delay and an upper limit for the allowable usage rate of each resource. In this way, the cloud controller 40 selects a switching destination within a controllable range so as to satisfy the quality upper limit notified by the integrated controller 60, and switches the cloud resources 30.

[0029] As an example of a case where the cloud controller 40 alone can handle the switching, a situation where cloud resources 30 installed at the same site are switched can be considered. For example, as shown in Fig. 1, if a user is using cloud resource 30-1 and the quality upper limit notified by the integrated controller 60 can be satisfied by switching the cloud resource 30 from cloud resource 30-1 to cloud resource 30-2, it is considered that the cloud controller 40 alone can handle the switching, since there is no need to switch the network path.

[0030] On the other hand, cases in which the cloud controller 40 alone cannot handle the switching include when there is no destination to switch to (for example, when it is necessary to switch the network path used by the user), or when the quality upper limit notified by the integrated controller 60 cannot be met by simply changing the settings of the cloud resources 30 even if the network path used by the user is not switched.

[0031] As described above, when the cloud controller 40 is not capable of handling the switching by itself, the cloud controller 40 receives control from the integrated controller 60 and controls the switching of the cloud resources 30. The cloud controller 40 is one aspect of a control device.

[0032] The network controller 50 configures and monitors the communication devices 20 and monitors the network. Configuring the communication devices 20 involves configuring signal transfer paths. Monitoring the communication devices 20 involves monitoring whether a failure has occurred in the communication devices 20 and the usage status of the communication devices 20. Monitoring the network involves monitoring whether a failure (e.g., a disconnection) or congestion has occurred in the network, as well as bandwidth usage and transfer delays. The network controller 50 collects information about the communication devices 20 and the network (hereinafter referred to as "NW information"). The network controller 50 notifies the integrated controller 60 of the collected NW information. The network controller 50 may transmit the NW information to the integrated controller 60 periodically or only when a predetermined condition is met.

[0033] The NW information is information about the network formed by each communication device 20 and communication devices 20-1 to 20-4, and includes, for example, information such as device usage status, line bandwidth usage rate, line transfer delay time, and flow information. The device usage status indicates whether each communication device 20 is being used. The line bandwidth usage rate indicates the percentage of the bandwidth used on the line connecting the communication devices 20. The line transfer delay time indicates the delay time required for transfer on the line connecting the communication devices 20. The flow information indicates the communication content being processed by each communication device 20.

[0034] The network controller 50 determines whether or not a path change is necessary based on the collected NW information. If a path change is necessary and the network controller 50 can handle the change by itself, the network controller 50 controls the path change without receiving control from the integrated controller 60.

[0035] A case where the network controller 50 alone can handle the switching is a case where the quality upper limit notified by the integrated controller 60 can be satisfied by switching the network path alone, without switching the cloud resource 30 used by the user. In this way, the network controller 50 selects a switching destination within a controllable range so as to satisfy the quality upper limit notified by the integrated controller 60, and switches the network path.

[0036] As an example of a case where the network controller 50 alone can handle the switching, a situation where a route to a cloud resource 30 installed at the same site is switched can be considered. For example, as shown in Figure 1, if a user is using line R1 to use cloud resource 30-1 and the quality upper limit notified by the integrated controller 60 can be satisfied by switching the line used from line R1 to line R2, there is no need to switch the cloud resource, and therefore the network controller 50 alone can handle the switching.

[0037] On the other hand, cases in which the network controller 50 alone is unable to handle the switching include when there is no destination to switch to (for example, when it is necessary to switch the cloud resource 30 used by the user), or when the quality limit notified by the integrated controller 60 cannot be met by simply switching the network path even if the cloud resource 30 used by the user is not switched.

[0038] As described above, when the network controller 50 is not capable of handling the switching by itself, the network controller 50 controls the switching of the network path under control of the integrated controller 60. The network controller 50 is one aspect of a control device.

[0039] In response to receiving a notification from the cloud controller 40 or a notification from the network controller 50, the integrated controller 60 determines the cloud resource 30 and the network path for using the cloud resource 30 so as to satisfy the quality requirements requested by the user. The integrated controller 60 instructs at least one of the cloud controller 40 or the network controller 50 to switch in accordance with the determined cloud resource 30 and network path. Note that if switching of either the cloud controller 40 or the network controller 50 is not necessary, the integrated controller 60 need only instruct the controller that requires switching to switch.

[0040] As described above, the integrated controller 60 operates when the cloud controller 40 alone cannot handle the switching, or when the network controller 50 alone cannot handle the switching, thereby reducing the transmission and reception of information between controllers. This reduces the network load. Furthermore, the processing time required for transmission to the integrated controller 60 can also be reduced. As a result, delays can be reduced. Below, a specific configuration of the communication system 100 for realizing the above operations will be described.

[0041] 2 is a diagram showing an example of the functional configuration of the cloud controller 40, the network controller 50, and the integrated controller 60 in the embodiment. The functional configurations of the cloud controller 40, the network controller 50, and the integrated controller 60 will be described below in order.

[0042] (Functional configuration of cloud controller 40) The cloud controller 40 includes a cloud information collection unit 41, an information DB 42, a switching determination unit 43, a switching decision unit 44, and a switching instruction unit 45. The cloud information collection unit 41 collects cloud information from each cloud resource 30. The frequency with which the cloud information collection unit 41 collects the cloud information can be set arbitrarily. The cloud information collection unit 41 stores the collected cloud information in the information DB 42. The cloud information collection unit 41 is one aspect of a first information collection unit.

[0043] The information DB 42 stores the cloud information collected by the cloud information collection unit 41 and information about the cloud resources 30 used by the user (hereinafter referred to as "used cloud resource information"). The used cloud resource information is information for identifying which cloud resource 30, among the cloud resources 30-1 to 30-3, a user using a service is using. Furthermore, the information DB 42 synchronizes the cloud information with the information DB 61 of the integrated controller 60. Specifically, the information DB 42 saves the stored cloud information and used cloud resource information in the information DB 61 of the integrated controller 60 at a predetermined timing. The used cloud resource information may be acquired by the cloud information collection unit 41.

[0044] The switching determination unit 43 determines whether the quality upper limit is satisfied based on the threshold notified by the integrated controller 60 and the cloud information stored in the information DB 42. For example, the switching determination unit 43 compares the threshold notified by the integrated controller 60 with the processing delay time of the cloud resource 30 used by the user, and determines whether the processing delay time of the cloud resource 30 used by the user exceeds the threshold.

[0045] The switching determination unit 43 determines that switching is necessary when the processing delay time of the cloud resource 30 used by the user exceeds a threshold. On the other hand, the switching determination unit 43 determines that switching is unnecessary when the processing delay time of the cloud resource 30 used by the user does not exceed the threshold. When determining that switching is necessary, the switching determination unit 43 notifies the switching decision unit 44 of the threshold notified by the integrated controller 60, as well as information identifying the user who has exceeded the threshold (e.g., user identification information).

[0046] The switching determination unit 44 determines the destination of the cloud resource 30 used by the user notified by the switching determination unit 43. Specifically, the switching determination unit 44 refers to information on the free resource amount of each cloud resource 30 stored in the information DB 42, and searches for a free resource that can be below a threshold for the user notified by the switching determination unit 43. If the switching determination unit 44 is able to find a free resource that can be below the threshold, it determines the corresponding cloud resource 30 as the switching destination. If the search is successful, the switching determination unit 44 outputs a switching instruction to the switching instruction unit 45, including information identifying the user and information identifying the switching destination cloud resource 30. If the switching determination unit 44 is unable to find a free resource that can be below the threshold, it notifies the integrated controller 60 of the information identifying the user.

[0047] Furthermore, the switching determination unit 44 notifies the information DB 42 of the information identifying the user and the information identifying the cloud resource 30 to be switched to. As a result, the information DB 42 updates the stored usage cloud resource information. For example, the information DB 42 updates the usage cloud resource information by overwriting, in the usage cloud resource information, the information identifying the cloud resource 30 associated with the user identified by the information identifying the user notified by the switching determination unit 44 with the information identifying the cloud resource 30 to be switched to.

[0048] The switching instruction unit 45 instructs the corresponding cloud resource 30 to change the setting in response to a switching instruction from the switching determination unit 44 or the integrated controller 60. The switching instruction unit 45 is one aspect of a first switching instruction unit.

[0049] (Functional Configuration of Network Controller 50) The network controller 50 includes a NW information collection unit 51, an information DB 52, a switching determination unit 53, a switching decision unit 54, and a switching instruction unit 55. The NW information collection unit 51 collects NW information from each communication device 20. The frequency at which the NW information collection unit 51 collects NW information can be set arbitrarily. The NW information collection unit 51 stores the collected NW information in the information DB 52. Note that the NW information collection unit 51 may collect end-to-end delay times, including network delays and cloud delays, measured by the termination device 10 via the communication device 20. The NW information collection unit 51 is one aspect of a second information collection unit.

[0050] The information DB 52 stores the NW information collected by the NW information collection unit 51 and information on the network routes used by users (hereinafter referred to as "used network route information"). The used network route information is information for identifying which line a user using a service is using. The line here refers to a route connecting communication devices 20. Furthermore, the information DB 52 synchronizes the NW information with the information DB 61 held by the integrated controller 60. Specifically, the information DB 52 saves the stored NW information and used network route information in the information DB 61 held by the integrated controller 60 at a predetermined timing. The used network route information may be acquired by the NW information collection unit 51.

[0051] The switching determination unit 53 determines whether or not the quality upper limit is satisfied based on the threshold notified by the integrated controller 60 and the NW information stored in the information DB 52. For example, the switching determination unit 53 compares the threshold notified by the integrated controller 60 with the transfer delay time of the network route used by the user, and determines whether or not the transfer delay time of the network route used by the user exceeds the threshold.

[0052] The switching determination unit 53 determines that switching is necessary when the transfer delay time of the network path used by the user exceeds a threshold. On the other hand, the switching determination unit 53 determines that switching is unnecessary when the transfer delay time of the network path used by the user does not exceed the threshold. When determining that switching is necessary, the switching determination unit 53 notifies the switching decision unit 54 of the threshold notified by the integrated controller 60, as well as information identifying the user who has exceeded the threshold (e.g., user identification information).

[0053] The switching determination unit 54 determines the switching destination of the network route used by the user notified by the switching determination unit 53. Specifically, the switching determination unit 54 refers to information on the transfer delay time of each line stored in the information DB 52 and searches for a network route that can be below a threshold for the user notified by the switching determination unit 53. If the switching determination unit 54 is able to search for a network route that can be below the threshold, it determines the corresponding network route as the switching destination. For example, the switching determination unit 54 determines each line used as a network route as the switching destination. If the search is successful, the switching determination unit 54 outputs a switching instruction to the switching instruction unit 55, including information identifying the user and information on the switching destination network route. Note that if the switching determination unit 54 is unable to search for a network route that can be below the threshold, it notifies the integrated controller 60 of the information identifying the user.

[0054] Furthermore, the switching determination unit 54 notifies the information DB 52 of information identifying the user and information identifying the network route to be switched to (e.g., information indicating the line). As a result, the information DB 52 updates the used network route information stored therein. For example, the information DB 52 updates the used network route information by overwriting, in the used network route information, information identifying the network route associated with the user identified by the user identification information notified by the switching determination unit 54 with information identifying the network route to be switched to.

[0055] The switching instruction unit 55 instructs each of the corresponding communication devices 20 to change the settings in response to a switching instruction from the switching determination unit 54 or the integrated controller 60. The switching instruction unit 55 is one aspect of a second switching instruction unit.

[0056] (Functional Configuration of Integrated Controller 60 ) The integrated controller 60 includes an information DB 61 , a quality requirement DB 62 , a threshold value determination unit 63 , a switching determination unit 64 , and a switching instruction unit 65 .

[0057] The information DB 61 stores information stored in the information DB 42 (e.g., cloud information and used cloud resource information) and information stored in the information DB 52 (e.g., NW information and used network path information). When information stored in the information DB 42 or the information DB 52 is updated, the information DB 61 updates the information upon receiving a notification from the information DB 42 or the information DB 52 that updated the information. In this way, the information DB 61 synchronizes with the information DB 42 and the information DB 52.

[0058] The quality requirement DB 62 is a database that stores information about quality requirements required by each user of the service. The quality requirements include, for example, an upper limit of end-to-end delay, an upper limit of allowable utilization of each CPU, FPGA, etc.

[0059] The threshold determination unit 63 calculates the delay time to be allocated to each of the cloud resources 30 and the network path for each user based on the quality requirements for each user registered in the quality requirement DB 62. The threshold determination unit 63 notifies the switching determination unit 43 of the cloud controller 40 of the calculated delay time to be allocated to the cloud resources 30 for each user as a threshold. Furthermore, the threshold determination unit 63 notifies the switching determination unit 53 of the network controller 50 of the calculated delay time to be allocated to the network path for each user as a threshold. In this way, the threshold determination unit 63 determines a different threshold for each user. Note that the threshold determination unit 63 may also notify the allowable usage upper limit of each cloud resource 30 as a threshold.

[0060] In response to receiving a notification from the switching determination unit 44 or the switching determination unit 54, the switching determination unit 64 determines a switching destination so as to satisfy the quality requirements registered in the quality requirement DB 62. In other words, the switching determination unit 64 determines a switching destination when the cloud controller 40 or the network controller 50 cannot internally determine a switching destination.

[0061] In the search for determining a switching destination, the switching determination unit 64 extracts the cloud resources 30 and the quality of the network routes that are the switching destination candidates from the information DB 61, measures the quality, and determines whether the switching destination candidate satisfies the requirements. If the switching determination unit 64 finds a switching destination that satisfies the quality requirements, it outputs a switching instruction to the switching instruction unit 65, including information for identifying the user and information about the cloud resource 30 and the network route of the switching destination.

[0062] Furthermore, the switching determination unit 64 notifies the information DB 61 of the information for identifying the user, the information on the cloud resource 30 to be switched to, and the information on the network path to be switched to. As a result, the information DB 61 updates the stored used network path information or used cloud resource information.

[0063] Note that the switching determination unit 64 may not search for a switching destination if the quality requirements are satisfied with the current resources, even when a notification is received from the switching determination unit 44 or the switching determination unit 54. In this case, the switching determination unit 64 may instruct the threshold determination unit 63 to revise the threshold, and the threshold determination unit 63 may take measures such as setting the threshold higher than the current threshold.

[0064] The switching instruction unit 65 notifies the switching instruction unit 45 of a switching instruction including information for identifying the user and information about the cloud resource 30 to which the switching is to be performed, and notifies the switching instruction unit 55 of a switching instruction including information for identifying the user and information about the network path to which the switching is to be performed.

[0065] FIG. 3 is a diagram showing an example of the quality requirement DB 62 in an embodiment. The quality requirement DB 62 has multiple records in which information about the quality requirements required by each user who uses the service is registered. Each record has values ​​for the user, the total delay upper limit, and the CPU usage upper limit. The user represents a user who uses the service. The total delay upper limit represents the upper limit of delay for the entire service requested by the user who uses the service. The CPU usage upper limit represents the upper limit of CPU usage requested by the user who uses the service. Note that the information registered in the quality requirement DB 62 is an example, and is newly added or updated in response to a service application or update instruction from a user, etc.

[0066] Next, the flow of processing performed by the communication system 100 will be described with reference to Figures 4 to 7. Specifically, Figure 4 describes the flow of processing when the cloud controller 40 alone can handle switching, Figure 5 describes the flow of processing when the network controller 50 alone can handle switching, and Figures 6 and 7 describe the flow of processing when the integrated controller 60 performs control.

[0067] 4 is a sequence diagram showing a first example of a process performed by the communication system 100 according to the embodiment. The process in FIG. 4 is described assuming that user A is using cloud resource 30-1.

[0068] The cloud information collection unit 41 collects cloud information from each cloud resource 30 (step S101). The cloud information collection unit 41 saves the collected cloud information in the information DB 42, thereby updating the cloud information stored in the information DB 42 (step S102). When the stored information is updated, the information DB 42 transmits the updated information to the information DB 61 (step S103). As a result, the information DB 42 synchronizes the information with the information DB 61.

[0069] The information DB 61 of the integrated controller 60 receives the information transmitted from the information DB 42 of the cloud controller 40. The information DB 61 updates the stored information based on the received information (step S104). Thereafter, the switching determination unit 43 determines whether switching of the cloud resources 30 is necessary based on the information stored in the information DB 42 (step S105). Specifically, the switching determination unit 43 compares the threshold value for each user notified by the integrated controller 60 with the processing delay time of the cloud resources 30 used by each user stored in the information DB 42, and determines for each user whether the processing delay time of the cloud resources 30 used by the user exceeds the threshold value.

[0070] As an example, assume that the threshold for each user (e.g., user A) notified by the integrated controller 60 is 80 ms. The switching determination unit 43 determines that a switch of the cloud resource 30 is necessary when the processing delay time of the cloud resource 30 used by each user (e.g., user A) stored in the information DB 42 exceeds 80 ms. Assume here that the processing delay time of the cloud resource 30 used by user A exceeds 80 ms. In this case, the switching determination unit 43 determines that a switch of the cloud resource 30 is necessary. Therefore, the switching determination unit 43 notifies the switching decision unit 44 of the threshold "80 ms" as well as information identifying the user who exceeded the threshold (e.g., user A's identification information).

[0071] The switching determination unit 44 acquires the threshold value "80 ms" and information identifying the user (e.g., user A's identification information) notified by the switching judgment unit 43. The switching determination unit 44 determines the optimal switching destination based on the acquired information and the information DB 42 (step S106). Specifically, the switching determination unit 44 refers to the information DB 42 and searches for a cloud resource 30 that can achieve a speed below the threshold value "80 ms" by switching to an alternative cloud resource 30 without switching the network path. Here, it is assumed that cloud resource 30-2, which is installed at the same site as cloud resource 30-1, has a resource that can achieve a speed below the threshold value "80 ms" without switching the network path. In this case, the switching determination unit 44 determines cloud resource 30-2 as the optimal switching destination.

[0072] The switching determination unit 44 outputs a switching instruction including information for identifying the user (e.g., user A's identification information) and information for identifying the switching destination cloud resource 30-2 to the switching instruction unit 45. Furthermore, the switching determination unit 44 outputs the information for identifying the user (e.g., user A's identification information) and information for identifying the switching destination cloud resource 30-2 to the information DB 42. The information DB 42 updates the information stored therein based on the information for identifying the user (e.g., user A's identification information) and the information for identifying the switching destination cloud resource 30-2 output from the switching determination unit 44.

[0073] The switching instruction unit 45 instructs the cloud resource 30-2 to change the settings in response to the switching instruction from the switching determination unit 44 (step S107). Specifically, the switching instruction unit 45 instructs the cloud resource 30-2 to switch the resource allocation amount. For example, the switching instruction unit 45 instructs the cloud resource 30-2 to allocate the resources requested by user A.

[0074] 5 is a sequence diagram showing a second processing flow performed by the communication system 100 according to the embodiment. The description will be given assuming that the cloud resource 30-1 is being used by user A via line R1 at the start of the processing in FIG.

[0075] The NW information collection unit 51 collects NW information from each communication device 20 (step S201). The NW information collection unit 51 saves the collected NW information in the information DB 52, thereby updating the NW information stored in the information DB 52 (step S202). When the stored information is updated, the information DB 52 transmits the updated information to the information DB 61 (step S203). In this way, the information DB 52 synchronizes the information with the information DB 61.

[0076] The information DB 61 of the integrated controller 60 receives the information transmitted from the information DB 52 of the network controller 50. The information DB 61 updates the stored information based on the received information (step S204). Thereafter, the switching determination unit 53 determines whether or not a network route needs to be switched based on the information stored in the information DB 52 (step S205). Specifically, the switching determination unit 53 compares the threshold value for each user notified by the integrated controller 60 with the transfer delay time of the network route used by each user stored in the information DB 52, and determines for each user whether the transfer delay time of the network route used by the user exceeds the threshold value.

[0077] As an example, let us assume that the threshold for each user (e.g., user A) notified by the integrated controller 60 is 80 ms. The switching determination unit 53 determines that a network route needs to be switched if the forwarding delay time of the network route used by each user (e.g., user A) stored in the information DB 52 exceeds 80 ms. Here, let us assume that the forwarding delay time of the network route used by user A exceeds 80 ms. In this case, the switching determination unit 53 determines that a network route needs to be switched. Therefore, the switching determination unit 53 notifies the switching decision unit 54 of the threshold value "80 ms" as well as information identifying the user who exceeded the threshold (e.g., user A's identification information).

[0078] The switching determination unit 54 acquires the threshold value "80 ms" and information identifying the user (e.g., user A's identification information) notified by the switching judgment unit 53. The switching determination unit 54 determines an optimal switching destination based on the acquired information and the information DB 52 (step S206). Specifically, the switching determination unit 54 refers to the information DB 52 and searches for a network path that can be switched to an alternative network path without switching the cloud resource 30, thereby achieving a speed below the threshold value "80 ms." Here, it is assumed that line R2 connecting the communication device 20-1 and the communication device 20-2 is a network path that can achieve a speed below the threshold value "80 ms" without switching the cloud resource 30. In this case, the switching determination unit 54 determines line R2 as the optimal switching destination.

[0079] The switching determination unit 54 outputs a switching instruction including information for identifying the user (e.g., identification information of user A) and information for identifying the switching destination line R2 to the switching instruction unit 55. Furthermore, the switching determination unit 54 outputs the information for identifying the user (e.g., identification information of user A) and information for identifying the switching destination line R2 to the information DB 52. The information DB 52 updates the information stored therein based on the information for identifying the user (e.g., identification information of user A) and the information for identifying the switching destination line R2 output from the switching determination unit 54.

[0080] The switching instruction unit 55 instructs the communication device 20 to change the settings in response to the switching instruction from the switching determination unit 54 (step S207). Specifically, the switching instruction unit 55 instructs the communication device 20-1 to switch the network path. For example, the switching instruction unit 55 instructs the communication device 20-1 to switch the path so that the signal from user A is transferred via line R2.

[0081] 6 and 7 are sequence diagrams showing a third processing flow performed by the communication system 100 according to the embodiment. The description will be given assuming that, at the start of the processing shown in FIG. 5, the cloud resource 30-1 is being used by user A via line R1.

[0082] The cloud information collection unit 41 collects cloud information from each cloud resource 30 (step S301). The cloud information collection unit 41 saves the collected cloud information in the information DB 42, thereby updating the cloud information stored in the information DB 42 (step S302). When the stored information is updated, the information DB 42 transmits the updated information to the information DB 61 (step S303). As a result, the information DB 42 synchronizes the information with the information DB 61.

[0083] The NW information collection unit 51 collects NW information from each communication device 20 (step S304). The NW information collection unit 51 saves the collected NW information in the information DB 52, thereby updating the NW information stored in the information DB 52 (step S305). When the stored information is updated, the information DB 52 transmits the updated information to the information DB 61 (step S306). In this way, the information DB 52 synchronizes the information with the information DB 61.

[0084] The information DB 61 of the integrated controller 60 receives the information transmitted from the information DB 42 of the cloud controller 40 and the information transmitted from the information DB 52 of the network controller 50 at different times. The information DB 61 updates the stored information based on the received information (step S307). As a result, the information DB 61 stores the information stored in the information DB 42 and the information stored in the information DB 52.

[0085] Thereafter, the switching determination unit 43 of the cloud controller 40 determines whether switching of the cloud resources 30 is necessary based on the information stored in the information DB 42 (step S308). Specifically, the switching determination unit 43 compares the threshold value for each user notified by the integrated controller 60 with the processing delay time of the cloud resources 30 used by each user stored in the information DB 42, and determines for each user whether the processing delay time of the cloud resources 30 used by the user exceeds the threshold value. Here, it is assumed that the switching determination unit 43 determines that switching of the cloud resources 30 is necessary. In this case, the switching determination unit 43 notifies the switching decision unit 44 of the threshold value as well as information identifying the user whose threshold value has been exceeded (e.g., identification information of user A).

[0086] The switching determination unit 44 acquires the threshold and user identification information (e.g., user A's identification information) notified by the switching judgment unit 43. The switching determination unit 44 determines the optimal switching destination based on the acquired information and the information DB 42 (step S309). Specifically, the switching determination unit 44 references the information DB 42 and searches for a cloud resource 30 that can reduce the threshold by switching to an alternative cloud resource 30 without switching the network path. Here, it is assumed that there is no resource that can reduce the threshold without switching the network path. In this case, the switching determination unit 44 generates a notification including user identification information (e.g., user A's identification information) and a notification indicating that there is no switching destination, and transmits the generated notification to the integrated controller 60 (step S310).

[0087] The switching determination unit 64 of the integrated controller 60 receives the notification transmitted from the cloud controller 40. The switching determination unit 64 determines whether or not switching of the cloud resource 30 or the network path is necessary for user A identified by information identifying the user (e.g., user A's identification information) included in the received notification (step S311). Specifically, the switching determination unit 64 first refers to the information DB 61 and adds up the processing delay time of the cloud resource 30 used by user A and the transfer delay time of the network path used by user A.

[0088] Next, the switching decision unit 64 compares the summed value with the end-to-end delay upper limit value for user A stored in the quality requirement DB 62. If the summed value is equal to or less than the end-to-end delay upper limit value, the switching decision unit 64 determines that the user's quality requirements are met and therefore switching is not necessary. On the other hand, if the summed value exceeds the end-to-end delay upper limit value, the switching decision unit 64 determines that the user's quality requirements are not met and therefore switching is necessary.

[0089] As an example, assume that the upper limit of end-to-end delay is 200 ms. For example, if the processing delay time of the cloud resource 30-1 used by user A is 100 ms and the transfer delay time of the network path used by user A is 70 ms, the combined value is 170 ms, which is below the upper limit of delay of 200 ms. Therefore, the switching determination unit 64 determines that switching is not necessary. For example, if the processing delay time of the cloud resource 30-1 used by user A is 140 ms and the transfer delay time of the network path used by user A is 70 ms, the combined value is 210 ms, which is above the upper limit of delay of 200 ms. Therefore, the switching determination unit 64 determines that switching is necessary. Here, it is assumed that it has been determined that switching is necessary.

[0090] The switching determination unit 64 determines the optimal switching destination based on information specifying the user (e.g., identification information of user A) and the information DB 61 (step S312). Specifically, the switching determination unit 64 refers to the information DB 61 and searches for a cloud resource 30 and a network route that can satisfy the quality requirement of user A (e.g., upper limit of end-to-end delay).

[0091] If the search results in multiple candidate switching destinations, the switching determination unit 64 determines, for example, the candidate with the shortest total delay as the optimal switching destination. Here, it is assumed that the cloud resource 30-3 is determined as the switching destination of the cloud resource 30, and the line between the communication device 20-1 and the communication device 20-4 (for example, line 4) is determined as the switching destination of the network path. The switching determination unit 64 outputs information about the determined switching destination to the switching instruction unit 65.

[0092] The switching instruction unit 65 generates a switching instruction based on the switching destination information output from the switching determination unit 64 (step S313). Specifically, the switching instruction unit 65 generates a cloud switching instruction including information about the cloud resource 30 included in the switching destination information (e.g., cloud resource 30-3) and information indicating the switching target user (e.g., user A), and a NW switching instruction including information about the network path (e.g., line 4) and information indicating the switching target user (e.g., user A). The switching instruction unit 65 transmits the generated NW switching instruction to the network controller 50 (step S314), and transmits a cloud switching instruction to the cloud controller 40 (step S315).

[0093] The switching instruction unit 55 of the network controller 50 receives the NW switching instruction transmitted from the integrated controller 60. The switching instruction unit 55 instructs the communication device 20 to change the settings in response to the received NW switching instruction (step S316). Specifically, the switching instruction unit 55 instructs the communication device 20-1 to switch the network path. For example, the switching instruction unit 55 instructs the communication device 20-1 to switch the path so that the signal from user A is transferred via line 4.

[0094] The switching instruction unit 45 of the cloud controller 40 receives the cloud switching instruction sent from the integrated controller 60. In response to the received cloud switching instruction, the switching instruction unit 45 instructs the cloud resource 30-2 to change its settings (step S317). Specifically, the switching instruction unit 45 instructs the cloud resource 30-3 to switch the amount of resource allocation. For example, the switching instruction unit 45 instructs the cloud resource 30-3 to allocate the resources requested by user A.

[0095] In the process of step S312, if the switching determination unit 64 does not find a candidate switching destination as a result of the search, it notifies the switching instruction unit 65 that there is no switching destination that satisfies the conditions. The switching instruction unit 65 generates a switching instruction including the fact that there is no switching destination that satisfies the conditions. The switching instruction unit 65 transmits the generated switching instruction to the cloud controller 40 and the network controller 50.

[0096] 6 and 7 show a configuration in which the integrated controller 60 performs processing in response to a notification from the cloud controller 40, but the integrated controller 60 may also perform processing (determine whether switching is necessary, determine the optimal switching destination, etc.) in response to a notification from the network controller 50. In the case where notification is from the network controller 50, the network controller 50 performs processing from step S308 to step S310 shown in FIG. 6. Furthermore, the integrated controller 60 may also perform processing in response to notifications from the cloud controller 40 and the network controller 50.

[0097] According to the communication system 100 configured as described above, the cloud controller 40 includes a cloud information collection unit 41 that collects cloud information from each of the multiple cloud resources 30, and a switching instruction unit 45 that, when it is determined based on the collected cloud information and the quality upper limit obtained from the integrated controller 60 that switching of the cloud resources 30 is necessary and there is a cloud resource 30 that satisfies the quality upper limit, instructs the cloud resource 30 that satisfies the quality upper limit to switch to the cloud resource 30 that satisfies the quality upper limit. The network controller 50 includes a NW information collection unit 51 that collects NW information related to the multiple communication devices 20 and the network formed by the multiple communication devices 20 from each of the multiple communication devices 20, and a switching instruction unit 55 that, when it is determined based on the collected NW information and the quality upper limit obtained from the integrated controller 60 that switching of the network path is necessary and there is a network path that satisfies the quality upper limit, instructs the communication devices 20 that are related to the network path that satisfies the quality upper limit to switch to the network path that satisfies the quality upper limit.

[0098] As described above, the cloud controller 40 and the network controller 50 each autonomously determine whether switching is necessary and perform switching. This reduces the amount of control information sent and received between the controllers, thereby reducing the processing load and response time. Furthermore, since the cloud controller 40 and the network controller 50 can each perform autonomous control without transmitting information to the integrated controller 60, it is possible to reduce processing time.

[0099] Furthermore, in the communication system 100, if the cloud controller 40 or the network controller 50 cannot determine the optimal switching destination, the integrated controller 60 determines the optimal switching destination. In this way, the integrated controller 60 does not always determine the optimal switching destination, but determines the optimal switching destination only when necessary. Therefore, it is possible to reduce control via the integrated controller 60. As a result, it is possible to reduce processing time.

[0100] Furthermore, in the communication system 100, even if the cloud controller 40 determines that a cloud resource 30 needs to be switched or the network controller 50 determines that a network path needs to be switched and the optimal switching destination cannot be determined, if the integrated controller 60 determines that the user's quality requirements can be met without switching, the switching will not be performed. Therefore, unnecessary switching of the cloud resource 30 or network path does not occur. This makes it possible to reduce the network load and the processing load on the controller.

[0101] (Modification 1) The communication system 100 shown in Fig. 1 may be configured as shown in Fig. 8. Fig. 8 is a diagram showing an example of the functional configuration of the cloud controller 40, the network controller 50, and the integrated controller 60a in Modification 1. The configuration shown in Fig. 8 differs only in the configuration of the integrated controller 60a. The following description will focus on the differences.

[0102] The integrated controller 60a includes an information DB 61, a quality requirement DB 62, a threshold determination unit 63a, a switching determination unit 64, and a switching instruction unit 65. The threshold determination unit 63a calculates the delay time allocated to each of the cloud resource 30 and the network path for each user based on the quality requirements for each user registered in the quality requirement DB 62. Furthermore, the threshold determination unit 63a may vary the threshold based on the information stored in the information DB 61. For example, if the threshold determination unit 63a determines that the processing delay time of the cloud resource 30 is increasing, the threshold determination unit 63a may lower the threshold on the network side because the tolerance on the network side is also decreasing.

[0103] (Variation 2) In the above-described embodiment, a configuration in which a cloud resource 30 is used at one location (e.g., termination device 10) has been described. However, as shown in FIG. 9 , the cloud controller 40, network controller 50, and integrated controller 60 in the embodiment may perform similar processing in a situation in which the cloud resource 30 is used while passing information from one location (e.g., termination device 10) to another location (e.g., termination device 70). FIG. 9 is a diagram illustrating an example configuration of a communication system 100b in Variation 2 of the embodiment. The communication system 100b includes a termination device 10, multiple communication devices 20-1 to 20-4, multiple cloud resources 30-1 to 30-3, a cloud controller 40, a network controller 50, an integrated controller 60, and a termination device 70. The communication system 100b has the same system configuration as the communication system 100, except for the addition of the termination device 70. The differences will be described below. The termination device 70 is a device with which the termination device 10 communicates. The signal transmitted from the termination device 10 is processed using the cloud resource 30-1 and then terminated at the termination device 70.

[0104] Some of the functional units of the cloud controller 40, the network controller 50, and the integrated controllers 60 and 60a in the above-described embodiments may be implemented by a computer. In this case, a program for implementing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0105] Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, optical magnetic disks, ROMs (Read Only Memory), and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording media" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs over networks like the Internet or communication lines like telephone lines, or devices that store programs for a fixed period of time, such as volatile memory within the computer systems that serve as servers or clients. Furthermore, the programs may be designed to implement some of the aforementioned functions, or may be capable of implementing the aforementioned functions in combination with programs already stored in the computer system, or may be implemented using programmable logic devices such as FPGAs (Field-Programmable Gate Arrays).

[0106] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0107] The present invention can be applied to a communication system that uses cloud resources via a network.

[0108] DESCRIPTION OF SYMBOLS 10... Termination device, 20... Communication device, 30... Cloud resource, 40... Cloud controller, 41... Cloud information collection unit, 42, 52, 61... Information DB, 43, 53... Switching determination unit, 44, 54, 64... Switching decision unit, 45, 55, 65... Switching instruction unit, 50... Network controller, 51... NW information collection unit, 60, 60a... Integrated controller, 62... Quality requirement DB, 100, 100b... Communication system

Claims

1. A control device comprising: an information collecting unit that collects cloud information regarding a plurality of cloud resources from each of the plurality of cloud resources; and a switching instruction unit that instructs the cloud resource that satisfies the quality upper limit to switch to the cloud resource that satisfies the quality upper limit when switching of the cloud resource is necessary based on the collected cloud information and a quality upper limit obtained from a higher-level device and there is a cloud resource that satisfies the quality upper limit.

2. The control device of claim 1, wherein the switching instruction unit notifies the upper device when there is no cloud resource that satisfies the quality upper limit or when switching of the network path is necessary, and when an instruction to switch the cloud resource is received from the upper device, instructs the relevant cloud resource to switch.

3. A control device comprising: an information collecting unit that collects network information relating to a plurality of communication devices and a network formed by the plurality of communication devices from each of the plurality of communication devices; and a switching instruction unit that, when it is necessary to switch a network route based on the collected network information and a quality upper limit obtained from a higher-level device and there is a network route that satisfies the quality upper limit, instructs a communication device related to the network route that satisfies the quality upper limit to switch to the network route that satisfies the quality upper limit.

4. The control device according to claim 3, wherein the switching instruction unit notifies the upper device when there is no network route that satisfies the quality upper limit or when switching of cloud resources is necessary, and when an instruction to switch the network route is received from the upper device, instructs the communication device related to the relevant network route to switch.

5. A communication system comprising a plurality of cloud resources, a plurality of communication devices provided on a path for using any of the plurality of cloud resources, a cloud controller controlling the plurality of cloud resources, a network controller controlling the plurality of communication devices, and an integrated controller controlling the cloud controller and the network controller, wherein the cloud controller comprises: a first information collection unit collecting cloud information relating to the plurality of cloud resources from each of the plurality of cloud resources; and a first switching instruction unit instructing the cloud resource satisfying the quality upper limit to switch to a cloud resource satisfying the quality upper limit when switching of the cloud resource is necessary and there is a cloud resource that satisfies the quality upper limit based on the collected cloud information and a quality upper limit obtained from the integrated controller; and the network controller comprises: a second information collection unit collecting network information relating to the plurality of communication devices and a network formed by the plurality of communication devices from each of the plurality of communication devices, and a second switching instruction unit that, when it is necessary to switch the network path based on the collected network information and the quality upper limit obtained from the integrated controller and there is a network path that satisfies the quality upper limit, instructs a communication device related to the network path that satisfies the quality upper limit to switch to the network path that satisfies the quality upper limit.

6. The communication system described in claim 5, wherein the first switching instruction unit notifies the integrated controller when there is no cloud resource that satisfies the quality upper limit or when switching of the network path is necessary, and when an instruction to switch the cloud resource is obtained from the integrated controller, instructs the relevant cloud resource to switch; the second switching instruction unit notifies the integrated controller when there is no network path that satisfies the quality upper limit or when switching of the cloud resource is necessary, and when an instruction to switch the network path is obtained from the integrated controller, instructs the communication device related to the relevant network path to switch; and the integrated controller determines an optimal switching destination when a notification is obtained from the first switching instruction unit or the second switching instruction unit.

7. A switching method comprising: collecting cloud information regarding a plurality of cloud resources from each of the plurality of cloud resources; and, if switching of the cloud resources is necessary based on the collected cloud information and a quality upper limit obtained from a higher-level device and there is a cloud resource that satisfies the quality upper limit, instructing the cloud resource that satisfies the quality upper limit to switch to the cloud resource that satisfies the quality upper limit.

8. A switching method comprising: collecting network information relating to a plurality of communication devices and a network formed by the plurality of communication devices from each of the plurality of communication devices; and, when it is determined based on the collected network information and a quality upper limit obtained from a higher-level device that a network route needs to be switched and there is a network route that satisfies the quality upper limit, instructing a communication device related to the network route that satisfies the quality upper limit to switch to the network route that satisfies the quality upper limit.

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