Policy decision device, policy decision method and program

Abstract

Dynamically determine a policy for controlling requested booting. A policy decision device according to one embodiment of the present invention includes a policy decision unit, a change condition determination unit, and a change request unit. The policy decision unit determines a first policy for a first boot control device to control a requested boot target including first target address data based on monitoring data related to a state of a device within a network received from an external device. The change condition determination unit determines whether a predetermined policy change condition is satisfied based on the monitoring data. When it is determined that the policy change condition is satisfied, the change request unit requests a change to a second policy from the first policy decision device that determines a second policy, i.e., the second policy is for a second boot control device different from the first boot control device to control a requested boot target including first target address data.

Description

Technical Field

[0001] The present invention relates to load distribution on a network. Background Art

[0002] In a network system, HTTP (Hypertext Transfer Protocol) requests are not concentrated on a single server, such as the source server in a CDN (Content Delivery Network), but are distributed to the server or its substitute servers, thereby improving the scalability and availability of the system. Related load distribution technologies are roughly divided into two methods: a method of directing requests to each server according to a predetermined strategy such as round-robin matching or weighted round-robin matching (static distribution method); and a method of monitoring the status of each server, such as the number of connections, the number of clients, the amount of data communication, the response time, the server load, etc. in real time, and directing the request to the appropriate server (dynamic distribution method).

[0003] In recent years, load distribution technology has been applied to edge computing technology, CDN technology, etc. Non-patent document 1 describes research on CDN technology to economically and efficiently distribute high-definition and high-context next-generation image content represented by 4K / 8K and AR / VR.

[0004] Non-patent document 1: Masahiro Yaskawa and others, "Future Future Materials Materialization System", NTT Technical Journal, March 2018, pages 23 to 30 Summary of the invention

[0005] The aforementioned static distribution method is easy to achieve load distribution through a simple strategy, but on the other hand, its efficiency may decrease when the state of the candidate for the guidance target changes. On the other hand, the aforementioned dynamic distribution method is that the efficiency of load distribution is unlikely to decrease even if the state of the guidance target changes, but on the other hand, the load balancer needs to monitor the state of the candidate for the guidance target in real time and select the guidance target.

[0006] The present invention aims to dynamically determine a strategy for controlling the steering of requests.

[0007] The first embodiment of the present invention involves a policy decision device including a monitoring data acquisition unit, a policy decision unit, a policy notification unit, a change condition determination unit, and a change request unit. The monitoring data acquisition unit acquires monitoring data related to the status of a device in a network received from an external device. The policy decision unit determines a first policy for a first boot control device to control a first requested boot target including first target address data based on the monitoring data. The policy notification unit notifies the first boot control device of the first policy. The change condition determination unit determines whether a predetermined first policy change condition is satisfied based on the monitoring data. When it is determined that the first policy change condition is satisfied, the change request unit requests a change to a second policy from the first policy decision device that determines the second policy, wherein the second policy is used for a second boot control device different from the first boot control device to control a second requested boot target including first target address data.

[0008] As described above, the policy decision device involved in the first method determines whether the first policy change condition is satisfied, and when it is determined that the first policy decision device is satisfied, requests the first policy decision device to change the second policy determined by it. On the other hand, the first policy decision device corrects the second policy determined by it based on the received policy change request. That is, according to the policy decision device, a local change in the state of the device in the network is captured and a policy change request is issued, and the first policy decision device corrects the second policy determined by itself in response to the request. Therefore, even if a large-scale load distribution system is constructed using the policy decision device, the policy is corrected in a manner that can adapt to the local change in the state of the device in the network, so that the guidance control device using the relevant policy can appropriately guide the request.

[0009] The policy decision device involved in the first embodiment may also include an update condition determination unit and an update request unit. The update condition determination unit determines whether a predetermined policy update condition is satisfied. When it is determined that the policy update condition is satisfied, the update request unit requests an update of the first policy. The policy decision device (hereinafter referred to as the policy decision device involved in the second embodiment of the present invention) determines whether the policy update condition is satisfied, and when it is determined that the policy update condition is satisfied, requests an update of the first policy. Therefore, according to the policy decision device, the first policy used by the first guidance control device under the policy decision device can be dynamically determined.

[0010] Based on the policy decision device involved in the first aspect or the second aspect, the monitoring data may represent the load of at least a part of a plurality of first candidates of the requested boot target including the first target address data. The first policy change condition may be that the load of the first boot target included in the first candidate exceeds the first load threshold. According to the policy decision device (hereinafter referred to as the policy decision device involved in the third aspect of the present invention), it is possible to request the first policy decision device to correct the second policy according to the size of the load of the first boot target.

[0011] Based on the policy decision device involved in the first aspect or the second aspect, the monitoring data may indicate the number of customers of at least a part of a plurality of first candidates of the requested guidance destination including the first target address data. The first policy change condition may be that the number of customers of the first guidance destination included in the first candidate exceeds a first customer number threshold. According to the policy decision device (hereinafter referred to as the policy decision device involved in the fourth aspect of the present invention), it is possible to request the first policy decision device to correct the second policy according to the number of customers of the first guidance destination.

[0012] In the policy decision device according to the first aspect or the second aspect, the monitoring data may indicate availability of at least a portion of a plurality of first candidates for a requested boot target including the first target address data. The first policy change condition may be that the first boot target included in the first candidate is not available. According to the policy decision device, correction of the second policy can be requested from the first policy decision device according to the availability of the first boot target.

[0013] Based on the policy decision device according to the third aspect or the fourth aspect, the second policy may indicate a ratio at which the second guidance control device guides the second request to each of the plurality of second candidates of the guidance targets of the second request. When it is determined that the first policy change condition is satisfied, the change request unit may request the first policy decision device to cause the second guidance control device to reduce the ratio at which the second request is guided to the first guidance target. According to the policy decision device, it is possible to request the first policy decision device to cause the second guidance control device to reduce the ratio at which the request is guided to the first guidance target, depending on the size of the load of the first guidance target or the number of customers of the first guidance target.

[0014] On the basis of the policy decision device involved in the third embodiment, the change condition determination unit can also determine whether a predetermined second policy change condition is met based on monitoring data. The second policy change condition can be that the load of the first boot target exceeds a second load threshold, and the second load threshold is greater than the first load threshold. In the case where it is determined that the second policy change condition is met, the change request unit can request a change in the second policy from the first policy decision device, and request a change in the third policy from the second policy decision device that determines the third policy, and the third policy is used for a third boot control device different from the first boot control device and the second boot control device to control the boot target of the third request including the first target address data. According to the policy decision device (hereinafter referred to as the policy decision device involved in the fifth embodiment of the present invention), as the load of the first boot target increases, the required target of the policy change can be expanded in stages.

[0015] On the basis of the policy decision device involved in the fourth aspect, the change condition determination unit can also determine whether a predetermined second policy change condition is satisfied based on monitoring data. The second policy change condition can be that the number of customers of the first guide target exceeds a second customer number threshold, and the second customer number threshold is greater than the first customer number threshold. In the case where it is determined that the second policy change condition is satisfied, the change request unit can request a change in the second policy from the first policy decision device, and request a change in the third policy from the second policy decision device that determines the third policy, wherein the third policy is used for a third guide control device different from the first guide control device and the second guide control device to control the third requested guide target including the first target address data. According to this policy decision device (hereinafter referred to as the policy decision device involved in the sixth aspect of the present invention), as the number of customers of the first guide target increases, the required targets for policy changes can be expanded in stages.

[0016] Based on the policy decision device involved in the fifth or sixth aspect, the second policy may indicate the ratio at which the second guidance control device guides the second request to each of the plurality of second candidates for the guidance target of the second request. The third policy may indicate the ratio at which the third guidance control device guides the third request to each of the plurality of third candidates for the guidance target of the third request. When it is determined that the second policy change condition is satisfied, the change request unit may request the first policy decision device to reduce the ratio at which the second guidance control device guides the second request to the first guidance target, and request the second policy decision device to reduce the ratio at which the third guidance control device guides the third request to the first guidance target. According to the policy decision device, as the load of the first guidance target or the number of customers of the first guidance target increases, the policy change request targets can be expanded in stages, and each request target can be requested to reduce the ratio at which the lower-level guidance control device guides the request to the first guidance target.

[0017] Based on the policy decision device involved in the first to sixth aspects of the present invention, the policy decision unit may further determine a fourth policy based on monitoring data, the fourth policy being used for the first guidance control device to control the guidance target of the request satisfying the first condition in the first request. The policy notification unit may further notify the first guidance control device and the first policy decision device of the fourth policy. According to the policy decision device, even if the guidance control device that processes the request from the terminal user that sends the request satisfying the first condition moves and the terminal user is switched, the same policy can be applied to the request from the terminal user.

[0018] The policy decision method involved in the seventh embodiment of the present invention has the following steps: obtaining monitoring data related to the status of the equipment in the network received from an external device; determining a first policy for a first boot control device to control the boot target of a first request including first target address data based on the monitoring data; notifying the first boot control device of the first policy; determining whether a predetermined first policy change condition is satisfied based on the monitoring data; and requesting a change to a second policy from the first policy decision device that determines a second policy when it is determined that the first policy change condition is satisfied, wherein the second policy is used for a second boot control device different from the first boot control device to control the boot target of a second request including first target address data.

[0019] As described above, the policy decision method involved in the seventh mode determines whether the first policy change condition is satisfied, and when it is determined to be satisfied, requests the first policy decision device to change the second policy it has decided. On the other hand, the first policy decision device corrects the second policy it has decided based on the received policy change request. That is, according to the policy decision method, a policy change request is issued by capturing a local change in the state of a device in the network, and the first policy decision device corrects the second policy it has decided in response to the request. Therefore, even if a large-scale load distribution system is constructed using the policy decision method, the policy is corrected in a manner that can adapt to local changes in the state of the device in the network, so that the guidance control device using the relevant policy can appropriately guide the request.

[0020] The program involved in the eighth embodiment of the present invention causes a computer to function as the following units: a unit for acquiring monitoring data related to the status of a device within a network received from an external device; a unit for determining a first strategy for a first boot control device to control a boot target of a first request including first target address data based on the monitoring data; a unit for notifying the first boot control device of the first strategy; a unit for determining whether a predetermined first policy change condition is satisfied based on the monitoring data; and a unit for requesting a change to a second strategy from a first policy decision device that determines a second strategy when it is determined that the first policy change condition is satisfied, wherein the second strategy is used for a second boot control device, which is different from the first boot control device, to control a boot target of a second request including first target address data.

[0021] As described above, the program involved in the eighth method determines whether the first policy change condition is satisfied, and when it is determined to be satisfied, requests the first policy decision device to change the second policy it has decided. On the other hand, the first policy decision device corrects the second policy it has decided based on the received policy change request. That is, according to the program, a policy change request is issued by capturing a local change in the state of a device in the network, and the first policy decision device corrects the second policy it has decided in response to the request. Therefore, even if a large-scale load distribution system is constructed using the program, the policy is corrected in a manner that can adapt to local changes in the state of the device in the network, so that the guidance control device using the relevant policy can appropriately guide the request.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to dynamically determine a policy for controlling the routing of requests. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram illustrating an example of a load distribution system including a policy decision device according to an embodiment.

[0025] Figure 2 yes Figure 1 A diagram illustrating coordination among multiple policy decision devices of a load distribution system.

[0026] Figure 3 This is a block diagram illustrating a policy decision device according to an embodiment.

[0027] Figure 4 This is an example of saving Figure 3 A graph of the metrics of the monitoring data store and their scores.

[0028] Figure 5 yes Figure 3 An illustration of the operation of the strategy decision unit.

[0029] Figure 6 This is an example of saving Figure 3 A policy storage unit is a diagram of the policy.

[0030] Figure 7 This is an example of Figure 3 The strategic decision-making department will Figure 6 A graph of new policies obtained by changing the policy based on policy change requests from other policy decision devices.

[0031] Figure 8 It means by Figure 3 A flowchart of an example of an action of requesting a policy change to another policy decision device by a policy decision device.

[0032] Fig. 9 It means by Figure 3 A flowchart of another example of an action of requesting a policy change to another policy decision device by a policy decision device.

[0033] Fig.10 This is an example of Figure 3 Flowchart of the policy update action performed by the policy decision device.

[0034] Fig.11 It is an example of Figure 1 FIG. 1 is a diagram of a modified example of a load distribution system.

[0035] Fig.12 It is an example of Figure 1 FIG. 1 is a diagram of a modified example of a load distribution system. DETAILED DESCRIPTION

[0036] Hereinafter, the embodiments will be described with reference to the accompanying drawings. In addition, the same or similar reference numerals will be used for the elements that are the same as or similar to the elements that have been described, and repeated descriptions will be basically omitted. For example, when there are multiple same or similar elements, sometimes a common reference numeral is used in order not to distinguish the elements from each other, and sometimes a sub-numeral is used on the basis of the common reference numeral in order to distinguish the elements from each other.

[0037] (Implementation Method)

[0038] exist Figure 1 The load distribution system including the policy decision device 10 according to the embodiment is illustrated in the figure. The load distribution system includes the policy decision device 10, ..., guidance control devices 20A, 20B, ..., detection servers 41, ..., monitoring systems 42, ..., terminal users 50A, 50B, ..., source servers 60, edge servers 70A, 70B, 70C, ..., CDNs 100A, 100B, ....

[0039] Details of the use of the policy decision device 10 Figure 3 This will be described later, and an overview is given here. The policy decision device 10 collects monitoring data from the detection server 41 and / or the monitoring system 42 (S10). The policy decision device 10, for example, uses a policy update request (S11) from its subordinate guidance control device 20A, 20B, ... as a trigger, and can determine (update) the policy used by the guidance control device 20, which is the source of the policy update request. Here, the guidance control device 20 that uses the policy determined by the policy decision device 10 is referred to as the guidance control device 20 under the policy decision device 10. In addition, the policy decision device 10 notifies the guidance control device 20, which is the source of the policy update request, of the determined policy (S12).

[0040] Here, the policy may represent a plurality of candidates for the guidance destination of the request and a ratio of guiding the request to each of the candidates. The guidance control device 20 can use the ratio as a weight in, for example, a weighted round-robin comparison to distribute the request.

[0041] In addition, Figure 1 A policy decision device 10 is depicted in FIG. Figure 1 The load distribution system may also include a plurality of policy decision devices 10. In addition, the total number of the guidance control devices 20 under each policy decision device 10 may be 2, 1, or more than or equal to 3.

[0042] The guidance control device 20 may be equivalent to an L7 load balancer (also referred to as an HTTP load balancer), for example. A region is defined for each guidance control device 20, and the guidance control device 20 can guide requests to a PoP (Point Of Presence) belonging to the corresponding region. Here, PoP represents a location of a guidance target having a connection point to an external network.

[0043] The guidance control device 20 receives a request including target address data to the source server 60 from the terminal user 50A (S21), and guides the request to any one of the source server 60, the edge servers 70A, 70B, 70C, ... and the CDNs 100A, 100B, ... according to the policy determined by the policy decision device 10, that is, transmits the request to the guidance target (S22). In addition, the guidance target of the request (other than the source server 60) can be connected to the source server 60 as needed, for example, when the content as the object of the request is not cached (S23).

[0044] The detection server 41 and / or the monitoring system 42 continuously monitors the devices in the network, such as Figure 1The detection server 41 and / or the monitoring system 42 monitors the status of the origin server 60, the edge server 70 and / or the CDN 100 in the policy decision device 10 to generate monitoring data. The detection server 41 and / or the monitoring system 42 transmits the monitoring data to the policy decision device 10 (S10).

[0045] The terminal user 50 may be, for example, a smart phone, a tablet, a PC, a car (including an onboard device), a sensor, or other devices. For example, the terminal user 50 may issue a request including a URL (Uniform Resource Locator) indicating the location of the content as target address data in order to obtain the content (Web page, etc.) stored in the source server 60. The terminal user 50 connects to the guidance control device 20 using domain name resolution using the DNS (Domain Name System) or broadcasting for the issued request. Then, the terminal user 50 sends the request to the guidance control device 20 (S21).

[0046] The origin server 60 is a server that stores original content. The original content stored by the origin server 60 may be cached by, for example, edge servers 70A, 70B, 70C, ..., and / or cache servers within the CDN 100A, 100B.

[0047] The edge servers 70A, 70B, 70C, ..., and / or the CDNs 100A, 100B are candidates for the destination of the request. The edge servers 70A, 70B, 70C, ..., and / or the CDNs 100A, 100B can cache the original content stored by the origin server 60.

[0048] The policy decision device 10 according to the embodiment captures the devices in the network, such as Figure 1 In response to the local change in the state of the source server 60, edge server 70 and / or CDN 100, the other policy decision device 10 is requested to change the policy it has decided. On the other hand, the other policy decision device 10 that has been requested to change the policy corrects the policy it has decided in response to the request.

[0049] For example, Figure 2As shown, the load distribution system includes three policy decision devices 10-1, 10-2, and 10-3. The policy decision device 10-1 determines the policy used by at least one guiding control device 20-1A, ... Similarly, the policy decision device 10-2 determines the policy used by at least one guiding control device 20-2A, ..., and the policy decision device 10-3 determines the policy used by at least one guiding control device 20-3A, ... Here, for example, if the policy decision device 10-1 captures that the load of a specific edge server 70 exceeds the load threshold, the policy decision device 10-2 and / or the policy decision device 10-3 can be requested to control the request to direct the request to the specific edge server 70. The policy decision device 10-2 and / or the policy decision device 10-3 that receive the relevant request can reduce the proportion of the request to direct the request to the specific edge server 70 in the policy determined by itself. Thus, the guidance control device 20-2A, ..., and / or the guidance control device 20-3A, ... using the relevant policy reduces the proportion of the request directed to the specific edge server 70, and conversely increases the proportion of the request directed to a guidance target other than the specific edge server 70. That is, even in a large-scale load distribution system including a plurality of policy decision devices 10, each policy decision device 10 can correct the policy in a manner adapted to local changes in the state of the device in the network, so the guidance control device 20 using the relevant policy can appropriately guide the request.

[0050] like Figure 3 As an example, the policy decision device 10 according to the embodiment includes a communication I / F (interface) 110 , a processor 120 , and a memory 130 .

[0051] The communication I / F 110 may be a module for communicating with external devices such as the guidance control device 20 , the detection server 41 , the monitoring system 42 , other policy decision devices 10 , etc. via a network, such as an optical communication module.

[0052] Typically, the processor 120 is a CPU (Central Processing Unit) and / or a GPU (Graphics Processing Unit), and may also be a microcomputer, FPGA (Field Programmable Gate Array), DSP (Digital Signal Processor), or other general or dedicated processors, etc. The processor 120 performs processing related to input / output control, communication control, and policy determination, for example.

[0053] The memory 130 includes a memory for temporarily storing programs executed by the processor 120 and data used by the processor 120, such as monitoring data, policy change requests, setting data, policies, etc., in order for the processor 120 to implement various processes. The memory may include a RAM (Random Access Memory) having a work area for related programs / data to be developed.

[0054] The processor 120 can be used as a computer by executing the program stored in the memory 130. Figure 3 The received data acquisition unit 121 (including the monitoring data acquisition unit 122 and the change request acquisition unit 123), the update condition determination unit 124, the policy update request unit 125, the policy decision unit 126, the policy notification unit 127, the change condition determination unit 128 and the policy change request unit 129 function. In addition, the memory 130 may include Figure 3 The monitoring data storage unit 131, the change request storage unit 132, the setting data storage unit 133 and the policy storage unit 134.

[0055] The communication I / F 110 receives various data from an external device and transmits the data to the received data acquisition unit 121 , or vice versa, transmits various data to an external device.

[0056] For example, the communication I / F 110 receives monitoring data related to the status of the device in the network from the detection server 41 or the monitoring system 42 via the network, and sends it to the received data acquisition unit 121. Here, the monitoring data may include, for example, a metric indicating the status of a candidate, such as the edge server 70 and / or the CDN 100, that the guidance control device 20 under the policy decision device 10 can select as a guidance target for a request including target address data from the terminal user 50 to the source server 60. Here, the status of the candidate of the guidance target may include part or all of the candidate's load, response time (such as RTT (Round-Trip Time)), cost (communication fee), availability, number of connections, number of clients, data communication volume, response time, etc., or may not include them.

[0057] In addition, the communication I / F 110 receives a policy change request from another policy decision device 10 via the network, and sends it to the received data acquisition unit 121. Here, the policy change request may be, for example, a request for the guidance control device 20 under the policy decision device 10 to reduce or increase the ratio of guiding the request to a specific part of the multiple candidates for the guidance target of the above request. In addition, the policy change request may be a request for the policy decision device 10 to reduce or increase the priority that can be assigned to a specific part of the metrics described later in order to determine the policy. In addition, the policy change request may include metrics collected in other policy decision devices 10, or their processed values ​​or statistical values, and request the policy decision device 10 to change the policy based on these metrics.

[0058] Furthermore, the communication I / F 110 receives the policy and data (e.g., address) identifying the guidance control device 20 under the policy decision device 10 that is the notification target from the policy notification unit 127, and transmits the policy to the guidance control device 20 via the network. The policy is used by the guidance control device 20 that is the notification target to control the guidance target of the request including the target address data from the terminal user 50 to the source server 60.

[0059] Then, the communication I / F 110 receives the policy change request and data (eg, address) identifying another policy decision device 10 as the requested target from the policy change request unit 129, and transmits the policy change request to the other policy decision device 10 via the network.

[0060] The received data acquisition unit 121 acquires various data received by the communication I / F 110 and writes the data into the memory 130. The received data acquisition unit 121 may include a monitoring data acquisition unit 122 and a change request acquisition unit 123.

[0061] The monitoring data acquisition unit 122 acquires the monitoring data received by the communication I / F 110 , and writes the monitoring data into the monitoring data storage unit 131 in the memory 130 .

[0062] The monitoring data storage unit 131 stores the monitoring data, particularly the metrics, acquired by the monitoring data acquisition unit 122. The monitoring data stored in the monitoring data storage unit 131 can be read by various functional units of the processor 120, such as the update condition determination unit 124, the policy decision unit 126, and / or the change condition determination unit 128.

[0063] As described above, the metric indicates the state of a candidate that can be selected as the guidance target of the above request. The metric may be the value itself included in the monitoring data, or a processed value or statistical value of a correlation value.

[0064] Here, each metric may be normalized to a score between 0 and 1, for example. In addition, the functional unit that performs the related processing may be called a metric normalization unit (not shown). The monitoring data storage unit 131 may store the metric and / or the score of the candidate in association with the candidate of the guidance target. Figure 4 , RTT and cost as metrics, and their scores are shown as examples for each candidate (edge) of the guidance target.

[0065] The change request acquisition unit 123 acquires the policy change request received by the communication I / F 110 , and writes the policy change request into the change request storage unit 132 in the memory 130 .

[0066] The change request storage unit 132 stores the policy change request acquired by the change request acquisition unit 123. The policy change request stored in the change request storage unit 132 can be read by various functional units of the processor 120, such as the update condition determination unit 124 and / or the policy determination unit 126.

[0067] The setting data storage unit 133 stores various setting data. Here, the setting data may include, for example, parameters related to the decision of the policy, data related to the guidance control device 20 under the policy decision device 10, and data related to the candidates of the guidance target that can be selected by the guidance control device 20. The parameters related to the decision of the policy may include, for example, a parameter for scoring the candidates of the guidance target based on the weighted sum of the metrics, a priority (weight) that can be assigned to each metric, a parameter for specifying the number of candidates of the guidance target that can be included in the policy, and various thresholds.

[0068] The update condition determination unit 124 determines whether a predetermined policy update condition is satisfied. If the update condition determination unit 124 determines that the policy update condition is satisfied, it notifies the policy update request unit 125 that the policy update condition is satisfied. In addition, when there are multiple guidance control devices 20 under the policy decision device 10, the update condition determination unit 124 may determine whether the policy used by each guidance control device 20 satisfies the policy update condition.

[0069] For example, the policy update condition may be that the metric and / or score stored in the monitoring data storage unit 131 has changed, or has changed beyond a threshold. In addition, the policy update condition may be that the time elapsed since the last policy update (or decision) has exceeded a threshold. In addition, the policy update condition may be that a new policy change request is stored in the change request storage unit 132. In addition, the policy update condition may be that a policy update request is received from the guidance control device 20 under the policy decision device 10 and stored in the memory 130.

[0070] When notified by the update condition determination unit 124 that the policy update condition is satisfied, the policy update request unit 125 requests the policy determination unit 126 to update the policy.

[0071] The policy decision unit 126 determines the policy based on various data stored in the memory 130 and writes it to the policy storage unit 134, for example, at the time of initial setting of the policy decision device 10, at the time of additional setting of the guidance control device 20 under the policy decision device 10, or when the policy update request unit 125 requests the update of the policy. In order to determine the policy, the policy decision unit 126 can refer to the monitoring data (which can include metrics) stored in the monitoring data storage unit 131, the policy change request stored in the change request storage unit 132, the setting data stored in the setting data storage unit 133, and / or the policy stored in the policy storage unit 134.

[0072] For example, the policy decision unit 126 may determine the score of the candidate by weighted addition of a plurality of metrics (scores) of the candidate for the guidance target according to the priority assigned to each metric. Figure 5 An example of a related score is shown in Figure 5 In the example, "edge 1", "edge 2", ..., "edge 7" are candidates for the guidance target, and the priorities assigned to "RTT score" and "cost score" are "0.8" and "0.2", respectively. In addition, the priorities can be set according to the preferences of the administrator of the policy decision device 10, the guidance control device 20, and / or the administrator of the source server 60. Figure 5 In the example, "RTT" is given more importance than "cost", but "cost" may be given more importance conversely, or metrics other than "cost" and "RTT" may be given more importance (scores).

[0073] Here, the policy decision unit 126 may select the guidance destination candidates included in the policy based on the scores of the candidates and / or the availability or other metrics of the candidates. For example, the policy decision unit 126 may exclude candidates whose scores are lower than a predetermined order, exclude candidates whose scores are lower than a predetermined threshold, or exclude candidates that are not in an available state.

[0074] Furthermore, the strategy determination unit 126 determines a weight indicating the ratio of the guidance control device 20 to request guidance to the candidate using the strategy determined thereafter, based on the score of the candidate for guidance destination. Figure 6As shown in FIG. 1 , the strategy decision unit 126 may determine the ratio of the score of each candidate to the total score of all candidates for the guidance target included in the strategy as the weight of the candidate. In addition, this is only an example of a method for determining the weight, and for example, the weight may be determined in advance according to the order of different scores. The weight may be used, for example, as a weight in a load distribution technology of a weighted round-robin comparison method. That is, using Figure 6 The control device 20 directs 55% of the requests to edge 1 and the remaining 45% to edge 7 according to the guiding strategy.

[0075] Furthermore, the policy decision unit 126 can correct the policy according to the policy change request when the policy change request storage unit 132 stores the policy change request. Assume that the policy change request is to request the policy decision device 10 to reduce the edge score of edge 1 by 20% (≈14). In this case, the policy decision unit 126 reads, for example, Figure 6 The strategy reduces the edge score of edge 1 from "72" to "58", recalculates the weight and changes the strategy to Figure 7 As an example, as a result, the guidance control device 20 can guide 51% of the requests to the edge 7 and the remaining 49% to the edge 1. That is, the load applied to the edge 1 can be suppressed compared with the strategy before the change.

[0076] The policy storage unit 134 stores the policy determined by the policy determination unit 126. The policy stored in the policy storage unit 134 can be read by various functional units of the processor 120, for example, the policy notification unit 127.

[0077] If a new policy (including an updated policy) is stored in the policy storage unit 134, the policy notification unit 127 reads the policy and notifies the corresponding guidance control device 20. Specifically, the policy notification unit 127 sends the policy and data identifying the guidance control device 20 as the notification target to the communication I / F 110, and the communication I / F 110 sends the policy to the guidance control device 20 via the network.

[0078] The change condition determination unit 128 determines whether a predetermined policy change condition is satisfied based on various data stored in the memory 130, such as monitoring data (which may include metrics). Furthermore, when the change condition determination unit 128 determines that the policy change condition is satisfied, it notifies the policy change request unit 129 that the policy change condition is satisfied. In addition, the change condition determination unit 128 may determine whether a plurality of policy change conditions are satisfied. Furthermore, when the change condition determination unit 128 determines that any one of the policy change conditions is satisfied, it may notify the policy change request unit 129 which policy change condition is satisfied.

[0079] Specifically, the policy change condition may be that the load of a specific candidate of the guidance target exceeds a load threshold, the number of customers of the candidate exceeds a customer number threshold, the candidate is not in an available state, etc. In addition, with respect to a common viewpoint, multiple phased policy change conditions may be specified. For example, with respect to the load, the load of a specific candidate of the guidance target exceeding a first load threshold may be defined as a first policy change condition, and the load exceeding a second load threshold (>first load threshold) may be defined as a second policy change condition. Similarly, with respect to the number of customers, the number of customers of a specific candidate of the guidance target exceeding a first customer number threshold may be defined as a first policy change condition, and the number of customers exceeding a second customer number threshold (>first customer number threshold) may be defined as a second policy change condition.

[0080] If the change condition determination unit 128 notifies that the policy change condition has been satisfied, the policy change request unit 129 requests the other policy decision device 10 to change the policy it has decided. Specifically, the policy change request unit 129 generates a policy change request indicating the content of the change requested from the other policy decision device 10, for example, a reduction in the weight of a portion of the candidates for the guidance target in the policy decided by the other policy decision device 10. The policy change request unit 129 sends the generated policy change request and data identifying the policy decision device 10 that is the requested target to the communication I / F 110, and the communication I / F 110 sends the policy change request to the policy decision device 10 via the network.

[0081] In addition, the policy change request unit 129 may select other policy decision devices 10 as the request target according to the satisfied policy change condition. For example, when the load of a specific candidate of the guidance target is greater than the first load threshold but less than the second load threshold (>the first load threshold) (case 1-1), and when the load is greater than the second load threshold (case 1-2), the policy change request unit 129 may make the other policy decision devices 10 included in the request target different.

[0082] Specifically, in case 1-2, the load of the candidate for the guidance target is more serious than in case 1-1, so in order to appropriately control the load of the candidate, it may be necessary to request a reduction in the weight of the candidate to more other policy decision devices 10. On the other hand, in case 1-1, the load of the candidate for the guidance target is not as serious as in case 1-2, so if a reduction in the weight of the candidate is requested to fewer other policy decision devices 10, the load of the candidate may be appropriately controlled.

[0083] Similarly, in the case where the number of customers of a specific candidate for the guidance target is greater than the first customer number threshold but less than the second customer number threshold (>1st customer number threshold) (case 2-1), and in the case where the number of customers is greater than the second customer number threshold (case 2-2), the policy change request unit 129 can make other policy decision devices 10 included in the requested target different.

[0084] Specifically, in case 2-2, the number of customers of the candidate for the guidance target is greater than that of case 2-1, so in order to appropriately control the load of the candidate, it may be necessary to request a reduction in the weight of the candidate to more other policy decision devices 10. On the other hand, in case 2-1, the number of customers of the candidate for the guidance target is not greater than that of case 2-2, so if a reduction in the weight of the candidate is requested to fewer other policy decision devices 10, the load of the candidate may be appropriately controlled.

[0085] In addition, the policy change request unit 129 may select the change content requested from other policy decision devices 10 according to the satisfied policy change conditions. For example, in the above-mentioned situations 1-2 and 2-2, the weight of the candidate of the guidance target may be more significantly reduced than in the above-mentioned situations 1-1 and 2-1.

[0086] Next, use Figure 8 An example of a policy change request operation performed by a policy decision device 10 to another policy decision device 10 will be described. Figure 8 The action may be performed periodically or irregularly. For example, whenever new monitoring data, a policy update request from the guidance control device 20 under the policy decision device 10, etc. are stored in the memory 130, the action may be performed periodically or irregularly. Figure 8 action.

[0087] First, the change condition determination unit 128 reads monitoring data from the monitoring data storage unit 131 (step S401 ). In step S401 , the change condition determination unit 128 may read other data from the memory 130 .

[0088] Then, the change condition determination unit 128 determines whether the policy change condition is satisfied based on the monitoring data (and other data) read out in step S401 (step S402). If the change condition determination unit 128 determines that the policy change condition is satisfied, the process proceeds to step S403. If not, the process ends. Figure 8 action.

[0089] In step S403, the policy change request unit 129 generates a policy change request indicating the change content requested to other policy decision devices 10. In step S403, the policy change request unit 129 may select the content of the policy change request and / or its requested target based on the policy change condition determined to be satisfied in step S402.

[0090] Next, the communication I / F 110 transmits the policy change request generated in step S403 to the policy decision device 10 as the target of the request via the network (step S404), and the process ends. Figure 8 action.

[0091] Next, use Fig. 9 Another example of the policy change request action executed by the policy decision device 10 to another policy decision device 10 is described. Fig. 9 The action example is different from the one in that it specifies the first policy change condition and the second policy change condition in stages. Figure 8 The action examples are different. Fig. 9 The action may be performed periodically or irregularly. For example, whenever new monitoring data, a policy update request from the lower guidance control device 20 of the policy decision device 10, etc. is stored in the memory 130, the action may be performed periodically or irregularly. Fig. 9 action.

[0092] First, the change condition determination unit 128 reads the monitoring data from the monitoring data storage unit 131 (step S411 ). In step S411 , the change condition determination unit 128 can read other data from the memory 130 .

[0093] Then, the change condition determination unit 128 determines whether the first policy change condition is satisfied based on the monitoring data (and other data) read out in step S411 (step S412). If the change condition determination unit 128 determines that the first policy change condition is satisfied, the process proceeds to step S413. If not, the process ends. Fig. 9 action.

[0094] In step S413, the change condition determination unit 128 determines whether the second policy change condition is satisfied based on the monitoring data (and other data) read out in step S411. If the change condition determination unit 128 determines that the second policy change condition is satisfied, the process proceeds to step S417, and if not, the process proceeds to step S414.

[0095] In step S414, the policy change request unit 129 generates a first policy change request indicating the change content requested to other policy decision devices 10. In step S414, the policy change request unit 129 may select the change content indicated by the first policy change request based on the first policy change condition determined to be satisfied in step S412.

[0096] In addition, in step S415, the policy change request unit 129 selects the first policy decision device group. Here, the first policy decision device group represents one or more other policy decision devices 10 that are the request targets of the first policy change request generated in step S414. In addition, in step S415, the policy change request unit 129 may select the first policy decision device group based on the first policy change condition determined to be satisfied in step S412.

[0097] After step S414 and step S415, the communication I / F 110 transmits the first policy change request generated in step S414 to the first policy decision device group selected in step S415 via the network (step S416), and the process ends. Fig. 9 action.

[0098] In step S417, the policy change request unit 129 generates a second policy change request indicating the change content requested to the other policy decision device 10. In addition, in step S417, the policy change request unit 129 may select the change content indicated by the second policy change request based on the second policy change condition determined to be satisfied in step S413. The change content indicated by the second policy change request may be the same as or different from the change content indicated by the first policy change request.

[0099] In addition, in step S418, the policy change request unit 129 selects the second policy decision device group. Here, the second policy decision device group represents one or more other policy decision devices 10 that are the target of the second policy change request generated in step S417. In addition, in step S418, the policy change request unit 129 may select the second policy decision device group based on the second policy change condition determined to be satisfied in step S413. The second policy decision device group may be the same as or different from the first policy decision device group.

[0100] After step S417 and step S418, the communication I / F 110 transmits the second policy change request generated in step S417 to the second policy determination device group selected in step S418 via the network (step S419), and the process ends. Fig. 9 action.

[0101] also, Figure 8 as well as Fig. 9However, a typical action example is shown, and policy change conditions greater than or equal to three stages can be defined. When higher-level policy change conditions are met, in addition to increasing the required targets for policy changes, as mentioned above, greater changes can be required for each required target, such as a greater reduction in the weight of the object's guidance target.

[0102] Next, use Fig.10 An example of the policy update operation performed by the policy decision device 10 will be described. Fig.10 The action may be performed periodically or irregularly. For example, whenever new monitoring data, policy change requests, policy update requests from the guidance control device 20 under the policy decision device 10, etc. are stored in the memory 130, the action may be performed periodically or irregularly. Fig.10 action.

[0103] First, the update condition determination unit 124 determines whether the policy update condition is satisfied (step S501). The update condition determination unit 124 can determine whether the policy update condition is satisfied based on, for example, the monitoring data stored in the monitoring data storage unit 131, the policy change request stored in the change request storage unit 132, and / or the policy update request from the guidance control device 20 under the policy decision device 10 stored in the memory 130. If the update condition determination unit 124 determines that the policy update condition is satisfied, the process proceeds to step S502. If not, the process ends. Fig.10 action.

[0104] In step S502, the policy update request unit 125 requests the policy decision unit 126 to update the policy. In step S502, the policy update request unit 125 may select a policy to be updated based on the policy update condition determined to be satisfied in step S501.

[0105] Next, the policy decision unit 126 reads various data required for updating the policy from the memory 130 (step S503). The relevant data may be, for example, monitoring data, setting data, and / or a policy change request. Furthermore, the relevant data may include the policy before the update.

[0106] Then, the policy determination unit 126 determines a policy based on the data read out in step S503 , and stores the determined policy in the policy storage unit 134 (step S504 ).

[0107] Next, the policy notification unit 127 reads the policy stored in step S504 from the policy storage unit 134, notifies the guidance control device 20 using the policy (step S505), and ends. Fig.10 action.

[0108] As described above, the policy decision device involved in the implementation method determines whether a predetermined policy change condition is satisfied, and if it is determined to be satisfied, it requests other policy decision devices to change the policy they have decided. On the other hand, other policy decision devices correct the policy they have decided based on the received policy change request. That is, according to the above-mentioned policy decision device, any policy decision device captures local changes in the state of a device in the network and issues a policy change request, and other policy decision devices respond to the request and correct the policy they have decided. Therefore, even if a large-scale load distribution system is constructed using the policy decision device, the policy is corrected in a manner that can adapt to local changes in the state of the device in the network, so that the guidance control device using the relevant policy can appropriately guide the request.

[0109] In addition, the policy decision device determines whether predetermined policy update conditions are met. If it is determined that the conditions are met, it can dynamically determine the policy used by the guidance control device under the policy decision device based on monitoring data related to the status of equipment within the network received from external devices, policy change requests received from other policy decision devices, etc.

[0110] (Variant 1)

[0111] In the above-mentioned embodiment, it is assumed that the guidance control device 20 can be equivalent to an L7 load balancer. However, instead of the guidance control device 20, a guidance control device 30 that can be equivalent to an L4 load balancer (also called a DNS load balancer) may be used.

[0112] Fig.11 as well as Fig.12 It is shown in Figure 1 The load distribution system is a modified example of a load distribution system. The load distribution system includes a guidance control device 30A, 30B, ... instead of the guidance control device 20A, 20B, ..., and adds a DNS resolver 80 and an authoritative DNS server 90 ( Fig.12 ) Figure 1 The load distribution system is different.

[0113] The policy decision device 10 collects monitoring data from the detection server 41 and / or the monitoring system 42 (S10). The policy decision device 10 can be triggered by, for example, a policy update request (S11) from its lower-level guidance control device 30A, 30B, ..., and determine (update) the policy used by the guidance control device 30 that is the source of the policy update request. In addition, the policy decision device 10 notifies the guidance control device 30 that is the source of the policy update request of the determined policy (S12).

[0114] In addition, Figure 1 Similar to the example, the total number of the guidance control devices 30 under each policy decision device 10 can be 2, 1, or greater than or equal to 3.

[0115] The guidance control device 30 may be equivalent to a L4 load balancer, for example. A zone may be defined for each guidance control device 30, and the guidance control device 30 may guide requests to PoPs belonging to its corresponding zone.

[0116] The guidance control device 30 receives an inquiry about the IP (Internet Protocol) address corresponding to the domain name of the source server 60 from the DNS resolver 80 (S32). In response to the inquiry, the guidance control device 30 returns the IP address of the guidance target (e.g., the source server 60, the edge servers 70A, 70B, 70C, ..., and CDNs 100A, 100B, ...) selected according to the policy determined by the policy decision device 10 (S33), or returns the information of the authoritative DNS server that manages the IP address (S43), that is, guides the above request. In addition, the requested guidance target (other than the source server 60) can be connected to the source server 60 as needed, for example, when the content that is the object of the request is not cached (S36, S48).

[0117] For example, the terminal user 50 may issue a request including a URL indicating the location of the content as target address data in order to obtain the content stored in the source server 60. The terminal user 50 sends the issued request to the DNS resolver 80 (S31). In addition, the terminal user 50 is notified of the IP address of the requested guide target by the DNS resolver 80 (S34, S46). The terminal user 50 sends the request to the guide target based on the notified IP address (S35, S47).

[0118] The DNS resolver 80 receives an inquiry from the terminal user 50A regarding the IP address corresponding to the domain name of the source server 60 (S31). The DNS resolver 80 inquires the guidance control device 30, which is equivalent to the authoritative DNS server storing information of the domain name, about the IP address corresponding to the domain name (S32). Furthermore, the DNS resolver 80 receives a response to the inquiry from the guidance control device 30 (S33, S43).

[0119] exist Fig.11 In the example of , the IP address of the guidance destination is known to the guidance control device 30, so the reply includes the IP address of the guidance destination. The DNS resolver 80 notifies the terminal user 50A of the IP address of the guidance destination (S34).

[0120] On the other hand, Fig.12In the example of FIG. 4 , the IP address of the cache server in CDN#2, which is the guidance target, is unknown to the guidance control device 30, so the DNS resolver 80 guides the authoritative DNS server 90 of CDN#2. The DNS resolver 80 inquires the authoritative DNS server 90 about the IP address corresponding to the domain name of the source server 60 (S44). The DNS resolver 80 receives, for example, the IP address of the cache server in CDN#2 as a response to the inquiry (S45). In addition, the DNS resolver 80 notifies the terminal user 50A of the IP address (S46).

[0121] The authoritative DNS server 90 of CDN#2 manages the domain names of the cache servers and other devices included in CDN#2 and their corresponding IP addresses. The authoritative DNS server 90 receives an inquiry for the IP address corresponding to the domain name of the source server 60 (S44). In response to the inquiry, the authoritative DNS server 90 returns the IP address of the device such as the cache server in CDN#2 (S45).

[0122] (Variant 2)

[0123] In the above-mentioned embodiment, it is described that the policy decision device determines the policy for its subordinate guidance control device to control the guidance target of the request including the target address data to the given source server. However, the policy determined by the policy decision device is not limited to its subordinate guidance control device, and can also be shared with the guidance control device under other policy decision devices. Thus, for example, even if the terminal user moves and the guidance control device that processes the request from the terminal user is switched, the same policy can be applied to the request from the terminal user.

[0124] As an example, the policy decision device (the policy decision unit 126) can determine that its subordinate guidance control device applies a general policy in principle to requests including target address data to a given source server, and a special policy that is limited to requests that meet given conditions in the request. Moreover, the policy decision device (the policy notification unit 127) can notify the latter policy to its subordinate guidance control device, and notify the guidance control device subordinate to the other policy decision device via other policy decision devices. In addition, the policy does not need to be shared by all guidance control devices at the same time, so for example, the policy determined for a given guidance control device can be preferentially notified to the guidance control device corresponding to the area geographically adjacent to the guidance control device.

[0125] Here, the given condition may be defined by parameters such as device type, content type, or a combination of multiple parameters. When the terminal user 50 is a car or a vehicle-mounted device thereof, the device type may indicate a vehicle type, a model, etc. In addition, the content type may indicate the type of content (e.g., image data, video data, location data, etc.) that is to be acquired or contributed by the request.

[0126] The above-mentioned embodiments are merely specific examples for helping to understand the concept of the present invention, and are not intended to limit the scope of the present invention. Various structural elements may be added, deleted or modified without departing from the gist of the present invention.

[0127] In the above embodiments, several functional units are described, but these are only examples of the installation of each functional unit. For example, multiple functional units described as being installed in one device can be installed in multiple different devices, and conversely, functional units described as being installed in multiple different devices can also be installed in one device.

[0128] The various functional units described in the above embodiments can be implemented using circuits. The circuits may be dedicated circuits that implement specific functions or general-purpose circuits such as processors.

[0129] At least a part of the processing of each of the above-mentioned embodiments can be implemented, for example, using a processor such as a CPU and / or GPU, a microcomputer, an FPGA, or a DSP mounted on a general-purpose computer as basic hardware. The program for implementing the above-mentioned processing can be stored in a recording medium that can be read by a computer and provided. The program is stored in a recording medium as a file in an installable form or a file in an executable form. As a recording medium, it is a disk, an optical disk (CD-ROM, CD-R, DVD, etc.), an optical magnetic disk (MO, etc.), a semiconductor memory, etc. The recording medium can store the program, and if the computer can read it, it can be any medium. In addition, the program for implementing the above-mentioned processing can be stored in a computer (server) connected to a network such as Ethernet, and downloaded to a computer (client) via a network.

[0130] Description of the label

[0131] 10, 10-1, 10-2, 10-3…Strategy decision device

[0132] 20, 20A, 20B, 20-1A, 20-2A, 20-3A, 30, 30A, 30B...Guidance control device

[0133] 41…Detection server

[0134] 42…Surveillance system

[0135] 50, 50A, 50B…end users

[0136] 60…Source Server

[0137] 70, 70A, 70B, 70C…Edge Server

[0138] 80…DNS resolver

[0139] 90…Authoritative DNS server

[0140] 100, 100A, 100B…CDN

[0141] 110…Communication I / F

[0142] 120…Processor

[0143] 121…Receive data acquisition unit

[0144] 122…Monitoring data acquisition unit

[0145] 123…Change Request Acquisition Department

[0146] 124 ... Update condition determination unit

[0147] 125…Strategy Update Request Department

[0148] 126…Strategy Decision Department

[0149] 127…Strategy Notification Department

[0150] 128…Change condition determination unit

[0151] 129…Strategy Change Request Department

[0152] 130…Memory

[0153] 131…Monitoring data storage unit

[0154] 132…Change Request Storage

[0155] 133…Setting data storage unit

[0156] 134…Strategy Storage Department

Claims

1. A strategy decision device, wherein: The policy decision device comprises: a monitoring data acquisition unit that acquires monitoring data related to the status of the equipment within the network received from an external device; a policy determination unit that determines, based on the monitoring data, a first policy for the first navigation control device to control the navigation target of the first request including the first target address data; a strategy notification unit configured to notify the first guidance control device of the first strategy; a change condition determination unit that determines whether a predetermined first policy change condition is satisfied based on the monitoring data; as well as a change request unit that, when determining that the first policy change condition is satisfied, requests a first policy decision device that determines a second policy to change the second policy, wherein the second policy is used for a second boot control device that is different from the first boot control device to control a boot target of a second request including the first target address data, The first strategy and the second strategy respectively represent a plurality of candidates for the guidance destination of the request and a ratio of guiding the request to each of the candidates. An area is defined for each guidance control device, and the guidance control device can guide a request to a PoP (Point Of Presence) belonging to the corresponding area, the PoP indicating a location of a guidance target having a connection point to an external network.

2. The policy decision device according to claim 1, wherein: The strategy decision device also has: an update condition determination unit that determines whether a predetermined policy update condition is satisfied; as well as The update request unit requests updating of the first policy when it is determined that the policy update condition is satisfied.

3. The policy decision device according to claim 1 or 2, wherein: The monitoring data indicates a load of at least a portion of a plurality of first candidates for a requested boot target including the first target address data, The first policy change condition is that a load of a first notification target included in the first candidate exceeds a first load threshold.

4. The policy decision device according to claim 1 or 2, wherein: The monitoring data indicates the number of customers of at least a part of a plurality of first candidates for the requested guidance destination including the first destination address data, The first policy change condition is that the number of customers of the first guidance destination included in the first candidate exceeds a first customer number threshold.

5. The policy decision device according to claim 1 or 2, wherein: The monitoring data indicates availability of at least a portion of a plurality of first candidates for the requested guidance destination including the first destination address data, The first policy change condition is that the first notification target included in the first candidate is not in an available state.

6. The policy decision device according to claim 3, wherein: The second policy indicates a ratio at which the second guidance control device guides the second request to each of a plurality of second candidates for guidance destinations of the second request. When it is determined that the first policy change condition is satisfied, the change request unit requests the first policy determination device to cause the second guidance control device to reduce the ratio of guiding the second request to the first guidance target.

7. The policy decision device according to claim 3, wherein: The change condition determination unit further determines whether a predetermined second policy change condition is satisfied based on the monitoring data. The second policy change condition is that the load of the first guidance target exceeds a second load threshold, and the second load threshold is greater than the first load threshold. When it is determined that the second policy change condition is satisfied, the change request unit requests a change to the second policy from the first policy decision device, and requests a change to the third policy from the second policy decision device that determines the third policy, wherein the third policy is used by a third boot control device that is different from the first boot control device and the second boot control device to control the boot target of the third request including the first target address data.

8. The policy decision device according to claim 4, wherein: The change condition determination unit further determines whether a predetermined second policy change condition is satisfied based on the monitoring data. The second policy change condition is that the number of customers of the first guidance target exceeds a second customer number threshold, and the second customer number threshold is greater than the first customer number threshold. When it is determined that the second policy change condition is satisfied, the change request unit requests a change to the second policy from the first policy decision device, and requests a change to the third policy from the second policy decision device that determines the third policy, wherein the third policy is used by a third boot control device that is different from the first boot control device and the second boot control device to control the boot target of the third request including the first target address data.

9. The policy decision device according to claim 7 or 8, wherein: The second policy indicates a ratio at which the second guidance control device guides the second request to each of a plurality of second candidates for guidance destinations of the second request. The third policy indicates a ratio at which the third guidance control device guides the third request to each of a plurality of third candidates for guidance destinations of the third request. When it is determined that the second policy change condition is met, the change request unit requests the first policy decision device to cause the second guidance control device to reduce the proportion of guiding the second request toward the first guidance target, and requests the second policy decision device to cause the third guidance control device to reduce the proportion of guiding the third request toward the first guidance target.

10. The policy decision device according to claim 7 or 8, wherein: The policy determination unit further determines a fourth policy based on the monitoring data, the fourth policy being used by the first guidance control device to control a guidance target of the first request that satisfies a first condition. The policy notification unit further notifies the first guidance control device and the first policy determination device of the fourth policy.

11. A strategy decision method, wherein: The strategy decision method has the following steps: acquiring monitoring data related to the status of equipment within the network received from an external device; determining, based on the monitoring data, a first policy for a first boot control device to control a boot target of a first request including first target address data; notifying the first guidance control device of the first strategy; determining whether a predetermined first policy change condition is satisfied based on the monitoring data; as well as requesting a first policy decision device that determines a second policy to change the second policy when it is determined that the first policy change condition is satisfied, wherein the second policy is used for a second boot control device that is different from the first boot control device to control a boot target of a second request including the first target address data, The first strategy and the second strategy respectively represent a plurality of candidates for the guidance destination of the request and a ratio of guiding the request to each of the candidates. An area is defined for each guidance control device, and the guidance control device can guide a request to a PoP (Point Of Presence) belonging to the corresponding area, the PoP indicating a location of a guidance target having a connection point to an external network.

12. A recording medium having a program recorded thereon, wherein: The program causes the computer to function as the following unit: a unit for acquiring monitoring data related to the status of the equipment within the network received from an external device; means for determining a first strategy for a first navigation control device to control a navigation target of a first request including first target address data based on the monitoring data; a unit for notifying the first guidance control device of the first strategy; a unit for determining whether a predetermined first policy change condition is satisfied based on the monitoring data; as well as a unit for requesting a first policy decision device that determines a second policy to change the second policy when it is determined that the first policy change condition is satisfied, wherein the second policy is used for a second boot control device that is different from the first boot control device to control a boot target of a second request including the first target address data, The first strategy and the second strategy respectively represent a plurality of candidates for the guidance destination of the request and a ratio of guiding the request to each of the candidates. An area is defined for each guidance control device, and the guidance control device can guide a request to a PoP (Point Of Presence) belonging to the corresponding area, the PoP indicating a location of a guidance target having a connection point to an external network.

Images