Control apparatus, control method and program

A control device includes an information acquisition unit that receives a source address of a packet from a node that receives the packet transmitted from a user terminal, and acquires position information about the user terminal on a basis of the source address, a determination unit that determines a hub to which the user terminal should connect, on a basis of the position information, and a control execution unit that launches an application in the hub and changes a routing such that packets transmitted from the user terminal are transmitted to the application.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application under 35 U.S.C. § 371 of International Application No. PCT/JP2019/047241, having an International Filing Date of Dec. 3, 2019. The disclosure of the prior application is considered part of the disclosure of this application, and is incorporated in its entirety into this application.

TECHNICAL FIELD

The present invention relates to a technology that controls communication for the use of an application on a user terminal.

BACKGROUND ART

Recently, edge computing, in which service processing is performed at locations close to a user terminal or device (hereinafter referred to as the user terminal), is proliferating.

With edge computing, computational resources such as an application server are distributively installed at each hub, and the user terminal uses an application running on the computational resources of a hub close to the user terminal itself.

If the application is running but not being used, computational resources will be wasted. Accordingly, a technology called Scale to Zero has been proposed in which an application is launched after a request is received (Non-Patent Literature 1, 2).

CITATION LIST

SUMMARY OF THE INVENTION

Technical Problem

With a technology that launches an application after receiving a request like the related technology above, it is necessary for the user terminal to discover the nearest hub and transmit a request for using an application in the hub. However, achieving the above necessitates a complex process, and is not preferable for a user terminal with limited computational resources.

The present technology has been devised in light of the above points, and an objective thereof is to provide a technology enabling a user terminal to use an application in the nearest hub without performing a complex process.

Means for Solving the Problem

According to the technology of the disclosure, there is provided a control device comprising:

an information acquisition unit that receives a source address of a packet from a node that receives the packet transmitted from a user terminal, and acquires position information about the user terminal on a basis of the source address;

a determination unit that determines a hub to which the user terminal should connect, on a basis of the position information; and

a control execution unit that launches an application in the hub and changes a routing such that packets transmitted from the user terminal are transmitted to the application.

Effects of the Invention

According to the technology of the disclosure, a technology enabling a user terminal to use an application in the nearest hub without performing a complex process can be provided.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described hereinafter is merely an example, and embodiments to which the present invention is applied are not limited to the following embodiment.

FIG.1illustrates an overall configuration example of a system according to the embodiment of the present invention. InFIG.1, a hub A and a hub B are illustrated as examples of hubs, but these are an example, and in actuality, more hubs exist. Hereinafter, when the hub A and the hub B are not being distinguished, the signs “A” and “B” will not be appended, as in the “computational resources10” and the “load balancer20” for example.

In the embodiment, a “hub” is assumed to be a location (such as a building, a mobile phone base station, a telephone exchange, a building in which transmission equipment/forwarding equipment related to the provision of network services, or a geographical area, for example) provided with facilities such as computational resources10and a load balancer20. A “hub” may also be a location (such as a data center including a server group, for example) with facilities that provide cloud services.

As illustrated inFIG.1, the system includes a controller100, an application information storage device200, a subscriber information storage device300, an overlay NW information storage device400, and computational resources10and a load balancer20in each hub, which are connected to a network50. Note that the application information storage device200is used in Examples 1 and 2. The subscriber information storage device300is used in Examples 2-1 and 2-2. The overlay NW information storage device400is used in Example 2-2. The application information storage device200, the subscriber information storage device300, and the overlay NW information storage device400are collectively referred to as storage devices.

The network50is a for example a network including a mobile network (for example, a 5G network) and a data network (for example, the Internet). One or more forwarding devices40exist on the network50. For example, a user terminal30wirelessly connects to a 5G network and communicates with an application that runs on the computational resources10through the 5G network and the data network.

The controller100, the application information storage device200, the subscriber information storage device300, the overlay NW information storage device400, the computational resources10, the load balancer20, and the forwarding device40may all be achieved by physical devices (such as servers and communication devices), but may also be achieved by virtual machines such as the cloud, or by virtual containers that run using a container runtime such as Docker or CRI-O, for example.

The controller100is a device that controls each of the computational resources10, the load balancer20, and the forwarding device40.

Note that in the case where the computational resources10, the load balancer20, the forwarding device40, and the like are in the cloud, the control of the computational resources10, the load balancer20, the forwarding device40, and the like by the controller100is achieved through a cloud management device.

The application information storage device200stores correspondence information associating position information about each hub with an IP address and position information for each user terminal. The subscriber information storage device300and the overlay NW information storage device400will be described later.

The computational resources10are a device that executes an application, and may also be referred to as an application server. Note that an application in the embodiment may be an application with any type of functions, and for example, the application analyzes video data received from the user terminal30and transmits an analysis result to the user terminal30or a higher-layer server.

Also, in the embodiment, Scale to Zero technology is applied. In other words, in the computational resources10, the application is not launched in cases where there is no demand to use the application from the user terminal30. Note that the application not being launched also includes the computational resources10not being launched.

The load balancer20is a device that distributes requests for the application among the plurality of computational resources. The load balancer20of the embodiment is an L4-7 load balancer, for example. The load balancer20of the embodiment has a function of acquiring the source address of a packet received from the user terminal30and notifying the controller100of the source address.

Note that in this specification, the source address is described specifically as a source IP address as an example. However, the source address is not limited to a source IP address, and may be any address that can be used to uniquely identify the source terminal. For example, the MAC address may also be used as the source address.

The user terminal30is a smartphone, a PC, an IoT device, or the like. The forwarding device40is a Layer 3 (L3) switch that forwards packets on the basis of the IP address, for example. The forwarding device40may also be a device forming the User Plane Function (UPF) on a 5G network.

FIG.2illustrates an example of communication in the case where the user terminal30accesses an application11running on the computational resources10. As illustrated inFIG.2, when the user terminal30transmits a packet containing processing request data for the application11, the packet goes through the forwarding device40and the load balancer20to reach the computational resources10, is delivered to the application11inside the computational resources10, and the application11executes processing according to the processing request.

Note that the packet transmitted from the user terminal30needs to go through an interface or the like of the computational resources10before arriving at the application11(specifically, a process running on the computational resources10). For convenience, “transmitting (forwarding) a packet to an application” is taken to mean transmitting the packet to the computational resources10and handing over data contained in the packet to the application inside the computational resources10.

(Overview of Operations by System)

FIGS.3to6will be referenced to describe an overview of operations by the system according to the embodiment. Here, in a situation where the application11A of the hub A is being used from the user terminal30A but the application11B of the hub B has not been launched, suppose that the user terminal B is positioned nearest to the hub B and wants to use the application11. Also, assume that other hubs besides the hub A and hub B exist, and of the multiple hubs where the application11has been launched (such as hub A, hub A′, and hub A″), the hub A is the hub closest to the user terminal30B.

Note that terms such as “near(est)” and “close” used in this specification may refer a short physical distance, a short distance over the network (number of hops or the round-trip time (RTT)), a small number of AS to go through, or a small number of NW operators to go through.

As illustrated inFIG.3, first, the user terminal30B transmits a packet addressed to the anycast address. The packet is a packet requesting processing with respect to the application11.

A portion of all of the nodes (such as the load balancer20, the computational resources10, and the forwarding device40) in the embodiment are assigned the anycast address that acts as an IP address, and in the case where a packet addressed to the anycast address is transmitted from a source user terminal30, the packet is forwarded to the node which has the anycast address and which is closest to the user terminal30.

Here, according to a mechanism described later, the packet addressed to the anycast address and transmitted from the user terminal30B is forwarded to the application11A of the hub A, as illustrated inFIG.4. With this arrangement, the user terminal30B can use the application11A.

Next, the application11B of the hub B is launched under control by the controller100, as illustrated inFIG.5. Next, the packet transmitted from the user terminal30B is routed to the application11B under control by the controller100, as illustrated inFIG.6. With this arrangement, the user terminal30B can use the application11B.

Through a process like the above, the user terminal30B is capable of using the application11B in the nearest hub B without performing a complex process. Also, as illustrated inFIG.4, because packets are routed to the application11A until the application11B is launched, the user terminal30B can start using the application11with low latency.

FIG.7illustrates a functional configuration diagram of the controller100. As illustrated inFIG.7, the controller100includes an information acquisition unit110, a determination unit120, and a control execution unit130. Note that the controller100may also be referred to as a control device.

The information acquisition unit110acquires the source address of the user terminal30from the load balancer20. Also, the information acquisition unit110acquires position information and the like about the user terminal30from a storage device by issuing a query based on the source address to the storage device.

The determination unit120determines the hub to which the user terminal30should connect on the basis of the information acquired by the information acquisition unit110. The hub to which the user terminal30should connect refers to the hub closest to the user terminal30. Also, “connecting to a hub” refers to communicating with the computational resources10of the hub to use an application.

The control execution unit130controls the load balancer20, the forwarding device40, the computational resources10, and the like on the basis of the content determined by the determination unit120.

The load balancer20, the control device100, the storage devices200to400, and the forwarding device40are all achievable by causing a computer to execute a program stating the processing content described in the embodiment. Note that the “computer” may also be a virtual machine or a virtual container provided by an infrastructure service in which computational resources such as cloud services are operated as a virtual machine or a virtual container. In the case of using a virtual machine, the “hardware” described herein refers to virtual hardware.

The devices (the load balancer20, the control device100, the storage devices200to400, and the forwarding device40) are achievable by using hardware resources such as a CPU and memory built into the computer to execute a program corresponding to the processes performed in the devices. The program may be saved and distributed by being recorded onto a computer-readable medium (such as portable memory). In addition, the program may also be provided through a network, such as the Internet or email.

FIG.8is a diagram illustrating a hardware configuration example of the computer according to the embodiment. The computer inFIG.8includes components such as a drive device1000, an auxiliary storage device1002, a memory device1003, a CPU1004, an interface device1005, a display device1006, and an input device1007, which are interconnected by a bus B.

A program that achieves processing on the computer is provided by a recording medium1001such as a CD-ROM or a memory card, for example. When the recording medium1001is placed in the drive device1000, the program is installed from the recording medium1001to the auxiliary storage device1002through the drive device1000. However, the program does not necessarily have to be installed from the recording medium1001, and may also be downloaded from another computer over a network. The auxiliary storage device1002stores the installed program, and also stores information such as necessary files and data.

When an instruction to launch the program is given, the memory device1003reads out and stores the program from the auxiliary storage device1002. The CPU1004achieves functions related to the devices by following the program stored in the memory device1003. The interface device1005is used as an interface for connecting to a network. The display device1006displays a graphical user interface (GUI) according to the program. The input device1007includes components such as a keyboard and mouse, buttons, or a touch panel, and is used to input various operation instructions. Note that in the case where operation over the network is presumed, the display device1006and the input device1007do not have to be provided.

Hereinafter, specific working examples of the system according to the embodiment will be described as Example 1, Example 2, Example 2-1, and Example 2-2.

First,FIGS.9to12will be referenced to describe Example 1 in step number order (S101to S104). Example 1 is an example of the case where the application11and the load balancer20are separated. Also, the application information storage device200stores correspondence information associating IP addresses with position information, as well as position information about each hub.

As illustrated inFIG.9, in S101, the application11A of the hub A has been launched, and the user terminal30A is using the application11A. In the hub B, the application11B has not been launched. Also, a user terminal30B wanting to use the application11exists. The hub closest to the user terminal30B is the hub B.

The user terminal30B transmits a packet addressed to the anycast address requesting the use of the application11. The packet arrives at the load balancer20B, which is the nearest of the nodes assigned the anycast address. Note that in Example 1, the anycast address is not assigned to the forwarding device40B.

In S102illustrated inFIG.10, the load balancer20B receiving the packet from the user terminal30B temporarily assigns communication with the user terminal30B to the application11A launched in the hub A. In other words, packets arriving at the load balancer20B from the user terminal30B are temporarily addressed to the application11A and forwarded to the application11A. The forwarding is performed on the basis of the load balancer20B detecting that the application11B has not been launched, for example.

With this arrangement, the user terminal30B communicates with the application11A until the routing is switched (until the application11B is launched) as described later.

The load balancer20B notifies the controller100with information indicating that communication from the user terminal30B, which should have been connected to the hub B originally, has been assigned to another hub. The information includes the source address of the packets received from the user terminal30B. In the controller100, the information acquisition unit110acquires the information.

Next, in S103ofFIG.11, the information acquisition unit110of the controller100transmits the source address (the IP address of the user terminal30B) acquired from the load balancer20B to the application information storage device200.

On the basis of the correspondence information, the application information storage device200acquires position information corresponding to the source address (position information about the user terminal30B) and the position information about each hub, and transmits the acquired information to the controller100.

The information acquisition unit110of the controller100acquires the position information about the user terminal30B and the position information about each hub from the application information storage device200. Next, on the basis of the position information about the user terminal30B and the position information about each hub, the determination unit120of the controller100determines that the hub nearest to the user terminal30B is the hub B, and determines to launch the application11B in the hub B. The control execution unit130of the controller100launches the application11B in the hub B.

Note that the control execution unit130launching the application11B in the hub B may refer to instructing the computational resources10B of the hub B to launch the application11B, or instructing a management device of the infrastructure such as the cloud in which a virtual machine or virtual container running on the computational resources10B are operated to launch the application11B.

In S104ofFIG.12, if the determination unit120of the controller100determines that the application11B has entered a standby state, the control execution unit130instructs the load balancer20B to change the routing such that packets sent from the user terminal30B to the load balancer20B are forwarded to the application11B. Thereafter, packets sent from the user terminal30B to the load balancer20B are forwarded to the application11B.

To determine that the application11B has entered a standby state, the standby state may be determined after a predetermined time has elapsed since the launch instruction, an ICMP packet (for example, an ICMP echo request) in L3addressed to the IP address of the computational resources10B running the application11B may be sent and the standby state may be determined if there is a response, the initiation of a TCP session with a standby port of the application11B may be attempted and the standby state may be determined if a connection is established, or an application layer service initiation request may be transmitted to the application11B and the standby state may be determined if there is a response.

Next,FIGS.13to16will be referenced to describe Example 2 in step number order (S201to S204). Example 2 is an example of the case where the application11B and the load balancer20B are combined in the hub B. The application11B and the load balancer20B being combined means that, for example, the load balancer20B is a type of application that is launched and made to run on computational resources, with the application11B and the load balancer20B functioning as a set (either one does not function alone).

In S201ofFIG.13, the application11A and the load balancer20A in the hub A have been launched, and the user terminal30A is using the application11A. In the hub B, the application11B and the load balancer20B have not been launched. A user terminal30B wanting to use the application11exists, and the hub nearest to the user terminal30B is the hub B.

The user terminal30B transmits a packet addressed to the anycast address requesting the use of the application11. The packet arrives at the nearest forwarding device40B. In Example 2, the anycast address is assigned to the forwarding device40B.

In S202ofFIG.14, the forwarding device40B is one of the devices forming the UPF of a 5G network for example, and has an uplink classifier function that identifies packets intended for a specific IP address and routes the packets differently from normal. The forwarding device40B according to the embodiment is set such that packets addressed to the anycast address are forwarded on a route leading to a hub other than the hub B.

Consequently, as illustrated inFIG.14, the forwarding device40B receiving packets from the user terminal30B forwards the packets to the above route. The packets arrive at the application11A or the load balancer20A, which are the nearest nodes assigned the anycast address.FIG.14illustrates an example in which the packets arrive at the load balancer20A. The packets are forwarded from the load balancer20A to the application11A. With this arrangement, the user terminal30B communicates with the application11A until the routing is switched (until the application11B is launched) as described later. Hereinafter, the application11A in the case where packets arrive at the application11A from the forwarding device40B will be indicated in parentheses as (application11A).

The load balancer20A (application11A) detects that communication from the user terminal30B, which should have been connected to the hub B originally, has been assigned to another hub, and notifies the controller100with information indicating the above. The information includes the source address of the packets received from the user terminal30B. Note that the load balancer20A (application11A) detects from the source address of the packets that the communication from the user terminal30B which should have been connected to the hub B has been assigned to another hub, for example.

In the controller100, the information acquisition unit110acquires information including the above source address.

In S203ofFIG.15, the information acquisition unit110of the controller100transmits the source address (the address of the user terminal30B) acquired from the load balancer20B (application11A) to the application information storage device200.

The application information storage device200acquires position information corresponding to the source address (position information about the user terminal30B) and the position information about each hub, and transmits the acquired information to the controller100.

The information acquisition unit110of the controller100acquires the position information about the user terminal30B and the position information about each hub from the application information storage device200. Next, on the basis of the position information about the user terminal30B and the position information about each hub, the determination unit120of the controller100determines that the hub nearest to the user terminal30B is the hub B, and determines to launch the application11B and the load balancer20B in the hub B. The control execution unit130of the controller100launches the application11B and the load balancer20B in the hub B.

In S204ofFIG.16, if the determination unit120of the controller100determines that the application11B has entered the standby state, the control execution unit130instructs the forwarding device40B to change the routing such that packets sent from the user terminal30B to the forwarding device40B are forwarded to the load balancer40B. Thereafter, packets from the user terminal30B are sent to the load balancer20B and forwarded to the application11B.

The determination of whether or not the application11B has entered the standby state is similar to Example 1.

Hereinafter, Examples 2-1 and 2-2 will be described. Examples 2-1 and 2-2 are examples of modifications to Example 2, but Example 1 may also be modified in a similar way.

In Example 1 and Example 2, the IP address of the user terminal30is presumed to be an IP address according to the geographical location of the user terminal30.

However, if the user terminal30connects to a mobile network (for example, 3G, LTE, or 5G), a mechanism (Session and Service Continuity) for preventing frequent changes of the IP address of the user terminal30may be implemented, and in this case, determining the geographical location of the user terminal30from the source address as described so far is more difficult.

On the other hand, it is possible to identify the geographical location by using a cell ID associated with the source address, or by using GPS information. Example 2-1 identifies the geographical location of the user terminal30according to such a method.

Example 2-1 is an example that anticipates the above situation in Example 2. In Example 2-1, the subscriber information storage device300that stores mobile network subscriber information is provided. The subscriber information storage device300may be a subscriber information storage device used on a mobile network or a device that stores information acquired from a subscriber information storage device used on a mobile network.

In the subscriber information storage device300, an IP address of a user terminal and position information indicating the position where the user terminal is located are stored in association with each other for each user terminal, for example. “Position information indicating the position where the user terminal is located” refers to information such as the cell ID of a cell to which the user terminal is connected or position information acquired by a GPS device in the user terminal, for example. In Example 2-1, because the controller100can acquire geographical location information immediately from the cell ID, the cell ID is information that is substantially the same as position information.

In Example 2-1, the process of acquiring position information about the user terminal30B described inFIG.15(S203) of Example 2 is different from Example 2. In Example 2-1, subscriber information including subscriber information about the mobile network to which the user terminal30B is subscribed to is stored in the subscriber information storage device300.

In Example 2-1, as illustrated inFIG.17, after the controller100is notified of the source address of the user terminal30B from the load balancer20A (application11A), the controller100transmits the source address to the subscriber information storage device300. The subscriber information storage device300acquires position information corresponding to the source address (for example, the cell ID of the cell where the user terminal30B is located), and transmits the acquired position information to the controller100.

The information acquisition unit110of the controller100receives the cell ID and acquires position information from the subscriber information storage device300, and acquires position information about each hub from the application information storage device200. The process thereafter is the same as Example 2.

Example 2-2 is an example of a case where the technology according to the embodiment is carried out on an overlay NW such as an SD-WAN. In Example 2-2, as illustrated inFIG.18for example, a plurality of customer-premises equipment (CPE) are included, and the user terminal30is connected to a network formed by interconnecting the CPE on a wide area network (WAN)500.

The network50illustrated inFIG.1corresponds to the WAN500, and equipment such as the computational resources10, the load balancer20, the controller100, and the various storage devices illustrated inFIG.1are provided on the WAN500.

In such an overlay NW configuration, each user terminal is assigned a private address on the overlay NW as an IP address. Consequently, with the method described in Examples 1, 2, and 2-1, position information about the user terminal30cannot be acquired from the source address of the user terminal30.

On the other hand, on an overlay NW, the private address assigned to a user terminal, the CPE hosting the user terminal, and the IP address assigned outside the CPE (in the example ofFIG.18, the address of the portion labeled A) are typically managed by a management device.

Example 2-2 is an example that anticipates the above situation in Example 2. In Example 2-2, the CPE are assumed to be connected to a mobile network, and the external IP addresses of the CPE are managed as subscriber information in the mobile network together with information (such as the cell ID of the cell or GPS information) indicating the position where the CPE is located.

In Example 2-2, the subscriber information storage device300described in Example 2-1 and the overlay NW information storage device400storing information about the overlay NW are provided.

As described above, correspondence information associating the IP addresses of the CPE with information indicating position are stored in the subscriber information storage device300. In the overlay NW information storage device400, the private address of each hosted user terminal and an IP address assigned outside the CPE are stored in association with each other for each CPE.

In Example 2-2, the process of acquiring position information about the user terminal30B described inFIG.15of Example 2 is different from Example 2.

In Example 2-2, as illustrated inFIG.19, after the controller100is notified of the source address of the user terminal30B from the load balancer20A (application11A), the controller100transmits the source address to the overlay NW information storage device400. The overlay NW information storage device400acquires the external IP address of the CPE corresponding to the source address (private address), and transmits the acquired external IP address to the controller100.

The controller100receiving the external IP address of the CPE transmits the IP address to the subscriber information storage device300. The subscriber information storage device300acquires position information corresponding to the IP address (for example, the cell ID of the cell where the CPE hosting the user terminal30B is located), and transmits the acquired position information to the controller100.

The information acquisition unit110of the controller100receives the position information (cell ID) of the CPE from the subscriber information storage device300, and also acquires position information about each hub from the application information storage device200. The process thereafter is the same as Example 2. In Example 2-2, the position of the CPE hosting the user terminal is considered to be the position of the user terminal.

Note that the subscriber information storage device300and the overlay NW information storage device400may also be collectively referred to as a “storage device that stores correspondence information associating the IP address of a user terminal with position information about the user terminal”.

As described above, according to the embodiment, the user terminal is capable of using an application in the nearest hub without performing a complex process. Furthermore, the user terminal can start using the application with low latency. Further details are given below.

In the case where the user terminal uses an application in the nearest hub, if the application has not been launched at the time of use, and the user terminal waits until the application is launched, it will take some time until the user terminal uses the application.

On the other hand, if the user terminal continues to use an already-launched application in a hub that is not the nearest hub, there is a problem of being unable to enjoy good performance of the service utilizing low latency, wideband communication, and the like. Furthermore, the above situation is inefficient from a traffic management perspective.

According to the technology according to the embodiment, the above problems are addressed, making it to shorten the lead time until the start of application use without having the user terminal perform a complex process, while in addition, by using the nearest application after the nearest application is launched, better performance of the service can be enjoyed, and the traffic efficiency is also improved.

This specification discloses at least the control device, the control method, and the program described in each of the following items.

A control device comprising:

an information acquisition unit that receives a source address of a packet from a node that receives the packet transmitted from a user terminal, and acquires position information about the user terminal on a basis of the source address;

a determination unit that determines a hub to which the user terminal should connect, on a basis of the position information; and

a control execution unit that launches an application in the hub and changes a routing such that packets transmitted from the user terminal are transmitted to the application.

The control device according to the first item, wherein

the hub to which the user terminal should connect is the hub closest to the user terminal.

The control device according to the first or second item, wherein

the information acquisition unit issues a query based on the source address to a storage device that stores correspondence information associating an IP address with position information, and thereby acquires the position information from the storage device.

The control device according to any one of the first to third items, wherein

a destination address of a packet transmitted from the user terminal is an anycast address, and the node is the node closest to the user terminal, and

until the application is launched, the node forwards packets transmitted from the user terminal to an application in a hub different from the hub to which the user terminal should connect.

The control device according to any one of the first to fourth items, wherein

the information acquisition unit issues a query based on the source address to a subscriber information storage device that stores mobile network subscriber information, and thereby acquires the position information from the subscriber information storage device.

A control method executed by a control device, the control method comprising:

an information acquisition step of receiving a source address of a packet from a node that receives the packet transmitted from a user terminal, and acquiring position information about the user terminal on a basis of the source address;

a determination step of determining a hub to which the user terminal should connect, on a basis of the position information; and

a control execution step of launching an application in the hub and changing a routing such that packets transmitted from the user terminal are transmitted to the application.

A program for causing a computer to function as each unit of the control device according to any one of the first to fifth items.

Although the foregoing describes an embodiment, the present invention is not limited to such a specific embodiment, and various alterations and modifications are possible within the scope of the gist of the present invention stated in the claims.

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