A method and system for extending edge storage capacity

Abstract

The application relates to the technical field of edge storage, and provides a method for expanding edge storage capacity, which comprises the following steps: S1, acquiring an access network closest to an edge node, and deploying a storage server on the access network; S2, when the edge node needs to use a storage service, initiating a storage request to the access network, and the access network allocating storage space on the storage server for the edge node and returning the storage space to the edge node; and S3, the edge node performing data transmission between the edge node and the access network, and accessing and using the storage space on the storage server allocated by the access network. By deploying a storage server on an access network closest to an edge node and through a set of general storage configuration protocols, the edge node can acquire unified storage resources, and the performance is not worse than that of local storage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of edge storage, and in particular to a method and system for extending edge storage capacity. BACKGROUND

[0002] The development of IT infrastructure has gone through two stages of IDC (Internet Data Center) and central cloud computing, and is now expanding to edge computing. Central cloud computing is the coordinator, responsible for big data analysis of long-period data, and can operate in the fields of periodic maintenance and business decision-making. Edge computing is closer to the device end and closer to the user, focusing on real-time and short-period data analysis to better support local business and timely processing. In reality, there are many application scenarios that cannot receive data uploaded to the central cloud for decision-making and interaction. For example, in the scenarios of self-driving or precision machine tools, if the transmission delay is too long, the scenario may be outdated and not applicable. In these scenarios, the central cloud cannot meet the low-latency or ultra-low-latency requirements, and edge computing can perform computing at a location closer to the data source. On the other hand, with the development of IOT (Internet of Things) devices, the amount of data will grow exponentially.

[0003] The application requirements of edge computing put higher requirements on edge storage capacity:

[0004] (1) Data storage demand is exploding, and data storage is tilting from the center to the end side, so edge devices need a large amount of storage capacity.

[0005] (2) Edge devices generally have computing and bandwidth capabilities, but the storage capacity is weak, especially edge IOT devices, which require a certain amount of storage capacity to unleash the computing and bandwidth capabilities of edge nodes, such as edge caching.

[0006] (3) With the explosive growth of hardware connected to the Internet of Things, storage types are becoming increasingly complex and diverse, and how to handle these complex and diverse heterogeneous storage is a huge challenge to R&D personnel.

[0007] (4) The current access network only has network resource allocation functions, but no storage resource allocation functions, and this infrastructure is not fully utilized. SUMMARY

[0008] To solve the above problems, the purpose of the present application is to provide a method and system for extending edge storage capacity, which deploys a storage server in the access network closest to the edge node, and then uses a set of general storage configuration protocols to enable edge nodes to obtain unified storage resources without compromising the performance of local storage.

[0009] The above invention purpose of the present application is realized by the following technical solutions:

[0010] A method for extending edge storage capacity, comprising:

[0011] S1: acquiring an access network closest to a nearest hop of an edge node, and deploying a storage server on the access network;

[0012] S2: when the edge node needs to use a storage service, initiating a storage request to the access network, and the access network allocates storage space on the storage server for the edge node and returns to the edge node;

[0013] S3: the edge node performs data transmission between the edge node and the access network, accesses and uses the storage space on the storage server allocated by the access network.

[0014] Further, in step S1, the edge node includes any one of edge terminal devices such as a personal computer (PC), a router, a set-top box, a network attached storage (NAS) device, and an Internet of Things (IOT) device.

[0015] Further, in step S1, further comprising:

[0016] deploying a storage access server (SBRAS) on the access network;

[0017] The storage access server (SBRAS) includes a network bearing function, a storage allocation function, and a control implementation function;

[0018] The network bearing function is responsible for terminating the PPPoE connection of the edge node, and converging the traffic function of the edge node, the storage allocation function is responsible for allocating storage space on the storage server for the edge node, and the control implementation function is responsible for connecting with systems including an authentication system, a charging system, a customer management system, and a service policy control system.

[0019] Further, in step S2, when the edge node needs to use a storage service, a storage request is initiated to the access network, the access network allocates storage space on the storage server for the edge node and returns to the edge node, specifically:

[0020] The edge node establishes a session with the storage access server (SBRAS) on the access network, and establishes a connection between the edge node and the access network in the session using an extended PPP protocol;

[0021] The extended PPP protocol is based on link layer connection established by a link control protocol (LCP) and IP address allocation for the edge node by a network layer control protocol, and further includes a storage configuration protocol (SCP) for allocating storage resources stored in the storage server.

[0022] Further, in step S2, the storage resources stored in the storage server are allocated by the storage configuration protocol (SCP), and specifically:

[0023] The edge node initiates a storage request to the storage access server (SBRAS) and selects initial parameters including storage space size;

[0024] The storage access server (SBRAS) initiates a challenge to the edge node, and the challenge carries a username of the edge node;

[0025] The edge node finds its password according to the username, hashes the username and the password to obtain a first hash value, and sends the first hash value to the storage access server (SBRAS);

[0026] The storage access server (SBRAS) finds the password corresponding to the username in a local information base according to the username, hashes the username and the password to obtain a second hash value, and compares the second hash value with the first hash value. If they are the same, the authentication is passed, the storage space on the storage server is allocated to the edge node, otherwise, the authentication fails, and no storage space is allocated.

[0027] Further, in step S2, the access network allocates the storage space on the storage server to the edge node and returns to the edge node, and further includes:

[0028] Returning a storage directory for allocating the storage space on the storage server to the edge node;

[0029] The edge node accesses the storage space on the storage server according to the storage directory.

[0030] Further, the edge node establishes a session with the storage access server (SBRAS) on the access network, and further includes:

[0031] The edge node discovers the storage access server (SBRAS) by using four messages PADI, PADO, PADR and PADS in the discovery phase of the PPPoE protocol;

[0032] The storage access server (SBRAS) ends the session with the edge node by using a message PADT in the end phase of the PPPoE protocol.

[0033] A system for performing the method of extending edge storage capability as described above, comprising:

[0034] a storage service deployment module for acquiring an access network closest to a next hop of an edge node, and deploying a storage server on the access network;

[0035] a storage service allocation module for initiating a storage request to the access network when the edge node needs to use a storage service, and the access network allocates storage space on the storage server for the edge node and returns to the edge node;

[0036] a storage service use module for providing the edge node to access and use the storage space on the storage server allocated by the access network for data transmission between the edge node and the access network.

[0037] A computer device comprising a memory and one or more processors, the memory storing computer code, the computer code being executed by the one or more processors to cause the one or more processors to perform the method as described above.

[0038] A computer-readable storage medium storing computer code, when the computer code is executed, the method as described above is performed.

[0039] Compared with the prior art, the present application includes at least one of the following beneficial effects:

[0040] (1) By providing a method for extending edge storage capability, comprising: S1: acquiring an access network closest to a next hop of an edge node, and deploying a storage server on the access network; S2: when the edge node needs to use a storage service, initiating a storage request to the access network, and the access network allocates storage space on the storage server for the edge node and returns to the edge node; S3: the edge node transmits data between the edge node and the access network, accesses and uses the storage space on the storage server allocated by the access network. The above technical solution extends the storage capability of the edge node, especially the access network (such as a home node). Combined with the computing and bandwidth capability of the edge node itself, the capability of the edge node can be greatly improved to meet the growing demand for edge computing applications.

[0041] (2) By using the storage method of the present application, the requirement of terminal devices for local storage can be simplified or even eliminated, such as the current use of a large number of home NAS servers. After using the storage method of the present application, external storage devices can be eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The overall flow chart of the method for extending the edge storage capacity of the present application;

[0043] Figure 2 The network structure diagram of the present application extending the edge storage capacity;

[0044] Figure 3 The schematic diagram of the edge node and the SBRAS server establishing a session of the present application;

[0045] Figure 4 The schematic diagram of the present application using the SCP storage configuration protocol to allocate storage resources;

[0046] Figure 5 The overall structure diagram of the system for extending the edge storage capacity of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0048] Those skilled in the art can understand that, unless specifically stated, the singular forms "a", "an" and "the" used herein also include the plural forms. It should be further understood that the phrase "comprising" used in the specification of the present application means that the features, integers, steps, operations, elements and / or components exist, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0049] First, the technology involved in the present application is briefly introduced:

[0050] (1) PPP protocol

[0051] The point-to-point protocol (PPP, Point-to-Point Protocol) is mainly used to establish a connection between two network nodes and send data through dial-up or leased line. PPP is a solution for simple connection between hosts, bridges and routers of various types. The PPP protocol is described in detail in RFC1661. The PPP protocol is one of the most widely used protocols on a wide area network. Its advantages are simplicity, user authentication capability, and can solve IP allocation, etc.

[0052] PPP is a member of the TCP / IP suite of protocols. PPP is an extension of TCP / IP that adds two additional functional groups: A: TCP / IP packets can be transported over serial interfaces; B: Secure login is possible.

[0053] When using a serial interface as part of a public telephone system, it is important to ensure the authenticity of all communications. The terminal PPP incorporates a username and password security. Therefore, when a router or server receives a request via PPP, the request must be authorized if the source is not secure. This authorization is part of PPP. Because of its ability to route TCP / IP packets over serial interfaces and its authorization capabilities, ISPs (Internet Service Providers) typically use PPP to allow dial-up users to connect to the Internet.

[0054] When a user dials into an ISP, the modem of the router acknowledges the dial and establishes a physical connection (up to the bottom layer). The PC sends a series of LCP (Link Control Protocol, which defines methods for establishing, configuring, and testing data link layer connections) packets (encapsulated into multiple PPP frames) to the router.

[0055] These packets and their responses select some PPP parameters, and perform network layer configuration (if previously authenticated by PAP or CHAP authentication), NCP (Network Control Protocol, which contains a set of protocols for connection establishment and parameter negotiation for different network layer protocols) to assign a temporary IP address to the newly connected PC, making the PC a host on the Internet.

[0056] When the communication is complete, the NCP releases the network layer connection and reclaims the IP address that was previously assigned. Next, the LCP releases the data link layer connection. Finally, the physical layer connection is released.

[0057] (2) BRAS Broadband Remote Access Server

[0058] The Broadband Remote Access Server (BRAS) is a new type of access gateway for broadband network applications. It is located at the edge of the backbone network and can complete the data access of the user bandwidth IP / ATM network (the access means is mainly based on xDSL / Cable Modem / High-speed Ethernet technology (LAN) / Wireless Broadband Data Access (WLAN) / FTTx, etc.), realize the broadband Internet access of commercial buildings and residential users, IPVPN service based on IPSec (IP Security Protocol), build an enterprise intranet, and support ISP wholesale services to users and other applications.

[0059] (3) PPPoE protocol

[0060] PPPoE (PPP over Ethernet) protocol is a link layer protocol that encapsulates PPP frames into Ethernet frames. PPPoE can enable multiple hosts in an Ethernet network to connect to a remote broadband access server. Carriers want to connect multiple hosts in a site to the same remote access device, while the access device can provide similar access control and billing functions as dial-up. Among the many access technologies, Ethernet is the most economical way to connect multiple hosts to an access device, and the PPP protocol can provide good access control and billing functions, so the technology of transmitting PPP packets over Ethernet, i.e. PPPoE, is generated. PPPoE uses Ethernet to form a network of a large number of hosts, connects to the Internet through a remote access device, and uses the PPP protocol to control each host connected, and has the characteristics of wide application range, high security and convenient billing.

[0061] The PPPoE protocol has four messages PADI, PADO, PADR and PADS in the discovery phase, and one message PADT to end the session. Specifically, it includes:

[0062] A: PADI (PPPoE Active Discovery Initiation) message

[0063] The first step of the PPPoE discovery phase, i.e. a message is first sent by the user side. The user host sends this message in a broadcast manner, so the destination address field of the Ethernet frame corresponding to the message should be filled with all 1s, and the source address field is filled with the MAC address of the user host. The broadcast packet can be received by multiple access concentrators.

[0064] B: PADO (PPPoE Active Discovery Offer) message

[0065] The second step of the PPPoE discovery phase, i.e. the access concentrator responds to the PADI message sent by each user host, at this time the source address of the Ethernet frame corresponding to the message is filled with the MAC address of the access concentrator, and the destination address is filled with the MAC address of the user host obtained from the PADI.

[0066] C: PADR (PPPoE Active Discovery Request) message

[0067] The third step of the PPPoE discovery phase is that the user host sends a unicast request message to the access server. When the user host receives the PADO message, it selects one of the access concentrators as the object of the subsequent session. Since the user host knows the MAC address of the access concentrator after receiving the PADO message, the source address of the Ethernet frame of the PADR message is filled with the MAC address of the user host, and the destination address of the Ethernet frame is filled with the MAC address of the access concentrator.

[0068] D: PADS (PPPoE Active Discovery Session-confirmation) message

[0069] The fourth step of the PPPoE discovery phase, which is the last step of the discovery phase, is that the access concentrator is ready to start a PPP session after receiving the PADR message, and the access concentrator allocates a unique session process ID for the session and carries the session ID in the PADS message sent to the host. If the access concentrator does not satisfy the service applied by the user, it sends a PADS message to the user, which carries a service name error mark, and the session ID in the PADS message is filled with 0x0000.

[0070] E: PADT (PPPoE Active Discovery Terminate) message

[0071] The PADT message can be sent at any time after the start of the session, and is mainly used to terminate a PPPoE session. It can be sent by the host or the access concentrator, and the destination address is filled with the MAC address of the opposite end of the Ethernet.

[0072] (4) DHCP protocol

[0073] DHCP (Dynamic Host Configuration Protocol) is a standard protocol defined in RFC 1541 (replaced by RFC 2131), which allows a server to dynamically allocate IP addresses and configuration information to a client. DHCP is a network protocol for a local area network. It refers to a server controlling a range of IP addresses, and a client automatically obtaining an IP address and subnet mask allocated by the server when logging in to the server. By default, DHCP is not automatically installed by the system as a service component of Windows Server, and needs to be manually installed and configured by the administrator.

[0074] Generally be applied in large LAN environment, the main role is centralized management, distribution IP address, make the host in network environment dynamicly obtain IP address, gateway address, DNS server address and so on, and can promote the use rate of address.

[0075] Secondly, the technical highlights of the present application are introduced:

[0076] (1) The storage server of the present application is centrally stored in the access layer closest to the edge node, rather than locally or in the central cloud, which not only reduces the dependence of the edge node or the end device on physical storage, but also does not lose the speed and performance of storage access.

[0077] (2) By establishing a general storage configuration protocol SCP (StorageConfigProtocol) to allocate storage resources in the storage server centrally stored in the access layer closest to the edge node (similar to NCP network control protocol to allocate IP address), the edge node can not only obtain IP address and bandwidth resources, but also can obtain storage resources.

[0078] (3) The present application is applicable to SCP extension using PPP protocol, allocation of intranet IP address and storage through DHCP server, home network, access network and other scenarios that expand the storage capacity of edge node by setting shared storage closest to edge node (but not limited to access layer).

[0079] The specific content of the present application is described below through specific embodiments. In the embodiments, the SCP extension using PPP protocol is mainly described, but it cannot be used to limit the present application. The present application is applicable to any scenario that expands the storage capacity of edge node by setting shared storage closest to edge node in access network.

[0080] First embodiment

[0081] As shown in Figure 1 , the present embodiment provides a method for expanding the storage capacity of edge, comprising:

[0082] S1: Obtain the access network closest to the edge node, and deploy a storage server on the access network.

[0083] Specifically, in the present embodiment, unlike the method of deploying storage server in central cloud or using terminal NAS server for storage in the prior art, the storage server is deployed on the access network closest to the edge node in the present embodiment, which not only reduces the dependence of the edge node or the end device on physical storage, but also does not lose the speed and performance of storage access.

[0084] The edge node of the present application can be any edge terminal device, including a personal computer (PC), a router, a set-top box, a network attached storage (NAS) device, and an Internet of Things (IOT) device.

[0085] Further, as shown in Figure 2 To implement the allocation of storage space on the storage server by the access network closest to the edge node, and to implement some functions including network bearing, control implementation, the present embodiment deploys a storage access server (SBRAS) on the access network; the storage access server (SBRAS) includes a network bearing function, a storage allocation function, and a control implementation function; wherein the network bearing function is responsible for terminating the PPPoE connection of the edge node and converging the traffic function of the edge node, the storage allocation function is responsible for allocating storage space on the storage server for the edge node, and the control implementation function is responsible for connecting with systems including an authentication system, a charging system, a customer management system, and a service policy control system.

[0086] S2: When the edge node needs to use a storage service, a storage request is initiated to the access network, the access network allocates storage space on the storage server for the edge node and returns to the edge node, and specifically:

[0087] As shown in Figure 3 The edge node establishes a session with the storage access server (SBRAS) on the access network, and uses an extended PPP protocol to establish a connection between the edge node and the access network in the session; wherein the extended PPP protocol, on the basis of establishing a link layer connection through a link control protocol (LCP) and allocating an IP address for the edge node through a network layer control protocol, extends and adds a storage configuration protocol (SCP) to allocate storage resources concentrated in the storage server.

[0088] Further, as shown in Figure 4 The storage configuration protocol (SCP) is used to allocate storage resources concentrated in the storage server, and the specific steps are as follows:

[0089] Request: The edge node initiates a storage request to the storage access server (SBRAS) and selects initialization parameters including storage space size;

[0090] Challenge: The storage access server (SBRAS) initiates a challenge to the edge node, and carries the username of the edge node in the challenge;

[0091] Response: The edge node looks up its own password according to the username, hashes the username and the password to obtain a first hash value, and sends the first hash value to the storage access server SBRAS;

[0092] Result: The storage access server SBRAS looks up the password corresponding to the username in a local information base according to the username, hashes the username and the password to obtain a second hash value, and compares the second hash value with the first hash value. If they are the same, the authentication is passed, the storage space on the storage server is allocated to the edge node, otherwise the authentication fails, and no storage space is allocated.

[0093] Further, the access network allocates the storage space on the storage server to the edge node and returns to the edge node, and further comprises: returning a storage directory of the storage space on the storage server allocated to the edge node; the edge node accesses the storage space on the storage server according to the storage directory.

[0094] S3: The edge node performs data transmission between the edge node and the access network, accesses and uses the storage space on the storage server allocated by the access network.

[0095] Specifically, after the last-hop access network allocates the storage space to the edge node, in the process of the session between the edge node and the storage access server SBRAS on the access network, the edge node performs data transmission between the edge node and the access network, accesses and uses the storage space on the storage server allocated by the access network.

[0096] Further, the edge node establishes a session with the storage access server SBRAS on the access network, and further comprises:

[0097] Before establishing the session, the edge node discovers the storage access server SBRAS by using four messages PADI, PADO, PADR and PADS in the discovery stage of the PPPoE protocol; after the session ends, the storage access server SBRAS ends the session with the edge node by using the message PADT in the end stage of the PPPoE protocol.

[0098] Second embodiment

[0099] As shown in Figure 5 The embodiment provides an extended edge storage capacity system for performing the method of the extended edge storage capacity as in the first embodiment, comprising:

[0100] A storage service deployment module 1 is configured to obtain an access network closest to an edge node, and deploy a storage server on the access network.

[0101] a storage service allocation module 2 configured to initiate a storage request to the access network when the edge node needs to use the storage service, and the access network allocates storage space on the storage server to the edge node and returns to the edge node;

[0102] a storage service usage module 3 configured to provide the edge node with data transmission between the edge node and the access network, and access and use the storage space on the storage server allocated by the access network.

[0103] A computer readable storage medium stores computer code, when the computer code is executed, the above method is executed. Those skilled in the art can understand that all or part of the steps of the above method can be completed by a program instructing the relevant hardware, and the program can be stored in a computer readable storage medium, and the storage medium can include a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0104] The above is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above embodiment. Any technical solution falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements shall also be considered as falling within the protection scope of the present application.

[0105] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they shall be considered as falling within the scope of the present application.

[0106] It should be noted that the above embodiments can be freely combined as needed. The above is only the preferred embodiment of the present application, and it should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements shall also be considered as falling within the protection scope of the present application.

Claims

1. A method of extending edge storage capacity, the method comprising: Comprise: S1: access to the nearest edge node hop access network, deploy storage server on the access network; S2: when the edge node needs to use storage service, initiate a storage request to the access network, the access network allocates the edge node storage space on the storage server and returns to the edge node; S3: the edge node transmits data between the edge node and the access network, accesses and uses the storage space on the storage server allocated by the access network; In step S1, also includes: Deploy storage access server SBRAS on the access network; The storage access server SBRAS includes network bearing function, storage allocation function and control implementation function; Wherein, the network bearing function is responsible for terminating the PPPoE connection of the edge node, converging the traffic function of the edge node, the storage allocation function is responsible for allocating the storage space on the storage server for the edge node, and the control implementation function is responsible for connecting with the system including authentication system, charging system, customer management system and service policy control system.

2. The method of extending edge storage capability of claim 1, wherein, In step S1, the edge node includes any one of edge terminal devices including personal computer PC, router, set top box, network attached storage NAS device and Internet of Things IOT device.

3. The method of extending edge storage capability of claim 2, wherein, In step S2, when the edge node needs to use storage service, initiate a storage request to the access network, the access network allocates the edge node storage space on the storage server and returns to the edge node, specifically: The edge node establishes a session with the storage access server SBRAS on the access network, and establishes the connection between the edge node and the access network in the session by using the extended PPP protocol; Wherein, the extended PPP protocol extends and adds storage configuration protocol SCP on the basis of establishing link layer connection through link control protocol LCP and allocating IP address for the edge node through network layer control protocol, to allocate the storage resources concentrated in the storage server.

4. The method of extending edge storage capability of claim 3, wherein, In step S2, the storage resources concentrated in the storage server are allocated by using the storage configuration protocol SCP, specifically: The edge node initiates a storage request to the storage access server SBRAS, and selects initialization parameters including storage space size; The storage access server SBRAS initiates a challenge to the edge node, and carries the username of the edge node in the challenge; The edge node finds its own password according to the username, hashes the username and the password to obtain a first hash value, and sends the first hash value to the storage access server SBRAS; The storage access server SBRAS sends the first hash value to the storage access server SBRAS; The storage access server SBRAS looks up the password corresponding to the username in a local information base according to the username, hashes the username and the password, obtains a second hash value, and compares the second hash value with the first hash value. If they are the same, authentication is passed, the storage space on the storage server is allocated to the edge node, otherwise, verification fails, and no storage space is allocated.

5. The method of extending edge storage capacity of claim 1, wherein, In step S2, the access network allocates the storage space on the storage server to the edge node and returns to the edge node, further comprising: returning a storage directory for allocating the storage space on the storage server to the edge node; the edge node accesses the storage space on the storage server according to the storage directory.

6. The method of extending edge storage capability of claim 3, wherein, The edge node establishes a session with the storage access server SBRAS on the access network, further comprising: The edge node discovers the storage access server SBRAS by using four messages PADI, PADO, PADR and PADS in the discovery phase of the PPPoE protocol; The storage access server SBRAS uses the message PADT in the end phase of the PPPoE protocol to end the session with the edge node.

7. A system for performing the method of extending edge storage capabilities as claimed in any one of claims 1-6, characterized by comprising: a storage service deployment module configured to obtain an access network closest to a next hop of an edge node, and deploy a storage server on the access network; a storage service allocation module configured to initiate a storage request to the access network when the edge node needs to use a storage service, and the access network allocates storage space on the storage server to the edge node and returns to the edge node; a storage service use module configured to provide the edge node with data transmission between the edge node and the access network, access and use the storage space on the storage server allocated by the access network.

8. A computer device comprising a memory and one or more processors, the memory storing computer code, the computer code being executed by the one or more processors to cause the one or more processors to perform the method of any one of claims 1 to 6.

9. A computer readable storage medium storing computer code, the computer code being executed to perform the method of any one of claims 1 to 6.

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