SECOND NETWORK, COMMUNICATION METHOD AND PROGRAM

Description

Technical Field

[0001] The present invention relates to a second network, a communication method and a program.Background Art

[0002] Along with a progress of globalization, the number of devices connected to a computer network such as the Internet has increased, and the idea of Internet of Things in which everything is networked is spreading. Hereinafter, a networked device is referred to as an "IoT device." There are various network connection methods for IoT devices, but cases where a cellular network is utilized are focused on herein.

[0003] It is also common that an IoT device connected to a network by a cellular network is exported across a national border and, for example, a case can be considered in which a SIM card contracted with a European mobile network operator (MNO) or a carrier is inserted into a product in a European factory and is imported into Japan.

[0004] When the IoT device attempts to access the computer network in Japan, an identification number such as IMSI or ICCID is allocated to the SIM card, and since information for specifying the aforementioned European carrier which is the home location is associated with the identification number, a connection initiation request to the computer network is transferred to the European carrier via the Japanese carrier which is in a mutual-connection relationship with the European carrier.

[0005] More specifically, as illustrated in Fig. 1, when a wireless terminal 100 in which a SIM card contracted with a European carrier 110 is inserted is located in the area of a Japanese carrier 120 and initiates accessing an IP network 130, the wireless terminal 100 first sends a connection initiation request including IMSI to a gateway (SGSN in 3G, and S-GW in LTE) (hereinafter referred to as a "visiting gateway" or a "visiting carrier gateway") deployed in a core network of the Japanese carrier 120 via a wireless base station which is an entry point of the Japanese carrier 120.

[0006] Upon receiving the connection initiation request, if the visiting gateway determines that an identification number is associated with the European carrier 110 other than the Japanese carrier 120, the visiting gateway performs an authentication with the European carrier 110 including presence or absence of a contract and the like based on information on the SIM card inserted in the wireless terminal 100, and thereafter DNS is referred based on the Access Point Name (APN) received from the wireless terminal 100 to obtain the IP address corresponding to the APN. The IP address designates a gateway (GGSN in 3G, and P-GW in LTE) (hereinafter also referred to as a "home gateway" or a "home carrier gateway") which is an end point of a core network of the European carrier 110, and the visiting gateway sends or transfers the connection initiation request to the home gateway on a C-plane of a tunneling protocol such as GTP via a network for providing an inter-carrier mutual connection such as GRX, and a tunnel is formed between the visiting gateway of the Japanese carrier 120 and the home gateway of the European carrier 110. Communication of the wireless terminal 100 is transferred through the tunnel from the Japanese carrier 120 to the European carrier 110, and transferred from the European carrier 110 to an external IP network or the like.

[0007] WO2014093086 discloses how hub breakout roaming enables providing data access to a user network device, subscribed with a home network and roaming into a visited network, by a hub breakout system through the visited network. Upon receiving a request for data access from the visited network, the hub breakout system assigns an IP address to the user network device. The hub breakout system then routes data packets, associated with the data access requested by the user network device, to and from at least one corresponding data source, using the assigned IP address. The data source includes the Internet, a private network associated with home network, or any other service provider entity.

[0008] US2010211628 discloses a system and method for selecting a proxy gateway server for controlling data traffic initiated by a user device roaming on a visited network is disclosed. The method includes utilizing a mobility anchor server associated with the visited network to receive a request to activate a data traffic session from a user device, identify the user device as a roaming user device, and select a proxy gateway server from one or more servers associated with the visited network for controlling the data traffic initiated by the roaming user device. The selection of a proxy server is accomplished by querying a DNS server associated with the visited network with a pre-defined roaming APN string associated with the visited network and, in response to the query, receiving an Internet Protocol (IP) address of the proxy gateway server from the DNS server.Summary of InventionTechnical Problem

[0009] Although it is possible to use a communication service within a service area of a partner carrier even outside a service area of a carrier that issued the SIM card by an international roaming using an inter-carrier mutual connection network such as GRX, an access must be made via a home location as illustrated in the example in Fig. 1. This causes delay of data communication due to increase in the communication distance, the number of network hops, etc. This is a so-called "triangle routing" problem.

[0010] A similar problem also occurs, for example, in a case where a SIM card issued by a European carrier is inserted into an IoT device such as an in-vehicle device and used worldwide.

[0011] The present invention has been made in view of the aforementioned problem, and an objective of the present invention is to provide a second network, a communication method and a program for providing an access to a network via the second network (for example, the Japanese carrier) to a wireless terminal on which an identification number for accessing a first network (for example, the European carrier) is stored (directly or indirectly), which can suppress a delay.

[0012] The objective of the present invention is to provide a second network (for example, the Japanese carrier) or a communication method by which an access to a network is provided to a wireless terminal on which an identification number for accessing a first network (for example, the European carrier) is stored, which can suppress a delay.Solution to Problem

[0013] The first aspect of the present invention is a second network whichis configured to communicate with a communication system for providing an access to a fourth network via the second network to a wireless terminal on which an identification number for accessing a first network is stored, as according to independent claim 1.

[0014] The second aspect of the present invention is a communication method to communicate with a communication system for providing an access to a fourth network via a second network to a wireless terminal on which an identification number for accessing a first network is stored, as according to independent claim 2.

[0015] The third aspect of the present is a program for causing a computer of a second network to perform a communication method tc communicate with a communication system for providing an access to a fourth network via a second network to a wireless terminal on which an identification number for accessing a first network is stored, as according to independent claim 3.Advantageous Effect of Invention

[0016] According to one aspect of the present invention, a gateway on U-plane connected to a visiting gateway performing the C-plane function is selected based on a network ID of the visiting gateway, such that a communication path is established between the gateways, whereby it is possible to suppress delay due to passing through a home location.Brief Description of Drawings

[0017] Fig. 1 is a diagram illustrating a conventional international roaming. Fig. 2 is a diagram illustrating a communication network including a communication system. Fig. 3 is a diagram illustrating a signal flow in a communication network. Fig. 4 is a diagram illustrating details of a communication system. Description of Embodiments

[0018] Hereinafter, embodiments of the present invention and embodiments not encompassed by the wording of the claims will be described in detail with reference to the drawings.(Outline of the Present Invention)

[0019] Fig. 2 illustrates a communication network including a communication system (a communication system as such is not encompassed by the wording of the claims). For the sake of convenience, an example is explained in a case where a first network 210 is a network of a European carrier whose service area is a predetermined area in Europe, and a second network 220 is a network of a Japanese carrier whose service area is a predetermined area in Japan. The SIM card inserted in the wireless terminal 100 is contracted with the European carrier in the same way as in Fig. 1, and the card holds an identification number for accessing the European carrier.

[0020] Incidentally, two or more IMSIs may be stored in the SIM card inserted in the wireless terminal 100, and in addition to being stored in a physical SIM card of the wireless terminal 100, one or a plurality of IMSIs may be stored on a semiconductor chip (also referred to as "eSIM") embedded in the wireless terminal 100 or one or the plurality of IMSIs may be stored on a software installed in a secure area within a module of the wireless terminal 100, and various embodiments in which the wireless terminal 100 holds the identification number directly or indirectly may be considered.

[0021] Here, a communication system 200A is connected to a first network 210 directly or via an inter-carrier mutual connection network such as GRX. With respect to the first network 210 which is an MNO, the communication system 200A for providing a wireless communication service to an end user by using its wireless communication infrastructure is located as a part of a network of a mobile virtual network operator (MVNO), and selects among a plurality of networks a third network 200B for forming of a tunnel by the wireless terminal 100 requesting an access to a network 130 such as an IP network, as will be described in detail below. Such a configuration can be said to have been made possible only after trying to operate the communication system 200A and the third network 200B across a national border by the same operator, which is a novel idea that did not exist in the past.

[0022] In the following description, it is assumed that the communication system 200A is a network separate from the first network 210, but it is noted that the present invention can also be applied, for example, to a case where the communication system 200A is built as a part of the first network on the same network as the first network.

[0023] First, in order to access a computer network 130, the wireless terminal 100 sends a connection initiation request to the second network 220 (S301). Upon receiving the connection initiation request, the second network 220 determines whether the carrier associated with an identification number, such as an IMSI included in the connection initiation request, is the second network 220 based on the identification number. In a case where it is not the second network 220, that is, in a case where the second network 220 is a visiting gateway for the wireless terminal 100, presence or absence of a contract between the first network 210 and the wireless terminal 100 (or the SIM card inserted therein) is authenticated, and then an inquiry is made to a DNS which holds a correspondence between an APN received from the wireless terminal 100 and an IP address of a gateway based on the APN (S302). Based on the received APN, the DNS sends an IP address of an access destination server corresponding to the APN to the second network 220 (S303).

[0024] The DNS can be a part of the communication system 200A or can also be arranged at a position accessible from the communication system 200A or the second network 220 (according to the claimed invention the DNS is accessible from the second network 220). For each APN, it is not necessary that one IP address correspond to the APN, but it is possible that a plurality of IP addresses is made to correspond to the APN and an IP address can be allocated in a round robin manner when an APN is received or an IP address can be selected according to an identification number such as IMSI. Further, it is possible that, a network ID for identifying the second network 220 or the visiting gateway of the second network 220 such as a mobile country code (MCC) and a mobile network code (MNC), an IP address, and the likes is received at the DNS and then the selection is performed according to the network ID. More specifically, it is possible to select a nearby one by using an over-network distance or a geographical distance from the second network 220 or the visiting gateway of the second network 220 specified by the network ID as a criterion. In a case where there is a plurality of IP addresses at the same distance, one of them may be randomly selected.

[0025] Subsequently, the second network 220 sends, to the communication system 200A or a server in the communication system 200A designated by the IP address corresponding to the APN, the connection initiation request (in the present specification, the "connection initiation request" also includes a request sent by the second network 220 which substantially corresponding to the connection initiation request received by the second network 220) or an identification number included in the connection initiation request (the latter alternative of an identification number is not encompassed by the wording of the claims), and a network ID for identifying the second network 220 (S304). Specifically, an ID of the gateway of the second network 220, such as a mobile country code (MCC) and a mobile network code (MNC), an IP address, or the likes can be used as the network ID. In a signaling on C-plane sent from the second network 220, an IP address of the second network 220 or the visiting gateway of the second network 220 is included as a U-plane destination, and this can be used as the network ID.

[0026] In addition to the network ID, the second network 220 may further send auxiliary information for assisting the communication system 200A in selecting a gateway or a third network 200B including the gateway for the wireless terminal 100 to establish a connection, to the communication system 200A.

[0027] The communication system 200A stores a gateway table that retains a correspondence between a network ID and a gateway on U-plane associated with the network with the network ID, and based on the received network ID, the wireless terminal 100 can select the gateway or the third network 200B including the gateway for the wireless terminal 100 to establish the connection. In addition, in response to the received connection initiation request, the communication system 200A also makes a request to generate a tunnel end point (TE) ID to the selected third network 200B or the gateway thereof as necessary (S305).

[0028] The communication system 200A receives an ID of the tunnel end point (TEID) from the third network 200B (S306), and sends the same together with the gateway ID to the second network 220 (S307). The gateway ID is, for example, an IP address of a selected gateway on U-plane. In a case where the gateway of the third network 200B has two or more servers connectable to the second network 220, an IP address of any one of them is selected as the gateway ID.

[0029] Upon receiving the gateway ID and the TEID, the second network 220 forms a tunnel between the visiting gateway of the second network 220 and the gateway of the third network 200B designated by the gateway ID (S308).

[0030] In the conventional international roaming, it is always required to return to the first network 210 that is a home carrier to perform communication, which causes a delay, but according to the present invention, the wireless terminal 100 can form a tunnel on U-plane between itself and the gateway of the third network 200B associated with the second network 220 that is the visiting carrier, and the home location can be shortcut to improve the delay remarkably.

[0031] Incidentally, an example of an access destination network by the wireless terminal 100 is not only an IP network such as the Internet but also a non-IP network. In addition to a public system, a private system may also be mentioned. In addition to an on-premises private system, in a case where at least a part of the third network 200B is realized on the cloud, the private system includes a different IP network on the same cloud, an IP network on a different cloud, or the like, and these private systems and the third network 200B may be connected to each other by a dedicated line or a virtual dedicated line.(Details of Communication System)

[0032] Fig. 4 illustrates details of a server included in a communication system (a server as such is not encompassed by the wording of the claims). Each of one or a plurality of servers 400 included in the communication system 200A can be a server including a communication unit 401 such as a communication interface that receives a connection initiation request on C-plane from the wireless terminal 100 and a processing unit 403 such as a CPU that selects a gateway to the computer network 130 connected to the second network 220 by referring to the gateway table stored in a storage unit 402 such as a memory and a hard disk based on the obtained network ID of the second network 220 in response to the connection initiation request. The communication unit 401 sends the gateway ID of the selected gateway to the second network 220. If the ID of a tunnel end point generated by the selected gateway has been received, the communication unit 401 also sends the same to the second network 220.

[0033] The server is not limited to a single physical server but can also be a plurality of accessible servers, and the storage unit 402 may be a storage device accessible from the server on the computer network. In addition, an operation in one or both of the communication unit 401 and the processing unit 403 can be realized by executing one or a plurality of programs to cause the computer to perform the pertinent operation.

[0034] The server 400 may be an instance on a public cloud or a private cloud. Here, in the present specification, the term "cloud" refers to a system capable of dynamically provisioning and providing computing resources such as a CPU, a memory, a storage, and a network bandwidth according to demand on a network. For example, the cloud can be used by AWS or the like.

[0035] In order to provide an access to the network 130 via the second network 220 to the wireless terminal 100, the communication system 200A can be configured to perform a C-plane function when initiating the connection and not perform a U-plane function. The U-plane function is performed in the third network 200B whose service area is outside a service area or outside an area of one or both of the first network 210 and the communication system 200A, such as abroad. That the third network 200B is outside the service area or outside the area of the communication system 200A does not necessarily mean that the third network 200B is abroad with respect to the communication system 200A. The third network 200B performs a U-plane function when providing the access to the computer network 130 via the second network 220 to the wireless terminal 100, but it can be configured not to perform a C-plane function.(Details of Gateway Table)

[0036] The gateway table that can be held or accessed by the communication system 200A determines a correspondence relationship between a network ID and a gateway or server associated with the network with the network ID or the network including the gateway.

[0037] In one aspect, the gateway table determines a correspondence relationship between a network ID, such as an IP address, and one or a plurality of gateways or a network (that is, the third network 200B) including the gateways that are located in the vicinity of a network (that is, the second network 220) with the network ID or its gateway among the scattered networks or gateways. Here, a "distance" to the gateway can be an over-network distance measured by delay time. The over-network distance can be calculated by, for example, the number of hops. Further, it can be considered that geographically close gateways are located in the vicinity in that order.

[0038] Further, in another embodiment, it is also possible to determine a correspondence relationship between a network ID and one or a plurality of gateways outside the service area of the network (that is, the second network 220) with the network ID or a network including the gateways.

[0039] Further, in examples not according to the wording of the claims, it is also possible to associate a plurality of gateways or a network including the gateways with one network ID, and determine which gateway is in charge in accordance with an identification number such as IMSI included in the connection initiation request. Then, with respect to a specific identification number, it is possible to associate a gateway for which a specific service on U-plane is available or a network including the gateway regardless of the distance, and for example, it is possible to select the gateway on U-plane based only on the identification number.

[0040] Further, at the communication system 200A or the server accessible from the communication system 200A, metrics of a processing capability of each of a plurality of U-plane gateways associated with the second network 220 may be monitored, and the gateway with a lower processing load may be selected. Examples of the metrics to be monitored include CPU load, memory utilization rate, disk read, disk write, amount of receiving network traffic, amount of sending network traffic, and the like. One or a plurality of servers of each gateway associated with the second network 220 can be instances on the public cloud or private cloud. In the selection of the gateway on U-plane by using the distance described above as a criterion, it is also advantageous to finally select the one with the lower processing load when there is a plurality of equivalent gateways.

[0041] Further, the communication system 200A may receive the auxiliary information from the second network 220. As a specific example, there may be one or a plurality of servers serving as outlets for a connection between the second network 220 and the third network 200B, and an IP address of each server may be received as the auxiliary information. In this case, in the communication system 200A, a gateway of a connection destination or the third network 200B including the gateway may be selected by using each server as the basis, and a combination of the shortest distance between the second network 220 and the third network 200B may be selected. It is also possible to regard the IP address of each server as a network ID and to interpret that a plurality of network IDs are being received by the communication system 200A.(HLR / HSS)

[0042] Regarding the network ID of the second network 220, the mobile country code (MCC) and the mobile network code (MNC), the IP address that is the U-plane destination included in the signaling on C-plane, or the likes are exemplified in the above description, but it is also possible for the communication system 200A to refer to HLR / HSS or subscriber information management database based on the identification number such as IMSI to obtain a network ID such as an IP address of a visiting gateway or the second network 220 including the same as a registered network of the wireless terminal 100. More specifically, in the HLR / HSS or the subscriber information management database, it is possible that a registered network table retaining the registered network where each wireless terminal exists is stored and a network ID such as the mobile country code (MCC) and the mobile network code (MNC), or the likes can be determined by referring to the table.(Details of Second Network)

[0043] Like the communication system 200A, the second network 220 includes one or a plurality of servers, each of which includes a communication unit such as a communication interface, a storage unit such as a memory and a hard disk, and a processing unit such as a CPU, performs sending and / or receiving of the data in the communication unit, and performs required processing in the processing unit. The storage unit may be a storage device that can be accessed from the server on the computer network, and an operation in one or both of the communication unit and the processing unit can be realized by executing one or a plurality of programs for causing the computer to perform the pertinent operation. Further, one or the plurality of servers of the second network 220 can be instances on a public cloud or a private cloud.Reference Signs List

[0044] 100WIRELESS TERMINAL 110EUROPEAN CARRIER 120JAPANESE CARRIER 130IP NETWORK 200ACOMMUNICATION SYSTEM 200BTHIRD NETWORK 210FIRST NETWORK 220SECOND NETWORK 400SERVER 401COMMUNICATION UNIT 402STORAGE UNIT 403PROCESSING UNIT

Claims

1. A second network (220) which is configured to communicate with a communication system (200A) for providing access to a fourth network (130) other than a first network (210), via the second network (220), to a wireless terminal (100) on which an identification number for accessing the first network (210) is stored, comprising: means for receiving an Access Point Name, APN, and a first connection initiation request on C-plane from the wireless terminal (100) to send a second connection initiation request corresponding to the first connection initiation request to the communication system (200A) designated by an IP address corresponding to the APN received from the wireless terminal (100); means for making an inquiry to a DNS accessible from the second network (220) to obtain the IP address corresponding to the APN received from the wireless terminal (100), wherein the IP address is determined by the DNS based on the APN and sent to the second network (220); means for sending a network ID of the second network (220) and the second connection initiation request to the IP address corresponding to the APN received from the wireless terminal (100); means for receiving a gateway ID of a gateway on U-plane to the fourth network (130)in response to the second connection initiation request, wherein the gateway is within a third network other than the first network (210) and the gateway is connected to the second network (220); and means for establishing a communication path between the second network (220) and the gateway on U-plane designated by the gateway ID.

2. A communication method to communicate with a communication system (200A) for providing access to a fourth network (130) other than a first network (210), via a second network (220), to a wireless terminal (100) on which an identification number for accessing the first network (210) is stored, the communication method is performed by the second network (220) and comprises: receiving an Access Point Name, APN, and a first connection initiation request on C-plane from the wireless terminal (100) to send a second connection initiation request corresponding to the first connection initiation request to the communication system (200A) designated by an IP address corresponding to the APN received from the wireless terminal (100); making an inquiry to a DNS accessible from the second network (220) to obtain the IP address corresponding to the APN received from the wireless terminal (100), wherein the IP address is determined by the DNS based on the APN and sent to the second network (220); sending a network ID of the second network (220) and the second connection initiation request to the IP address corresponding to the APN received from the wireless terminal (100); receiving a gateway ID of a gateway on U-plane to the fourth network (130) in response to the second connection initiation request, wherein the gateway is within a third network other than the first network (210) and the gateway is connected to the second network (220); and establishing a communication path between the second network (220) and the gateway on U-plane designated by the gateway ID.

3. A program, which, when executed, causes a computer of a second network (220) to perform a communication method to communicate with a communication system (200A) for providing access to a fourth network (130) other than a first network (210), via the second network (220), to a wireless terminal (100) on which an identification number for accessing the first network (210) is stored, comprising: receiving an Access Point Name, APN, and a first connection initiation request on C-plane from the wireless terminal (100) to send a second connection initiation request corresponding to the first connection initiation request to the communication system (200A) designated by an IP address corresponding to the APN received from the wireless terminal (100); making an inquiry to a DNS accessible from the second network (220) to obtain the IP address corresponding to the APN received from the wireless terminal (100), wherein the IP address is determined by the DNS based on the APN and sent to the second network (220); sending a network ID of the second network (220) and the second connection initiation request to the IP address corresponding to the APN received from the wireless terminal (100); receiving a gateway ID of a gateway on U-plane to the fourth network (130) in response to the second connection initiation request, wherein the gateway is within a third network other than the first network (210) and the gateway is connected to the second network (220); and establishing a communication path between the second network (220) and the gateway on U-plane designated by the gateway ID.