System, PGW, and SMF

Abstract

To execute a data communication of a communication terminal via a specific path or make the communication path to be used for the data communication redundant when performing an LTE communication according to a Home Routed system.SOLUTION: A PGW having a first IP address and a second IP address comprises: a session information generation section which generates first session information of a communication terminal including the first IP address and second session information of the communication terminal including the second IP address in a case where the communication terminal is registered so as to execute both data communications over a network of a first ASN and a network of a second ASN; a session information synchronization section which synchronizes the second session information between a first storage section corresponding to the PGW and a second storage section corresponding to the other PGW; and a communication tunnel establishment section which establishes a communication tunnel between the PGW and an SGW based on the first session information or the second session information in accordance with a registration content of the communication terminal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system, a PGW, and an SMF. [Background technology]

[0002] Patent Document 1 describes a communication system that reduces packet transmission delays in international roaming. Patent Document 2 describes a communication system that reduces communication delays in roaming communications. [Prior art document] [Patent documents] [Patent Document 1] International Publication No. 2014 / 049668 [Patent Document 2] International Publication No. 2020 / 261458 Summary of the Invention [Means for solving the problem]

[0003] According to one embodiment of the present invention, there is provided a system. The system may include a first PGW (Packet data network Gateway) that is located in a network of a first ASN (Autonomous System number) and that is assigned a first IP (Internet Protocol) address and a second IP address different from the first IP address. The system may include a second PGW that is located in a network of a second ASN different from the first ASN and that is assigned the second IP address. The system may include a first storage unit corresponding to the first PGW. The system may include a second storage unit corresponding to the second PGW. The first PGW may have a request receiving unit that receives, from an SGW (Serving Gateway), a session creation request from a communications terminal that requests creation of a session to a PDN (Packet Data Network). In response to the request reception unit receiving the session creation request, when the communication terminal is registered so that only data communication via the network of the first ASN can be executed out of data communication via the network of the first ASN and data communication via the network of the second ASN, the first PGW receives an IP address of the communication terminal, the first IP address of the first PGW, and a TEID (Tunnel Endpoint Identity Data (TEID)) assigned to a communication tunnel of the first PGW. and when the communications terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed, generates second session information for the communications terminal including the IP address of the communications terminal, the second IP address of the first PGW, TEIDs assigned to the communications tunnel of the first PGW and the communications tunnel of the second PGW, the IP address of the SGW, and the TEID assigned to the communications tunnel of the SGW.The first PGW may include a registration unit that registers the second session information generated by the session information generation unit in the first storage unit. The system may further include a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit. The first PGW may further include a first communication tunnel establishment unit that, to generate a session to a PDN for the communication terminal, establishes a communication tunnel between the first PGW and the SGW based on the first session information when the communication terminal is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, and establishes a communication tunnel between the first PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are executable. The second PGW may have a second communication tunnel establishment unit that establishes a communication tunnel between the second PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that data communication via the network of the first ASN and data communication via the network of the second ASN are both possible in order to generate a session to a PDN of the communication terminal.

[0004] The system may further include the SGW, and the first PGW may further have a response sending unit that sends a session generation response of the communication terminal to the SGW in response to the second session information being synchronized between the first memory unit and the second memory unit, and the SGW may have a response receiving unit that receives the session generation response, and a data sending unit that sends uplink data of the communication terminal to a PGW selected from the first PGW and the second PGW as a destination for the uplink data based on predetermined PGW selection conditions, when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are possible.

[0005] In any of the above systems, the second PGW may further have a data receiving unit that receives the uplink data when the second PGW is selected as the transmission target of the uplink data, and the second communication tunnel establishment unit may establish a communication tunnel between the second PGW and the SGW by acquiring the second session information from the second storage unit when the data receiving unit receives the uplink data and the second PGW does not hold the second session information.

[0006] In any of the systems described above, the second communication tunnel establishment unit may acquire the second session information from the second storage unit when the data receiving unit receives the uplink data for the first time.

[0007] In any of the above systems, the data transmission unit may transmit the uplink data to the PGW selected as the destination for the uplink data via a communication path selected according to a best path selection algorithm of BGP (Border Gateway Protocol).

[0008] In any of the above systems, the first PGW may be located in the network of a first country, and the second PGW may be located in the network of a second country different from the first country.

[0009] In any of the above systems, the network in which the first PGW is located and the network in which the second PGW is located may be a HPLMN (Home Public Land Mobile Network), and the network in which the SGW is located may be a VPLMN (Visited PLMN).

[0010] According to one embodiment of the present invention, there is provided a PGW that is placed in a network of a first ASN and that is assigned a first IP address and a second IP address different from the first IP address. The PGW may include a request receiving unit that receives, from an SGW, a session creation request of a communications terminal that requests creation of a session to a PDN. In response to the request receiving unit receiving the session creation request, if the communications terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via a network of a second ASN different from the first ASN, the PGW generates first session information for the communications terminal that includes the IP address of the communications terminal, the first IP address of the PGW, a TEID assigned to a communication tunnel of the PGW, the IP address of the SGW, and the TEID assigned to the communication tunnel of the SGW, The present invention may further include a session information generation unit that generates, when the communications terminal is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, second session information for the communications terminal, the second session information including the IP address of the communications terminal, the second IP address of the PGW, TEIDs assigned to a communication tunnel of the PGW and a communication tunnel of another PGW that is located in the network of the second ASN and to which the second IP address is assigned, the IP address of the SGW, and the TEID assigned to the communication tunnel of the SGW. The PGW may further include a registration unit that registers the second session information generated by the session information generation unit in a first storage unit corresponding to the PGW. The PGW may further include a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and a second storage unit corresponding to the other PGW.The PGW may include a communication tunnel establishment unit that, in order to generate a session to a PDN of the communication terminal, establishes a communication tunnel between the PGW and the SGW based on the first session information when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, and establishes a communication tunnel between the PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed.

[0011] According to one embodiment of the present invention, there is provided a system. The system may include a first PGW located in a network of a first ASN. The system may include a second PGW located in a network of a second ASN different from the first ASN. The system may include a first storage unit corresponding to the first PGW. The system may include a second storage unit corresponding to the second PGW. The first PGW may be separated into a first PGW-C (PGW-Control plane function) and a first PGW-U (PGW-User plane function), and the first PGW-U may be assigned a first IP address and a second IP address different from the first IP address. The second PGW may be separated into a second PGW-C and a second PGW-U, and the second IP address may be assigned to the second PGW-U. The first PGW-C may include a request receiving unit that receives a session creation request from a communications terminal requesting the creation of a session to a PDN from an SGW separated into an SGW-C (SGW-Control plane function) and an SGW-U (SGW-User plane function).When the communication terminal is registered so that only data communication via the network of the first ASN can be executed out of data communication via the network of the first ASN and data communication via the network of the second ASN, in response to the request receiving unit receiving the session creation request, the first PGW-C generates a communication terminal information including an IP address of the communication terminal, the first IP address of the first PGW-U, a TEID assigned to a communication tunnel of the first PGW-U, an IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U. The system may include a session information generation unit configured to generate first session information for the communications terminal, and when the communications terminal is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, generate second session information for the communications terminal, the second IP address of the first PGW-U, TEIDs assigned to the communication tunnel of the first PGW-U and the communication tunnel of the second PGW-U, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. The first PGW-C may include a registration unit configured to register the second session information generated by the session information generation unit in the first storage unit. The system may further include a session information synchronization unit configured to synchronize the second session information registered in the first storage unit between the first storage unit and the second storage unit.The first PGW-U may include a first communication tunnel establishment unit that, in order to generate a session to a PDN of the communication terminal, establishes a communication tunnel between the first PGW-U and the SGW-U based on the first session information when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, and establishes a communication tunnel between the first PGW-U and the SGW-U based on the second session information synchronized between the first memory unit and the second memory unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed. The second PGW-U may include a second communication tunnel establishment unit that establishes a communication tunnel between the second PGW-U and the SGW-U based on the second session information synchronized between the first memory unit and the second memory unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are possible, in order to generate a session to a PDN of the communication terminal.

[0012] According to one embodiment of the present invention, there is provided a PGW arranged in a network of a first ASN. The PGW may be separated into a PGW-C and a PGW-U, and a first IP address and a second IP address different from the first IP address may be assigned to the PGW-U. The PGW-C may include a request receiving unit that receives, from an SGW separated into an SGW-C and an SGW-U, a session creation request of a communications terminal requesting the creation of a session to a PDN. In response to the request receiving unit receiving the session creation request, if the communications terminal is registered so that only data communication via the network of the first ASN is executable among data communication via the network of the first ASN and data communication via a network of a second ASN different from the first ASN, the PGW-C may generate a first session request of the communications terminal including the IP address of the communications terminal, the first IP address of the PGW-U, a TEID assigned to a communication tunnel of the PGW-U, an IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U. The PGW-C may include a session information generation unit that generates second session information for the communications terminal, when the communications terminal is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, and generates second session information for the communications terminal, the second session information including the IP address of the communications terminal, the second IP address of the PGW-U, TEIDs assigned to a communication tunnel of the PGW-U and a communication tunnel of another PGW-U to which the second IP address is assigned, the IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U. The PGW-C may include a registration unit that registers the second session information generated by the session information generation unit in a first storage unit corresponding to the PGW. The PGW-C may include a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and a second storage unit corresponding to another PGW that is located in the network of the second ASN and is separated into another PGW-C and the other PGW-U.The PGW-U may have a communication tunnel establishment unit that, in order to generate a session to a PDN of the communication terminal, establishes a communication tunnel between the PGW-U and the SGW-U based on the first session information when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, and establishes a communication tunnel between the PGW-U and the SGW-U based on the second session information synchronized between the first memory unit and the second memory unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed.

[0013] According to one embodiment of the present invention, there is provided a system. The system may include a first SMF (Session Management Function) located in a network of a first ASN. The system may include a first UPF (User Plane Function) located in the network in which the first SMF is located and assigned a first IP address and a second IP address different from the first IP address. The system may include a second SMF located in a network of a second ASN different from the first ASN. The system may include a second UPF located in the network in which the second SMF is located and assigned the second IP address. The system may include a first storage unit corresponding to the first UPF. The system may include a second storage unit corresponding to the second UPF. The first SMF may include a request receiving unit that receives, from a third SMF, a session creation request from a communication terminal requesting creation of a session to a DN (Data Network).In response to the request receiving unit receiving the session creation request, when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, the first SMF receives an IP address of the communication terminal, the first IP address of the first UPF, a TEID assigned to a communication tunnel of the first UPF, an IP address of a third UPF located in a network in which the third SMF is located, and a TEID assigned to a communication tunnel of the third UPF. The system may further include a session information generation unit that generates first session information for the communication terminal including a TEID and a TEID assigned to the communication tunnel of the third UPF when the communication terminal is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, and generates second session information for the communication terminal including the IP address of the communication terminal, the second IP address of the first UPF, TEIDs assigned to the communication tunnel of the first UPF and the communication tunnel of the second UPF, the IP address of the third UPF, and a TEID assigned to the communication tunnel of the third UPF. The first SMF may include a registration unit that registers the second session information generated by the session information generation unit in the first storage unit. The system may further include a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit.The first SMF may further have a first communication tunnel establishment unit that, when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on the first session information in order to generate a session to the DN of the communication terminal, and that, when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed, causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on the second session information synchronized between the first memory unit and the second memory unit. The second SMF may have a second communication tunnel establishment unit that causes the second UPF to establish a communication tunnel between the second UPF and the third UPF based on the second session information synchronized between the first memory unit and the second memory unit when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed to create a session to the DN of the communication terminal.

[0014] According to one embodiment of the present invention, there is provided an SMF arranged in a network of a first ASN. The SMF may include a request receiving unit that receives, from another SMF, a session creation request from a communication terminal requesting the creation of a session to a DN. In response to the request receiving unit receiving the session creation request, if the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via a network of a second ASN different from the first ASN, the SMF may, in response to the request receiving unit receiving the session creation request, acquire an IP address of the communication terminal, a first IP address assigned to a first UPF arranged in the network in which the SMF is arranged, a TEID assigned to a communication tunnel of the first UPF, an IP address of a second UPF arranged in the network in which the other SMF is arranged, and a TEID assigned to a communication tunnel of the second UPF. The SMF may include a session information generation unit configured to generate first session information for the communication terminal including the IP address of the communication terminal, a second IP address assigned to the first UPF, a TEID assigned to a communication tunnel of the first UPF and a communication tunnel of a third UPF that is located in the network of the second ASN and to which the second IP address is assigned, and, when the communication terminal is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, generate second session information for the communication terminal including the IP address of the communication terminal, a second IP address assigned to the first UPF, a TEID assigned to a communication tunnel of the first UPF and a communication tunnel of a third UPF that is located in the network of the second ASN and to which the second IP address is assigned, the IP address of the second UPF, and a TEID assigned to the communication tunnel of the second UPF. The SMF may include a registration unit configured to register the second session information generated by the session information generation unit in a first storage unit corresponding to the first UPF. The SMF may include a session information synchronization unit configured to synchronize the second session information registered in the first storage unit between the first storage unit and a second storage unit corresponding to the third UPF.The SMF may include a communication tunnel establishment unit that, when the communication terminal is registered so that only data communication via the network of the first ASN can be performed out of data communication via the network of the first ASN and data communication via the network of the second ASN, causes the first UPF to establish a communication tunnel between the first UPF and the second UPF based on the first session information in order to generate a session to the DN of the communication terminal, and that, when the communication terminal is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN can be performed, causes the first UPF to establish a communication tunnel between the first UPF and the second UPF based on the second session information synchronized between the first memory unit and the second memory unit.

[0015] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions. [Brief explanation of the drawings]

[0016] [Figure 1] An example of a system 10 is shown schematically. [Figure 2] FIG. 2 is an explanatory diagram for explaining an example of a processing flow of the system 10. [Figure 3] 2 shows an example of a functional configuration of the PGW 100. [Figure 4] 2 shows an example of a functional configuration of the SGW 300. [Figure 5] Another example of the system 10 is shown schematically. [Figure 6] FIG. 10 is an explanatory diagram for explaining another example of the processing flow of the system 10. [Figure 7] 2 shows an example of the functional configuration of the PGW-C120. [Figure 8] 2 shows an example of a functional configuration of the PGW-U 140. [Figure 9] 10 shows an example of the functional configuration of the SGW-C320. [Figure 10] 10 shows an example of the functional configuration of the SGW-U340. [Figure 11] Another example of the system 10 is shown schematically. [Figure 12] FIG. 10 is an explanatory diagram for explaining another example of the processing flow of the system 10. [Figure 13] 10 shows an example of the functional configuration of the H-SMF 420. [Figure 14] 10 shows an example of the functional configuration of the H-UPF 440. [Figure 15] 10 shows an example of the functional configuration of the V-SMF 620. [Figure 16] 10 shows an example of the functional configuration of the V-UPF 640. [Figure 17] An example of the hardware configuration of a computer 1200 that functions as PGW100, PGW-C120, PGW-U140, SGW300, SGW-C320, SGW-U340, H-SMF420, H-UPF440, V-SMF620, or V-UPF640 is shown schematically. DETAILED DESCRIPTION OF THE INVENTION

[0017] When LTE (Long Term Evolution) communication is performed using the Home Routed method, a GTP (GPRS Tunneling Protocol) tunnel is established between the SGW of the VPLMN and the PGW of the HPLMN, thereby creating a session between the SGW of the VPLMN and the PGW of the HPLMN. In this case, it is desirable to be able to execute data communication of a communication terminal over a specific communication path or to make the communication path used for data communication of the communication terminal redundant. In the system according to this embodiment, for example, a mechanism is employed in which two IP addresses are assigned to one PGW of the HPLMN. The first IP address is assigned exclusively to the one PGW. The second IP address is assigned using IP Anycast to each of multiple PGWs of geographically different HPLMNs, including the one PGW. If a communication terminal is registered to perform data communication using a communication path via the one PGW, the one PGW that receives the communication terminal's session creation request creates a session for the communication terminal using the first IP address. When a communication terminal is registered to perform data communication using a redundant communication path, the PGW that receives a session creation request from the communication terminal creates session information for the communication terminal using a second IP address. As a result, the system according to this embodiment can achieve both performing data communication for the communication terminal over a specific communication path and providing redundancy to the communication path used for data communication of the communication terminal, while saving the number of IP addresses used for data communication compared to when a PGW is installed for each user.

[0018] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0019] 1 illustrates an example of a system 10. The system 10 provides mobile communication services to users of communication terminals 800.

[0020] The mobile communication service includes, for example, a roaming service, an international roaming service, and a domestic roaming service.

[0021] The communication terminal 800 may be any communication terminal that can use a mobile communication service, for example, a mobile phone such as a smartphone, a tablet terminal, a wearable terminal, or the like.

[0022] The mobile communication service is, for example, an LTE communication service. The mobile communication service is, for example, a 5G (5th Generation) communication service. The mobile communication service may be a 6G (6th Generation) communication service or later. The mobile communication service may be a 3G (3rd Generation) communication service. FIG. 1 illustrates an example in which the system 10 provides an LTE communication service.

[0023] The system 10 may include a PGW 100. The system 10 may include a PGW 200. The system 10 may include an SGW 300. The system 10 may include a database 150. The system 10 may include a database 250. The system 10 may include a router 21. The system 10 may include a router 22. The system 10 may include a router 23. The system 10 may include a terminal information management device 50. The system 10 may include a request generation device 70.

[0024] The PGW 100 has a function of relaying access to an external network. The PGW 100 is connected to the external network via, for example, an SGi interface. The PGW 100 may be an example of a first PGW or an example of a second PGW.

[0025] The PGW 100 has a function of relaying access to, for example, the PDN 40. The PGW 100 has a function of relaying access to, for example, the PDN 60. The PGW 100 may also have a function of relaying access to other PDNs.

[0026] The PDN 40 is, for example, a private network, but may also be a public network.

[0027] The PDN 60 is, for example, a private network, but may also be a public network.

[0028] The PGW 100 is located, for example, in a network of a first ASN. The PGW 100 is located, for example, in a network of a first country. The PGW 100 is located, for example, in an HPLMN. The HPLMN is a network of a telecommunications carrier that has issued a SIM (Subscriber Identity Module) card to the user of the communication terminal 800. In the example shown in FIG. 1 , the PGW 100 is located in an HPLMN that is based in Tokyo, Japan, and has an ASN of 65001.

[0029] The PGW 100 may be assigned an IP address. For example, the PGW 100 is assigned a plurality of mutually different IP addresses. For example, the PGW 100 is assigned a first IP address and a second IP address different from the first IP address. The first IP address of the PGW 100 may be used to access the PDN 40. The second IP address of the PGW 100 may be used to access the PDN 60. The PGW 100 may be assigned three or more mutually different IP addresses. In the example of the system 10 shown in FIG. 1 , the PGW 100 is assigned an IP address AAAA of the subnet mask 32 as the first IP address, and an IP address BBBB of the subnet mask 32 as the second IP address.

[0030] The PGW 200 has a function of relaying access to an external network. The PGW 200 is connected to the external network via, for example, an SGi interface. The PGW 200 may have the same function as the PGW 100. The PGW 200 may be an example of a first PGW or an example of a second PGW.

[0031] The PGW 200 has a function of relaying access to, for example, the PDN 60. The PGW 200 may also have a function of relaying access to other PDNs.

[0032] For example, the PGW 200 is located in a network of a second ASN that is different from the first ASN. For example, the PGW 200 is located in a network of a second country that is different from the first country. For example, the PGW 200 is located in an HPLMN. In the example shown in Figure 1, the PGW 200 is located in an HPLMN that is based in Singapore and has an ASN of 65002.

[0033] The PGW 200 may be located in a network of a first country. For example, if the PGW 100 is located in a network based in Tokyo, Japan, the PGW 200 is located in a network based in Osaka, Japan.

[0034] The PGW 200 may be assigned an IP address. For example, the PGW 200 is assigned the second IP address of the PGW 100. For example, the same IP address is assigned to the PGW 100 and the PGW 200 using IP Anycast. The PGW 200 may be assigned multiple IP addresses that are different from each other. In the example of the system 10 shown in FIG. 1, the PGW 200 is assigned an IP address BBBB with a subnet mask of 32.

[0035] The SGW 300 has a function of relaying access from a wireless access network, and is connected to the wireless access network via, for example, an S1 interface.

[0036] The SGW 300 is connected to the PGW 100 via, for example, the network 20. The SGW 300 is connected to the PGW 200 via, for example, the network 20.

[0037] The network 20 may include, for example, a core network, a radio access network, a PDN such as PDN 40 or PDN 60, or the Internet.

[0038] The SGW 300 is arranged, for example, in a network of a third ASN that is different from the first ASN and the second ASN. The SGW 300 may be arranged in the network of the first ASN or in the network of the second ASN.

[0039] The SGW 300 may be located in a network of a first country, or may be located in a network of a second country, or may be located in a network of a third country different from the first country and the second country.

[0040] The SGW 300 is located, for example, in a VPLMN. The VPLMN is a network of a telecommunications carrier that the user of the communication terminal 800 visits. The telecommunications carrier of the HPLMN and the telecommunications carrier of the VPLMN may have a pre-existing business partnership. In the example shown in FIG. 1, the SGW 300 is located in a VPLMN that is based in Singapore and has an ASN of 65003.

[0041] An IP address may be assigned to the SGW 300. In the example of the system 10 shown in Figure 1, the SGW 300 is assigned an IP address CCCC with a subnet mask 32.

[0042] The router 21 has a function of relaying data. The router 21 relays, for example, uplink data. The router 21 relays, for example, downlink data.

[0043] The router 21 is arranged, for example, in a network in which the PGW 100 is arranged. The router 21 is arranged, for example, in a network of a first ASN. The router 21 may be arranged in a network different from the network in which the PGW 100 is arranged.

[0044] The router 21 is, for example, separate from the PGW 100. The router 21 may also be integrated with the PGW 100.

[0045] The router 22 has a function of relaying data. The router 22 relays, for example, uplink data. The router 22 relays, for example, downlink data.

[0046] The router 22 is arranged, for example, in a network in which the PGW 200 is arranged. The router 22 is arranged, for example, in a network of a second ASN. The router 22 may be arranged in a network different from the network in which the PGW 200 is arranged.

[0047] The router 22 is, for example, separate from the PGW 200. The router 22 may also be integrated with the PGW 200.

[0048] The router 23 has a function of relaying data. The router 23 relays, for example, uplink data. The router 23 relays, for example, downlink data.

[0049] The router 23 is arranged, for example, in the network in which the SGW 300 is arranged. The router 23 is arranged, for example, in the network of a third ASN. The router 23 may be arranged in a network different from the network in which the SGW 300 is arranged.

[0050] The router 23 is, for example, separate from the SGW 300. The router 23 may be integrated with the SGW 300.

[0051] For example, communication path information between organizations is exchanged among the router 21, the router 22, and the router 23 in accordance with BGP. For example, in response to a change in the communication path information, the communication path information is exchanged among the router 21, the router 22, and the router 23. The communication path information may also be exchanged periodically among the router 21, the router 22, and the router 23.

[0052] The communication path information includes, for example, the ASN of the network in which the router is located. The communication path information includes, for example, an IP address assigned to a device located on the network. The communication path information may also include a subnet mask of the IP address assigned to the device located on the network. The subnet mask is expressed, for example, in prefix notation.

[0053] Router 21 advertises the communication path information to, for example, router 23. Router 21 may also advertise the communication path information to an IPX (IP exchange) that relays between the HPLMN and the VPLMN. Router 22 may also advertise the communication path information in the same manner as router 21.

[0054] In the example of the system 10 shown in Fig. 1, the router 21 advertises ASN=65001, the first IP address of the PGW 100=AAAA / 32, and the second IP address of the PGW 100=BBBB / 32. In the example of the system 10 shown in Fig. 1, the router 22 advertises ASN=65002 and the IP address of the PGW 200=BBBB / 32.

[0055] The router 23 advertises the communication path information toward, for example, the routers 21 and 22. The router 23 may also advertise the communication path information toward IPX. In the example of the system 10 shown in Fig. 1, the router 23 advertises the ASN=65003 and the IP address of the SGW 300=CCCC / 32.

[0056] The router 23 generates, for example, a route table. The router 23 generates the route table based on, for example, communication path information advertised by each of the routers 21 and 22. The router 23 generates the route table by, for example, associating the ASN of the network in which the router is located with the IP addresses assigned to devices located in that network. In the example of the system 10 shown in FIG. 1 , the router 23 generates a route table including ASN=65001 and a first IP address of the PGW 100=AAAA / 32, ASN=65001 and a second IP address of the PGW 100=BBBB / 32, and ASN=65002 and an IP address of the PGW 200=BBBB / 32.

[0057] The terminal information management device 50 manages terminal information of the communication terminal 800. In the example of the system 10 shown in Fig. 1, the terminal information management device 50 may be an HSS (Home Subscriber Server).

[0058] The terminal information includes, for example, an International Mobile Subscriber Identity (IMSI). The terminal information includes, for example, executable data communication information indicating data communication that the communication terminal 800 can perform. The executable data communication information indicates, for example, that the communication terminal 800 can perform only data communication via the network of the first ASN out of data communication via the network of the first ASN and data communication via the network of the second ASN. The executable data communication information indicates, for example, that the communication terminal 800 can perform both data communication via the network of the first ASN and data communication via the network of the second ASN. The terminal information may further include any other information related to the communication terminal 800.

[0059] The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to a PDN. The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to PDN 40, for example. The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to PDN 60, for example. The request generating device 70 may also generate a session creation request for a communication terminal 800 requesting the creation of a session to another PDN.

[0060] The request generating device 70 receives, for example, terminal information of the communication terminal 800 from the terminal information management device 50 via the network 20, and generates a session generation request for the communication terminal 800 based on the received terminal information of the communication terminal 800. In the example of the system 10 shown in Fig. 1, the request generating device 70 may be an MME (Mobility Management Entity).

[0061] The session creation request includes, for example, the IP address of the communication terminal 800. The session creation request includes, for example, the IMSI of the communication terminal 800. The session creation request includes, for example, the IP address of the SGW 300. The session creation request includes, for example, a TEID assigned to the communication tunnel of the SGW 300. The session creation request includes, for example, a first IP address of the PGW 100 or a second IP address of the PGW 100. For example, if the communication terminal 800 is registered in the terminal information management device 50 so that only data communication via the first ASN network is executable, out of data communication via the network of the first ASN and data communication via the network of the second ASN, the session creation request includes the first IP address of the PGW 100. For example, if the communication terminal 800 is registered in the terminal information management device 50 so that data communication via both the network of the first ASN and data communication via the network of the second ASN is executable, the session creation request includes the second IP address of the PGW 100. The session creation request may further include any other information for creating a session to the PDN.

[0062] 1, the HPLMN may be established in three or more locations. In this case, the second IP address of the PGW 100 may be assigned to each of the PGWs in the three or more locations.

[0063] Here, an example of creating a session to the PDN of the communication terminal 800 of a user who has visited the VPLMN in which the SGW 300 is located will be described. First, an example of creating a session to the PDN 40 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that, of data communication via the network of the first ASN and data communication via the network of the second ASN, only data communication via the network of the first ASN is executable.

[0064] The communication terminal 800 transmits an attach request to the request generation device 70 via the wireless base station 30. In response to receiving the attach request from the communication terminal 800, the request generation device 70 generates a session generation request for the communication terminal 800.

[0065] Since communication terminal 800 is registered in terminal information management device 50 so that only data communication via the first ASN network is executable out of data communication via the first ASN network and data communication via the second ASN network, request generation device 70 generates a session creation request for communication terminal 800 that includes the first IP address of PGW 100. Request generation device 70 transmits the generated session creation request for communication terminal 800 to SGW 300 via network 20.

[0066] The SGW 300 transmits the received session creation request from the communication terminal 800 to the router 23. If the session creation request from the communication terminal 800 includes the first IP address of the PGW 100, the router 23 forwards the session creation request from the communication terminal 800 to the router 21 via the network 20. The router 21 forwards the session creation request from the communication terminal 800 to the PGW 100.

[0067] In response to receiving a session creation request from communication terminal 800, PGW100 generates session information for communication terminal 800. PGW100 generates the session information for communication terminal 800, for example, based on the session creation request from communication terminal 800. When the session creation request from communication terminal 800 includes the first IP address of PGW100, the session information of communication terminal 800 includes, for example, the IP address of communication terminal 800, the first IP address of PGW100, a TEID assigned to the communication tunnel of PGW100, the IP address of SGW300, and the TEID assigned to the communication tunnel of SGW300. The session information of communication terminal 800 may further include any other information for creating a session to PDN 40. The session information of communication terminal 800 including the first IP address of PGW100 may be an example of the first session information of communication terminal 800. The PGW 100 may register the generated session information of the communication terminal 800 in the database 150 corresponding to the PGW 100 .

[0068] The PGW 100 establishes a communication tunnel between the PGW 100 and the SGW 300 to create a session to the PDN 40 of the communication terminal 800. The PGW 100 establishes the communication tunnel between the PGW 100 and the SGW 300 based on, for example, session information of the communication terminal 800.

[0069] PGW 100 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 21. Router 21 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW 300. When SGW 300 receives the create session response from communication terminal 800, a session to PDN 40 for communication terminal 800 is created.

[0070] The create session response includes, for example, the first IP address of the PGW 100 and the TEID assigned to the communication tunnel of the PGW 100. The create session response may further include any other information for creating a session to the PDN 40 of the communication terminal 800.

[0071] Thereafter, the SGW 300 receives the uplink data of the communication terminal 800. The SGW 300 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW 100. The PGW 100 transmits the uplink data of the communication terminal 800 to the destination via the PDN 40.

[0072] Next, an example of generating a session to the PDN 60 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that data communication via both the network of the first ASN and the network of the second ASN can be performed.

[0073] In response to receiving an attach request from communication terminal 800, request generation device 70 generates a session creation request for communication terminal 800. Because communication terminal 800 is registered in terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, request generation device 70 generates a session creation request for communication terminal 800 that includes the second IP address of PGW 100. Request generation device 70 transmits the generated session creation request for communication terminal 800 to SGW 300 via network 20.

[0074] The SGW 300 transmits the received session creation request from the communication terminal 800 to the router 23. When the session creation request from the communication terminal 800 includes the second IP address of the PGW 100, the router 23 selects a PGW to forward the session creation request from the communication terminal 800 from among a plurality of PGWs to which the same IP address is assigned. Here, the explanation will be continued assuming that the router 23 selects a PGW to forward the session creation request from the communication terminal 800 from among the PGW 100 and the PGW 200.

[0075] Router 23 selects a PGW to which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path along which the session creation request of communication terminal 800 is to be transferred. Router 23 selects a communication path along which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path from router 23 to a router corresponding to a PGW to which the session creation request of communication terminal 800 is to be transferred. Here, the explanation will be continued assuming that the communication distance of the communication path from router 23 to router 22 is shorter than the communication distance of the communication path from router 23 to router 21.

[0076] Router 23 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, based on a route table. Router 23 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, according to a BGP best path selection algorithm. Router 23 selects, as the communication path along which the session creation request of communication terminal 800 will be forwarded, a communication path with the shortest communication distance from router 23 to routers corresponding to each of multiple PGWs to which the same IP address is assigned. Here, the explanation will continue assuming that router 23 has selected the communication path from router 23 to router 22 as the communication path along which the session creation request of communication terminal 800 will be forwarded.

[0077] Router 23 selects a communication path from router 23 to router 22 as the communication path along which the session creation request of communication terminal 800 is to be transferred, thereby selecting PGW200 as the PGW to which the session creation request of communication terminal 800 is to be transferred. Router 23 transfers the session creation request of communication terminal 800 to router 22 via network 20. Router 22 transfers the session creation request of communication terminal 800 to PGW200.

[0078] In response to receiving a session creation request from communication terminal 800, PGW200 creates session information for communication terminal 800. When the session creation request from communication terminal 800 includes the second IP address of PGW100, the session information of communication terminal 800 includes, for example, the IP address of communication terminal 800, the second IP address of PGW100, TEIDs assigned to the communication tunnel of PGW100 and the communication tunnel of PGW200, the IP address of SGW300, and the TEID assigned to the communication tunnel of SGW300. The session information of communication terminal 800 may further include any other information for creating a session to PDN 60. The session information of communication terminal 800 including the second IP address of PGW100 may be an example of second session information of communication terminal 800.

[0079] PGW 200, for example, registers the generated session information of communication terminal 800 in database 250 corresponding to PGW 200. Database 250 includes, for example, a message queue that temporarily stores the session information of communication terminal 800. Database 250 may be an example of a first storage unit or an example of a second storage unit.

[0080] The database 250 is, for example, separate from the PGW 200. The database 250 may also be integrated with the PGW 200.

[0081] Database 250 is located, for example, in the network in which PGW 200 is located. Database 250 is located, for example, in the network of a second ASN. Database 250 may also be located in a network different from the network in which PGW 200 is located.

[0082] Database 250, for example, synchronizes session information of communication terminal 800 registered in database 250 between database 250 and database 150 corresponding to PGW 100. Database 250 may be an example of a session information synchronization unit. Database 150 may be an example of a first storage unit or an example of a second storage unit.

[0083] Database 250 uses, for example, a Pub / Sub (Publish / Subscribe) method to synchronize session information of communication terminal 800 between database 250 and database 150. In this case, database 250 may be the publisher, and database 150 may be the subscriber.

[0084] For example, the database 250 sends a message including session information of the communication terminal 800 to a topic. The database 150 acquires the session information of the communication terminal 800 by receiving a message from a subscription corresponding to the topic to which the message was sent by the database 250. As a result, the session information of the communication terminal 800 is synchronized between the database 250 and the database 150.

[0085] For example, database 250 sends PGW 200 a synchronization completion notification notifying that synchronization processing for synchronizing session information of communication terminal 800 between database 250 and database 150 has been completed. The synchronization completion notification includes, for example, the session information of communication terminal 800.

[0086] The database 150, for example, notifies the PGW 100 of the completion of synchronization. Therefore, the PGW 200 may be a publisher, and the PGW 100 may be a subscriber.

[0087] The database 150 is, for example, separate from the PGW 100. The database 150 may also be integrated with the PGW 100.

[0088] The database 150 is located, for example, in the network in which the PGW 100 is located. The database 150 is located, for example, in the network of the first ASN. The database 150 may also be located in a network different from the network in which the PGW 100 is located.

[0089] The PGW 200 establishes a communication tunnel between the PGW 200 and the SGW 300 in order to create a session for the communication terminal 800 to the PDN 60. The PGW 200 establishes the communication tunnel between the PGW 200 and the SGW 300, for example, based on the created session information for the communication terminal 800.

[0090] The PGW 100 establishes a communication tunnel between the PGW 100 and the SGW 300 to generate a session for the communication terminal 800 to the PDN 60. The PGW 100 establishes the communication tunnel between the PGW 100 and the SGW 300 based on, for example, session information for the communication terminal 800 included in a synchronization completion notification notified from the database 150.

[0091] PGW 200 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 22. Router 22 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW 300. When SGW 300 receives the create session response from communication terminal 800, a session from communication terminal 800 to PDN 60 is created.

[0092] The create session response includes, for example, the second IP address of the PGW 100 and the TEIDs assigned to the communication tunnel of the PGW 100 and the communication tunnel of the PGW 200. The create session response may further include any other information for creating a session of the communication terminal 800 to the PDN 60.

[0093] Thereafter, the SGW 300 receives the uplink data of the communication terminal 800. The SGW 300 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 selects a PGW to forward the uplink data of the communication terminal 800. The router 23 may select a PGW to forward the uplink data of the communication terminal 800 from among a plurality of PGWs to which the same IP address is assigned, in the same manner as when selecting a PGW to forward a session creation request of the communication terminal 800 from among a plurality of PGWs to which the same IP address is assigned. Here, the description will continue assuming that the router 23 has selected the PGW 200 as the PGW to forward the uplink data of the communication terminal 800.

[0094] The router 23 transfers the uplink data of the communication terminal 800 to the router 22 via the network 20. The router 22 transfers the uplink data of the communication terminal 800 to the PGW 200. The PGW 200 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0095] Thereafter, when the communication path between the SGW 300 and the PGW 200 becomes unavailable, for example, when a failure occurs in the PGW 200 or when maintenance work is performed on the PGW 200, the router 22 advertises the communication path information. The router 23 receives the communication path information advertised by the router 22 and updates the route table. In this case, the router 23 may change the PGW that forwards the uplink data of the communication terminal 800 from the PGW 200 to the PGW 100, based on the updated route table.

[0096] The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW 100. The PGW 100 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0097] If the communication path between the SGW 300 and the PGW 200 is unavailable when the SGW 300 receives a session creation request from the communication terminal 800, the router 23 forwards the session creation request from the communication terminal 800 to the router 21 via the network 20. The router 21 forwards the session creation request from the communication terminal 800 to the PGW 100.

[0098] In response to receiving a session creation request from communication terminal 800, PGW 100 generates session information for communication terminal 800. PGW 100 may generate the session information for communication terminal 800 in the same manner as when PGW 200 generates session information for communication terminal 800 in order to create a session for communication terminal 800 to PDN 60.

[0099] PGW 100 registers the generated session information of communication terminal 800 in database 150. Database 150 synchronizes the session information of communication terminal 800 registered in database 150 between database 150 and database 250. Database 150 may synchronize the session information of communication terminal 800 between database 150 and database 250 in the same way as when database 250 synchronizes the session information of communication terminal 800 between database 250 and database 150. Database 150 may be an example of a session information synchronization unit.

[0100] The database 150 may notify the PGW 100 of the synchronization completion notification. The database 250 may notify the PGW 200 of the synchronization completion notification.

[0101] The PGW 100 establishes a communication tunnel between the PGW 100 and the SGW 300 in order to create a session for the communication terminal 800 to the PDN 60. The PGW 100 establishes the communication tunnel between the PGW 100 and the SGW 300, for example, based on the created session information for the communication terminal 800.

[0102] PGW 100 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 21. Router 21 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW 300. When SGW 300 receives the create session response from communication terminal 800, a session from communication terminal 800 to PDN 60 is created.

[0103] Thereafter, the SGW 300 receives the uplink data of the communication terminal 800. The SGW 300 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW 100. The PGW 100 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0104] Thereafter, when a communication path between the SGW 300 and the PGW 200 becomes available, the PGW 200 establishes a communication tunnel between the PGW 200 and the SGW 300 to generate a session of the communication terminal 800 to the PDN 60. The PGW 200 establishes the communication tunnel between the PGW 200 and the SGW 300 based on, for example, session information of the communication terminal 800 included in a synchronization completion notification notified from the database 250.

[0105] The router 22 advertises communication path information after the communication path between the SGW 300 and the PGW 200 becomes available. The router 23 receives the communication path information advertised by the router 22 and updates the route table. In this case, the router 23 may change the PGW that forwards the uplink data of the communication terminal 800 from the PGW 100 to the PGW 200 based on the updated route table.

[0106] After changing the PGW that forwards the uplink data of the communication terminal 800 from PGW100 to PGW200, the router 23 forwards the uplink data of the communication terminal 800 to the router 22 via the network 20. The router 22 forwards the uplink data of the communication terminal 800 to the PGW200. The PGW200 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0107] In a situation where HPLMNs are established at multiple locations by telecommunications carriers that provide roaming services, there is a need for mobile communication service users to access PDNs via an appropriate network depending on their usage. For example, User A visiting a VPLMN wants to be able to access a PDN via a specific HPLMN regardless of the location of the VPLMN in order to perform highly secure data communication. Also, for example, User B visiting a VPLMN wants to be able to access a PDN via an HPLMN that is located at a shorter distance from the VPLMN in order to perform high-speed data communication.

[0108] One example of accessing a PDN via an appropriate network depending on the user's intended use of a mobile communication service is to install a unique PGW for each user. However, this requires hardware resources such as many computing devices. In particular, when the number of users of the mobile communication service is large, enormous hardware resources are required. Another example of accessing a PDN via an appropriate network depending on the user's intended use of a mobile communication service is to assign a unique IP address to each user. However, this requires network resources such as many IP addresses. In particular, when the number of users of the mobile communication service is large, enormous network resources are required. For these reasons, it is desirable to realize a mobile communication service that allows access to a PDN via an appropriate network depending on the user's intended use with fewer resources.

[0109] 1, when the PGW 100 receives a session creation request for the communication terminal 800 from the SGW 300, and the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the PGW 100 creates session information for the communication terminal 800 that includes the first IP address of the PGW 100. Because the first IP address of the PGW 100 is assigned only to the PGW 100 out of the PGW 100 and the PGW 200, a communication path that accesses the PDN 40 via the HPLMN in which the PGW 100 is located can be used for data communication by the communication terminal 800, regardless of the location of the VPLMN in which the SGW 300 is located. Furthermore, when PGW 100 receives a session creation request for communication terminal 800 from SGW 300, and communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, PGW 100 generates session information for communication terminal 800 including the second IP address of PGW 100, and registers the session information for communication terminal 800 in database 150. The session information for communication terminal 800 registered in database 150 is synchronized between database 150 and database 250. Because the same IP address is assigned to both PGW 100 and PGW 200, by synchronizing the session information for communication terminal 800 between database 150 and database 250, the communication path available for data communication by communication terminal 800 can be made redundant, with a communication path for accessing PDN 60 via the HPLMN in which PGW 100 is located and a communication path for accessing PDN 60 via the HPLMN in which PGW 200 is located. This allows the communication terminal 800 to use, for data communication, a communication route to access the PDN 60 via the HPLMN, which has a shorter communication distance from the VPLMN in which the SGW 300 is located, selected according to the BGP best path selection algorithm.1, communication terminal 800 registers in advance whether it is capable of performing only data communication via the first ASN network out of data communication via the network of the first ASN and data communication via the network of the second ASN, or whether it is capable of performing both data communication via the network of the first ASN and data communication via the network of the second ASN, and by determining the communication path used for data communication by communication terminal 800 in both cases using the above-mentioned method, it is possible to access a PDN via an appropriate network depending on the user's purpose without installing a unique PGW for each user or assigning a unique IP address to each user. As described above, system 10 shown in FIG. 1 can realize an LTE communication service that allows access to a PDN via an appropriate network depending on the user's purpose with fewer resources.

[0110] 2 is an explanatory diagram illustrating an example of the processing flow of the system 10. Here, the description will be given assuming that the start state is a state in which the user of the communication terminal 800, which is registered in the terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, visits the VPLMN in which the SGW 300 is located.

[0111] In step (sometimes abbreviated as S) 102, SGW300 transmits the session creation request for communication terminal 800 received from request generation device 70 to the PGW. Here, since the communication path between SGW300 and PGW200 is unavailable at the time SGW300 receives the session creation request for communication terminal 800, the explanation will continue assuming that SGW300 transmits the session creation request for communication terminal 800 to PGW100.

[0112] In S104, PGW 100 generates session information for communication terminal 800 based on the session creation request for communication terminal 800 received from SGW 300 in S102, and registers the session information for communication terminal 800 in database 150. In S106, in response to registering the session information for communication terminal 800 in database 150 in S104, PGW 100 transmits to SGW 300 a create session response for communication terminal 800 in response to the session creation request from communication terminal 800.

[0113] In S108, database 150 synchronizes the session information of communication terminal 800 registered by PGW 100 in S104 between database 150 and database 250. In S110, database 150 notifies PGW 100 of a synchronization completion notification in response to the synchronization of the session information of communication terminal 800 between database 150 and database 250 in S108. In S112, database 250 notifies PGW 200 of a synchronization completion notification in response to the synchronization of the session information of communication terminal 800 between database 150 and database 250 by database 150 in S108.

[0114] In S114, the SGW 300 transmits the uplink data of the communication terminal 800 received from the communication terminal 800 to the PGW 100. The PGW 100 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0115] Thereafter, in S116 after the communication path between the SGW 300 and the PGW 200 becomes available, the SGW 300 transmits the uplink data of the communication terminal 800 received from the communication terminal 800 to the PGW 200. The PGW 200 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0116] 2, the process in which PGW100 transmits a create session response for communication terminal 800 to SGW300 in response to PGW100 registering session information for communication terminal 800 in database 150 may be replaced with a process in which PGW100 transmits a create session response for communication terminal 800 to SGW300 in response to PGW100 receiving a synchronization completion notification from database 150. That is, S106 shown in FIG. 2 may be performed after S110 shown in FIG. 2.

[0117] 3 shows an example of the functional configuration of the PGW 100. The PGW 100 includes a request receiving unit 102, a session information generating unit 106, a registration unit 108, a session information synchronizing unit 110, a notification receiving unit 112, a response transmitting unit 114, a communication tunnel establishing unit 116, a data receiving unit 118, and a data transmitting unit 119. It is not essential that the PGW 100 include all of these components.

[0118] The request receiving unit 102 receives a session creation request from a communication terminal 800 requesting the creation of a session to a PDN. For example, the request receiving unit 102 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 40. For example, the request receiving unit 102 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 60. The request receiving unit 102 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another PDN.

[0119] The request receiving unit 102 receives, for example, a session creation request for the communication terminal 800 from the SGW 300. The request receiving unit 102 receives, for example, the session creation request for the communication terminal 800 from the SGW 300 via the network 20. The request receiving unit 102 receives, for example, the session creation request for the communication terminal 800 from the SGW 300 via the network 20 and the router 21.

[0120] The session information generating unit 106 generates session information of the communication terminal 800. The session information generating unit 106 generates the session information of the communication terminal 800, for example, in response to the request receiving unit 102 receiving a session generation request from the communication terminal 800.

[0121] Session information generation unit 106 generates session information for communication terminal 800, for example, based on a session generation request from communication terminal 800. For example, when communication terminal 800 is registered so that only data communication via the first ASN network is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, session information generation unit 106 generates session information for communication terminal 800 that includes a first IP address of PGW 100. For example, when communication terminal 800 is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are executable, session information generation unit 106 generates session information for communication terminal 800 that includes a second IP address of PGW 100.

[0122] The registration unit 108 registers the session information of the communication terminal 800 in the database 150. The registration unit 108 registers the session information of the communication terminal 800 generated by the session information generation unit 106 in the database 150, for example.

[0123] Registration unit 108 registers, for example, session information of communication terminal 800 including the second IP address of PGW 100 in database 150. Registration unit 108 may also register, in database 150, session information of communication terminal 800 including the first IP address of PGW 100.

[0124] The session information synchronization unit 110 synchronizes the session information of the communication terminal 800, which is registered in the database 150 by the registration unit 108 and includes the second IP address of the PGW 100, between the database 150 and the database 250. The session information synchronization unit 110 may synchronize the session information between the database 150 and the database 250 in the same manner as when the database 250 synchronizes the session information of the communication terminal 800 between the database 250 and the database 150.

[0125] The session information synchronization unit 110 may notify the PGW 200 of a synchronization completion notification in response to synchronizing the session information between the database 150 and the database 250. The session information synchronization unit 110 notifies the PGW 200 of the synchronization completion notification, for example, via the network 20. The session information synchronization unit 110 notifies the PGW 200 of the synchronization completion notification, for example, via the router 21 and the network 20.

[0126] The notification receiving unit 112 receives the synchronization completion notification. The notification receiving unit 112 receives the synchronization completion notification from, for example, the database 150. The notification receiving unit 112 receives the synchronization completion notification from, for example, the database 250. The notification receiving unit 112 may also receive the synchronization completion notification from the PGW 200.

[0127] The notification receiving unit 112 receives the synchronization completion notification via, for example, the network 20. The notification receiving unit 112 receives the synchronization completion notification via, for example, the network 20 and the router 21.

[0128] Response transmitting unit 114 transmits a session creation response of communication terminal 800 in response to a session creation request of communication terminal 800. Response transmitting unit 114 transmits, for example, a session creation response of communication terminal 800 in response to a session creation request of communication terminal 800 received by request receiving unit 102.

[0129] The response transmitting unit 114 transmits, for example, a create session response of the communication terminal 800 to the SGW 300. The response transmitting unit 114 transmits, for example, the create session response of the communication terminal 800 to the SGW 300 via the network 20. The response transmitting unit 114 transmits, for example, the create session response of the communication terminal 800 to the SGW 300 via the network 20 and the router 21.

[0130] The response transmitting unit 114 transmits a session generation response for the communication terminal 800 in response to, for example, the session information generating unit 106 generating session information for the communication terminal 800. The response transmitting unit 114 transmits a session generation response for the communication terminal 800 in response to, for example, the registration unit 108 registering the session information for the communication terminal 800 in the database 150. The response transmitting unit 114 transmits a session generation response for the communication terminal 800 in response to, for example, the session information for the communication terminal 800 being synchronized between the database 150 and the database 250. The response transmitting unit 114 transmits a session generation response for the communication terminal 800 in response to, for example, the session information synchronizing unit 110 synchronizing the session information for the communication terminal 800 between the database 150 and the database 250. The response transmitting unit 114 may transmit a session generation response for the communication terminal 800 in response to, for example, the notification receiving unit 112 receiving a synchronization completion notification.

[0131] The communication tunnel establishment unit 116 establishes a communication tunnel to create a session to the PDN of the communication terminal 800. The communication tunnel establishment unit 116 establishes a communication tunnel between the PGW 100 and the SGW 300, for example, to create a session to the PDN of the communication terminal 800.

[0132] The communication tunnel establishment unit 116 establishes a communication tunnel, for example, to create a session to the PDN 40 of the communication terminal 800. The communication tunnel establishment unit 116 establishes a communication tunnel, for example, to create a session to the PDN 60 of the communication terminal 800. The communication tunnel establishment unit 116 may establish a communication tunnel to create a session to another PDN of the communication terminal 800.

[0133] The communication tunnel establishment unit 116 establishes, for example, a GTP tunnel, but may also establish any other communication tunnel.

[0134] The communication tunnel establishment unit 116 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 generated by the session information generation unit 106. The communication tunnel establishment unit 116 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 synchronized between the database 150 and the database 250 by the session information synchronization unit 110. The communication tunnel establishment unit 116 may establish the communication tunnel based on the session information of the communication terminal 800 included in the synchronization completion notification received by the notification reception unit 112.

[0135] For example, when communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, communication tunnel establishment unit 116 establishes the communication tunnel based on session information of communication terminal 800 including a first IP address of PGW 100. For example, when communication terminal 800 is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are executable, communication tunnel establishment unit 116 establishes the communication tunnel based on session information of communication terminal 800 including a second IP address of PGW 100 that is synchronized between database 150 and database 250.

[0136] The communication tunnel establishment unit 116 may be an example of a first communication tunnel establishment unit. The communication tunnel establishment unit 116 may be an example of a second communication tunnel establishment unit.

[0137] The data receiving unit 118 receives data related to data communication of the communication terminal 800. The data receiving unit 118 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 118 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 21. The data receiving unit 118 receives data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishment unit 116.

[0138] The data receiving unit 118 receives, for example, uplink data of the communication terminal 800. The data receiving unit 118 receives the uplink data of the communication terminal 800 when, for example, the PGW 100 is selected as a transmission target of the uplink data of the communication terminal 800 from among a plurality of PGWs to which the same IP address is assigned.

[0139] The data receiving unit 118 receives, for example, downlink data of the communication terminal 800. For example, when the PGW 100 is selected as a transmission target of the downlink data of the communication terminal 800 from among a plurality of PGWs to which the same IP address is assigned, the data receiving unit 118 receives the downlink data of the communication terminal 800.

[0140] For example, when data receiving unit 118 receives uplink data of communication terminal 800 and PGW 100 does not hold session information of communication terminal 800, communication tunnel establishing unit 116 establishes a communication tunnel by acquiring the session information of communication terminal 800 from database 150. For example, when data receiving unit 118 receives uplink data of communication terminal 800 for the first time, communication tunnel establishing unit 116 acquires the session information of communication terminal 800 from database 150.

[0141] For example, when data receiving unit 118 receives downlink data of communication terminal 800 and PGW 100 does not hold session information of communication terminal 800, communication tunnel establishing unit 116 establishes a communication tunnel by acquiring the session information of communication terminal 800 from database 150. For example, when data receiving unit 118 receives downlink data of communication terminal 800 for the first time, communication tunnel establishing unit 116 acquires the session information of communication terminal 800 from database 150.

[0142] The data transmitting unit 119 transmits data related to data communication of the communication terminal 800. The data transmitting unit 119 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmitting unit 119 transmits data related to data communication of the communication terminal 800, for example, via the router 21 and the network 20. The data transmitting unit 119 transmits data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishing unit 116.

[0143] The data transmitting unit 119 transmits, for example, uplink data of the communication terminal 800 to a destination of the uplink data of the communication terminal 800. The data transmitting unit 119 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0144] 4 shows an example of the functional configuration of the SGW 300. The SGW 300 includes a storage unit 302, a route information receiving unit 304, a table generating unit 306, a request receiving unit 310, a request transmitting unit 312, a response receiving unit 314, a data receiving unit 318, and a data transmitting unit 319. Note that it is not essential for the SGW 300 to include all of these components.

[0145] The storage unit 302 stores various types of information, such as a route table.

[0146] The route table includes, for example, communication path information indicating the communication path between the SGW 300 and the PGW 100. The route table includes, for example, communication path information indicating the communication path between the SGW 300 and the PGW 200.

[0147] The route information receiving unit 304 receives communication route information. The route information receiving unit 304 receives the communication route information, for example, via the network 20. The route information receiving unit 304 receives the communication route information, for example, via the network 20 and the router 23. The route information receiving unit 304 may store the received communication route information in the storage unit 302.

[0148] The route information receiving unit 304 receives, for example, communication route information advertised by the router 21. The route information receiving unit 304 receives, for example, communication route information advertised by the router 22. The route information receiving unit 304 may also receive communication route information advertised by IPX.

[0149] The route information receiving unit 304 receives, for example, communication route information indicating a communication route between the SGW 300 and the PGW 100. The route information receiving unit 304 receives, for example, communication route information indicating a communication route between the SGW 300 and the PGW 200.

[0150] The table generation unit 306 generates a route table. The table generation unit 306 generates the route table based on, for example, the communication route information stored in the storage unit 302. The table generation unit 306 generates the route table based on, for example, the communication route information received by the route information receiving unit 304. The table generation unit 306 may generate the route table in the same manner as when the router 23 generates a route table. The table generation unit 306 may store the generated route table in the storage unit 302.

[0151] The request receiving unit 310 receives a session creation request from a communication terminal 800 requesting the creation of a session to a PDN. For example, the request receiving unit 310 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 40. For example, the request receiving unit 310 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 60. The request receiving unit 310 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another PDN.

[0152] The request receiving unit 310 receives a session creation request for the communication terminal 800, for example, from the request generating device 70. The request receiving unit 310 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20. The request receiving unit 310 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20 and the router 23.

[0153] The request transmitting unit 312 transmits a session creation request from the communication terminal 800. The request transmitting unit 312 transmits the session creation request from the communication terminal 800 that the request receiving unit 310 has received, for example.

[0154] The request sending unit 312 sends the session creation request of the communication terminal 800, for example, via the network 20. The request sending unit 312 sends the session creation request of the communication terminal 800, for example, via the router 23 and the network 20.

[0155] The request sending unit 312 sends a session creation request for the communication terminal 800, for example, based on the route table stored in the storage unit 302. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the request sending unit 312 sends a session creation request for the communication terminal 800, which includes the first IP address of the PGW 100, to the PGW 100.

[0156] For example, when communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, request sending unit 312 sends a session creation request from communication terminal 800, which includes the second IP address of PGW 100, to a PGW selected as a destination of the session creation request from among multiple PGWs to which the same IP address is assigned based on predetermined PGW selection conditions. In this case, request sending unit 312 sends, for example, the session creation request to the PGW selected as a destination of the session creation request from PGW 100 and PGW 200 based on the PGW selection conditions. For example, request sending unit 312 sends the session creation request to the PGW selected as a destination of the session creation request via a communication path selected according to a BGP best path selection algorithm.

[0157] The response receiving unit 314 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800. For example, the response receiving unit 314 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800 transmitted by the request transmitting unit 312. The response receiving unit 314 may store the received session creation response from the communication terminal 800 in the storage unit 302.

[0158] The response receiving unit 314 receives the create session response of the communication terminal 800 from, for example, the PGW 100. The response receiving unit 314 receives the create session response of the communication terminal 800 from, for example, the PGW 200.

[0159] The response receiving unit 314 receives the session creation response from the communication terminal 800, for example, via the network 20. The response receiving unit 314 receives the session creation response from the communication terminal 800, for example, via the network 20 and the router 23.

[0160] The data receiving unit 318 receives data related to data communication of the communication terminal 800. The data receiving unit 318 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 318 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 23.

[0161] The data receiving unit 318 receives, for example, uplink data of the communication terminal 800. The data receiving unit 318 receives, for example, downlink data of the communication terminal 800.

[0162] The data transmitting unit 319 transmits data related to data communication of the communication terminal 800. The data transmitting unit 319 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmitting unit 319 transmits data related to data communication of the communication terminal 800, for example, via the router 23 and the network 20.

[0163] The data transmitting unit 319 transmits, for example, uplink data of the communication terminal 800. The data transmitting unit 319 transmits the uplink data of the communication terminal 800, for example, based on the route table stored in the storage unit 302. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the data transmitting unit 319 transmits the uplink data of the communication terminal 800 to the PGW 100.

[0164] For example, when communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, data transmission unit 319 transmits uplink data of communication terminal 800 to a PGW selected as a transmission destination of the uplink data of communication terminal 800 from among multiple PGWs to which the same IP address is assigned based on predetermined PGW selection conditions. In this case, data transmission unit 319 transmits the uplink data of communication terminal 800 to a PGW selected as a transmission destination of the uplink data of communication terminal 800 from among PGW100 and PGW200 based on the PGW selection conditions. Data transmission unit 319 transmits the uplink data of communication terminal 800 to the PGW selected as a transmission destination of the uplink data of communication terminal 800, for example, via a communication path selected according to a BGP best path selection algorithm.

[0165] The data transmitting unit 319 transmits, for example, downlink data of the communication terminal 800. The data transmitting unit 319 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0166] 5 is a schematic diagram of another example of the system 10. Here, differences from the system 10 of FIG. 1 will be mainly described.

[0167] 5 provides an LTE communication system in which a CUPS (Control and User Plane Separation) architecture is implemented. In this case, PGW 100 is separated into PGW-C 120 and PGW-U 140, PGW 200 is separated into PGW-C 220 and PGW-U 240, and SGW 300 is separated into SGW-C 320 and SGW-U 340.

[0168] An IP address may be assigned to the PGW-C 120. In the example of the system 10 shown in Fig. 5, the PGW-C 120 is assigned the IP address AAAA with the subnet mask 32.

[0169] The PGW-U 140 may be assigned an IP address. For example, the PGW-U 140 is assigned a plurality of IP addresses that are different from each other. For example, the PGW-U 140 is assigned a first IP address and a second IP address that is different from the first IP address. The first IP address of the PGW-U 140 may be used to access the PDN 40. The second IP address of the PGW-U 140 may be used to access the PDN 60. The PGW-U 140 may be assigned three or more IP addresses that are different from each other. In the example of the system 10 shown in FIG. 5 , the PGW-U 140 is assigned an IP address BBBB of the subnet mask 32 as the first IP address, and an IP address CCCC of the subnet mask 32 as the second IP address.

[0170] An IP address may be assigned to the PGW-C 220. For example, the PGW-C 220 is assigned the same IP address as the IP address assigned to the PGW-C 120. For example, the same IP address is assigned to the PGW-C 120 and the PGW-C 220 using IP Anycast. In the example of the system 10 shown in FIG. 5, the PGW-C 220 is assigned the IP address AAAA with subnet mask 32.

[0171] The PGW-U 240 may be assigned an IP address. For example, the second IP address of the PGW-U 140 is assigned to the PGW-U 240. For example, the same IP address is assigned to the PGW-U 140 and the PGW-U 240 using IP Anycast. The PGW-U 240 may be assigned multiple IP addresses that are different from each other. In the example of the system 10 shown in FIG. 5, the PGW-U 240 is assigned an IP address CCCC with a subnet mask of 32.

[0172] An IP address may be assigned to the SGW-C 320. In the example of the system 10 shown in Figure 5, the SGW-C 320 is assigned the IP address DDDD of the subnet mask 32.

[0173] An IP address may be assigned to the SGW-U 340. In the example of the system 10 shown in Figure 5, the SGW-U 340 is assigned an IP address EEEE with a subnet mask 32.

[0174] The router 21 is, for example, separate from the PGW-C 120 and the PGW-U 140. The router 21 may be integrated with the PGW-C 120 or the PGW-U 140.

[0175] The router 22 is, for example, separate from the PGW-C 220 and the PGW-U 240. The router 22 may be integrated with the PGW-C 220 or the PGW-U 240.

[0176] The router 23 is, for example, separate from the SGW-C 320 and the SGW-U 340. The router 23 may be integrated with the SGW-C 320 or the SGW-U 340.

[0177] In the example of the system 10 shown in Fig. 5, the router 21 advertises ASN=65001, the IP address of the PGW-C 120=AAAA / 32, the first IP address of the PGW-U 140=BBBB / 32, and the second IP address of the PGW-U 140=CCCC / 32. In the example of the system 10 shown in Fig. 5, the router 22 advertises ASN=65002, the IP address of the PGW-C 220=AAAA / 32, and the IP address of the PGW-U 240=CCCC / 32. In the example of the system 10 shown in Fig. 5, the router 23 advertises ASN=65003, the IP address of the SGW-C 320=DDDD / 32, and the IP address of the SGW 300=EEEE / 32.

[0178] The router 23 generates a route table based on, for example, communication path information advertised by each of the router 21 and the router 22. In the example of the system 10 shown in Fig. 5, the router 23 generates a route table including: ASN=65001 and an IP address of the PGW-C120=AAAA / 32; ASN=65001 and a first IP address of the PGW-U140=BBBB / 32; ASN=65001 and a second IP address of the PGW-U140=CCCC / 32; ASN=65002 and an IP address of the PGW-C220=AAAA / 32; and ASN=65002 and an IP address of the PGW-U240=CCCC / 32.

[0179] When the CUPS architecture is introduced into the LTE communication system, the session creation request generated by the request generation device 70 may include the following information: The session creation request includes, for example, the IP address of the communication terminal 800. The session creation request includes, for example, the IMSI of the communication terminal 800. The session creation request includes, for example, the IP address of the SGW-C320. The session creation request includes, for example, the IP address of the SGW-U340. The session creation request includes, for example, the TEID assigned to the communication tunnel of the SGW-C320. The session creation request includes, for example, the TEID assigned to the communication tunnel of the SGW-U340. The session creation request includes, for example, the IP address of the PGW-C120. The session creation request includes, for example, the first IP address of the PGW-U140 or the second IP address of the PGW-U140. For example, if communication terminal 800 is registered in terminal information management device 50 so that, of data communication via the network of the first ASN and data communication via the network of the second ASN, only data communication via the network of the first ASN is executable, the session creation request includes the first IP address of PGW-U 140. For example, if communication terminal 800 is registered in terminal information management device 50 so that data communication via both the network of the first ASN and data communication via the network of the second ASN is executable, the session creation request includes the second IP address of PGW-U 140. The session creation request may further include any other information for creating a session to a PDN.

[0180] Here, an example of creating a session to the PDN of the communication terminal 800 of a user who has visited the VPLMN in which the SGW 300 is located will be described. First, an example of creating a session to the PDN 40 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that, of data communication via the network of the first ASN and data communication via the network of the second ASN, only data communication via the network of the first ASN is executable.

[0181] In response to receiving an attach request from communication terminal 800, request generation device 70 generates a session creation request for communication terminal 800. Because communication terminal 800 is registered in terminal information management device 50 so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, request generation device 70 generates a session creation request for communication terminal 800 that includes the first IP address of PGW-U 140. Request generation device 70 transmits the generated session creation request for communication terminal 800 to SGW-C 320 via network 20.

[0182] The SGW-C320 transmits the received session creation request from the communication terminal 800 to the router 23. If the session creation request from the communication terminal 800 includes the first IP address of the PGW-U140, the router 23 forwards the session creation request from the communication terminal 800 to the router 21 via the network 20. The router 21 forwards the session creation request from the communication terminal 800 to the PGW-C120.

[0183] In response to receiving the session creation request from the communication terminal 800, the PGW-C120 creates session information for the communication terminal 800. When the session creation request from the communication terminal 800 includes the first IP address of the PGW-U140, the session information of the communication terminal 800 includes, for example, the IP address of the communication terminal 800, the first IP address of the PGW-U140, the TEID assigned to the communication tunnel of the PGW-U140, the IP address of the SGW-U340, and the TEID assigned to the communication tunnel of the SGW-U340. The session information of the communication terminal 800 may further include the IP address of the PGW-C120, the TEID assigned to the communication tunnel of the PGW-C120, the IP address of the SGW-C320, and the TEID assigned to the communication tunnel of the SGW-C320. The session information of the communication terminal 800 may further include any other information for creating a session to the PDN40. The session information of the communication terminal 800 including the first IP address of the PGW-U 140 may be an example of the first session information of the communication terminal 800.

[0184] The PGW-C120 may register the generated session information of the communication terminal 800 in the database 150 corresponding to the PGW 100. The PGW-C120 may provide the generated session information of the communication terminal 800 to the PGW-U140.

[0185] The PGW-U140 establishes a communication tunnel between the PGW-U140 and the SGW-U340 to create a session of the communication terminal 800 to the PDN 40. The PGW-U140 establishes the communication tunnel between the PGW-U140 and the SGW-U340 based on, for example, session information of the communication terminal 800 provided by the PGW-C120.

[0186] PGW-C120 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 21. Router 21 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW-C320. When SGW-C320 receives the create session response from communication terminal 800, a session to PDN40 for communication terminal 800 is created.

[0187] The create session response includes, for example, the first IP address of the PGW-U 140 and the TEID assigned to the communication tunnel of the PGW-U 140. The create session response may further include the IP address of the PGW-C 120 and the TEID assigned to the communication tunnel of the PGW-C 120. The create session response may further include any other information for creating a session to the PDN 40 of the communication terminal 800.

[0188] Thereafter, the SGW-U340 receives the uplink data of the communication terminal 800. The SGW-U340 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW-U140. The PGW-U140 transmits the uplink data of the communication terminal 800 to the destination via the PDN 40.

[0189] Next, an example of generating a session to the PDN 60 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that data communication via both the network of the first ASN and the network of the second ASN can be performed.

[0190] In response to receiving the attach request from communication terminal 800, request generation device 70 generates a session creation request for communication terminal 800. Because communication terminal 800 is registered in terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, request generation device 70 generates a session creation request for communication terminal 800 that includes the second IP address of PGW-U 140. Request generation device 70 transmits the generated session creation request for communication terminal 800 to SGW-C 320 via network 20.

[0191] The SGW-C 320 transmits the received session creation request from the communication terminal 800 to the router 23. When the session creation request from the communication terminal 800 includes the second IP address of the PGW-U 140, the router 23 selects a PGW-C to forward the session creation request from the communication terminal 800 from among multiple PGW-Cs to which the same IP address is assigned. Here, the explanation will be continued assuming that the router 23 selects a PGW-C to forward the session creation request from the communication terminal 800 from among PGW-C 120 and PGW-C 220.

[0192] Router 23 selects a PGW-C to which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path along which the session creation request of communication terminal 800 is to be transferred. Router 23 selects a communication path along which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path from router 23 to a router corresponding to the PGW-C to which the session creation request of communication terminal 800 is to be transferred.

[0193] Router 23 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, based on a route table. Router 23 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, according to a BGP best path selection algorithm. Router 23 selects, as the communication path along which the session creation request of communication terminal 800 will be forwarded, a communication path with the shortest communication distance from router 23 to routers corresponding to each of multiple PGW-Cs to which the same IP address is assigned. Here, the explanation will continue assuming that router 23 has selected the communication path from router 23 to router 22 as the communication path along which the session creation request of communication terminal 800 will be forwarded.

[0194] Router 23 selects a communication path from router 23 to router 22 as the communication path along which the session creation request of communication terminal 800 is to be transferred, thereby selecting PGW-C 220 as the PGW-C to which the session creation request of communication terminal 800 is to be transferred. Router 23 transfers the session creation request of communication terminal 800 to router 22 via network 20. Router 22 transfers the session creation request of communication terminal 800 to PGW-C 220.

[0195] In response to receiving the session creation request from communication terminal 800, PGW-C220 creates session information for communication terminal 800 based on the session creation request from communication terminal 800. When the session creation request from communication terminal 800 includes the second IP address of PGW-U140, the session information of communication terminal 800 includes, for example, the IP address of communication terminal 800, the second IP address of PGW-U140, TEIDs assigned to the communication tunnel of PGW-U140 and the communication tunnel of PGW-U240, the IP address of SGW-U340, and the TEID assigned to the communication tunnel of SGW-U340. The session information of communication terminal 800 may further include the IP address of PGW-C120, the TEIDs assigned to the communication tunnel of PGW-C120 and PGW-C220, the IP address of SGW-C320, and the TEID assigned to the communication tunnel of SGW-C320. The session information of communication terminal 800 may include any other information for creating a session to PDN 60. The session information of communication terminal 800 including the second IP address of PGW-U 140 may be an example of second session information of communication terminal 800.

[0196] The PGW-C 220 registers the generated session information of the communication terminal 800 in the database 250 corresponding to the PGW 200. The database 250 synchronizes, for example, the session information of the communication terminal 800 registered in the database 250 between the database 250 and the database 150 corresponding to the PGW 100.

[0197] The database 250, for example, notifies the PGW-U 240 of the completion of synchronization. The database 250 may also notify the PGW-C 220 of the completion of synchronization.

[0198] The database 250 is, for example, separate from the PGW-C 220 and the PGW-U 240. The database 250 may be integrated with the PGW-C 220 or the PGW-U 240.

[0199] For example, the database 150 notifies the PGW-U 140 of the completion of synchronization. The database 150 may also notify the PGW-C 120 of the completion of synchronization.

[0200] The database 150 is, for example, separate from the PGW-C 120 and the PGW-U 140. The database 150 may also be integrated with the PGW-C 120 or the PGW-U 140.

[0201] The PGW-U240 establishes a communication tunnel between the PGW-U240 and the SGW-U340 in order to generate a session of the communication terminal 800 to the PDN 60. The PGW-U240 establishes the communication tunnel between the PGW-U240 and the SGW-U340 based on, for example, session information of the communication terminal 800 included in the synchronization completion notification notified from the database 250.

[0202] The PGW-U140 establishes a communication tunnel between the PGW-U140 and the SGW-U340 in order to generate a session of the communication terminal 800 to the PDN 60. The PGW-U140 establishes the communication tunnel between the PGW-U140 and the SGW-U340 based on, for example, session information of the communication terminal 800 included in the synchronization completion notification notified from the database 150.

[0203] PGW-C220 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 22. Router 22 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW-C320. When SGW-C320 receives the create session response from communication terminal 800, a session to PDN60 for communication terminal 800 is created.

[0204] The create session response includes, for example, the second IP address of PGW-U 140 and the TEIDs assigned to the communication tunnel of PGW-U 140 and the communication tunnel of PGW-U 240. The create session response may further include the IP address of PGW-C 120 and the TEIDs assigned to the communication tunnel of PGW-C 120 and the communication tunnel of PGW-C 220. The create session response may further include any other information for creating a session to PDN 60 of communication terminal 800.

[0205] Thereafter, the SGW-U 340 receives the uplink data of the communication terminal 800. The SGW-U 340 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 selects a PGW-U to forward the uplink data of the communication terminal 800. The router 23 may select a PGW-U to forward the uplink data of the communication terminal 800 from among multiple PGW-Us to which the same IP address is assigned, in the same way as when selecting a PGW-C to forward a session creation request of the communication terminal 800 from among multiple PGW-Cs to which the same IP address is assigned. Here, the description will continue assuming that the router 23 has selected the PGW-U 240 as the PGW-U to forward the uplink data of the communication terminal 800.

[0206] The router 23 transfers the uplink data of the communication terminal 800 to the router 22 via the network 20. The router 22 transfers the uplink data of the communication terminal 800 to the PGW-U 240. The PGW-U 240 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0207] Thereafter, if the communication path between the SGW 300 and the PGW 200 becomes unavailable, the router 22 advertises the communication path information. The router 23 receives the communication path information advertised by the router 22 and updates the route table. In this case, the router 23 may change the PGW-U that forwards the uplink data of the communication terminal 800 from PGW-U 240 to PGW-U 140 based on the updated route table.

[0208] The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW-U 140. The PGW-U 140 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0209] If the communication path between the SGW 300 and the PGW 200 is unavailable when the SGW-C 320 receives the session creation request from the communication terminal 800, the router 23 forwards the session creation request from the communication terminal 800 to the router 21 via the network 20. The router 21 forwards the session creation request from the communication terminal 800 to the PGW-C 120.

[0210] In response to receiving the session creation request from communication terminal 800, PGW-C120 generates session information for communication terminal 800. PGW-C120 may generate the session information for communication terminal 800 in the same manner as when PGW-C220 generates session information for communication terminal 800 in order to create a session for communication terminal 800 to PDN60.

[0211] PGW-C120 registers the generated session information of communication terminal 800 in database 150. Database 150 synchronizes the session information of communication terminal 800 registered in database 150 between database 150 and database 250. Database 150 may synchronize the session information of communication terminal 800 between database 150 and database 250 in the same way as when database 250 synchronizes the session information of communication terminal 800 between database 250 and database 150.

[0212] For example, the database 150 notifies the PGW-U 140 of the completion of synchronization. The database 150 may also notify the PGW-C 120 of the completion of synchronization.

[0213] The database 250, for example, notifies the PGW-U 240 of the completion of synchronization. The database 250 may also notify the PGW-C 220 of the completion of synchronization.

[0214] The PGW-U140 establishes a communication tunnel between the PGW-U140 and the SGW-U340 in order to generate a session of the communication terminal 800 to the PDN 60. The PGW-U140 establishes the communication tunnel between the PGW-U140 and the SGW-U340 based on, for example, session information of the communication terminal 800 included in the synchronization completion notification notified from the database 150.

[0215] PGW-C120 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 21. Router 21 forwards the create session response from communication terminal 800 to router 23. Router 23 forwards the create session response from communication terminal 800 to SGW-C320. When SGW-C320 receives the create session response from communication terminal 800, a session to PDN60 for communication terminal 800 is created.

[0216] Thereafter, the SGW-U340 receives the uplink data of the communication terminal 800. The SGW-U340 transmits the uplink data of the communication terminal 800 to the router 23. The router 23 transfers the uplink data of the communication terminal 800 to the router 21 via the network 20. The router 21 transfers the uplink data of the communication terminal 800 to the PGW-U140. The PGW-U140 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0217] Thereafter, when a communication path between the SGW300 and the PGW200 becomes available, the PGW-U240 establishes a communication tunnel between the PGW-U240 and the SGW-U340 to generate a session of the communication terminal 800 to the PDN 60. The PGW-U240 establishes the communication tunnel between the PGW-U240 and the SGW-U340 based on, for example, the session information of the communication terminal 800 included in the synchronization completion notification notified from the database 250.

[0218] The router 22 advertises communication path information after the communication path between the SGW 300 and the PGW 200 becomes available. The router 23 receives the communication path information advertised by the router 22 and updates the route table. In this case, the router 23 may change the PGW-U that forwards the uplink data of the communication terminal 800 from PGW-U 140 to PGW-U 240 based on the updated route table.

[0219] After changing the PGW-U that forwards the uplink data of the communication terminal 800 from PGW-U140 to PGW-U240, the router 23 forwards the uplink data of the communication terminal 800 to the router 22 via the network 20. The router 22 forwards the uplink data of the communication terminal 800 to the PGW-U240. The PGW-U240 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0220] 5, when PGW-C120 receives a session creation request for communication terminal 800 from SGW-C320, and communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, PGW-C120 generates session information for communication terminal 800 including the first IP address of PGW-U140. Because the first IP address of PGW-U140 is assigned only to PGW-U140 out of PGW-U140 and PGW-U240, a communication path for accessing PDN40 via the HPLMN in which PGW100 is located can be used for data communication of communication terminal 800, regardless of the location of the VPLMN in which SGW300 is located. Furthermore, when PGW-C120 receives a session creation request for communication terminal 800 from SGW-C320, if communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, PGW-C120 generates session information for communication terminal 800 including the second IP address of PGW-U140 and registers the session information for communication terminal 800 in database 150. The session information for communication terminal 800 registered in database 150 is synchronized between database 150 and database 250. Because the same IP address is assigned to both PGW-U140 and PGW-U240, synchronizing the session information for communication terminal 800 between database 150 and database 250 makes it possible to provide redundant communication paths available for data communication by communication terminal 800, such as a communication path for accessing PDN 60 via the HPLMN in which PGW100 is located and a communication path for accessing PDN 60 via the HPLMN in which PGW200 is located. This allows the communication terminal 800 to use, for data communication, a communication route to access the PDN 60 via the HPLMN, which has a shorter communication distance from the VPLMN in which the SGW 300 is located, selected according to the BGP best path selection algorithm.Therefore, according to the system 10 shown in Fig. 5, the communication terminal 800 registers in advance whether it is capable of performing only data communication via the first ASN network out of data communication via the network of the first ASN and data communication via the network of the second ASN, or whether it is capable of performing both data communication via the network of the first ASN and data communication via the network of the second ASN, and by determining the communication path used for data communication by the communication terminal 800 in both cases by the above-mentioned method, it is possible to access a PDN via an appropriate network depending on the user's purpose without installing a unique PGW for each user or assigning a unique IP address to each user. As described above, the system 10 shown in Fig. 5 can realize an LTE communication service that is capable of accessing a PDN via an appropriate network depending on the user's purpose and that adopts the CUPS architecture, with fewer resources.

[0221] 6 is an explanatory diagram illustrating another example of the processing flow of the system 10. Here, the description will be given assuming that the start state is a state in which the user of the communication terminal 800, which is registered in the terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, visits the VPLMN in which the SGW 300 is located.

[0222] In S202, SGW-C320 transmits to PGW-C the session creation request for communication terminal 800 received from request generation device 70. Here, since the communication path between SGW300 and PGW200 is unavailable at the time SGW-C320 receives the session creation request for communication terminal 800, the explanation will continue assuming that SGW300 transmits the session creation request for communication terminal 800 to PGW-C120.

[0223] In S204, the PGW-C120 generates session information for the communication terminal 800 based on the session creation request for the communication terminal 800 received from the SGW-C320 in S202, and registers the session information for the communication terminal 800 in the database 150. In S206, in response to the registration of the session information for the communication terminal 800 in the database 150 in S204, the PGW-C120 transmits to the SGW-C320 a create session response for the communication terminal 800 in response to the session creation request from the communication terminal 800.

[0224] In S208, database 150 synchronizes the session information of communication terminal 800 registered by PGW-C 120 in S204 between database 150 and database 250. In S210, database 150 notifies PGW-U 140 of a synchronization completion notification in response to the session information of communication terminal 800 being synchronized between database 150 and database 250 in S208. In S212, database 250 notifies PGW-U 240 of a synchronization completion notification in response to the session information of communication terminal 800 being synchronized between database 150 and database 250 by database 150 in S208.

[0225] In S214, the SGW-U 340 transmits the uplink data of the communication terminal 800 received from the communication terminal 800 to the PGW-U 140. The PGW-U 140 transmits the uplink data of the communication terminal 800 to the destination via the PDN 60.

[0226] Thereafter, in S216 after the communication path between SGW300 and PGW200 becomes available, SGW-U340 transmits the uplink data of communication terminal 800 received from communication terminal 800 to PGW-U240. PGW-U240 transmits the uplink data of communication terminal 800 to the destination via PDN60.

[0227] In the example of the processing flow of system 10 shown in Fig. 6, the process in which PGW-C120 transmits a create session response for communication terminal 800 to SGW-C320 in response to PGW-C120 registering session information of communication terminal 800 in database 150 may be replaced with a process in which PGW-C120 transmits a create session response for communication terminal 800 to SGW300 in response to PGW-U140 being notified of a synchronization completion notification from database 150. That is, S206 shown in Fig. 6 may be performed after S210 shown in Fig. 6.

[0228] 7 shows an example of the functional configuration of the PGW-C 120. The PGW-C 120 includes a request receiving unit 122, a session information generating unit 126, a registration unit 128, a session information synchronizing unit 130, a notification receiving unit 132, a response transmitting unit 134, and a communication tunnel establishing unit 136. Note that it is not essential that the PGW-C 120 include all of these components.

[0229] The request receiving unit 122 receives a session creation request from a communication terminal 800 requesting the creation of a session to a PDN. For example, the request receiving unit 122 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 40. For example, the request receiving unit 122 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 60. The request receiving unit 122 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another PDN.

[0230] The request receiving unit 122 receives, for example, a session creation request for the communication terminal 800 from the SGW 300. The request receiving unit 122 receives, for example, a session creation request for the communication terminal 800 from the SGW-C 320.

[0231] The request receiving unit 122 receives a session creation request from the communication terminal 800, for example, via the network 20. The request receiving unit 122 receives a session creation request from the communication terminal 800, for example, via the network 20 and the router 21.

[0232] The session information generating unit 126 generates session information of the communication terminal 800. The session information generating unit 126 generates the session information of the communication terminal 800, for example, in response to the request receiving unit 122 receiving a session generation request from the communication terminal 800.

[0233] The session information generation unit 126 generates session information of the communication terminal 800, for example, based on a session generation request from the communication terminal 800. For example, when the communication terminal 800 is registered so that only data communication via the first ASN network is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the session information generation unit 126 generates session information of the communication terminal 800 that includes a first IP address of the PGW-U 140. For example, when the communication terminal 800 is registered so that data communication via both the network of the first ASN and data communication via the network of the second ASN is executable, the session information generation unit 126 generates session information of the communication terminal 800 that includes a second IP address of the PGW-U 140.

[0234] The registration unit 128 registers the session information of the communication terminal 800 in the database 150. The registration unit 128 registers the session information of the communication terminal 800 generated by the session information generation unit 126 in the database 150, for example.

[0235] The registration unit 128 registers, for example, the session information of the communication terminal 800, which includes the second IP address of the PGW-U 140, in the database 150. The registration unit 128 may also register, in the database 150, the session information of the communication terminal 800, which includes the first IP address of the PGW-U 140.

[0236] The session information synchronization unit 130 synchronizes the session information of the communication terminal 800, which is registered in the database 150 by the registration unit 128 and includes the second IP address of the PGW-U 140, between the database 150 and the database 250. The session information synchronization unit 130 may synchronize the session information between the database 150 and the database 250 in the same manner as when the database 250 synchronizes the session information of the communication terminal 800 between the database 250 and the database 150.

[0237] The session information synchronization unit 130 may issue a synchronization completion notification in response to synchronizing the session information between the database 150 and the database 250. The session information synchronization unit 130, for example, issues the synchronization completion notification to the PGW-U 140. The session information synchronization unit 130, for example, issues the synchronization completion notification to the PGW-U 240. The session information synchronization unit 130 may also issue the synchronization completion notification to the PGW-C 220.

[0238] The session information synchronizer 130 issues a synchronization completion notification via, for example, the network 20. The session information synchronizer 130 issues a synchronization completion notification via, for example, the router 21 and the network 20.

[0239] The notification receiving unit 132 receives the synchronization completion notification. The notification receiving unit 132 receives the synchronization completion notification from, for example, the database 150. The notification receiving unit 132 receives the synchronization completion notification from, for example, the database 250. The notification receiving unit 132 may also receive the synchronization completion notification from the PGW-C 220.

[0240] The notification receiving unit 132 receives the synchronization completion notification via, for example, the network 20. The notification receiving unit 132 receives the synchronization completion notification via, for example, the network 20 and the router 21.

[0241] The response transmitting unit 134 transmits a session creation response of the communication terminal 800 in response to the session creation request of the communication terminal 800. The response transmitting unit 134 transmits, for example, a session creation response of the communication terminal 800 in response to the session creation request of the communication terminal 800 received by the request receiving unit 122.

[0242] The response transmitting unit 134 transmits, for example, the create session response of the communication terminal 800 to the SGW-C 320. The response transmitting unit 134 transmits, for example, the create session response of the communication terminal 800 to the SGW-C 320 via the network 20. The response transmitting unit 134 transmits, for example, the create session response of the communication terminal 800 to the SGW-C 320 via the network 20 and the router 21.

[0243] The response transmitting unit 134 transmits a session generation response for the communication terminal 800 in response to, for example, the session information generating unit 126 generating session information for the communication terminal 800. The response transmitting unit 134 transmits a session generation response for the communication terminal 800 in response to, for example, the registration unit 128 registering the session information for the communication terminal 800 in the database 150. The response transmitting unit 134 transmits a session generation response for the communication terminal 800 in response to, for example, the session information for the communication terminal 800 being synchronized between the database 150 and the database 250. The response transmitting unit 134 transmits a session generation response for the communication terminal 800 in response to, for example, the session information synchronizing unit 130 synchronizing the session information for the communication terminal 800 between the database 150 and the database 250. The response transmitting unit 134 may transmit a session generation response for the communication terminal 800 in response to, for example, the notification receiving unit 132 receiving a synchronization completion notification.

[0244] The communication tunnel establishment unit 136 establishes a communication tunnel to create a session to the PDN of the communication terminal 800. For example, the communication tunnel establishment unit 136 establishes a communication tunnel to create a session to the PDN 40 of the communication terminal 800. For example, the communication tunnel establishment unit 136 establishes a communication tunnel to create a session to the PDN 60 of the communication terminal 800. The communication tunnel establishment unit 136 may establish a communication tunnel to create a session to another PDN of the communication terminal 800.

[0245] The communication tunnel establishment unit 136 establishes, for example, a GTP tunnel. The communication tunnel establishment unit 116 may establish any other communication tunnel.

[0246] The communication tunnel establishment unit 136 establishes the communication tunnel, for example, by causing the PGW-U 140 to establish a communication tunnel between the PGW-U 140 and the SGW-U 340. In this case, the communication tunnel establishment unit 136 may instruct the PGW-U 140 to establish a communication tunnel between the PGW-U 140 and the SGW-U 340. The communication tunnel establishment unit 136 establishes the communication tunnel, for example, by establishing a communication tunnel between the PGW-C 120 and the SGW-C 320.

[0247] The communication tunnel establishment unit 136 establishes the communication tunnel based on, for example, session information of the communication terminal 800. The communication tunnel establishment unit 136 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 generated by the session information generation unit 126. The communication tunnel establishment unit 136 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 synchronized between the database 150 and the database 250 by the session information synchronization unit 130. The communication tunnel establishment unit 136 may establish the communication tunnel based on the session information of the communication terminal 800 included in the synchronization completion notification received by the notification reception unit 132.

[0248] For example, when communication terminal 800 is registered so that only data communication via the first ASN network is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, communication tunnel establishment unit 136 establishes the communication tunnel based on session information of communication terminal 800 including the first IP address of PGW-U 140. For example, when communication terminal 800 is registered so that both data communication via the network of the first ASN and data communication via the network of the second ASN are executable, communication tunnel establishment unit 136 establishes the communication tunnel based on session information of communication terminal 800 including the second IP address of PGW-U 140, which is synchronized between database 150 and database 250.

[0249] 8 illustrates an example of the functional configuration of the PGW-U 140. The PGW-U 140 includes a session information acquisition unit 142, a communication tunnel establishment unit 144, a data reception unit 146, and a data transmission unit 148. Note that it is not essential that the PGW-U 140 include all of these components.

[0250] The session information acquisition unit 142 acquires session information of the communication terminal 800. The session information acquisition unit 142 acquires the session information of the communication terminal 800 generated by the PGW-C 120, for example.

[0251] The session information acquisition unit 142 acquires session information of the communication terminal 800, for example, by receiving a synchronization completion notification. The session information acquisition unit 142 receives the synchronization completion notification, for example, via the network 20. The session information acquisition unit 142 receives the synchronization completion notification, for example, via the network 20 and the router 21.

[0252] The session information acquisition unit 142 receives a synchronization completion notification from, for example, the database 150. The session information acquisition unit 142 receives a synchronization completion notification from, for example, the database 250. The session information acquisition unit 142 receives a synchronization completion notification from, for example, the PGW-C 120. The session information acquisition unit 142 may also receive a synchronization completion notification from the PGW-C 220.

[0253] The communication tunnel establishment unit 144 establishes a communication tunnel to create a session to the PDN of the communication terminal 800. The communication tunnel establishment unit 144 establishes a communication tunnel between the PGW-U 140 and the SGW-U 340 to create a session to the PDN of the communication terminal 800.

[0254] The communication tunnel establishment unit 144 establishes the communication tunnel, for example, in accordance with an instruction from the PGW-C 120. The communication tunnel establishment unit 144 may also establish the communication tunnel autonomously without receiving an instruction from the PGW-C 120.

[0255] The communication tunnel establishment unit 144 establishes a communication tunnel, for example, to create a session to the PDN 40 of the communication terminal 800. The communication tunnel establishment unit 144 establishes a communication tunnel, for example, to create a session to the PDN 60 of the communication terminal 800. The communication tunnel establishment unit 144 may establish a communication tunnel to create a session to another PDN of the communication terminal 800.

[0256] The communication tunnel establishment unit 144 establishes, for example, a GTP tunnel, but may also establish any other communication tunnel.

[0257] The communication tunnel establishment unit 144 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 acquired by the session information acquisition unit 142. For example, when the communication terminal 800 is registered so that only data communication via the first ASN network is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the communication tunnel establishment unit 144 establishes the communication tunnel based on the session information of the communication terminal 800 including the first IP address of the PGW-U 140. For example, when the communication terminal 800 is registered so that data communication via both the network of the first ASN and data communication via the network of the second ASN is executable, the communication tunnel establishment unit 144 establishes the communication tunnel based on the session information of the communication terminal 800 including the second IP address of the PGW-U 140, which is synchronized between the database 150 and the database 250.

[0258] The communication tunnel establishment unit 144 may be an example of a first communication tunnel establishment unit. The communication tunnel establishment unit 144 may be an example of a second communication tunnel establishment unit.

[0259] The data receiving unit 146 receives data related to data communication of the communication terminal 800. The data receiving unit 146 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 146 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 21. The data receiving unit 146 receives data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishment unit 144.

[0260] The data receiving unit 146 receives, for example, uplink data of the communication terminal 800. The data receiving unit 146 receives the uplink data of the communication terminal 800 when, for example, the PGW-U 140 is selected as a transmission target of the uplink data of the communication terminal 800 from among a plurality of PGW-Us to which the same IP address is assigned.

[0261] The data receiving unit 146 receives, for example, downlink data of the communication terminal 800. For example, when the PGW-U 140 is selected as a transmission target of the downlink data of the communication terminal 800 from among a plurality of PGW-Us to which the same IP address is assigned, the data receiving unit 146 receives the downlink data of the communication terminal 800.

[0262] For example, when data receiving unit 146 receives uplink data of communication terminal 800 and PGW-U 140 does not hold session information of communication terminal 800, communication tunnel establishing unit 144 establishes a communication tunnel by acquiring the session information of communication terminal 800 from database 150. For example, when data receiving unit 146 receives uplink data of communication terminal 800 for the first time, communication tunnel establishing unit 144 acquires the session information of communication terminal 800 from database 150.

[0263] For example, when data receiving unit 146 receives downlink data of communication terminal 800 and PGW-U 140 does not hold session information of communication terminal 800, communication tunnel establishing unit 144 establishes a communication tunnel by acquiring the session information of communication terminal 800 from database 150. For example, when data receiving unit 146 receives downlink data of communication terminal 800 for the first time, communication tunnel establishing unit 144 acquires the session information of communication terminal 800 from database 150.

[0264] The data transmitting unit 148 transmits data related to data communication of the communication terminal 800. The data transmitting unit 148 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmitting unit 148 transmits data related to data communication of the communication terminal 800, for example, via the router 21 and the network 20. The data transmitting unit 148 transmits data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishing unit 144.

[0265] The data transmitting unit 148 transmits, for example, uplink data of the communication terminal 800 to a destination of the uplink data of the communication terminal 800. The data transmitting unit 148 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0266] 9 shows an example of the functional configuration of the SGW-C 320. The SGW-C 320 includes a storage unit 322, a route information receiving unit 324, a table generating unit 326, a request receiving unit 330, a request transmitting unit 332, a response receiving unit 334, and a response providing unit 335. It is not essential that the SGW-C 320 include all of these components.

[0267] The storage unit 322 stores various types of information, such as a route table.

[0268] The route table includes, for example, communication path information indicating the communication path between the SGW 300 and the PGW 100. The route table includes, for example, communication path information indicating the communication path between the SGW 300 and the PGW 200.

[0269] The route information receiving unit 324 receives communication route information. The route information receiving unit 324 receives the communication route information, for example, via the network 20. The route information receiving unit 324 receives the communication route information, for example, via the network 20 and the router 23. The route information receiving unit 324 may store the received communication route information in the storage unit 322.

[0270] The route information receiving unit 324 receives, for example, communication route information advertised by the router 21. The route information receiving unit 324 receives, for example, communication route information advertised by the router 22. The route information receiving unit 324 may also receive communication route information advertised by IPX.

[0271] The path information receiving unit 324 receives, for example, communication path information indicating a communication path between the SGW 300 and the PGW 100. The path information receiving unit 324 receives, for example, communication path information indicating a communication path between the SGW 300 and the PGW 200.

[0272] The table generation unit 326 generates a route table. For example, the table generation unit 326 generates the route table based on the communication route information stored in the storage unit 322. For example, the table generation unit 326 generates the route table based on the communication route information received by the route information receiving unit 324. The table generation unit 326 may generate the route table in the same manner as when the router 23 generates a route table.

[0273] The table generating unit 326 may store the generated route table in the storage unit 322. The table generating unit 326 may provide the generated route table to the SGW-U340.

[0274] The request receiving unit 330 receives a session creation request from a communication terminal 800 requesting the creation of a session to a PDN. For example, the request receiving unit 330 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 40. For example, the request receiving unit 330 receives a session creation request from a communication terminal 800 requesting the creation of a session to PDN 60. The request receiving unit 330 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another PDN.

[0275] The request receiving unit 330 receives a session creation request for the communication terminal 800, for example, from the request generating device 70. The request receiving unit 330 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20. The request receiving unit 330 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20 and the router 23.

[0276] The request transmitting unit 332 transmits a session creation request from the communication terminal 800. The request transmitting unit 332 transmits the session creation request from the communication terminal 800 received by the request receiving unit 330, for example.

[0277] The request sending unit 332 sends the session creation request of the communication terminal 800, for example, via the network 20. The request sending unit 332 sends the session creation request of the communication terminal 800, for example, via the router 23 and the network 20.

[0278] The request sending unit 332 sends a session creation request for the communication terminal 800, for example, based on the route table stored in the storage unit 322. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the request sending unit 332 sends a session creation request for the communication terminal 800, which includes the first IP address of the PGW-U 140, to the PGW 100.

[0279] For example, when communication terminal 800 is registered so that data communication via both the network of the first ASN and the network of the second ASN is possible, request sending unit 332 sends a session creation request from communication terminal 800, including the second IP address of PGW-U 140, to a PGW-C selected as a destination of the session creation request from among multiple PGW-Cs to which the same IP address is assigned based on predetermined PGW selection conditions. In this case, request sending unit 332 sends, for example, the session creation request to a PGW-C selected as a destination of the session creation request from among PGW-C 120 and PGW-C 220 based on the PGW selection conditions. For example, request sending unit 332 sends the session creation request to the PGW-C selected as a destination of the session creation request via a communication path selected according to a BGP best path selection algorithm.

[0280] The response receiving unit 334 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800. For example, the response receiving unit 334 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800 transmitted by the request transmitting unit 332. The response receiving unit 334 may store the received session creation response from the communication terminal 800 in the storage unit 322.

[0281] The response receiving unit 334 receives the create session response of the communication terminal 800 from, for example, the PGW-C 120. The response receiving unit 334 receives the create session response of the communication terminal 800 from, for example, the PGW-C 220.

[0282] The response receiving unit 334 receives the session creation response from the communication terminal 800, for example, via the network 20. The response receiving unit 334 receives the session creation response from the communication terminal 800, for example, via the network 20 and the router 23.

[0283] The response providing unit 335 provides the session creation response of the communication terminal 800 received by the response receiving unit 334. The response providing unit 335 provides the session creation response of the communication terminal 800 to the SGW-U340, for example.

[0284] 10 shows an example of the functional configuration of the SGW-U 340. The SGW-U 340 includes a storage unit 342, a table acquisition unit 344, a response acquisition unit 345, a data reception unit 348, and a data transmission unit 349. Note that it is not essential that the SGW-U 340 include all of these components.

[0285] The storage unit 342 stores various types of information, such as a route table.

[0286] For example, SGW-C 320 and SGW-U 340 share a storage unit. In this case, storage unit 322 and storage unit 342 are the same storage unit. SGW-C 320 and SGW-U 340 do not have to share a storage unit. In this case, storage unit 322 and storage unit 342 are different storage units.

[0287] The table acquisition unit 344 acquires a route table. For example, the table acquisition unit 344 acquires a route table provided by the SGW-C 320. The table acquisition unit 344 may store the acquired route table in the storage unit 342.

[0288] The response acquisition unit 345 acquires a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800. The response acquisition unit 345 acquires, for example, the session creation response from the communication terminal 800 provided by the SGW-C 320. The response acquisition unit 345 may store the acquired session creation response from the communication terminal 800 in the storage unit 342.

[0289] The data receiving unit 348 receives data related to data communication of the communication terminal 800. The data receiving unit 348 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 348 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 23.

[0290] The data receiving unit 348 receives, for example, uplink data of the communication terminal 800. The data receiving unit 348 receives, for example, downlink data of the communication terminal 800.

[0291] The data transmission unit 349 transmits data related to data communication of the communication terminal 800. The data transmission unit 349 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmission unit 349 transmits data related to data communication of the communication terminal 800, for example, via the router 23 and the network 20.

[0292] The data transmitting unit 349 transmits, for example, uplink data of the communication terminal 800. The data transmitting unit 349 transmits the uplink data of the communication terminal 800, for example, based on the route table stored in the storage unit 342. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the data transmitting unit 349 transmits the uplink data of the communication terminal 800 to the PGW 100.

[0293] For example, when communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, data transmission unit 349 transmits uplink data of communication terminal 800 to a PGW-U selected as a transmission destination of the uplink data of communication terminal 800 from among multiple PGW-Us to which the same IP address is assigned based on predetermined PGW selection conditions. In this case, data transmission unit 349 transmits the uplink data of communication terminal 800 to a PGW-U selected as a transmission destination of the uplink data of communication terminal 800 from among PGW-U 140 and PGW-U 240 based on the PGW selection conditions. Data transmission unit 349 transmits the uplink data of communication terminal 800 to the PGW-U selected as a transmission destination of the uplink data of communication terminal 800, for example, via a communication path selected according to a BGP best path selection algorithm.

[0294] The data transmitting unit 349 transmits, for example, downlink data of the communication terminal 800. The data transmitting unit 349 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0295] Fig. 11 schematically illustrates another example of the system 10. Fig. 11 illustrates an example in which the system 10 provides a 5G communication service.

[0296] The system 10 may include an H-SMF 420 and an H-UPF 440. The system 10 may include an H-SMF 520 and an H-UPF 540. The system 10 may include a V-SMF 620 and a V-UPF 640. The system 10 may include a database 450. The system 10 may include a database 550. The system 10 may include a router 24. The system 10 may include a router 25. The system 10 may include a router 26. The system 10 may include a terminal information management device 50. The system 10 may include a request generation device 70.

[0297] The H-SMF 420 has a function of managing sessions. The H-SMF 420 may be an example of a first SMF or an example of a second SMF.

[0298] The H-SMF 420 may be located in, for example, a network of a first ASN. The H-SMF 420 may be located in, for example, a network of a first country. The H-SMF 420 may be located in, for example, a HPLMN. In the example shown in Figure 11, the H-SMF 420 is located in a HPLMN based in Tokyo, Japan, with an ASN of 65001.

[0299] An IP address may be assigned to the H-SMF 420. In the example of the system 10 shown in Figure 11, the H-SMF 420 is assigned the IP address AAAA of the subnet mask 32.

[0300] H-UPF 440 has a function of relaying data related to data communication of communication terminal 800. H-UPF 440 has a function of relaying, for example, uplink data of communication terminal 800. H-UPF 440 has a function of relaying, for example, downlink data of communication terminal 800. H-UPF 440 may be an example of a first UPF, an example of a second UPF, or an example of a third UPF.

[0301] The H-UPF 440 transmits uplink data of the communication terminal 800 to a destination via, for example, an external network. The H-UPF 440 transmits uplink data of the communication terminal 800 to a destination via, for example, a DN 80. The H-UPF 440 transmits uplink data of the communication terminal 800 to a destination via, for example, a DN 90. The H-UPF 440 may transmit uplink data of the communication terminal 800 to a destination via another DN. The H-UPF 440 is connected to an external network via, for example, an N6 interface.

[0302] The DN 80 is, for example, a private network. The DN 80 may also be a public network.

[0303] DN90 is, for example, a private network. DN90 may also be a public network.

[0304] The H-UPF 440 transmits the downlink data of the communication terminal 800 to another UPF via, for example, the network 20. The H-UPF 440 transmits the downlink data of the communication terminal 800 to the V-UPF 640 via, for example, the network 20.

[0305] The network 20 includes, for example, a core network. The network 20 includes, for example, a radio access network. The network 20 includes, for example, DNs such as DN80 and DN90. The network 20 may include the Internet.

[0306] The H-UPF 440 is located, for example, in the network in which the H-SMF 420 is located. In the example shown in Figure 11, the H-UPF 440 is located in the HPLMN, which is based in Tokyo, Japan, and has an ASN of 65001.

[0307] The H-UPF 440 may be assigned an IP address. For example, the H-UPF 440 is assigned a plurality of mutually different IP addresses. For example, the H-UPF 440 is assigned a first IP address and a second IP address different from the first IP address. The first IP address of the H-UPF 440 may be used to access the DN80. The second IP address of the H-UPF 440 may be used to access the DN90. The H-UPF 440 may be assigned three or more mutually different IP addresses. In the example of the system 10 shown in FIG. 11 , the H-UPF 440 is assigned IP address BBBB of the subnet mask 32 as the first IP address, and IP address CCCC of the subnet mask 32 as the second IP address.

[0308] The H-SMF 520 has a function of managing sessions. The H-SMF 520 may have the same function as the H-SMF 420. The H-SMF 520 may be an example of a first SMF or an example of a second SMF.

[0309] The H-SMF 520 may be located in a network of a second ASN that is different from the first ASN. The H-SMF 520 may be located in a network of a second country that is different from the first country. The H-SMF 520 may be located in an HPLMN. In the example shown in Figure 11, the H-SMF 520 is located in an HPLMN that is based in Singapore and has an ASN of 65002.

[0310] The H-SMF 520 may be located in a network in a first country. For example, if the H-SMF 420 is located in a network based in Tokyo, Japan, the H-SMF 520 may be located in a network based in Osaka, Japan.

[0311] The H-SMF 520 may be assigned an IP address. For example, the H-SMF 520 is assigned the same IP address as the IP address assigned to the H-SMF 420. For example, the same IP address is assigned to the H-SMF 420 and the H-SMF 520 using IP Anycast. In the example of the system 10 shown in FIG. 11 , the H-SMF 520 is assigned the IP address AAAA with a subnet mask of 32.

[0312] H-UPF 540 has a function of relaying data related to data communication of communication terminal 800. H-UPF 540 has a function of relaying, for example, uplink data of communication terminal 800. H-UPF 540 has a function of relaying, for example, downlink data of communication terminal 800. H-UPF 540 may be an example of a first UPF, an example of a second UPF, or an example of a third UPF.

[0313] The H-UPF 540 transmits uplink data of the communication terminal 800 to a destination via, for example, an external network. The H-UPF 540 transmits uplink data of the communication terminal 800 to a destination via, for example, DN 90. The H-UPF 540 may transmit uplink data of the communication terminal 800 to a destination via another DN. The H-UPF 540 is connected to the external network via, for example, an N6 interface.

[0314] The H-UPF 540 transmits the downlink data of the communication terminal 800 to another UPF via, for example, the network 20. The H-UPF 540 transmits the downlink data of the communication terminal 800 to the V-UPF 640 via, for example, the network 20.

[0315] The H-UPF 540 is located, for example, in the network in which the H-SMF 520 is located. In the example shown in Figure 11, the H-UPF 540 is located in the HPLMN, which is based in Singapore and has an ASN of 65002.

[0316] The H-UPF 540 may be assigned an IP address. For example, the second IP address of the H-UPF 440 is assigned to the H-UPF 540. For example, the same IP address is assigned to the H-UPF 440 and the H-UPF 540 using IP Anycast. The H-UPF 540 may be assigned multiple different IP addresses. In the example of the system 10 shown in FIG. 11, the H-UPF 540 is assigned an IP address CCCC with a subnet mask of 32.

[0317] The V-SMF 620 has a function for managing sessions. The V-SMF 620 may be an example of a third SMF.

[0318] The V-SMF 620 is, for example, located in a network of a third ASN that is different from the first ASN and the second ASN. The V-SMF 620 may be located in the network of the first ASN or the network of the second ASN.

[0319] The V-SMF 620 may be located in a network in a first country, or may be located in a network in a second country. The V-SMF 620 may be located in a network in a third country different from the first country and the second country.

[0320] The V-SMF 620 is located in, for example, a VPLMN. In the example shown in Figure 11, the V-SMF 620 is located in a VPLMN based in Singapore with an ASN of 65003.

[0321] An IP address may be assigned to the V-SMF 620. In the example of the system 10 shown in Figure 11, the V-SMF 620 is assigned the IP address DDDD with the subnet mask 32.

[0322] V-UPF 640 has a function of relaying data related to data communication of communication terminal 800. V-UPF 640 has a function of relaying, for example, uplink data of communication terminal 800. V-UPF 640 has a function of relaying, for example, downlink data of communication terminal 800. V-UPF 640 may be an example of a second UPF or an example of a third UPF.

[0323] The V-UPF 640 transmits the uplink data of the communication terminal 800 to another UPF, for example, via the network 20. The V-UPF 640 transmits the uplink data of the communication terminal 800 to the H-UPF 440, for example, via the network 20. The V-UPF 640 transmits the uplink data of the communication terminal 800 to the H-UPF 540, for example, via the network 20.

[0324] The V-UPF 640 receives downlink data of the communication terminal 800 from, for example, another UPF via the network 20. The V-UPF 640 receives downlink data of the communication terminal 800 from, for example, the H-UPF 440 via the network 20. The V-UPF 640 receives downlink data of the communication terminal 800 from, for example, the H-UPF 540 via the network 20.

[0325] The V-UPF 640 is located, for example, in the network in which the V-SMF 620 is located. In the example shown in Figure 11, the V-UPF 640 is located in a VPLMN based in Singapore with an ASN of 65003.

[0326] An IP address may be assigned to the V-UPF 640. In the example of the system 10 shown in Figure 11, the V-UPF 640 is assigned the IP address EEEE of the subnet mask 32.

[0327] The router 24 has a function of relaying data. The router 24 relays, for example, uplink data. The router 24 relays, for example, downlink data.

[0328] The router 24 is located, for example, in the network in which the H-SMF 420 is located. The router 24 is located, for example, in the network of the first ASN. The router 24 may also be located in a network different from the network in which the H-SMF 420 is located.

[0329] The router 24 is, for example, separate from the H-SMF 420 and the H-UPF 440. The router 21 may be integrated with the H-SMF 420 or the H-UPF 440.

[0330] The router 25 has a function of relaying data. The router 25 relays, for example, uplink data. The router 25 relays, for example, downlink data.

[0331] The router 25 is disposed, for example, in a network in which the H-SMF 520 is disposed. The router 25 is disposed, for example, in a network of a second ASN. The router 25 may be disposed in a network different from the network in which the H-SMF 520 is disposed.

[0332] The router 25 is, for example, separate from the H-SMF 520 and the H-UPF 540. The router 25 may be integrated with the H-SMF 520 or the H-UPF 540.

[0333] The router 26 has a function of relaying data. The router 26 relays, for example, uplink data. The router 26 relays, for example, downlink data.

[0334] The router 26 is arranged, for example, in the network in which the V-SMF 620 is arranged. The router 26 is arranged, for example, in the network of a third ASN. The router 26 may be arranged in a network different from the network in which the V-SMF 620 is arranged.

[0335] The router 26 is, for example, separate from the V-SMF 620 and the V-UPF 640. The router 26 may be integrated with the V-SMF 620 or the V-UPF 640.

[0336] For example, communication path information between organizations is exchanged among the router 24, the router 25, and the router 26 in accordance with BGP. For example, in response to a change in the communication path information, the communication path information is exchanged among the router 24, the router 25, and the router 26. The communication path information may also be exchanged periodically among the router 24, the router 25, and the router 26.

[0337] The router 24 advertises the communication path information to, for example, the router 26. The router 24 may also advertise the communication path information to IPX. The router 25 may also advertise the communication path information in the same manner as the router 24.

[0338] 11, the router 24 advertises ASN=65001, the IP address of the H-SMF 420=AAAA / 32, the first IP address of the H-UPF 440=BBBB / 32, and the second IP address of the H-UPF 440=CCCC / 32. In the example of the system 10 shown in FIG. 11, the router 25 advertises ASN=65002, the IP address of the H-SMF 520=AAAA / 32, and the IP address of the H-UPF 540=CCCC / 32.

[0339] The router 26 advertises the communication path information, for example, to the routers 24 and 25. The router 26 may also advertise the communication path information to IPX. In the example of the system 10 shown in Fig. 11, the router 26 advertises ASN=65003, the IP address of the V-SMF 620=DDDD / 32, and the IP address of the V-UPF 640=EEEE / 32.

[0340] The router 26 generates a route table based on, for example, communication path information advertised by each of the routers 24 and 25. In the example of the system 10 shown in Fig. 11, the router 26 generates a route table including: ASN=65001 and an IP address of the H-SMF 420=AAAA / 32; ASN=65001 and a first IP address of the H-UPF 440=BBBB / 32; ASN=65001 and a second IP address of the H-UPF 440=CCCC / 32; ASN=65002 and an IP address of the H-SMF 520=AAAA / 32; and ASN=65002 and an IP address of the H-UPF 540=CCCC / 32.

[0341] The terminal information management device 50 manages terminal information of the communication terminal 800. In the example of the system 10 shown in Fig. 11, the terminal information management device 50 may be a UDM (Unified Data Management) device.

[0342] The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to a DN. The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to a DN 80, for example. The request generating device 70 generates a session creation request for a communication terminal 800 requesting the creation of a session to a DN 90, for example. The request generating device 70 may also generate a session creation request for a communication terminal 800 requesting the creation of a session to another DN.

[0343] The request generating device 70 generates a session generation request for the communication terminal 800 based on, for example, the terminal information of the communication terminal 800 received from the terminal information management device 50. In the example of the system 10 shown in Fig. 11, the request generating device 70 may be an AMF (Access and Mobility Management Function).

[0344] The session creation request includes, for example, the IP address of the communication terminal 800. The session creation request includes, for example, the IMSI of the communication terminal 800. The session creation request includes, for example, the IP address of the V-SMF 620. The session creation request includes, for example, the IP address of the V-UPF 640. The session creation request includes, for example, the TEID assigned to the communication tunnel of the V-SMF 620. The session creation request includes, for example, the TEID assigned to the communication tunnel of the V-UPF 640. The session creation request includes, for example, the IP address of the H-SMF 420. The session creation request includes, for example, the first IP address of the H-UPF 440 or the second IP address of the H-UPF 440. For example, if the communication terminal 800 is registered in the terminal information management device 50 so that only data communication via the network of the first ASN is executable between data communication via the network of the first ASN and data communication via the network of the second ASN, the session creation request includes the first IP address of the H-UPF 440. For example, if the communication terminal 800 is registered in the terminal information management device 50 so that data communication via both the network of the first ASN and the network of the second ASN is possible, the session creation request includes the second IP address of the H-UPF 440. The session creation request may further include any other information for creating a session to the DN.

[0345] 11, the HPLMN may be established at three or more locations. In this case, the second IP address of the H-UPF 440 may be assigned to the H-UPF at each of the three or more locations.

[0346] Here, an example of creating a session to the DN of the communication terminal 800 of a user who has visited the VPLMN where the V-SMF 620 is located will be described. First, an example of creating a session to the DN 80 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that, of data communication via the network of the first ASN and data communication via the network of the second ASN, only data communication via the network of the first ASN is executable.

[0347] The communication terminal 800 transmits an attach request to the request generation device 70 via the wireless base station 30. In response to receiving the attach request from the communication terminal 800, the request generation device 70 generates a session generation request for the communication terminal 800.

[0348] Since communication terminal 800 is registered in terminal information management device 50 so that only data communication via the first ASN network is executable out of data communication via the first ASN network and data communication via the second ASN network, request generation device 70 generates a session creation request for communication terminal 800 that includes the first IP address of H-UPF 440. Request generation device 70 transmits the generated session creation request for communication terminal 800 to V-SMF 620 via network 20.

[0349] V-SMF 620 transmits the received session creation request from communication terminal 800 to router 26. If the session creation request from communication terminal 800 includes the first IP address of H-UPF 440, router 26 transfers the session creation request from communication terminal 800 to router 24 via network 20. Router 24 transfers the session creation request from communication terminal 800 to H-SMF 420.

[0350] In response to receiving a session creation request from communication terminal 800, H-SMF420 generates session information for communication terminal 800. H-SMF420 generates the session information for communication terminal 800, for example, based on the session creation request from communication terminal 800. When the session creation request from communication terminal 800 includes the first IP address of H-UPF440, the session information of communication terminal 800 includes, for example, the IP address of communication terminal 800, the first IP address of H-UPF440, a TEID assigned to the communication tunnel of H-UPF440, an IP address of V-UPF640, and a TEID assigned to the communication tunnel of V-UPF640. The session information of communication terminal 800 may further include the IP address of H-SMF420, the TEID assigned to the communication tunnel of H-SMF420, the IP address of V-SMF620, and the TEID assigned to the communication tunnel of V-SMF620. The session information of the communication terminal 800 may further include any other information for creating a session to the DN 80. The session information of the communication terminal 800 including the first IP address of the H-UPF 440 may be an example of the first session information of the communication terminal 800.

[0351] The H-SMF 420 may register the generated session information of the communication terminal 800 in the database 450 corresponding to the H-UPF 440. The H-SMF 420 may provide the generated session information of the communication terminal 800 to the H-UPF 440.

[0352] The H-SMF 420 causes the H-UPF 440 to establish a communication tunnel between the H-UPF 440 and the V-UPF 640 in order to create a session for the communication terminal 800 to the DN 80. The H-SMF 420 causes the H-UPF 440 to establish a communication tunnel between the H-UPF 440 and the V-UPF 640, for example, by providing the H-UPF 440 with session information for the communication terminal 800. The H-UPF 440 may establish a communication tunnel between the H-UPF 440 and the V-UPF 640 based on the session information for the communication terminal 800 in accordance with an instruction from the H-SMF 420.

[0353] H-SMF 420 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 24. Router 24 transfers the create session response from communication terminal 800 to router 26. Router 26 transfers the create session response from communication terminal 800 to V-SMF 620. When V-SMF 620 receives the create session response from communication terminal 800, a session to DN 80 of communication terminal 800 is created.

[0354] The create session response includes, for example, the first IP address of the H-UPF 440 and the TEID assigned to the communication tunnel of the H-UPF 440. The create session response may further include the IP address of the H-SMF 420 and the TEID assigned to the communication tunnel of the H-SMF 420. The create session response may further include any other information for creating a session to the DN 80 of the communication terminal 800.

[0355] Thereafter, V-UPF 640 receives the uplink data of communication terminal 800. V-UPF 640 transmits the uplink data of communication terminal 800 to router 26. Router 26 transfers the uplink data of communication terminal 800 to router 24 via network 20. Router 24 transfers the uplink data of communication terminal 800 to H-UPF 440. H-UPF 440 transmits the uplink data of communication terminal 800 to the destination via DN 80.

[0356] Next, an example of creating a session to the DN90 of the communication terminal 800 will be described. Here, it is assumed that the communication terminal 800 is registered in the terminal information management device 50 so that data communication via both the network of the first ASN and the network of the second ASN can be performed.

[0357] In response to receiving an attach request from communication terminal 800, request generation device 70 generates a session creation request for communication terminal 800. Because communication terminal 800 is registered in terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, request generation device 70 generates a session creation request for communication terminal 800 that includes the second IP address of H-UPF 440. Request generation device 70 transmits the generated session creation request for communication terminal 800 to V-SMF 620 via network 20.

[0358] V-SMF 620 transmits the received session creation request from communication terminal 800 to router 26. When the session creation request from communication terminal 800 includes the second IP address of H-UPF 440, router 26 selects an H-SMF to forward the session creation request from communication terminal 800 from among multiple H-SMFs to which the same IP address is assigned. Here, the explanation will continue assuming that router 26 selects an H-SMF to forward the session creation request from communication terminal 800 from H-SMF 420 and H-SMF 520.

[0359] Router 26 selects an H-SMF to which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path to which the session creation request of communication terminal 800 is to be transferred. Router 26 selects a communication path to which the session creation request of communication terminal 800 is to be transferred, for example, by selecting a communication path from router 26 to a router corresponding to the H-SMF to which the session creation request of communication terminal 800 is to be transferred. Here, the explanation will be continued assuming that the communication distance of the communication path from router 26 to router 25 is shorter than the communication distance of the communication path from router 26 to router 24.

[0360] Router 26 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, based on a route table. Router 26 selects a communication path along which the session creation request of communication terminal 800 will be forwarded, for example, according to a BGP best path selection algorithm. Router 26 selects, for example, as the communication path along which the session creation request of communication terminal 800 will be forwarded, a communication path with the shortest communication distance from router 26 to routers corresponding to each H-SMF of multiple H-SMFs to which the same IP address is assigned. Here, the description will continue assuming that router 26 has selected the communication path from router 26 to router 25 as the communication path along which the session creation request of communication terminal 800 will be forwarded.

[0361] Router 26 selects a communication path from router 26 to router 25 as the communication path along which the session creation request of communication terminal 800 is to be transferred, thereby selecting H-SMF 520 as the H-SMF to which the session creation request of communication terminal 800 is to be transferred. Router 26 transfers the session creation request of communication terminal 800 to router 25 via network 20. Router 25 transfers the session creation request of communication terminal 800 to H-SMF 520.

[0362] In response to receiving a session creation request from communication terminal 800, H-SMF 520 creates session information for communication terminal 800. When the session creation request from communication terminal 800 includes the second IP address of H-UPF 440, the session information of communication terminal 800 includes, for example, the IP address of communication terminal 800, the second IP address of H-UPF 440, TEIDs assigned to the communication tunnel of H-UPF 440 and the communication tunnel of H-UPF 540, an IP address of V-UPF 640, and a TEID assigned to the communication tunnel of V-UPF 640. The session information of communication terminal 800 may further include the IP address of H-SMF 420, the communication tunnel of H-SMF 420 and the TEID assigned to H-SMF 520, an IP address of V-SMF 620, and a TEID assigned to the communication tunnel of V-SMF 620. The session information of the communication terminal 800 may include any other information for creating a session to the DN 90. The session information of the communication terminal 800 including the second IP address of the H-UPF 440 may be an example of the second session information of the communication terminal 800.

[0363] H-SMF 520, for example, registers the generated session information of communication terminal 800 in database 550 corresponding to H-UPF 540. Database 550 includes, for example, a message queue that temporarily stores the session information of communication terminal 800. Database 550 may be an example of a first storage unit or an example of a second storage unit.

[0364] The database 550 is, for example, separate from the H-SMF 520 and the H-UPF 540. The database 550 may be integrated with the H-SMF 520 or the H-UPF 540.

[0365] The database 550 is located, for example, in the network in which the H-SMF 520 is located. The database 550 is located, for example, in the network of the second ASN. The database 550 may be located in a network different from the network in which the H-SMF 520 is located.

[0366] For example, database 550 synchronizes session information of communication terminal 800 registered in database 550 between database 550 and database 450 corresponding to H-UPF 440. Database 550 may synchronize session information of communication terminal 800 between database 550 and database 450 in the same manner as when database 250 synchronizes session information of communication terminal 800 between database 250 and database 150. Database 550 may be an example of a session information synchronization unit. Database 450 may be an example of a first storage unit or an example of a second storage unit.

[0367] For example, the database 550 sends a synchronization completion notification to the H-UPF 540, notifying that a synchronization process for synchronizing the session information of the communication terminal 800 between the database 550 and the database 450 has been completed. The database 550 may send the synchronization completion notification to the H-SMF 520. The synchronization completion notification includes, for example, the session information of the communication terminal 800.

[0368] The database 450, for example, notifies the H-UPF 440 of the synchronization completion notification. The database 450 may also notify the H-SMF 420 of the synchronization completion notification.

[0369] The database 450 is, for example, separate from the H-SMF 420 and the H-UPF 440. The database 450 may be integrated with the H-SMF 420 or the H-UPF 440.

[0370] The database 450 is located, for example, in the network in which the H-SMF 420 is located. The database 450 is located, for example, in the network of the first ASN. The database 450 may also be located in a network different from the network in which the H-SMF 420 is located.

[0371] H-SMF 520 causes H-UPF 540 to establish a communication tunnel between H-UPF 540 and V-UPF 640 in order to create a session to DN 90 of communication terminal 800. H-UPF 540 may establish a communication tunnel between H-UPF 540 and V-UPF 640 in accordance with instructions from H-SMF 520, based on session information of communication terminal 800 included in the synchronization completion notification notified from database 550.

[0372] H-SMF420 causes H-UPF440 to establish a communication tunnel between H-UPF440 and V-UPF640 in order to generate a session to DN90 of communication terminal 800. H-UPF440 may establish a communication tunnel between H-UPF440 and V-UPF640 in accordance with instructions from H-SMF420 and based on session information of communication terminal 800 included in the synchronization completion notification notified from database 450.

[0373] H-SMF 520 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 25. Router 25 transfers the create session response from communication terminal 800 to router 26. Router 26 transfers the create session response from communication terminal 800 to V-SMF 620. When V-SMF 620 receives the create session response from communication terminal 800, a session to DN90 of communication terminal 800 is created.

[0374] The create session response includes, for example, the second IP address of H-UPF 440 and the TEIDs assigned to the communication tunnel of H-UPF 440 and the communication tunnel of H-UPF 540. The create session response may further include the IP address of H-SMF 420 and the TEIDs assigned to the communication tunnel of H-SMF 420 and the communication tunnel of H-SMF 520. The create session response may further include any other information for creating a session to DN 90 of communication terminal 800.

[0375] Thereafter, V-UPF 640 receives the uplink data of communication terminal 800. V-UPF 640 transmits the uplink data of communication terminal 800 to router 26. Router 26 selects an H-UPF to forward the uplink data of communication terminal 800. Router 26 may select an H-UPF to forward the uplink data of communication terminal 800 from among multiple H-UPFs to which the same IP address is assigned, in the same way as when selecting an H-SMF to forward a session creation request of communication terminal 800 from among multiple H-SMFs to which the same IP address is assigned. Here, the description will continue assuming that router 26 has selected H-UPF 540 as the H-UPF to forward the uplink data of communication terminal 800.

[0376] The router 26 transfers the uplink data of the communication terminal 800 to the router 25 via the network 20. The router 25 transfers the uplink data of the communication terminal 800 to the H-UPF 540. The H-UPF 540 transmits the uplink data of the communication terminal 800 to the destination via the DN90.

[0377] Thereafter, when the communication path between the V-UPF 640 and the H-UPF 540 becomes unavailable, for example, when a failure occurs in the H-UPF 540 or when maintenance work is performed on the H-UPF 540, the router 25 advertises the communication path information. The router 26 receives the communication path information advertised by the router 25 and updates the route table. In this case, the router 26 may change the H-UPF that forwards the uplink data of the communication terminal 800 from the H-UPF 540 to the H-UPF 440, based on the updated route table.

[0378] The router 26 transfers the uplink data of the communication terminal 800 to the router 24 via the network 20. The router 24 transfers the uplink data of the communication terminal 800 to the H-UPF 440. The H-UPF 440 transmits the uplink data of the communication terminal 800 to the destination via the DN90.

[0379] If the communication path between V-UPF 640 and H-UPF 540 is unavailable when V-SMF 620 receives a session creation request from communication terminal 800, router 26 transfers the session creation request from communication terminal 800 to router 24 via network 20. Router 24 transfers the session creation request from communication terminal 800 to H-SMF 420.

[0380] In response to receiving a session creation request from communication terminal 800, H-SMF 420 generates session information for communication terminal 800. H-SMF 420 may generate the session information for communication terminal 800 in the same manner as when H-SMF 520 generates session information for communication terminal 800 to create a session for communication terminal 800 to DN90.

[0381] H-SMF 420 registers the generated session information of communication terminal 800 in database 450. Database 450 synchronizes the session information of communication terminal 800 registered in database 450 between database 450 and database 550. Database 450 may synchronize the session information of communication terminal 800 between database 450 and database 550 in the same way as database 250 synchronizes the session information of communication terminal 800 between database 250 and database 150. Database 450 may be an example of a session information synchronization unit.

[0382] The database 450, for example, notifies the H-UPF 440 of the synchronization completion notification. The database 450 may also notify the H-SMF 420 of the synchronization completion notification.

[0383] The database 550, for example, notifies the H-UPF 540 of the synchronization completion notification. The database 550 may also notify the H-SMF 520 of the synchronization completion notification.

[0384] H-SMF420 causes H-UPF440 to establish a communication tunnel between H-UPF440 and V-UPF640 in order to generate a session to DN90 of communication terminal 800. H-UPF440 may establish a communication tunnel between H-UPF440 and V-UPF640 in accordance with instructions from H-SMF420 and based on session information of communication terminal 800 included in the synchronization completion notification notified from database 450.

[0385] H-SMF 420 transmits a create session response from communication terminal 800 in response to the create session request from communication terminal 800 to router 24. Router 24 transfers the create session response from communication terminal 800 to router 26. Router 26 transfers the create session response from communication terminal 800 to V-SMF 620. When V-SMF 620 receives the create session response from communication terminal 800, a session to DN90 of communication terminal 800 is created.

[0386] Thereafter, V-UPF 640 receives the uplink data of communication terminal 800. V-UPF 640 transmits the uplink data of communication terminal 800 to router 26. Router 26 transfers the uplink data of communication terminal 800 to router 24 via network 20. Router 24 transfers the uplink data of communication terminal 800 to H-UPF 440. H-UPF 440 transmits the uplink data of communication terminal 800 to the destination via DN90.

[0387] Thereafter, when a communication path between V-UPF 640 and H-UPF 540 becomes available, H-SMF 520 causes H-UPF 540 to establish a communication tunnel between H-UPF 540 and V-UPF 640 in order to generate a session to DN 90 of communication terminal 800. H-UPF 540 may establish a communication tunnel between H-UPF 540 and V-UPF 640 in accordance with instructions from H-SMF 520, based on session information of communication terminal 800 included in the synchronization completion notification notified from database 550.

[0388] The router 25 advertises communication path information after the communication path between the V-UPF 640 and the H-UPF 540 becomes available. The router 26 receives the communication path information advertised by the router 25 and updates the route table. In this case, the router 25 may change the H-UPF that forwards the uplink data of the communication terminal 800 from the H-UPF 440 to the H-UPF 540 based on the updated route table.

[0389] The router 26 transfers the uplink data of the communication terminal 800 to the router 25 via the network 20. The router 25 transfers the uplink data of the communication terminal 800 to the H-UPF 540. The H-UPF 540 transmits the uplink data of the communication terminal 800 to the destination via the DN90.

[0390] 11 , when H-SMF 420 receives a session creation request for communication terminal 800 from V-SMF 620, and communication terminal 800 is registered so that only data communication via the network of the first ASN is executable among data communication via the network of the first ASN and data communication via the network of the second ASN, H-SMF 420 creates session information for communication terminal 800 including the first IP address of H-UPF 440. Because the first IP address of H-UPF 440 is assigned only to H-UPF 440 out of H-UPF 440 and H-UPF 540, a communication path for accessing DN 80 via the HPLMN in which H-SMF 420 is located can be used for data communication of communication terminal 800, regardless of the location of the VPLMN in which V-SMF 620 is located. Furthermore, when H-SMF420 receives a session creation request for communication terminal 800 from V-SMF620, if communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, H-SMF420 generates session information for communication terminal 800 including the second IP address of H-UPF440 and registers the session information for communication terminal 800 in database 450. The session information for communication terminal 800 registered in database 450 is synchronized between database 450 and database 550. Since the same IP address is assigned to both H-UPF440 and H-UPF540, synchronizing the session information for communication terminal 800 between database 450 and database 550 makes it possible to provide redundant communication paths available for data communication by communication terminal 800, such as a communication path for accessing DN90 via the HPLMN in which H-SMF420 is located and a communication path for accessing DN90 via the HPLMN in which H-SMF520 is located. This allows the communication terminal 800 to use, for data communication, a communication route to access the DN90 via the HPLMN, which has a shorter communication distance from the VPLMN in which the V-SMF620 is located, selected according to the BGP best path selection algorithm.Therefore, according to the system 10 shown in Figure 11, the communication terminal 800 is registered in advance as to whether it can perform only data communication via the first ASN network out of data communication via the first ASN network and data communication via the second ASN network, or whether it can perform both data communication via the first ASN network and data communication via the second ASN network. In both cases, the communication path used for data communication by the communication terminal 800 is determined by the above-mentioned method, and the DN can be accessed via an appropriate network depending on the user's purpose without installing a unique UPF for each user or assigning a unique IP address to each user. As a result, the system 10 shown in Figure 11 can realize a 5G communication service that allows access to a DN via an appropriate network depending on the user's purpose with fewer resources.

[0391] 12 is an explanatory diagram illustrating another example of the processing flow of the system 10. Here, the description will be given assuming that the start state is a state in which the user of the communication terminal 800, which is registered in the terminal information management device 50 so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, visits the VPLMN in which the V-SMF 620 is located.

[0392] In S302, V-SMF 620 transmits to H-SMF the session creation request for communication terminal 800 received from request generation device 70. Here, since the communication path between V-UPF 640 and H-UPF 540 is unavailable at the time V-SMF 620 receives the session creation request for communication terminal 800, the explanation will continue assuming that V-SMF 620 transmits the session creation request for communication terminal 800 to H-SMF 420.

[0393] In S304, H-SMF420 generates session information for communication terminal 800 based on the session creation request for communication terminal 800 received from V-SMF620 in S302, and registers the session information for communication terminal 800 in database 450. In S306, in response to registering the session information for communication terminal 800 in database 450 in S304, H-SMF420 transmits to V-SMF620 a create session response for communication terminal 800 in response to the session creation request from communication terminal 800.

[0394] In S308, database 450 synchronizes the session information of communication terminal 800 registered by H-SMF 420 in S304 between database 450 and database 550. In S310, database 450 notifies H-UPF 440 of a synchronization completion notification in response to the synchronization of the session information of communication terminal 800 between database 450 and database 550 in S308. In S312, database 550 notifies H-UPF 540 of a synchronization completion notification in response to the synchronization of the session information of communication terminal 800 between database 450 and database 550 by database 450 in S308.

[0395] In S314, the V-UPF 640 transmits the uplink data of the communication terminal 800 received from the communication terminal 800 to the H-UPF 440. The H-UPF 440 transmits the uplink data of the communication terminal 800 to the destination via the DN90.

[0396] Thereafter, in S316 after the communication path between V-UPF 640 and H-UPF 540 becomes available, V-UPF 640 transmits the uplink data of communication terminal 800 received from communication terminal 800 to H-UPF 540. H-UPF 540 transmits the uplink data of communication terminal 800 to the destination via DN90.

[0397] 12, the process in which H-SMF 420 transmits a create session response for communication terminal 800 to V-SMF 620 in response to H-SMF 420 registering session information for communication terminal 800 in database 450 may be replaced with a process in which H-SMF 420 transmits a create session response for communication terminal 800 to V-SMF 620 in response to H-UPF 440 receiving a synchronization completion notification from database 450. That is, S306 shown in FIG. 12 may be performed after S310 shown in FIG.

[0398] 13 shows an example of the functional configuration of the H-SMF 420. The H-SMF 420 includes a request receiving unit 422, a session information generating unit 426, a registration unit 428, a session information synchronizing unit 430, a notification receiving unit 432, a response transmitting unit 434, and a communication tunnel establishing unit 436. It is not essential that the H-SMF 420 include all of these components.

[0399] The request receiving unit 422 receives a session creation request from a communication terminal 800 requesting the creation of a session to a DN. The request receiving unit 422 receives, for example, a session creation request from a communication terminal 800 requesting the creation of a session to a DN 80. The request receiving unit 422 receives, for example, a session creation request from a communication terminal 800 requesting the creation of a session to a DN 90. The request receiving unit 422 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another DN.

[0400] The request receiving unit 422 receives, for example, a session creation request for communication terminal 800 from V-SMF 620. The request receiving unit 422 receives, for example, a session creation request for communication terminal 800 from V-SMF 620 via network 20. The request receiving unit 422 receives, for example, a session creation request for communication terminal 800 from V-SMF 620 via network 20 and router 24.

[0401] The session information generating unit 426 generates session information of the communication terminal 800. The session information generating unit 426 generates the session information of the communication terminal 800, for example, in response to the request receiving unit 422 receiving a session generation request from the communication terminal 800.

[0402] The session information generation unit 426 generates session information for the communication terminal 800 based on, for example, a session generation request from the communication terminal 800. For example, if the communication terminal 800 is registered so that only data communication via the first ASN network is possible out of data communication via the network of the first ASN and data communication via the network of the second ASN, the session information generation unit 426 generates session information for the communication terminal 800 that includes a first IP address of the H-UPF 440. For example, if the communication terminal 800 is registered so that data communication via both the network of the first ASN and data communication via the network of the second ASN is possible, the session information generation unit 426 generates session information for the communication terminal 800 that includes a second IP address of the H-UPF 440.

[0403] The registration unit 428 registers the session information of the communication terminal 800 in the database 450. The registration unit 428 registers the session information of the communication terminal 800 generated by the session information generation unit 426 in the database 450, for example.

[0404] The registration unit 428, for example, registers the session information of the communication terminal 800, which includes the second IP address of the H-UPF 440, in the database 450. The registration unit 428 may also register the session information of the communication terminal 800, which includes the first IP address of the H-UPF 440, in the database 450.

[0405] The session information synchronization unit 430 synchronizes the session information of the communication terminal 800, which is registered in the database 450 by the registration unit 428 and includes the second IP address of the H-UPF 440, between the database 450 and the database 550. The session information synchronization unit 430 may synchronize the session information between the database 450 and the database 550 in the same manner as when the database 250 synchronizes the session information of the communication terminal 800 between the database 250 and the database 150.

[0406] The session information synchronization unit 430 may issue a synchronization completion notification in response to synchronizing the session information between the database 450 and the database 550. The session information synchronization unit 430, for example, issues the synchronization completion notification to the H-UPF 440. The session information synchronization unit 430, for example, issues the synchronization completion notification to the H-UPF 540. The session information synchronization unit 430 may also issue the synchronization completion notification to the H-SMF 520.

[0407] The session information synchronizer 430 issues a synchronization completion notification via, for example, the network 20. The session information synchronizer 430 issues a synchronization completion notification via, for example, the router 24 and the network 20.

[0408] The notification receiving unit 432 receives the synchronization completion notification. The notification receiving unit 432 receives the synchronization completion notification from, for example, the database 450. The notification receiving unit 432 receives the synchronization completion notification from, for example, the database 550. The notification receiving unit 432 may also receive the synchronization completion notification from the H-SMF 520.

[0409] The notification receiving unit 432 receives the synchronization completion notification, for example, via the network 20. The notification receiving unit 432 receives the synchronization completion notification, for example, via the network 20 and the router 24.

[0410] The response transmitting unit 434 transmits a session creation response of the communication terminal 800 in response to the session creation request of the communication terminal 800. The response transmitting unit 434 transmits, for example, a session creation response of the communication terminal 800 in response to the session creation request of the communication terminal 800 received by the request receiving unit 422.

[0411] The response transmitting unit 434 transmits, for example, a create session response of the communication terminal 800 to the V-SMF 620. The response transmitting unit 434 transmits, for example, the create session response of the communication terminal 800 to the V-SMF 620 via the network 20. The response transmitting unit 434 transmits, for example, the create session response of the communication terminal 800 to the V-SMF 620 via the network 20 and the router 24.

[0412] The response transmitting unit 434 transmits a session generation response for the communication terminal 800 in response to, for example, the session information generating unit 426 generating session information for the communication terminal 800. The response transmitting unit 434 transmits a session generation response for the communication terminal 800 in response to, for example, the registration unit 428 registering the session information for the communication terminal 800 in the database 450. The response transmitting unit 434 transmits a session generation response for the communication terminal 800 in response to, for example, the session information for the communication terminal 800 being synchronized between the database 450 and the database 550. The response transmitting unit 434 transmits a session generation response for the communication terminal 800 in response to, for example, the session information synchronizing unit 430 synchronizing the session information for the communication terminal 800 between the database 450 and the database 550. The response transmitting unit 434 may transmit a session generation response for the communication terminal 800 in response to the notification receiving unit 432 receiving a synchronization completion notification.

[0413] The communication tunnel establishment unit 436 establishes a communication tunnel to create a session to the DN of the communication terminal 800. The communication tunnel establishment unit 436 establishes a communication tunnel to create a session to, for example, DN 80 of the communication terminal 800. The communication tunnel establishment unit 436 establishes a communication tunnel to create a session to, for example, DN 90 of the communication terminal 800. The communication tunnel establishment unit 436 may establish a communication tunnel to create a session to another DN of the communication terminal 800.

[0414] The communication tunnel establishment unit 436 establishes, for example, a GTP tunnel, but may also establish any other communication tunnel.

[0415] The communication tunnel establishment unit 436 establishes the communication tunnel, for example, by causing the H-UPF 440 to establish a communication tunnel between the H-UPF 440 and the V-UPF 640. In this case, the communication tunnel establishment unit 436 may instruct the H-UPF 440 to establish a communication tunnel between the H-UPF 440 and the V-UPF 640. The communication tunnel establishment unit 436 establishes the communication tunnel, for example, by establishing a communication tunnel between the H-SMF 420 and the V-SMF 620.

[0416] The communication tunnel establishment unit 436 establishes the communication tunnel based on, for example, session information of the communication terminal 800. The communication tunnel establishment unit 436 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 generated by the session information generation unit 426. The communication tunnel establishment unit 436 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 synchronized between the database 450 and the database 550 by the session information synchronization unit 430. The communication tunnel establishment unit 436 may establish the communication tunnel based on the session information of the communication terminal 800 included in the synchronization completion notification received by the notification reception unit 432.

[0417] For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN out of data communication via the network of the first ASN and data communication via the network of the second ASN is possible, the communication tunnel establishment unit 436 establishes the communication tunnel based on session information of the communication terminal 800 including the first IP address of the H-UPF 440. For example, when the communication terminal is registered so that data communication via both the network of the first ASN and data communication via the network of the second ASN is possible, the communication tunnel establishment unit 436 establishes the communication tunnel based on session information of the communication terminal 800 including the second IP address of the H-UPF 440, which is synchronized between the database 450 and the database 550.

[0418] The communication tunnel establishment unit 436 may be an example of a first communication tunnel establishment unit. The communication tunnel establishment unit 436 may be an example of a second communication tunnel establishment unit.

[0419] 14 shows an example of the functional configuration of the H-UPF 440. The H-UPF 440 includes a session information acquisition unit 442, a communication tunnel establishment unit 444, a data reception unit 446, and a data transmission unit 448. It is not essential that the H-UPF 440 include all of these components.

[0420] The session information acquisition unit 442 acquires session information of the communication terminal 800. The session information acquisition unit 442 acquires the session information of the communication terminal 800 generated by the H-SMF 420, for example.

[0421] The session information acquisition unit 442, for example, receives a synchronization completion notification to acquire session information of the communication terminal 800. The session information acquisition unit 442 receives the synchronization completion notification, for example, via the network 20. The session information acquisition unit 442 receives the synchronization completion notification, for example, via the network 20 and the router 24.

[0422] The session information acquisition unit 442 receives, for example, a synchronization completion notification from the database 450. The session information acquisition unit 442 receives, for example, a synchronization completion notification from the database 550. The session information acquisition unit 442 receives, for example, a synchronization completion notification from the H-SMF 420. The session information acquisition unit 442 may receive the synchronization completion notification from the H-SMF 520.

[0423] The communication tunnel establishment unit 444 establishes a communication tunnel to create a session to the DN of the communication terminal 800. The communication tunnel establishment unit 444 establishes a communication tunnel between the H-UPF 440 and the V-UPF 640 to create a session to the DN of the communication terminal 800.

[0424] The communication tunnel establishment unit 444 establishes the communication tunnel, for example, in accordance with an instruction from the H-SMF 420. The communication tunnel establishment unit 444 may also establish the communication tunnel autonomously without receiving an instruction from the H-SMF 420.

[0425] The communication tunnel establishment unit 444 establishes a communication tunnel, for example, to create a session to DN 80 of the communication terminal 800. The communication tunnel establishment unit 444 establishes a communication tunnel, for example, to create a session to DN 90 of the communication terminal 800. The communication tunnel establishment unit 444 may establish a communication tunnel to create a session to another DN of the communication terminal 800.

[0426] The communication tunnel establishment unit 444 establishes, for example, a GTP tunnel, but may also establish any other communication tunnel.

[0427] The communication tunnel establishment unit 444 establishes the communication tunnel based on, for example, the session information of the communication terminal 800 acquired by the session information acquisition unit 442. For example, when the communication terminal 800 is registered so that only data communication via the first ASN network is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the communication tunnel establishment unit 444 establishes the communication tunnel based on the session information of the communication terminal 800 including the first IP address of the H-UPF 440. For example, when the communication terminal 800 is registered so that data communication via both the network of the first ASN and data communication via the network of the second ASN is executable, the communication tunnel establishment unit 444 establishes the communication tunnel based on the session information of the communication terminal 800 including the second IP address of the H-UPF 440, which is synchronized between the database 450 and the database 550.

[0428] The data receiving unit 446 receives data related to data communication of the communication terminal 800. The data receiving unit 446 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 446 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 24. The data receiving unit 446 receives data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishment unit 444.

[0429] The data receiving unit 446 receives, for example, uplink data of the communication terminal 800. The data receiving unit 446 receives the uplink data of the communication terminal 800 when, for example, the H-UPF 440 is selected from among a plurality of H-UPFs to which the same IP address is assigned as a transmission target of the uplink data of the communication terminal 800.

[0430] The data receiving unit 446 receives, for example, downlink data of the communication terminal 800. The data receiving unit 446 receives the downlink data of the communication terminal 800 when, for example, the H-UPF 440 is selected from among a plurality of H-UPFs to which the same IP address is assigned as a transmission target of the downlink data of the communication terminal 800.

[0431] For example, when the data receiving unit 446 receives uplink data from the communication terminal 800 and the H-UPF 440 does not hold session information for the communication terminal 800, the communication tunnel establishing unit 444 establishes a communication tunnel by acquiring the session information for the communication terminal 800 from the database 450. For example, when the data receiving unit 446 receives uplink data from the communication terminal 800 for the first time, the communication tunnel establishing unit 444 acquires the session information for the communication terminal 800 from the database 450.

[0432] For example, when the data receiving unit 446 receives downlink data from the communication terminal 800 and the H-UPF 440 does not hold session information for the communication terminal 800, the communication tunnel establishing unit 444 establishes a communication tunnel by acquiring the session information for the communication terminal 800 from the database 450. For example, when the data receiving unit 446 receives downlink data from the communication terminal 800 for the first time, the communication tunnel establishing unit 444 acquires the session information for the communication terminal 800 from the database 450.

[0433] The data transmitting unit 448 transmits data related to data communication of the communication terminal 800. The data transmitting unit 448 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmitting unit 448 transmits data related to data communication of the communication terminal 800, for example, via the router 24 and the network 20. The data transmitting unit 448 transmits data related to data communication of the communication terminal 800, for example, via the communication tunnel established by the communication tunnel establishing unit 444.

[0434] The data transmitting unit 448 transmits, for example, uplink data of the communication terminal 800 to a destination of the uplink data of the communication terminal 800. The data transmitting unit 448 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0435] 15 shows an example of the functional configuration of the V-SMF 620. The V-SMF 620 includes a storage unit 622, a route information receiver 624, a table generator 626, a request receiver 630, a request transmitter 632, a response receiver 634, and a response provider 635. It is not essential that the V-SMF 620 include all of these components.

[0436] The storage unit 622 stores various types of information, such as a route table.

[0437] The route table includes, for example, communication path information indicating the communication path between the V-SMF 620 and the H-SMF 420. The route table includes, for example, communication path information indicating the communication path between the V-UPF 640 and the H-UPF 440. The route table includes, for example, communication path information indicating the communication path between the V-SMF 620 and the H-SMF 520. The route table includes, for example, communication path information indicating the communication path between the V-UPF 640 and the H-UPF 540.

[0438] The route information receiving unit 624 receives communication route information. The route information receiving unit 624 receives the communication route information, for example, via the network 20. The route information receiving unit 624 receives the communication route information, for example, via the network 20 and the router 26. The route information receiving unit 624 may store the received communication route information in the storage unit 622.

[0439] The route information receiving unit 624 receives, for example, communication route information advertised by the router 24. The route information receiving unit 624 receives, for example, communication route information advertised by the router 25. The route information receiving unit 624 may also receive communication route information advertised by IPX.

[0440] The route information receiving unit 624 receives, for example, communication route information indicating the communication route between the V-SMF 620 and the H-SMF 420. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between the V-UPF 640 and the H-UPF 440. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between the V-SMF 620 and the H-SMF 520. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between the V-UPF 640 and the H-UPF 540.

[0441] The table generation unit 626 generates a route table. The table generation unit 626 generates the route table based on, for example, the communication route information stored in the storage unit 622. The table generation unit 626 generates the route table based on, for example, the communication route information received by the route information receiving unit 624. The table generation unit 626 may generate the route table in the same manner as when the router 26 generates a route table.

[0442] The table generator 626 may store the generated route table in the storage unit 622. The table generator 626 may provide the generated route table to the V-UPF 640.

[0443] The request receiving unit 630 receives a session creation request from a communication terminal 800 requesting the creation of a session to a DN. The request receiving unit 630 receives, for example, a session creation request from a communication terminal 800 requesting the creation of a session to a DN 80. The request receiving unit 630 receives, for example, a session creation request from a communication terminal 800 requesting the creation of a session to a DN 90. The request receiving unit 630 may also receive a session creation request from a communication terminal 800 requesting the creation of a session to another DN.

[0444] The request receiving unit 630 receives a session creation request for the communication terminal 800, for example, from the request generating device 70. The request receiving unit 630 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20. The request receiving unit 630 receives a session creation request for the communication terminal 800, for example, from the request generating device 70 via the network 20 and the router 26.

[0445] The request transmitting unit 632 transmits a session creation request from the communication terminal 800. The request transmitting unit 632 transmits the session creation request from the communication terminal 800 received by the request receiving unit 630, for example.

[0446] The request sending unit 632 sends the session creation request of the communication terminal 800, for example, via the network 20. The request sending unit 632 sends the session creation request of the communication terminal 800, for example, via the router 26 and the network 20.

[0447] The request sending unit 632 sends a session creation request for the communication terminal 800, for example, based on the route table stored in the storage unit 622. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the request sending unit 632 sends a session creation request for the communication terminal 800, which includes the first IP address of the H-UPF 440, to the H-SMF 420.

[0448] For example, when communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, request sending unit 632 sends a session creation request of communication terminal 800, including the second IP address of H-UPF 440, to an H-SMF selected as a destination of the session creation request from among multiple H-SMFs to which the same IP address is assigned based on predetermined SMF selection conditions. In this case, request sending unit 632 sends the session creation request to an H-SMF selected as a destination of the session creation request from H-SMF 420 and H-SMF 520 based on the SMF selection conditions. For example, request sending unit 632 sends the session creation request to the H-SMF selected as a destination of the session creation request via a communication path selected according to a BGP best path selection algorithm.

[0449] The response receiving unit 634 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800. For example, the response receiving unit 634 receives a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800 transmitted by the request transmitting unit 632. The response receiving unit 634 may store the received session creation response from the communication terminal 800 in the storage unit 622.

[0450] The response receiving unit 634 receives the create session response of the communication terminal 800 from, for example, the H-SMF 420. The response receiving unit 634 receives the create session response of the communication terminal 800 from, for example, the H-SMF 520.

[0451] The response receiving unit 634 receives the session creation response from the communication terminal 800, for example, via the network 20. The response receiving unit 634 receives the session creation response from the communication terminal 800, for example, via the network 20 and the router 26.

[0452] The response providing unit 635 provides the session creation response of the communication terminal 800 received by the response receiving unit 634. The response providing unit 635 provides the session creation response of the communication terminal 800 to the V-UPF 640, for example.

[0453] 16 shows an example of the functional configuration of the V-UPF 640. The V-UPF 640 includes a storage unit 642, a table acquisition unit 644, a response acquisition unit 645, a data reception unit 648, and a data transmission unit 649. Note that it is not essential that the V-UPF 640 include all of these components.

[0454] The storage unit 642 stores various types of information, such as a route table.

[0455] For example, V-SMF 620 and V-UPF 640 share a storage unit. In this case, storage unit 622 and storage unit 642 are the same storage unit. V-SMF 620 and V-UPF 640 do not have to share a storage unit. In this case, storage unit 622 and storage unit 642 are different storage units.

[0456] The table acquisition unit 644 acquires a route table. For example, the table acquisition unit 644 acquires a route table provided by the V-SMF 620. The table acquisition unit 644 may store the acquired route table in the storage unit 642.

[0457] The response acquisition unit 645 acquires a session creation response from the communication terminal 800 in response to the session creation request from the communication terminal 800. The response acquisition unit 645 acquires, for example, the session creation response from the communication terminal 800 provided by the V-SMF 620. The response acquisition unit 645 may store the acquired session creation response from the communication terminal 800 in the storage unit 642.

[0458] The data receiving unit 648 receives data related to data communication of the communication terminal 800. The data receiving unit 648 receives data related to data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 648 receives data related to data communication of the communication terminal 800, for example, via the network 20 and the router 26.

[0459] The data receiving unit 648 receives, for example, uplink data of the communication terminal 800. The data receiving unit 648 receives, for example, downlink data of the communication terminal 800.

[0460] The data transmission unit 649 transmits data related to data communication of the communication terminal 800. The data transmission unit 649 transmits data related to data communication of the communication terminal 800, for example, via the network 20. The data transmission unit 649 transmits data related to data communication of the communication terminal 800, for example, via the router 26 and the network 20.

[0461] The data transmitting unit 649 transmits, for example, uplink data of the communication terminal 800. The data transmitting unit 649 transmits the uplink data of the communication terminal 800, for example, based on the route table stored in the storage unit 642. For example, when the communication terminal 800 is registered so that only data communication via the network of the first ASN is executable out of data communication via the network of the first ASN and data communication via the network of the second ASN, the data transmitting unit 649 transmits the uplink data of the communication terminal 800 to the H-UPF 440.

[0462] For example, when communication terminal 800 is registered so as to be able to perform both data communication via the network of the first ASN and data communication via the network of the second ASN, data transmission unit 649 transmits uplink data of communication terminal 800 to an H-UPF selected as a transmission destination of the uplink data of communication terminal 800 from among multiple H-UPFs to which the same IP address is assigned based on predetermined UPF selection conditions. In this case, data transmission unit 649 transmits the uplink data of communication terminal 800 to an H-UPF selected as a transmission destination of the uplink data of communication terminal 800 from among H-UPF 440 and H-UPF 540 based on the UPF selection conditions. Data transmission unit 649 transmits the uplink data of communication terminal 800 to the H-UPF selected as a transmission destination of the uplink data of communication terminal 800, for example, via a communication path selected according to a BGP best path selection algorithm.

[0463] The data transmitting unit 649 transmits, for example, downlink data of the communication terminal 800. The data transmitting unit 649 transmits, for example, downlink data of the communication terminal 800 to the communication terminal 800.

[0464] 17 schematically illustrates an example of the hardware configuration of a computer 1200 functioning as the PGW 100, PGW-C 120, PGW-U 140, SGW 300, SGW-C 320, SGW-U 340, H-SMF 420, H-UPF 440, V-SMF 620, or V-UPF 640. A program installed on the computer 1200 can cause the computer 1200 to function as one or more “units” of an apparatus according to the present embodiment, or can cause the computer 1200 to perform operations associated with the apparatus according to the present embodiment or one or more “units,” and / or can cause the computer 1200 to perform a process according to the present embodiment or steps of the process. Such a program can be executed by the CPU 1212 to cause the computer 1200 to perform specific operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

[0465] The computer 1200 according to this embodiment includes a CPU 1212, a RAM 1214, and a graphics controller 1216, which are interconnected by a host controller 1210. The computer 1200 also includes input / output units such as a communications interface 1222, a storage device 1224, a DVD drive 1226, and an IC card drive, which are connected to the host controller 1210 via an input / output controller 1220. The DVD drive 1226 may be a DVD-ROM drive, a DVD-RAM drive, or the like. The storage device 1224 may be a hard disk drive, a solid-state drive, or the like. The computer 1200 also includes a ROM 1230 and legacy input / output units such as a keyboard, which are connected to the input / output controller 1220 via an input / output chip 1240.

[0466] The CPU 1212 operates according to programs stored in the ROM 1230 and the RAM 1214, thereby controlling each unit. The graphics controller 1216 acquires image data generated by the CPU 1212 into a frame buffer or the like provided in the RAM 1214 or into the graphics controller itself, and causes the image data to be displayed on the display device 1218.

[0467] The communication interface 1222 communicates with other electronic devices via a network. The storage device 1224 stores programs and data used by the CPU 1212 in the computer 1200. The DVD drive 1226 reads programs or data from a DVD-ROM 1227 or the like and provides them to the storage device 1224. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0468] The ROM 1230 stores therein a boot program or the like that is executed by the computer 1200 upon activation, and / or programs that depend on the hardware of the computer 1200. The input / output chip 1240 may also connect various input / output units to the input / output controller 1220 via a USB port, a parallel port, a serial port, a keyboard port, a mouse port, etc.

[0469] The programs are provided by a computer-readable storage medium such as a DVD-ROM 1227 or an IC card. The programs are read from the computer-readable storage medium, installed in the storage device 1224, RAM 1214, or ROM 1230, which are also examples of computer-readable storage media, and executed by the CPU 1212. Information processing described in these programs is read by the computer 1200, and causes cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be configured by implementing operations or processing of information in accordance with the use of the computer 1200.

[0470] For example, when communication is performed between the computer 1200 and an external device, the CPU 1212 may execute a communication program loaded into the RAM 1214 and instruct the communication interface 1222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 1212, the communication interface 1222 reads transmission data stored in a transmission buffer area provided in the RAM 1214, the storage device 1224, the DVD-ROM 1227, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes reception data received from the network to a reception buffer area or the like provided on the recording medium.

[0471] Furthermore, the CPU 1212 may cause all or a necessary portion of a file or database stored in an external recording medium such as the storage device 1224, the DVD drive 1226 (DVD-ROM 1227), an IC card, etc. to be read into the RAM 1214, and may perform various types of processing on the data on the RAM 1214. The CPU 1212 may then write back the processed data to the external recording medium.

[0472] Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and may undergo information processing. The CPU 1212 may perform various types of processing on data read from the RAM 1214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequences of the programs, and write the results back to the RAM 1214. The CPU 1212 may also search for information in a file, database, etc. on the recording medium. For example, if multiple entries, each having an attribute value of a first attribute associated with an attribute value of a second attribute, are stored on the recording medium, the CPU 1212 may search for an entry whose attribute value of the first attribute matches a specified condition from among the multiple entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0473] The above-described programs or software modules may be stored in a computer-readable storage medium on or near the computer 1200. A recording medium such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet can also be used as a computer-readable storage medium, thereby providing the programs to the computer 1200 via the network.

[0474] The blocks in the flowcharts and block diagrams in the present embodiments may represent stages of a process in which an operation is performed or "parts" of an apparatus responsible for performing the operation. Particular stages and "parts" may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable storage medium, and / or a processor provided with computer-readable instructions stored on a computer-readable storage medium. The dedicated circuitry may include digital and / or analog hardware circuits, including integrated circuits (ICs) and / or discrete circuits. The programmable circuitry may include reconfigurable hardware circuits, such as field programmable gate arrays (FPGAs) and programmable logic arrays (PLAs), including AND, OR, XOR, NAND, NOR, and other logical operations, flip-flops, registers, and memory elements.

[0475] A computer-readable medium may include any tangible device capable of storing instructions that are executed by a suitable device, such that the computer-readable medium having instructions stored thereon comprises an article of manufacture containing instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable media may include electronic, magnetic, optical, electromagnetic, and semiconductor storage media. More specific examples of computer-readable media may include floppy disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray disc, memory stick, integrated circuit card, and the like.

[0476] The computer readable instructions may include either assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0477] The computer-readable instructions may be provided to a processor or programmable circuit of a programmable data processing device, such as a computer, locally or via a wide area network (WAN) such as a local area network (LAN) or the Internet, and the computer-readable instructions may be executed to create means for performing the operations specified in the flowcharts or block diagrams. Here, the computer may be a personal computer (PC), a tablet computer, a smartphone, a workstation, a server computer, a general-purpose computer, a special-purpose computer, or the like, or may be a computer system in which multiple computers are connected. Such a computer system in which multiple computers are connected is also called a distributed computing system, and is a broad definition of computer. In a distributed computing system, the multiple computers collectively execute a program by each executing a portion of the program and passing data between the computers as needed during program execution.

[0478] Examples of processors include a computer processor, a central processing unit (CPU), a processing unit, a microprocessor, a digital signal processor, a controller, a microcontroller, etc. A computer may have one or more processors. In a multiprocessor system with multiple processors, each processor executes a portion of a program and passes data between processors as needed during program execution, allowing the multiple processors to collectively execute the program. For example, in multitasking, each of the multiple processors may execute a portion of each task in small chunks by switching tasks at time slice intervals. In this case, which portion of a program each processor executes changes dynamically. Which portion of a program each of the multiple processors executes may also be statically determined by multiprocessor-aware programming.

[0479] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0480] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0481] 10 system, 20 network, 21 router, 22 router, 23 router, 24 router, 25 router, 26 router, 30 wireless base station, 40 PDN, 50 terminal information management device, 60 PDN, 70 request generation device, 80 DN, 90 DN, 100 PGW, 102 request receiving unit, 106 session information generating unit, 108 registration unit, 110 session information synchronization unit, 112 notification receiving unit, 114 response transmitting unit, 116 communication tunnel establishment unit, 118 data receiving unit, 119 data transmitting unit, 120 PGW-C, 122 request receiving unit, 126 session information generating unit, 128 registration unit, 130 session information synchronization unit, 132 notification receiving unit, 134 response transmitting unit, 136 communication tunnel establishment unit, 140 PGW-U, 142 Session information acquisition unit, 144 communication tunnel establishment unit, 146 data reception unit, 148 data transmission unit, 150 database, 200 PGW, 220 PGW-C, 240 PGW-U, 250 database, 300 SGW, 302 storage unit, 304 route information reception unit, 306 table generation unit, 310 request reception unit, 312 request transmission unit, 314 response reception unit, 318 data reception unit, 319 data transmission unit, 320 SGW-C, 322 storage unit, 324 route information reception unit, 326 table generation unit, 330 request reception unit, 332 request transmission unit, 334 response reception unit, 335 response provision unit, 340 SGW-U, 342 storage unit, 344 table acquisition unit, 345 response acquisition unit, 348 data reception unit, 349 Data transmitter, 420 H-SMF, 422 Request receiver, 426 Session information generator, 428 Registration unit, 430 Session information synchronizer, 432 Notification receiver, 434 Response transmitter, 436 Communication tunnel establisher, 440 H-UPF, 442 Session information acquirer, 444 Communication tunnel establisher, 446 Data receiver, 448 Data transmitter, 450 Database, 520 H-SMF, 540 H-UPF, 550 Database, 620 V-SMF, 622 Storage unit, 624 Route information receiver, 626 Table generator, 630 Request receiver, 632 Request transmitter, 634 Response receiver, 635 Response provider, 640 V-UPF, 642 Storage unit, 644 Table acquirer, 645 Response acquirer, 648 Data receiver, 649Data transmission unit, 800 communication terminal, 1200 computer, 1210 host controller, 1212 CPU, 1214 RAM, 1216 graphic controller, 1218 display device, 1220 input / output controller, 1222 communication interface, 1224 storage device, 1226 DVD drive, 1227 DVD-ROM, 1230 ROM, 1240 input / output chip

Claims

1. 1. A system comprising: a first PGW (Packet data network Gateway) that is located in a first network and that is assigned a first IP (Internet Protocol) address and a second IP address that is different from the first IP address; a second PGW located in a second network and assigned the second IP address; a first storage unit corresponding to the first PGW; a second storage unit corresponding to the second PGW; Equipped with The first PGW, a request receiving unit that receives a session creation request from a communication terminal requesting creation of a session to a PDN (Packet Data Network) from an SGW (Serving Gateway); In response to the request reception unit receiving the session creation request, when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be executed, an IP address of the communication terminal, the first IP address of the first PGW, and a TEID (Tunnel Endpoint ID) assigned to a communication tunnel of the first PGW are a session information generation unit that generates first session information for the communication terminal, the first session information including a PGW IDentifier, an IP address of the SGW, and a TEID assigned to a communication tunnel of the SGW, and, when the communication terminal is registered so that data communication via both the first network and the second network can be performed, generates second session information for the communication terminal, the second IP address of the first PGW, TEIDs assigned to the communication tunnel of the first PGW and the communication tunnel of the second PGW, the IP address of the SGW, and the TEID assigned to the communication tunnel of the SGW; a registration unit that registers the second session information generated by the session information generation unit in the first storage unit; and The system comprises: a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit; Furthermore, The first PGW, a first communication tunnel establishment unit that, in order to generate a session to a PDN of the communication terminal, establishes a communication tunnel between the first PGW and the SGW based on the first session information when the communication terminal is registered so that only data communication via the first network of data communication via the first network and data communication via the second network is executable, and establishes a communication tunnel between the first PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network are executable. and The second PGW, a second communication tunnel establishment unit that establishes a communication tunnel between the second PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be executed in order to generate a session to a PDN of the communication terminal; A system having:

2. The SGW further comprises: The first PGW, a response transmission unit that transmits a session creation response of the communication terminal to the SGW in response to the second session information being synchronized between the first storage unit and the second storage unit; and The SGW is a response receiving unit that receives the session creation response; a data transmission unit that transmits uplink data of the communication terminal to a PGW selected as a transmission target of the uplink data from among the first PGW and the second PGW based on predetermined PGW selection conditions, when the communication terminal is registered so that both data communication via the first network and data communication via the second network are executable; The system of claim 1 , comprising:

3. The second PGW, a data receiving unit that receives the uplink data when the second PGW is selected as a transmission target of the uplink data; and When the data receiving unit receives the uplink data and the second PGW does not hold the second session information, the second communication tunnel establishment unit acquires the second session information from the second storage unit, thereby establishing a communication tunnel between the second PGW and the SGW. The system of claim 2 .

4. The system according to claim 3 , wherein the second communication tunnel establishment unit acquires the second session information from the second storage unit when the data receiving unit receives the uplink data for the first time.

5. 3. The system according to claim 2, wherein the data transmission unit transmits the uplink data to the PGW selected as a transmission destination of the uplink data via a communication path selected according to a best path selection algorithm of BGP (Border Gateway Protocol).

6. A system described in any one of claims 1 to 5, wherein the first PGW is located in a geographically different location from the second PGW.

7. 7. The system of claim 6, wherein the first PGW is located in the first network in a first country, and the second PGW is located in the second network in a second country different from the first country.

8. 8. The system according to claim 7, wherein the first network in which the first PGW is located and the second network in which the second PGW is located are HPLMNs (Home Public Land Mobile Networks), and the third network in which the SGW is located is a VPLMN (Visited PLMN).

9. The system according to claim 1, wherein the first PGW is located in the first network of a first ASN (Autonomous System number), and the second PGW is located in the second network of a second ASN different from the first ASN.

10. A PGW located in a first network and assigned a first IP address and a second IP address different from the first IP address, a request receiving unit that receives, from the SGW, a session creation request of a communication terminal that requests creation of a session to a PDN; a session information generation unit that, in response to the request reception unit receiving the session creation request, generates first session information for the communications terminal, including an IP address of the communications terminal, the first IP address of the PGW, a TEID assigned to a communication tunnel of the PGW, an IP address of the SGW, and a TEID assigned to a communication tunnel of the SGW, when the communications terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via a second network is executable, and generates second session information for the communications terminal, including the IP address of the communications terminal, the second IP address of the PGW, TEIDs assigned to a communication tunnel of the PGW and a communication tunnel of another PGW that is arranged in the second network and to which the second IP address is assigned, the IP address of the SGW, and a TEID assigned to a communication tunnel of the SGW, when the communications terminal is registered so that both data communication via the first network and data communication via the second network are executable; a registration unit that registers the second session information generated by the session information generation unit in a first storage unit corresponding to the PGW; a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and a second storage unit corresponding to the other PGW; a communication tunnel establishment unit that establishes a communication tunnel between the PGW and the SGW based on the first session information when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed, in order to create a session to a PDN of the communication terminal, and that establishes a communication tunnel between the PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed; PGW equipped with.

11. The PGW described in claim 10, wherein the PGW is located in a geographically different location from the other PGWs.

12. A PGW as described in claim 10 or 11, wherein the PGW is located in the first network of a first ASN, and the other PGW is located in the second network of a second ASN different from the first ASN.

13. 1. A system comprising: a first PGW located in a first network; a second PGW located in the second network; a first storage unit corresponding to the first PGW; a second storage unit corresponding to the second PGW; Equipped with The first PGW is separated into a first PGW-C (PGW-Control plane function) and a first PGW-U (PGW-User plane function), and a first IP address and a second IP address different from the first IP address are assigned to the first PGW-U; The second PGW is separated into a second PGW-C and a second PGW-U, and the second IP address is assigned to the second PGW-U; The first PGW-C is a request receiving unit that receives a session creation request from a communication terminal requesting creation of a session to a PDN from an SGW that is separated into an SGW-C (SGW-Control plane function) and an SGW-U (SGW-User plane function); a session information generation unit that, in response to the request reception unit receiving the session creation request, generates first session information for the communications terminal, including an IP address of the communications terminal, the first IP address of the first PGW-U, a TEID assigned to a communication tunnel of the first PGW-U, an IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U, when the communications terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network is executable, and generates second session information for the communications terminal, including the IP address of the communications terminal, the second IP address of the first PGW-U, TEIDs assigned to a communication tunnel of the first PGW-U and a communication tunnel of the second PGW-U, the IP address of the SGW-U, and the TEID assigned to a communication tunnel of the SGW-U, when the communications terminal is registered so that both data communication via the first network and data communication via the second network are executable; a registration unit that registers the second session information generated by the session information generation unit in the first storage unit; Including, The system comprises: a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit; Furthermore, The first PGW-U, a first communication tunnel establishment unit that, in order to generate a session to a PDN of the communication terminal, establishes a communication tunnel between the first PGW-U and the SGW-U based on the first session information when the communication terminal is registered so that only data communication via the first network of data communication via the first network and data communication via the second network is executable, and establishes a communication tunnel between the first PGW-U and the SGW-U based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network are executable. Including, The second PGW-U, a second communication tunnel establishment unit that establishes a communication tunnel between the second PGW-U and the SGW-U based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed in order to create a session to a PDN of the communication terminal; Including, the system.

14. The system described in claim 13, wherein the first PGW is located in a geographically different location from the second PGW.

15. A system as described in claim 13 or 14, wherein the first PGW is located in the first network of a first ASN, and the second PGW is located in the second network of a second ASN different from the first ASN.

16. A PGW located in a first network, the PGW is separated into a PGW-C and a PGW-U, and a first IP address and a second IP address different from the first IP address are assigned to the PGW-U; The PGW-C is a request receiving unit that receives a session creation request from a communication terminal requesting creation of a session to a PDN from an SGW separated into an SGW-C and an SGW-U; a session information generation unit that, in response to the request reception unit receiving the session creation request, generates first session information for the communications terminal, including an IP address of the communications terminal, the first IP address of the PGW-U, a TEID assigned to a communication tunnel of the PGW-U, an IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U, when the communications terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via a second network is executable, and generates second session information for the communications terminal, including the IP address of the communications terminal, the second IP address of the PGW-U, TEIDs assigned to a communication tunnel of the PGW-U and a communication tunnel of another PGW-U to which the second IP address is assigned, the IP address of the SGW-U, and a TEID assigned to a communication tunnel of the SGW-U, when the communications terminal is registered so that both data communication via the first network and data communication via the second network are executable; a registration unit that registers the second session information generated by the session information generation unit in a first storage unit corresponding to the PGW; a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and a second storage unit that is arranged in the second network and corresponds to another PGW that is separated into another PGW-C and the other PGW-U; and The PGW-U, a communication tunnel establishment unit that establishes a communication tunnel between the PGW-U and the SGW-U based on the first session information when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed, in order to generate a session to a PDN of the communication terminal, and that establishes a communication tunnel between the PGW-U and the SGW-U based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed PGW.

17. The PGW described in Claim 16, wherein the PGW is located in a geographically different location from the other PGWs.

18. A PGW as described in claim 16 or 17, wherein the PGW is located in the first network of a first ASN, and the other PGW is located in the second network of a second ASN different from the first ASN.

19. 1. A system comprising: a first SMF (Session Management Function) located in the first network; a first UPF (User Plane Function) that is located in the first network in which the first SMF is located and that is assigned a first IP address and a second IP address different from the first IP address; a second SMF located in the second network; a second UPF that is located in the second network in which the second SMF is located and that is assigned the second IP address; a first storage unit corresponding to the first UPF; a second storage unit corresponding to the second UPF; Equipped with The first SMF is a request receiving unit that receives, from the third SMF, a session creation request from a communication terminal that requests creation of a session to a DN (Data Network); a session information generating unit that, in response to the request receiving unit receiving the session creation request, generates first session information for the communication terminal, including an IP address of the communication terminal, the first IP address of the first UPF, a TEID assigned to a communication tunnel of the first UPF, an IP address of a third UPF located in a third network in which the third SMF is located, and a TEID assigned to a communication tunnel of the third UPF, when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed; and generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first UPF, TEIDs assigned to a communication tunnel of the first UPF and a communication tunnel of the second UPF, the IP address of the third UPF, and a TEID assigned to a communication tunnel of the third UPF, when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed; a registration unit that registers the second session information generated by the session information generation unit in the first storage unit; and The system comprises: a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit; Furthermore, The first SMF is a first communication tunnel establishment unit that causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on the first session information when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed, in order to generate a session to a DN of the communication terminal; and causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on the second session information when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed. and The second SMF is a second communication tunnel establishment unit that causes the second UPF to establish a communication tunnel between the second UPF and the third UPF based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed in order to create a session to the DN of the communication terminal; A system having:

20. The system described in Claim 19, wherein the first SMF and the first UPF are located in a geographically different location from the second SMF and the second UPF.

21. A system as described in claim 19 or 20, wherein the first SMF and the first UPF are located in the first network of a first ASN, and the second SMF and the second UPF are located in the second network of a second ASN different from the first ASN.

22. An SMF disposed in a first network, a request receiving unit that receives a session creation request from a communication terminal requesting creation of a session to a DN from another SMF; In response to the request reception unit receiving the session creation request, when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed, the request reception unit receives the session creation request, and the communication terminal receives the session creation request, ... a session information generation unit that generates first session information for a communication terminal, and when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed, generates second session information for the communication terminal including the IP address of the communication terminal, a second IP address assigned to the first UPF, a TEID assigned to a communication tunnel of the first UPF and a communication tunnel of a third UPF that is located in the second network and to which the second IP address is assigned, the IP address of the second UPF, and the TEID assigned to the communication tunnel of the second UPF; a registration unit that registers the second session information generated by the session information generation unit in a first storage unit corresponding to the first UPF; a session information synchronization unit that synchronizes the second session information registered in the first storage unit between the first storage unit and a second storage unit corresponding to the third UPF; a communication tunnel establishment unit that causes the first UPF to establish a communication tunnel between the first UPF and the second UPF based on the first session information when the communication terminal is registered so that only data communication via the first network out of data communication via the first network and data communication via the second network can be performed, in order to generate a session to the DN of the communication terminal, and that causes the first UPF to establish a communication tunnel between the first UPF and the second UPF based on the second session information synchronized between the first storage unit and the second storage unit when the communication terminal is registered so that both data communication via the first network and data communication via the second network can be performed; SMF equipped with.

23. The SMF described in Claim 22, wherein the SMF is located in a geographically different location from the third UPF.

24. An SMF as described in claim 22 or 23, wherein the SMF is located in the first network of a first ASN, and the third UPF is located in the second network of a second ASN different from the first ASN.

Images