System, PGW, and SMF

Abstract

It provides a Packet Data Network Gateway (PGW) for use in roaming. [Solution] A PGW to which first and second IP addresses are assigned includes a session information generation unit that generates first session information for a communication terminal including the first IP address when the communication terminal is registered to be able to perform data communication only over the network of the first ASN, and generates second session information for a communication terminal including the second IP address when the communication terminal is registered to be able to perform data communication over both the network of the first ASN and the network of the second ASN, a session information synchronization unit that synchronizes the second session information between a first storage unit corresponding to the PGW and a second storage unit corresponding to another PGW, and a communication tunnel establishment unit that establishes a communication tunnel between the PGW and the SGW based on the first session information or the second session information according to the registration details of the communication terminal.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a communication system that reduces packet transmission delay in international roaming. Patent Document 2 describes a communication system that reduces communication delay in roaming communication. [Prior Art Documents] [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 Problems

[0003] According to one embodiment of the present invention, a system is provided. The system may include a first PGW (Packet data network Gateway) located on a network of a first ASN (Autonomous System number) and 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 located on a network of a second ASN different from the first ASN and 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 session generation requests from a communication terminal requesting the generation of a session to a PDN (Packet Data Network) from an SGW (Serving Gateway). In response to the request receiving unit receiving the session creation request, the first PGW, if the communication terminal is registered to be able to perform only data communication over the network of the first ASN and data communication over the network of the second ASN, then the IP address of the communication terminal, the first IP address of the first PGW, and the TEID (Tunnel Endpoint) assigned to the communication tunnel of the first PGW The system may have a session information generation unit that generates first session information for the communication terminal, including an IDentifier, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW, and if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, it may generate second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first PGW, a TEID assigned to the communication tunnel of the first PGW and the communication tunnel of the second PGW, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW.The first PGW may have 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 have a first communication tunnel establishment unit that, in order to generate a session of the communication terminal to the PDN, establishes a communication tunnel between the first PGW and the SGW based on the first session information if the communication terminal is registered so that only data communication via the network of the first ASN and data communication via the network of the second ASN are possible, 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 if 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. 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 to be capable of both data communication over the network of the first ASN and data communication over the network of the second ASN in order to generate a session of the communication terminal to the PDN of the communication terminal.

[0004] The system may further include the SGW, the first PGW may further include a response transmission unit that transmits a session creation response from 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, the SGW may include a response receiving unit that receives the session creation response, and a data transmission unit that, if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, transmits the uplink data of the communication terminal to a PGW selected from the first PGW and the second PGW as the target for transmitting the uplink data based on predetermined PGW selection conditions.

[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 target for transmitting the uplink data, and the second communication tunnel establishment unit may establish a communication tunnel between the second PGW and the SGW by obtaining the second session information from the second storage unit when the data receiving unit has received the uplink data and the second PGW does not hold the second session information.

[0006] In any of the above systems, the second communication tunnel establishment unit may obtain the second session information from the second storage unit when the data reception 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 target for transmission of the uplink data via a communication path selected according to the BGP (Border Gateway Protocol) best path selection algorithm.

[0008] In either 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 either of the above systems, the network where the first PGW is located and the network where the second PGW is located may be an HPLMN (Home Public Land Mobile Network), and the network where the SGW is located may be a VPLMN (Visited PLMN).

[0010] According to one embodiment of the present invention, a PGW is provided which is located in the network of a first ASN and 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 session generation requests from a communication terminal requesting the creation of a session to a PDN from an SGW. In response to the request receiving unit receiving the session generation request, if the communication terminal is registered to be able to perform only data communication via the network of the first ASN among data communication via the network of the first ASN and data communication via the network of a second ASN different from the first ASN, the PGW generates first session information for the communication terminal including the IP address of the communication terminal, the first IP address of the PGW, a TEID assigned to the communication tunnel of the PGW, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW, and the If the communication terminal is registered to be capable of both data communication over the network of 1ASN and data communication over the network of 2ASN, the PGW may include a session information generation unit that generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the PGW, the communication tunnel of the PGW, a TEID assigned to the communication tunnel of another PGW located in the network of 2ASN and assigned the second IP address, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW. The PGW 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 may also 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 of the communication terminal to the PDN, establishes a communication tunnel between the PGW and the SGW based on the first session information if the communication terminal is registered to be able to perform only 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 if the communication terminal is registered 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.

[0011] According to one embodiment of the present invention, a system is provided. The system may include a first PGW located in the network of a first ASN. The system may include a second PGW located in the 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 PGW-U may be assigned the second IP address. The first PGW-C may include a request receiving unit that receives session creation requests from communication terminals requesting the creation of a session to the PDN from an SGW which is separated into an SGW-C (SGW-Control plane function) and an SGW-U (SGW-User plane function).In response to the request receiving unit receiving the session creation request, the first PGW-C, if the communication terminal is registered so that only data communication over the network of the first ASN is possible among data communication over the network of the first ASN and data communication over the network of the second ASN, includes the IP address of the communication terminal, the first IP address of the first PGW-U, the TEID assigned to the communication tunnel of the first PGW-U, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. The system may include a session information generation unit that generates first session information and generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first PGW-U, the TEIDs assigned to the communication tunnels of the first PGW-U and 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 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 and second storage units.The first PGW-U may include a first communication tunnel establishment unit that, in order to generate a session of the communication terminal to the PDN, establishes a communication tunnel between the first PGW-U and the SGW-U based on the first session information if the communication terminal is registered to be capable of performing only data communication over the network of the first ASN and data communication over 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 storage unit and the second storage unit if the communication terminal is registered to be capable of performing both data communication over the network of the first ASN and data communication over the network of the second ASN. 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 and second storage units, if the communication terminal is registered to be capable of both data communication over the network of the first ASN and data communication over the network of the second ASN in order to generate a session of the communication terminal to the PDN.

[0012] According to one embodiment of the present invention, a PGW is provided that is located in the network of a first ASN. The PGW may be separated into PGW-C and PGW-U, and the PGW-U may be assigned a first IP address and a second IP address different from the first IP address. The PGW-C may have a request receiving unit that receives session generation requests from communication terminals requesting the creation of a session to a PDN from SGWs separated into SGW-C and SGW-U. In response to the request receiving unit receiving the session generation request, if the communication terminal is registered so that only data communication over the network of the first ASN is executable among data communication over the network of the first ASN and data communication over the network of a second ASN different from the first ASN, the PGW-C will provide the first session of the communication terminal including the IP address of the communication terminal, the first IP address of the PGW-U, the TEID assigned to the communication tunnel of the PGW-U, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. If the communication terminal is registered to generate session information and enable both data communication over the network of the first ASN and data communication over the network of the second ASN, the PGW-C may have a session information generation unit that generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the PGW-U, the TEID assigned to the communication tunnel of the PGW-U and the communication tunnel of another PGW-U to which the second IP address is assigned, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. The PGW-C may have a registration unit that registers the second session information generated by the session information generation unit to a first storage unit corresponding to the PGW. The PGW-C may have a session information synchronization unit that synchronizes the second session information registered in the first storage unit with the first storage unit and a second storage unit corresponding to another PGW located in the network of the second ASN and separated into other PGW-Cs and other PGW-Us.The PGW-U may have a communication tunnel establishment unit that, in order to generate a session of the communication terminal to the PDN, establishes a communication tunnel between the PGW-U and the SGW-U based on the first session information if the communication terminal is registered to be able to perform only 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 storage unit and the second storage unit if the communication terminal is registered 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.

[0013] According to one embodiment of the present invention, a system is provided. The system may include a first SMF (Session Management Function) located in the network of a first ASN. The system may include a first UPF (User Plane Function) located in the network where the first SMF is located, and which is 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 the network of a second ASN different from the first ASN. The system may include a second UPF located in the network where the second SMF is located, and which is 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 have a request receiving unit that receives session generation requests from a communication terminal requesting the generation of a session to a Data Network (DN) from a third SMF.In response to the request receiving unit receiving the session generation request, the first SMF, if the communication terminal is registered such that only data communication over the network of the first ASN and data communication over the network of the second ASN are possible, then the IP address of the communication terminal, the first IP address of the first UPF, the TEID assigned to the communication tunnel of the first UPF, the IP address of the third UPF located in the network where the third SMF is located, and the TEID assigned to the communication tunnel of the third UPF The system may have a session information generation unit that generates first session information for the communication terminal, including the TEID, and if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, it may have a session information generation unit that generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first UPF, the TEID 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 the TEID assigned to the communication tunnel of the third UPF. The first SMF may have a registration unit that registers the second session information generated by the session information generation unit to 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 include a first communication tunnel establishment unit that, in order to generate a session of the communication terminal to the DN, if the communication terminal is registered so that only data communication over the network of the first ASN and data communication over the network of the second ASN are possible, causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on first session information, and if the communication terminal is registered so that both data communication over the network of the first ASN and data communication over the network of the second ASN are possible, causes the first UPF to establish a communication tunnel between the first UPF and the third UPF based on second session information synchronized between the first storage unit and the second storage unit. If the communication terminal is registered in the second SMF to be capable of both data communication over the network of the first ASN and data communication over the network of the second ASN in order to generate a session of the communication terminal to the DN, the second UPF 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 storage unit and the second storage unit.

[0014] According to one embodiment of the present invention, an SMF is provided located in the network of a first ASN. The SMF may include a request receiving unit that receives session generation requests from other SMFs of communication terminals requesting the creation of a session to a DN. In response to the request receiving unit receiving the session generation request, if the communication terminal is registered to be able to perform only data communication via the network of the first ASN 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 SMF will use the IP address of the communication terminal, a first IP address assigned to a first UPF located in the network where the SMF is located, a TEID assigned to the communication tunnel of the first UPF, the IP address of a second UPF located in the network where the other SMF is located, and a TEID assigned to the communication tunnel of the second UPF. The SMF may include a session information generation unit that generates first session information for the communication terminal, and if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, the SMF may include a session information generation unit that generates first session information for the communication terminal, and if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, the SMF may include a session information generation unit that 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 communication tunnel of the first UPF, and a TEID assigned to the communication tunnel of the third UPF which is located in the network of the second ASN and to which the second IP address is assigned, the SMF may include a registration unit that registers the second session information generated by the session information generation unit to a first storage unit corresponding to the first UPF. The SMF 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 the third UPF.The SMF may include a communication tunnel establishment unit that, in order to generate a session of the communication terminal to the DN, if the communication terminal is registered so that only data communication via the network of the first ASN and data communication via the network of the second ASN are possible, causes the first UPF to establish a communication tunnel between the first UPF and the second UPF based on the first session information, and if 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, 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.

[0015] Furthermore, the above summary of the invention does not enumerate all the necessary features of the present invention. Subcombinations of these features may also constitute an invention. [Brief explanation of the drawing]

[0016] [Figure 1] An example of System 10 is shown in a schematic manner. [Figure 2] This is an explanatory diagram illustrating an example of the processing flow of System 10. [Figure 3] A schematic example of the PGW100's functional configuration is shown below. [Figure 4] A schematic example of the SGW300's functional configuration is shown below. [Figure 5] Another example of System 10 is outlined below. [Figure 6] This is an explanatory diagram illustrating another example of the processing flow of System 10. [Figure 7] A schematic example of the PGW-C120's functional configuration is shown below. [Figure 8] A schematic example of the PGW-U140's functional configuration is shown below. [Figure 9] A schematic example of the SGW-C320's functional configuration is shown below. [Figure 10] An example of the functional configuration of the SGW-U340 is schematically shown. [Figure 11] Another example of the system 10 is schematically shown. [Figure 12] It is an explanatory diagram for explaining another example of the processing flow of the system 10. [Figure 13] An example of the functional configuration of the H-SMF420 is schematically shown. [Figure 14] An example of the functional configuration of the H-UPF440 is schematically shown. [Figure 15] An example of the functional configuration of the V-SMF620 is schematically shown. [Figure 16] An example of the functional configuration of the V-UPF640 is schematically shown. [Figure 17] An example of the hardware configuration of a computer 1200 that functions as the PGW100, PGW-C120, PGW-U140, SGW300, SGW-C320, SGW-U340, H-SMF420, H-UPF440, V-SMF620, or V-UPF640 is schematically shown.

Mode for Carrying Out the Invention

[0017] When using the Home Routed method for LTE (Long Term Evolution) communication, a session is created between the VPLMN's SGW and the HPLMN's PGW by establishing a GTP (GPRS Tunneling Protocol) tunnel between them. In this case, it is desirable to be able to perform data communication for a communication terminal on a specific communication path, or to have redundancy for the communication paths used for data communication for a communication terminal. In the system according to this embodiment, for example, a mechanism is adopted to assign two IP addresses to one PGW of an HPLMN. The first IP address is an IP address assigned only to that one PGW. The second IP address is an IP address assigned to each of multiple geographically different HPLMN PGWs, including that one PGW, using IP Anycast. If a communication terminal is registered to perform data communication using a communication path via that one PGW, the PGW that receives a session creation request from the communication terminal creates a session for the communication terminal using the first IP address. If a communication terminal is registered to perform data communication using a redundant communication path, the PGW that receives the session creation request from the communication terminal generates session information for the communication terminal using the second IP address. As a result, the system according to this embodiment can save the number of IP addresses used for data communication compared to the case where a PGW is installed for each user, while simultaneously performing data communication for communication terminals on a specific communication path and providing redundancy for the communication paths used for data communication by communication terminals.

[0018] The present invention will be described below through embodiments, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0019] Figure 1 schematically shows an example of system 10. System 10 provides mobile communication services to users of communication terminal 800.

[0020] Mobile communication services include, for example, roaming services. Roaming services include, for example, international roaming services. Roaming services include, for example, domestic roaming services.

[0021] The communication terminal 800 can be any communication terminal as long as it is capable of using mobile communication services. For example, the communication terminal 800 may be a mobile phone such as a smartphone, a tablet device, or a wearable device.

[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 also be a 6G (6th Generation) or later mobile communication service. The mobile communication service may also be a 3G (3rd Generation) communication service. Figure 1 shows an example where system 10 provides an LTE communication service.

[0023] System 10 may include a PGW100. System 10 may include a PGW200. System 10 may include an SGW300. System 10 may include a database150. System 10 may include a database250. System 10 may include a router21. System 10 may include a router22. System 10 may include a router23. System 10 may include a terminal information management device50. System 10 may include a request generation device70.

[0024] PGW100 has the function of relaying access to the external network. PGW100 is connected to the external network, for example, via an SGi interface. PGW100 may be an example of a first PGW, or an example of a second PGW.

[0025] PGW100 may have the function of relaying access to PDN40, for example. PGW100 may have the function of relaying access to PDN60, for example. PGW100 may also have the function of relaying access to other PDNs.

[0026] PDN40 is, for example, a private network. PDN40 could also be a public network.

[0027] PDN60 is, for example, a private network. PDN60 could also be a public network.

[0028] PGW100 is located, for example, in the network of the first ASN. PGW100 is located, for example, in the network of the first country. PGW100 is located, for example, in the HPLMN. The HPLMN is the network of the telecommunications carrier that issued SIM (Subscriber Identity Module) cards to the users of the communication terminal 800. In the example shown in Figure 1, PGW100 is located in the HPLMN based in Tokyo, Japan, with ASN 65001.

[0029] PGW100 may be assigned an IP address. For example, PGW100 may be assigned multiple IP addresses that are different from each other. For example, PGW100 may be assigned a first IP address and a second IP address that is different from the first IP address. The first IP address of PGW100 may be used to access PDN40. The second IP address of PGW100 may be used to access PDN60. PGW100 may be assigned three or more IP addresses that are different from each other. In the example of system 10 shown in Figure 1, PGW100 is assigned the IP address AAAA with subnet mask 32 as its first IP address and the IP address BBBB with subnet mask 32 as its second IP address.

[0030] PGW200 has the function of relaying access to the external network. PGW200 is connected to the external network, for example, via an SGi interface. PGW200 may have the same functions as PGW100. PGW200 may be an example of a first PGW, or an example of a second PGW.

[0031] PGW200 may have the function of relaying access to PDN60, for example. PGW200 may also have the function of relaying access to other PDNs.

[0032] PGW200 is located, for example, in the network of a second ASN different from the first ASN. PGW200 is located, for example, in the network of a second country different from the first country. PGW200 is located, for example, in an HPLMN. In the example shown in Figure 1, PGW200 is located in an HPLMN based in Singapore with ASN 65002.

[0033] PGW200 may be located in the network of the first country. For example, if PGW100 is located in the network based in Tokyo, Japan, then PGW200 may be located in the network based in Osaka, Japan.

[0034] PGW200 may be assigned an IP address. For example, PGW200 may be assigned the second IP address of PGW100. For example, the same IP address may be assigned to both PGW100 and PGW200 using IP Anycast. PGW200 may be assigned multiple different IP addresses. In the example of system 10 shown in Figure 1, PGW200 is assigned the IP address BBBB with subnet mask 32.

[0035] The SGW300 has the function of relaying access from a wireless access network. The SGW300 is connected to the wireless access network, for example, via the S1 interface.

[0036] SGW300 is connected to PGW100, for example, via network 20. SGW300 is also connected to PGW200, for example, via network 20.

[0037] Network 20 may include, for example, a core network. Network 20 may include, for example, a wireless access network. Network 20 may include, for example, PDNs such as PDN40 and PDN60. Network 20 may also include the Internet.

[0038] SGW300 is located in the network of a third ASN, which is different from the first and second ASNs. SGW300 may also be located in the network of the first ASN, or it may be located in the network of the second ASN.

[0039] SGW300 may be located in the network of Country 1, or in the network of Country 2. SGW300 may also be located in the network of a third country, different from Country 1 and Country 2.

[0040] SGW300 is located in, for example, VPLMN. VPLMN is the network of the telecommunications carrier to which the user of communication terminal 800 visits. The telecommunications carrier of HPLMN and the telecommunications carrier of VPLMN may have a prior business partnership. In the example shown in Figure 1, SGW300 is located in VPLMN, which is based in Singapore and has ASN 65003.

[0041] SGW300 may be assigned an IP address. In the example of system 10 shown in Figure 1, SGW300 is assigned the IP address CCCC with subnet mask 32.

[0042] Router 21 has the function of relaying data. Router 21 relays, for example, uplink data. Router 21 relays, for example, downlink data.

[0043] Router 21 is located in the network where PGW100 is located, for example. Router 21 is located in the network of the first ASN, for example. Router 21 may be located in a different network from the network where PGW100 is located.

[0044] Router 21 is, for example, isolated from PGW100. Router 21 may also be integrated with PGW100.

[0045] Router 22 has the function of relaying data. Router 22 relays, for example, uplink data. Router 22 relays, for example, downlink data.

[0046] Router 22 is located in the network where PGW200 is located, for example. Router 22 is located in the network of the second ASN, for example. Router 22 may be located in a different network from the network where PGW200 is located.

[0047] Router 22 is, for example, isolated from PGW200. Router 22 may also be integrated with PGW200.

[0048] Router 23 has the function of relaying data. Router 23 relays, for example, uplink data. Router 23 relays, for example, downlink data.

[0049] Router 23 is located in the same network as, for example, SGW300. Router 23 is located in the same network as, for example, the third ASN. Router 23 may be located in a different network than the one in which SGW300 is located.

[0050] Router 23 is, for example, separate from SGW300. Router 23 may also be integrated with SGW300.

[0051] For example, inter-organizational routing information is exchanged between routers 21, 22, and 23 according to BGP. For example, routing information is exchanged between routers 21, 22, and 23 in response to changes in routing information. Routing information may also be exchanged periodically between routers 21, 22, and 23.

[0052] The routing information includes, for example, the ASN of the network where the router is located. The routing information also includes, for example, the IP addresses assigned to devices located on that network. The routing information may also include the subnet mask of the IP addresses assigned to devices located on that network. The subnet mask is expressed, for example, in prefix notation.

[0053] Router 21 advertises routing information to, for example, Router 23. Router 21 may also advertise routing information to IPX (IP eXchange) which relays between HPLMN and VPLMN. Router 22 may advertise routing information in the same manner as Router 21.

[0054] In the example of system 10 shown in Figure 1, router 21 advertises ASN=65001, the first IP address of PGW100=AAAA / 32, and the second IP address of PGW100=BBBB / 32. In the example of system 10 shown in Figure 1, router 22 advertises ASN=65002 and the IP address of PGW200=BBBB / 32.

[0055] Router 23 advertises routing information to, for example, Router 21 and Router 22. Router 23 may also advertise routing information to IPX. In the example of system 10 shown in Figure 1, Router 23 advertises ASN=65003 and the IP address of SGW300=CCCC / 32.

[0056] Router 23 generates a route table, for example. Router 23 generates a route table based on the communication path information advertised by Router 21 and Router 22, respectively. Router 23 generates a route table by associating the ASN of the network where the router is located with the IP addresses assigned to the devices located in that network, for example. In an example of system 10 shown in Figure 1, Router 23 generates a route table that includes ASN=65001 and PGW100's first IP address=AAAA / 32, ASN=65001 and PGW100's second IP address=BBBB / 32, and ASN=65002 and PGW200's IP address=BBBB / 32.

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

[0058] Terminal information includes, for example, IMSI (International Mobile Subscriber Identity). Terminal information also includes, for example, executable data communication information indicating the data communications that the communication terminal 800 can perform. Executable data communication information may indicate, for example, that the communication terminal 800 can perform only data communications via the first ASN network, out of the two data communications: data communications via the first ASN network and data communications via the second ASN network. Executable data communication information may also indicate, for example, that the communication terminal 800 can perform both data communications via the first ASN network and data communications via the second ASN network. Terminal information may further include any other information relating to the communication terminal 800.

[0059] The request generation device 70 generates session generation requests for communication terminal 800 that request the creation of a session to a PDN. For example, the request generation device 70 generates a session generation request for communication terminal 800 that requests the creation of a session to PDN40. For example, the request generation device 70 generates a session generation request for communication terminal 800 that requests the creation of a session to PDN60. The request generation device 70 may also generate session generation requests for communication terminal 800 that request the creation of a session to any other PDN.

[0060] The request generation device 70, for example, receives terminal information of the communication terminal 800 from the terminal information management device 50 via the network 20, and generates a session creation 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 Figure 1, the request generation device 70 may be an MME (Mobility Management Entity).

[0061] A session creation request includes, for example, the IP address of the communication terminal 800. A session creation request includes, for example, the IMSI of the communication terminal 800. A session creation request includes, for example, the IP address of the SGW300. A session creation request includes, for example, the TEID assigned to the communication tunnel of the SGW300. A session creation request includes, for example, the first IP address or the second IP address of the PGW100. For example, if the communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the network of the first ASN is possible, the session creation request includes the first IP address of the PGW100. For example, if the communication terminal 800 is registered with the terminal information management device 50 so that both data communication via the network of the first ASN and data communication via the network of the second ASN are possible, the session creation request includes the second IP address of the PGW100. The session creation request may further include any other information necessary to create a session to the PDN.

[0062] In the example of system 10 shown in Figure 1, HPLMN may be established at three or more locations. In this case, the second IP address of PGW100 may be assigned to the PGW of each of the three or more locations.

[0063] Here, we will describe an example of generating a session to the PDN for a communication terminal 800 of a user visiting the VPLMN where SGW300 is located. First, we will describe an example of generating a session to the PDN 40 for communication terminal 800. Here, we assume that communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the network of the first ASN, out of the two data communication methods, is possible.

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

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

[0066] SGW300 sends the session creation request received from communication terminal 800 to router 23. If the session creation request from communication terminal 800 includes the first IP address of PGW100, router 23 forwards the session creation request from communication terminal 800 to router 21 via network 20. Router 21 forwards the session creation request from communication terminal 800 to PGW100.

[0067] PGW100 generates session information for communication terminal 800 in response to receiving a session creation request from communication terminal 800. PGW100 generates session information for communication terminal 800 based on, for example, the session creation request from communication terminal 800. If the session creation request from communication terminal 800 includes the first IP address of PGW100, the session information for communication terminal 800 includes, for example, the IP address of communication terminal 800, the first IP address of PGW100, the 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 for communication terminal 800 may further include any other information necessary to create a session to PDN40. The session information for communication terminal 800 including the first IP address of PGW100 is an example of the first session information for communication terminal 800. PGW100 may register the session information of the generated communication terminal 800 in the database 150 corresponding to PGW100.

[0068] PGW100 establishes a communication tunnel between itself and SGW300 in order to create a session for communication terminal 800 to PDN40. PGW100 establishes the communication tunnel between itself and SGW300 based, for example, on the session information of communication terminal 800.

[0069] PGW100 sends the session creation response from communication terminal 800 to router 21 in response to the session creation request from communication terminal 800. Router 21 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW300. Upon receiving the session creation response from communication terminal 800, SGW300 creates a session for communication terminal 800 to PDN40.

[0070] The session creation response includes, for example, the first IP address of PGW100 and the TEID assigned to the communication tunnel of PGW100. The session creation response may further include any other information necessary for creating a session of the communication terminal 800 to PDN40.

[0071] Subsequently, SGW300 receives the uplink data from communication terminal 800. SGW300 transmits the uplink data from communication terminal 800 to router 23. Router 23 forwards the uplink data from communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data from communication terminal 800 to PGW100. PGW100 transmits the uplink data from communication terminal 800 to the destination via PDN40.

[0072] Next, we will describe an example of generating a session from the communication terminal 800 to the PDN 60. Here, we assume that the communication terminal 800 is registered with the terminal information management device 50 so that it can perform both data communication via the first ASN network and data communication via the second ASN network.

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

[0074] SGW300 sends the session creation request received from communication terminal 800 to router 23. If the session creation request from communication terminal 800 includes the second IP address of PGW100, router 23 selects a PGW from among multiple PGWs assigned the same IP address to forward the session creation request from communication terminal 800. Here, we will continue the explanation assuming that router 23 selects a PGW from PGW100 and PGW200 to forward the session creation request from communication terminal 800.

[0075] Router 23 selects a PGW to forward the session creation request of communication terminal 800, for example, by selecting the communication path to which the session creation request of communication terminal 800 will be forwarded. Router 23 also selects a communication path to which the session creation request of communication terminal 800 will be forwarded, for example, by selecting the communication path from Router 23 to the router corresponding to the PGW to which the session creation request of communication terminal 800 will be forwarded. Here, we will continue the explanation 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 to which the session creation request of communication terminal 800 will be forwarded, for example, based on its route table. Router 23 selects a communication path to which the session creation request of communication terminal 800 will be forwarded, for example, according to the BGP best path selection algorithm. Router 23 selects the communication path with the shortest communication distance from Router 23 to the router corresponding to each of the multiple PGWs that are assigned the same IP address, as the communication path to which the session creation request of communication terminal 800 will be forwarded. Here, we will continue the explanation assuming that Router 23 has selected the communication path from Router 23 to Router 22 as the communication path to which the session creation request of communication terminal 800 will be forwarded.

[0077] Router 23 selects PGW200 as the PGW to forward the session creation request from communication terminal 800 by selecting the communication path from Router 23 to Router 22 as the communication path through which the session creation request from communication terminal 800 will be forwarded. Router 23 forwards the session creation request from communication terminal 800 to Router 22 via Network 20. Router 22 forwards the session creation request from communication terminal 800 to PGW200.

[0078] PGW200 generates session information for communication terminal 800 in response to receiving a session generation request from communication terminal 800. If the session generation request from communication terminal 800 includes the second IP address of PGW100, the session information for communication terminal 800 includes, for example, the IP address of communication terminal 800, the second IP address of PGW100, the TEID 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 for communication terminal 800 may further include other optional information for generating a session to PDN60. The session information for communication terminal 800 including the second IP address of PGW100 is an example of the second session information for communication terminal 800.

[0079] The PGW200, for example, registers the session information of the generated communication terminal 800 in the database 250 corresponding to the PGW200. The database 250 includes, for example, a message queue for temporarily storing the session information of the communication terminal 800. The database 250 may be an example of a first storage unit, or it may be an example of a second storage unit.

[0080] Database 250 is, for example, separate from PGW200. Database 250 may also be integrated with PGW200.

[0081] Database 250 is located, for example, on the network where PGW200 is located. Database 250 is located, for example, on the network of the second ASN. Database 250 may be located on a different network from the network where PGW200 is located.

[0082] 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. The database 250 may be an example of a session information synchronization unit. The database 150 may be an example of a first storage unit, or an example of a second storage unit.

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

[0084] For example, database 250 sends a message containing session information for communication terminal 800 to a topic. Database 150 obtains the session information for communication terminal 800 by receiving a message from the subscription corresponding to the topic from which the message was sent by database 250. This synchronizes the session information for communication terminal 800 between database 250 and database 150.

[0085] Database 250 notifies PGW200, for example, that the synchronization process 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] Database 150, for example, notifies PGW100 of the completion of synchronization. Therefore, PGW200 may be the publisher, and PGW100 may be the subscriber.

[0087] Database 150 is, for example, separate from PGW100. Database 150 may also be integrated with PGW100.

[0088] Database 150 is located, for example, on the network where PGW100 is located. Database 150 is located, for example, on the network of the first ASN. Database 150 may be located on a different network from the network where PGW100 is located.

[0089] PGW200 establishes a communication tunnel between itself and SGW300 in order to generate a session for communication terminal 800 to PDN60. PGW200 then establishes a communication tunnel between itself and SGW300, for example, based on the session information of communication terminal 800 that it has generated.

[0090] PGW100 establishes a communication tunnel between itself and SGW300 in order to create a session for communication terminal 800 to PDN60. PGW100 establishes the communication tunnel between itself and SGW300 based, for example, on the session information of communication terminal 800 included in the synchronization completion notification received from database 150.

[0091] PGW200 sends the session creation response from communication terminal 800 to router 22 in response to the session creation request from communication terminal 800. Router 22 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW300. Upon receiving the session creation response from communication terminal 800, SGW300 creates a session for communication terminal 800 to PDN60.

[0092] The session creation response includes, for example, the second IP address of PGW100 and the TEIDs assigned to the communication tunnels of PGW100 and PGW200. The session creation response may further include any other information necessary to create a session for the communication terminal 800 to PDN60.

[0093] Subsequently, SGW300 receives the uplink data from communication terminal 800. SGW300 sends the uplink data from communication terminal 800 to router 23. Router 23 selects a PGW to forward the uplink data from communication terminal 800. Router 23 may select a PGW to forward the uplink data from communication terminal 800 from among multiple PGWs that are assigned the same IP address, similar to how router 23 selects a PGW to forward the session creation request from communication terminal 800. Here, we will continue the explanation assuming that router 23 has selected PGW200 as the PGW to forward the uplink data from communication terminal 800.

[0094] Router 23 forwards the uplink data of communication terminal 800 to router 22 via network 20. Router 22 forwards the uplink data of communication terminal 800 to PGW200. PGW200 sends the uplink data of communication terminal 800 to the destination via PDN60.

[0095] Subsequently, if the communication path between SGW300 and PGW200 becomes unavailable, such as when PGW200 fails or when maintenance work is performed on PGW200, Router 22 will advertise communication path information. Router 23 will receive the communication path information advertised by Router 22 and update its route table. In this case, Router 23 may change the PGW that forwards the uplink data of the communication terminal 800 from PGW200 to PGW100 based on the updated route table.

[0096] Router 23 forwards the uplink data of communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data of communication terminal 800 to PGW100. PGW100 sends the uplink data of communication terminal 800 to the destination via PDN60.

[0097] If, at the time SGW300 receives a session creation request from communication terminal 800, the communication path between SGW300 and PGW200 is unavailable, router 23 forwards the session creation request from communication terminal 800 to router 21 via network 20. Router 21 then forwards the session creation request from communication terminal 800 to PGW100.

[0098] PGW100 generates session information for communication terminal 800 in response to receiving a session creation request from communication terminal 800. PGW100 may generate session information for communication terminal 800 in the same manner as when PGW200 generates session information for communication terminal 800 in order to create a session for communication terminal 800 to PDN60.

[0099] PGW100 registers the session information of the generated communication terminal 800 in database 150. Database 150 synchronizes the session information of the communication terminal 800 registered in database 150 with database 250. Database 150 may synchronize the session information of the communication terminal 800 with database 150 and database 250 in the same manner as when database 250 synchronizes the session information of the communication terminal 800 with database 250 and database 150. Database 150 may be an example of a session information synchronization unit.

[0100] Database 150 may notify PGW100 of the completion of synchronization. Database 250 may notify PGW200 of the completion of synchronization.

[0101] PGW100 establishes a communication tunnel between itself and SGW300 in order to generate a session for communication terminal 800 to PDN60. PGW100 then establishes a communication tunnel between itself and SGW300, for example, based on the session information of communication terminal 800 that it has generated.

[0102] PGW100 sends the session creation response from communication terminal 800 to router 21 in response to the session creation request from communication terminal 800. Router 21 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW300. Upon receiving the session creation response from communication terminal 800, SGW300 creates a session for communication terminal 800 to PDN60.

[0103] Subsequently, SGW300 receives the uplink data from communication terminal 800. SGW300 transmits the uplink data from communication terminal 800 to router 23. Router 23 forwards the uplink data from communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data from communication terminal 800 to PGW100. PGW100 transmits the uplink data from communication terminal 800 to the destination via PDN60.

[0104] Subsequently, when a communication path between SGW300 and PGW200 becomes available, PGW200 establishes a communication tunnel between itself and SGW300 in order to create a session for communication terminal 800 to PDN60. PGW200 establishes the communication tunnel between itself and SGW300, for example, based on the session information of communication terminal 800 included in the synchronization completion notification received from database 250.

[0105] Router 22 advertises the communication path information after the communication path between SGW300 and PGW200 becomes available. Router 23 receives the communication path information advertised by Router 22 and updates its route table. In this case, based on the updated route table, Router 23 may change the PGW that forwards the uplink data of the communication terminal 800 from PGW100 to PGW200.

[0106] Router 23 changes the PGW that forwards the uplink data of communication terminal 800 from PGW100 to PGW200, and then forwards the uplink data of communication terminal 800 to Router 22 via Network 20. Router 22 forwards the uplink data of communication terminal 800 to PGW200. PGW200 sends the uplink data of communication terminal 800 to the destination via PDN60.

[0107] In a situation where HPLMNs are established at multiple locations by a telecommunications carrier providing roaming services, there is a need for users of mobile communication services to access PDNs via the appropriate network depending on their usage. For example, user A visiting a VPLMN would want to access the PDN via a specific HPLMN regardless of the VPLMN's location in order to perform highly secure data communication. Similarly, user B visiting a VPLMN would want to access the PDN via an HPLMN with a shorter communication distance from the VPLMN in order to perform high-speed data communication.

[0108] One example of how mobile communication service users can access PDNs via an appropriate network depending on their usage is to install a unique PGW (Platform Gateway) for each user. However, this requires a large amount of hardware resources, such as computing power. In particular, if there are many mobile communication service users, a huge amount of hardware resources will be needed. Another example of how mobile communication service users can access PDNs via an appropriate network depending on their usage is to assign a unique IP address to each user. However, this also requires a large amount of network resources, such as IP addresses. In particular, if there are many mobile communication service users, a huge amount of network resources will be needed. Therefore, it is desirable to realize a mobile communication service that allows users to access PDNs via an appropriate network depending on their usage with fewer resources.

[0109] In contrast, according to the system 10 shown in Figure 1, when PGW100 receives a session creation request for communication terminal 800 from SGW300, if communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods (data communication via the first ASN network and data communication via the second ASN network), PGW100 generates session information for communication terminal 800, including PGW100's first IP address. Since PGW100's first IP address is assigned only to PGW100 out of PGW100 and PGW200, the communication path that accesses PDN40 via the HPLMN where PGW100 is located can be used for data communication of communication terminal 800, regardless of the location of the VPLMN where SGW300 is located. Furthermore, when PGW100 receives a session creation request for communication terminal 800 from SGW300, if communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, PGW100 generates session information for communication terminal 800, including PGW100's second IP address, 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. Since the same IP address is assigned to both PGW100 and PGW200, by synchronizing the session information for communication terminal 800 between database 150 and database 250, the communication paths available for data communication of communication terminal 800 can be made redundant, including a communication path that accesses PDN60 via the HPLMN where PGW100 is located and a communication path that accesses PDN60 via the HPLMN where PGW200 is located. This allows the communication path to access PDN60 via HPLMN, which has a shorter communication distance from VPLMN where SGW300 is located, as selected according to the BGP best path selection algorithm, to be used for data communication of the communication terminal 800.Therefore, according to the system 10 shown in Figure 1, the communication terminal 800 can either perform data communication via the first ASN network or data communication via the second ASN network, or both. By pre-registering whether the communication terminal 800 can perform data communication via the first ASN network or both, and determining the communication path used for data communication of the communication terminal 800 in both cases using the method described above, it is possible to access the PDN via the appropriate network according to the user's needs without installing a unique PGW for each user or assigning a unique IP address for each user. Thus, the system 10 shown in Figure 1 can realize an LTE communication service that allows access to the PDN via the appropriate network according to the user's needs with fewer resources.

[0110] Figure 2 is an explanatory diagram illustrating an example of the processing flow of System 10. Here, the starting state is described as a user of a communication terminal 800, which is registered with the terminal information management device 50 so that both data communication via the first ASN network and data communication via the second ASN network can be performed, visiting the VPLMN where the SGW300 is located.

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

[0112] In S104, PGW100 generates session information for communication terminal 800 based on the session generation request for communication terminal 800 received from SGW300 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, PGW100 sends a session generation response from communication terminal 800 to SGW300 for the session generation request from communication terminal 800.

[0113] In S108, database 150 synchronizes the session information of the communication terminal 800, which was registered by PGW100 in S104, between database 150 and database 250. In S110, database 150 notifies PGW100 of the completion of synchronization in response to the synchronization of the session information of the communication terminal 800 between database 150 and database 250 in S108. In S112, database 250 notifies PGW200 of the completion of synchronization in response to database 150 synchronizing the session information of the communication terminal 800 between database 150 and database 250 in S108.

[0114] In S114, SGW300 transmits the uplink data of communication terminal 800 received from communication terminal 800 to PGW100. PGW100 transmits the uplink data of communication terminal 800 to the destination via PDN60.

[0115] Subsequently, in S116, after the communication path between SGW300 and PGW200 becomes available, SGW300 transmits the uplink data of communication terminal 800 received from communication terminal 800 to PGW200. PGW200 transmits the uplink data of communication terminal 800 to the destination via PDN60.

[0116] In an example of the processing flow of system 10 shown in Figure 2, the process in which PGW100 sends a session creation response for communication terminal 800 to SGW300 in response to PGW100 registering session information of communication terminal 800 in database 150 may be replaced with the process in which PGW100 sends a session creation response for communication terminal 800 to SGW300 in response to PGW100 receiving a synchronization completion notification from database 150. In other words, S106 shown in Figure 2 may be performed after S110 shown in Figure 2.

[0117] Figure 3 schematically shows an example of the functional configuration of PGW100. PGW100 comprises a request receiving unit 102, a session information generation unit 106, a registration unit 108, a session information synchronization unit 110, a notification receiving unit 112, a response transmission unit 114, a communication tunnel establishment unit 116, a data receiving unit 118, and a data transmission unit 119. Note that it is not necessarily required that PGW100 include all of these components.

[0118] The request receiving unit 102 receives session creation requests from 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 communication terminal 800 requesting the creation of a session to PDN40. For example, the request receiving unit 102 receives a session creation request from communication terminal 800 requesting the creation of a session to PDN60. The request receiving unit 102 may also receive session creation requests from communication terminal 800 requesting the creation of a session to any other PDN.

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

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

[0121] The session information generation unit 106 generates session information for the communication terminal 800, for example, based on a session generation request from the communication terminal 800. If the communication terminal 800 is registered to be able to perform only data communication via the first ASN network, among data communication via the first ASN network and data communication via the second ASN network, the session information generation unit 106 generates session information for the communication terminal 800, including the first IP address of the PGW 100. If the communication terminal 800 is registered to be able to perform both data communication via the first ASN network and data communication via the second ASN network, the session information generation unit 106 generates session information for the communication terminal 800, including the second IP address of the PGW 100.

[0122] The registration unit 108 registers the session information of the communication terminal 800 in the database 150. For example, 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.

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

[0124] The session information synchronization unit 110 synchronizes the session information of the communication terminal 800, including the second IP address of the PGW 100, which has been registered in the database 150 by the registration unit 108, 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 the synchronization completion when it has synchronized 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, for example, via the network 20. The session information synchronization unit 110 notifies the PGW 200 of the synchronization completion, for example, via the router 21 and the network 20.

[0126] The notification receiving unit 112 receives a synchronization completion notification. The notification receiving unit 112 may receive a synchronization completion notification from, for example, database 150. The notification receiving unit 112 may also receive a synchronization completion notification from, for example, database 250. The notification receiving unit 112 may also receive a synchronization completion notification from PGW200.

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

[0128] The response transmission unit 114 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800. For example, the response transmission unit 114 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800 that was received by the request reception unit 102.

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

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

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

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

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

[0134] The communication tunnel establishment unit 116 establishes a communication tunnel based, for example, on the session information of the communication terminal 800 generated by the session information generation unit 106. The communication tunnel establishment unit 116 also establishes a communication tunnel based, for example, on 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 also establish a 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] If the communication terminal 800 is registered to be capable of performing only data communication via the first ASN network, for example, if the communication terminal 800 is registered to be capable of performing data communication via the first ASN network and data communication via the second ASN network, the communication tunnel establishment unit 116 establishes a communication tunnel based on the session information of the communication terminal 800, including the first IP address of the PGW 100, which is synchronized between the database 150 and the 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 the data communication of the communication terminal 800. The data receiving unit 118 receives data related to the data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 118 receives data related to the 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 the 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 from the communication terminal 800. The data receiving unit 118 receives uplink data from the communication terminal 800 when, for example, PGW 100 is selected from among multiple PGWs that have the same IP address assigned to them as the target for transmitting uplink data from the communication terminal 800.

[0139] The data receiving unit 118 receives, for example, downlink data from the communication terminal 800. The data receiving unit 118 receives downlink data from the communication terminal 800 when, for example, PGW 100 is selected from among multiple PGWs that have the same IP address assigned to them as the target for transmitting downlink data from the communication terminal 800.

[0140] The communication tunnel establishment unit 116 establishes a communication tunnel, for example, when the data reception unit 118 receives uplink data from the communication terminal 800 and the PGW 100 does not have session information for the communication terminal 800, by obtaining session information for the communication terminal 800 from the database 150. The communication tunnel establishment unit 116 also obtains session information for the communication terminal 800 from the database 150 when the data reception unit 118 receives uplink data from the communication terminal 800 for the first time.

[0141] The communication tunnel establishment unit 116 establishes a communication tunnel by obtaining session information for the communication terminal 800 from the database 150, for example, when the data reception unit 118 receives downlink data from the communication terminal 800 and the PGW 100 does not have session information for the communication terminal 800. The communication tunnel establishment unit 116 obtains session information for the communication terminal 800 from the database 150 when the data reception unit 118 receives downlink data from the communication terminal 800 for the first time.

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

[0143] The data transmission unit 119 transmits, for example, the uplink data of the communication terminal 800 to the destination of the communication terminal 800's uplink data. The data transmission unit 119 also transmits, for example, the downlink data of the communication terminal 800 to the communication terminal 800.

[0144] Figure 4 schematically shows an example of the functional configuration of the SGW300. The SGW300 comprises a storage unit 302, a route information receiving unit 304, a table generation unit 306, a request receiving unit 310, a request transmission unit 312, a response receiving unit 314, a data receiving unit 318, and a data transmission unit 319. Note that it is not necessarily required that the SGW300 include all of these components.

[0145] The storage unit 302 stores various types of information. For example, the storage unit 302 stores a route table.

[0146] The route table includes, for example, communication path information showing the communication path between SGW300 and PGW100. The route table also includes, for example, communication path information showing the communication path between SGW300 and PGW200.

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

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

[0149] The routing information receiving unit 304 receives, for example, communication route information indicating the communication route between SGW300 and PGW100. The routing information receiving unit 304 also receives, for example, communication route information indicating the communication route between SGW300 and PGW200.

[0150] The table generation unit 306 generates a route table. The table generation unit 306 generates a route table based on, for example, the communication path information stored in the storage unit 302. The table generation unit 306 generates a route table based on, for example, the communication path 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 session creation requests from 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 communication terminal 800 requesting the creation of a session to PDN40. For example, the request receiving unit 310 receives a session creation request from communication terminal 800 requesting the creation of a session to PDN60. The request receiving unit 310 may also receive session creation requests from communication terminal 800 requesting the creation of a session to any other PDN.

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

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

[0154] The request transmission unit 312 transmits a session creation request for the communication terminal 800, for example, via the network 20. The request transmission unit 312 transmits a session creation request for the communication terminal 800, for example, via the router 23 and the network 20.

[0155] The request transmission unit 312 transmits a session creation request for the communication terminal 800 based, for example, on the route table stored in the storage unit 302. If the communication terminal 800 is registered to be able to perform only data communication via the network of the first ASN, among data communication via the network of the first ASN and data communication via the network of the second ASN, the request transmission unit 312 transmits a session creation request for the communication terminal 800, including the first IP address of the PGW 100, to the PGW 100.

[0156] If the communication terminal 800 is registered to be capable of both data communication over the network of the first ASN and data communication over the network of the second ASN, the request transmission unit 312 sends a session creation request for the communication terminal 800, including the second IP address of PGW 100, to a PGW selected as the recipient of the session creation request from among multiple PGWs to which the same IP address has been assigned based on predetermined PGW selection conditions. In this case, the request transmission unit 312 sends the session creation request to a PGW selected as the recipient of the session creation request from among PGW 100 and PGW 200 based on the PGW selection conditions. The request transmission unit 312 also sends the session creation request to the PGW selected as the recipient of the session creation request via a communication path selected according to the BGP best path selection algorithm.

[0157] The response receiving unit 314 receives the session creation response from the communication terminal 800 to the session creation request from the communication terminal 800. For example, the response receiving unit 314 receives the session creation response from the communication terminal 800 to the session creation request from the communication terminal 800 sent by the request sending 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, for example, a session creation response from the PGW 100 to the communication terminal 800. The response receiving unit 314 also receives, for example, a session creation response from the PGW 200 to the communication terminal 800.

[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 also 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 from the communication terminal 800. The data receiving unit 318 also receives, for example, downlink data from the communication terminal 800.

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

[0163] The data transmission unit 319 transmits, for example, uplink data of the communication terminal 800. The data transmission unit 319 transmits the uplink data of the communication terminal 800 based, for example, on a route table stored in the storage unit 302. The data transmission unit 319 transmits the uplink data of the communication terminal 800 to the PGW 100 if, for example, the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods (data communication via the first ASN network and data communication via the second ASN network).

[0164] If the communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, the data transmission unit 319 transmits the uplink data of the communication terminal 800 to a PGW selected from among multiple PGWs to which the same IP address has been assigned based on predetermined PGW selection conditions. In this case, the data transmission unit 319 transmits the uplink data of the communication terminal 800 to a PGW selected from among PGW100 and PGW200 to be the target of the uplink data of the communication terminal 800 based on the PGW selection conditions. The data transmission unit 319 transmits the uplink data of the communication terminal 800 to a PGW selected to be the target of the uplink data of the communication terminal 800 via a communication path selected according to the BGP best path selection algorithm.

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

[0166] Figure 5 schematically shows another example of system 10. Here, we will mainly explain the differences from system 10 in Figure 1.

[0167] The system 10 shown in Figure 5 provides an LTE communication system that incorporates a CUPS (Control and User Plane Separation) architecture. In this case, PGW100 is separated into PGW-C120 and PGW-U140, PGW200 is separated into PGW-C220 and PGW-U240, and SGW300 is separated into SGW-C320 and SGW-U340.

[0168] PGW-C120 may be assigned an IP address. In the example of system 10 shown in Figure 5, PGW-C120 is assigned the IP address AAAA with subnet mask 32.

[0169] PGW-U140 may be assigned an IP address. For example, PGW-U140 may be assigned multiple IP addresses that are different from each other. For example, PGW-U140 may be assigned a first IP address and a second IP address that is different from the first IP address. The first IP address of PGW-U140 may be used to access PDN40. The second IP address of PGW-U140 may be used to access PDN60. PGW-U140 may be assigned three or more IP addresses that are different from each other. In the example of system 10 shown in Figure 5, PGW-U140 is assigned IP address BBBB with subnet mask 32 as its first IP address and IP address CCCC with subnet mask 32 as its second IP address.

[0170] PGW-C220 may be assigned an IP address. For example, PGW-C220 may be assigned the same IP address as PGW-C120. For example, the same IP address may be assigned to both PGW-C120 and PGW-C220 using IP Anycast. In the example of system 10 shown in Figure 5, PGW-C220 is assigned the IP address AAAA with subnet mask 32.

[0171] PGW-U240 may be assigned an IP address. For example, PGW-U240 may be assigned the second IP address of PGW-U140. For example, the same IP address may be assigned to both PGW-U140 and PGW-U240 using IP Anycast. PGW-U240 may be assigned multiple different IP addresses. In the example of system 10 shown in Figure 5, PGW-U240 is assigned the IP address CCCC with subnet mask 32.

[0172] The SGW-C320 may be assigned an IP address. In the example of system 10 shown in Figure 5, the SGW-C320 is assigned the IP address DDDD with subnet mask 32.

[0173] The SGW-U340 may be assigned an IP address. In the example of system 10 shown in Figure 5, the SGW-U340 is assigned the IP address EEEE with subnet mask 32.

[0174] Router 21 is, for example, separate from PGW-C120 and PGW-U140. Router 21 may also be integrated with PGW-C120 or PGW-U140.

[0175] Router 22 is, for example, separate from PGW-C220 and PGW-U240. Router 22 may also be integrated with PGW-C220 or PGW-U240.

[0176] Router 23 is, for example, separate from SGW-C320 and SGW-U340. Router 23 may also be integrated with SGW-C320 or SGW-U340.

[0177] In the example of system 10 shown in Figure 5, router 21 advertises ASN=65001, PGW-C120's IP address=AAAA / 32, PGW-U140's first IP address=BBBB / 32, and PGW-U140's second IP address=CCCC / 32. In the example of system 10 shown in Figure 5, router 22 advertises ASN=65002, PGW-C220's IP address=AAAA / 32, and PGW-U240's IP address=CCCC / 32. In the example of system 10 shown in Figure 5, router 23 advertises ASN=65003, SGW-C320's IP address=DDDD / 32, and SGW300's IP address=EEEE / 32.

[0178] Router 23 generates a route table based on, for example, the communication path information advertised by Router 21 and Router 22, respectively. In an example of System 10 shown in Figure 5, Router 23 generates a route table that includes ASN=65001 and PGW-C120's IP address=AAAA / 32, ASN=65001 and PGW-U140's first IP address=BBBB / 32, ASN=65001 and PGW-U140's second IP address=CCCC / 32, ASN=65002 and PGW-C220's IP address=AAAA / 32, and ASN=65002 and PGW-U240's IP address=CCCC / 32.

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

[0180] Here, we will describe an example of generating a session to the PDN for a communication terminal 800 of a user visiting the VPLMN where SGW300 is located. First, we will describe an example of generating a session to the PDN 40 for communication terminal 800. Here, we assume that communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the network of the first ASN, out of the two data communication methods, is possible.

[0181] The request generation device 70 generates a session creation request for the communication terminal 800 in response to receiving an attach request from the communication terminal 800. Since the communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the first ASN network is possible among data communication via the first ASN network and data communication via the second ASN network, the request generation device 70 generates a session creation request for the communication terminal 800 that includes the first IP address of the PGW-U140. The request generation device 70 transmits the generated session creation request for the communication terminal 800 to the SGW-C320 via the network 20.

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

[0183] PGW-C120 generates session information for communication terminal 800 in response to receiving a session generation request from communication terminal 800. If the session generation request from communication terminal 800 includes the first IP address of PGW-U140, the session information for communication terminal 800 includes, for example, the IP address of communication terminal 800, the first IP address of PGW-U140, the TEID assigned to the communication tunnel of PGW-U140, the IP address of SGW-U340, and the TEID assigned to the communication tunnel of SGW-U340. The session information for communication terminal 800 may further include the IP address of PGW-C120, the TEID assigned to the communication tunnel of PGW-C120, the IP address of SGW-C320, and the TEID assigned to the communication tunnel of SGW-C320. The session information for communication terminal 800 may further include any other information necessary to generate a session to PDN40. The session information of the communication terminal 800, including the first IP address of the PGW-U140, may be an example of the first session information of the communication terminal 800.

[0184] PGW-C120 may register the session information of the generated communication terminal 800 in the database 150 corresponding to PGW100. PGW-C120 may also provide the session information of the generated communication terminal 800 to PGW-U140.

[0185] PGW-U140 establishes a communication tunnel between itself and SGW-U340 in order to generate a session for communication terminal 800 to PDN40. PGW-U140 establishes the communication tunnel between itself and SGW-U340 based, for example, on the session information for communication terminal 800 provided by PGW-C120.

[0186] PGW-C120 sends the session creation response from communication terminal 800 to router 21 in response to the session creation request from communication terminal 800. Router 21 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW-C320. Upon receiving the session creation response from communication terminal 800, SGW-C320 creates a session for communication terminal 800 to PDN40.

[0187] The session creation response includes, for example, the first IP address of PGW-U140 and the TEID assigned to the communication tunnel of PGW-U140. The session creation response may further include the IP address of PGW-C120 and the TEID assigned to the communication tunnel of PGW-C120. The session creation response may further include any other information necessary to create a session from the communication terminal 800 to PDN40.

[0188] Subsequently, SGW-U340 receives the uplink data from communication terminal 800. SGW-U340 transmits the uplink data from communication terminal 800 to router 23. Router 23 forwards the uplink data from communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data from communication terminal 800 to PGW-U140. PGW-U140 transmits the uplink data from communication terminal 800 to the destination via PDN40.

[0189] Next, we will describe an example of generating a session from the communication terminal 800 to the PDN 60. Here, we assume that the communication terminal 800 is registered with the terminal information management device 50 so that it can perform both data communication via the first ASN network and data communication via the second ASN network.

[0190] The request generation device 70 generates a session creation request for the communication terminal 800 in response to receiving an attach request from the communication terminal 800. Since the communication terminal 800 is registered with the terminal information management device 50 so that it can perform both data communication over the first ASN network and data communication over the second ASN network, the request generation device 70 generates a session creation request for the communication terminal 800 that includes the second IP address of the PGW-U140. The request generation device 70 transmits the generated session creation request for the communication terminal 800 to the SGW-C320 via the network 20.

[0191] SGW-C320 sends the session creation request received from communication terminal 800 to router 23. If the session creation request from communication terminal 800 includes the second IP address of PGW-U140, router 23 selects a PGW-C from among several PGW-Cs assigned the same IP address to forward the session creation request from communication terminal 800. Here, we will continue the explanation assuming that router 23 selects a PGW-C from among PGW-C120 and PGW-C220 to forward the session creation request from communication terminal 800.

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

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

[0194] Router 23 selects PGW-C220 as the PGW-C to forward the session creation request from communication terminal 800 by selecting the communication path from Router 23 to Router 22 as the communication path to which the session creation request from communication terminal 800 will be forwarded. Router 23 forwards the session creation request from communication terminal 800 to Router 22 via Network 20. Router 22 forwards the session creation request from communication terminal 800 to PGW-C220.

[0195] Upon receiving a session creation request from the communication terminal 800, PGW-C220 generates session information for the communication terminal 800 based on the session creation request from the communication terminal 800. If the session creation request from the communication terminal 800 includes the second IP address of PGW-U140, the session information for the communication terminal 800 includes, for example, the IP address of the communication terminal 800, the second IP address of PGW-U140, the TEID 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 for the communication terminal 800 may further include the IP address of PGW-C120, the TEID 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 the communication terminal 800 may include any other information necessary to generate a session to the PDN60. The session information of the communication terminal 800, including the second IP address of the PGW-U140, may be an example of the second session information of the communication terminal 800.

[0196] PGW-C220 registers the session information of the generated communication terminal 800 in the database 250 corresponding to PGW200. Database 250, for example, synchronizes the session information of the communication terminal 800 registered in database 250 with database 150 corresponding to PGW100.

[0197] For example, database 250 notifies PGW-U240 of the synchronization completion. Database 250 may also notify PGW-C220 of the synchronization completion.

[0198] Database 250 is, for example, separate from PGW-C220 and PGW-U240. Database 250 may also be integrated with PGW-C220 or PGW-U240.

[0199] For example, database 150 notifies PGW-U140 of the synchronization completion. Database 150 may also notify PGW-C120 of the synchronization completion.

[0200] Database 150 is, for example, separate from PGW-C120 and PGW-U140. Database 150 may also be integrated with PGW-C120 or PGW-U140.

[0201] PGW-U240 establishes a communication tunnel between itself and SGW-U340 in order to create a session for communication terminal 800 to PDN60. PGW-U240 establishes the communication tunnel between itself and SGW-U340 based, for example, on the session information of communication terminal 800 included in the synchronization completion notification received from database 250.

[0202] PGW-U140 establishes a communication tunnel between itself and SGW-U340 in order to create a session for communication terminal 800 to PDN60. PGW-U140 establishes the communication tunnel between itself and SGW-U340 based, for example, on the session information of communication terminal 800 included in the synchronization completion notification received from database 150.

[0203] PGW-C220 sends the session creation response from communication terminal 800 to router 22 in response to the session creation request from communication terminal 800. Router 22 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW-C320. Upon receiving the session creation response from communication terminal 800, SGW-C320 creates a session for communication terminal 800 to PDN60.

[0204] The session creation response includes, for example, the second IP address of PGW-U140 and the TEID assigned to the communication tunnel of PGW-U140 and the communication tunnel of PGW-U240. The session creation response may further include the IP address of PGW-C120 and the TEID assigned to the communication tunnel of PGW-C120 and the communication tunnel of PGW-C220. The session creation response may further include any other information necessary to create a session of the communication terminal 800 to PDN60.

[0205] Subsequently, SGW-U340 receives the uplink data from communication terminal 800. SGW-U340 then transmits the uplink data from communication terminal 800 to router 23. Router 23 selects a PGW-U to forward the uplink data from communication terminal 800. Router 23 may select a PGW-U to forward the uplink data from communication terminal 800 from among multiple PGW-Us assigned the same IP address, similar to how router 23 selects a PGW-C to forward the session creation request from communication terminal 800 from among multiple PGW-Cs assigned the same IP address. Here, we will continue the explanation assuming that router 23 has selected PGW-U240 as the PGW-U to forward the uplink data from communication terminal 800.

[0206] Router 23 forwards the uplink data of communication terminal 800 to router 22 via network 20. Router 22 forwards the uplink data of communication terminal 800 to PGW-U240. PGW-U240 sends the uplink data of communication terminal 800 to the destination via PDN60.

[0207] Subsequently, if the communication path between SGW300 and PGW200 becomes unavailable, router 22 will advertise the communication path information. Router 23 will receive the communication path information advertised by router 22 and update its route table. In this case, based on the updated route table, router 23 may change the PGW-U that forwards the uplink data of communication terminal 800 from PGW-U240 to PGW-U140.

[0208] Router 23 forwards the uplink data of communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data of communication terminal 800 to PGW-U140. PGW-U140 sends the uplink data of communication terminal 800 to the destination via PDN60.

[0209] If the communication path between SGW300 and PGW200 is unavailable when SGW-C320 receives a session creation request from communication terminal 800, router 23 forwards the session creation request from communication terminal 800 to router 21 via network 20. Router 21 then forwards the session creation request from communication terminal 800 to PGW-C120.

[0210] PGW-C120 generates session information for communication terminal 800 in response to receiving a session creation request from communication terminal 800. PGW-C120 may generate 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] The PGW-C120 registers the session information of the generated communication terminal 800 in the database 150. The database 150 synchronizes the session information of the communication terminal 800 registered in the database 150 with the database 250. The database 150 may synchronize the session information of the communication terminal 800 with the database 250 in the same manner as when the database 250 synchronizes the session information of the communication terminal 800 with the database 250.

[0212] For example, database 150 notifies PGW-U140 of the synchronization completion. Database 150 may also notify PGW-C120 of the synchronization completion.

[0213] For example, database 250 notifies PGW-U240 of the synchronization completion. Database 250 may also notify PGW-C220 of the synchronization completion.

[0214] PGW-U140 establishes a communication tunnel between itself and SGW-U340 in order to create a session for communication terminal 800 to PDN60. PGW-U140 establishes the communication tunnel between itself and SGW-U340 based, for example, on the session information of communication terminal 800 included in the synchronization completion notification received from database 150.

[0215] PGW-C120 sends the session creation response from communication terminal 800 to router 21 in response to the session creation request from communication terminal 800. Router 21 forwards the session creation response from communication terminal 800 to router 23. Router 23 forwards the session creation response from communication terminal 800 to SGW-C320. Upon receiving the session creation response from communication terminal 800, SGW-C320 creates a session for communication terminal 800 to PDN60.

[0216] Subsequently, SGW-U340 receives the uplink data from communication terminal 800. SGW-U340 transmits the uplink data from communication terminal 800 to router 23. Router 23 forwards the uplink data from communication terminal 800 to router 21 via network 20. Router 21 forwards the uplink data from communication terminal 800 to PGW-U140. PGW-U140 transmits the uplink data from communication terminal 800 to the destination via PDN60.

[0217] Subsequently, when a communication path between SGW300 and PGW200 becomes available, PGW-U240 establishes a communication tunnel between itself and SGW-U340 in order to create a session for communication terminal 800 to PDN60. PGW-U240 establishes the communication tunnel between itself and SGW-U340, for example, based on the session information of communication terminal 800 included in the synchronization completion notification received from database 250.

[0218] Router 22 advertises the communication path information after the communication path between SGW300 and PGW200 becomes available. Router 23 receives the communication path information advertised by Router 22 and updates its route table. In this case, based on the updated route table, Router 23 may change the PGW-U that forwards the uplink data of the communication terminal 800 from PGW-U140 to PGW-U240.

[0219] Router 23 changes the PGW-U that forwards the uplink data of communication terminal 800 from PGW-U140 to PGW-U240, and then forwards the uplink data of communication terminal 800 to Router 22 via Network 20. Router 22 forwards the uplink data of communication terminal 800 to PGW-U240. PGW-U240 then sends the uplink data of communication terminal 800 to the destination via PDN60.

[0220] According to the system 10 shown in Figure 5, when PGW-C120 receives a session creation request for communication terminal 800 from SGW-C320, if communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods via the first ASN network, PGW-C120 generates session information for communication terminal 800, including the first IP address of PGW-U140. Since the first IP address of PGW-U140 is assigned only to PGW-U140 out of PGW-U140 and PGW-U240, the communication path that accesses PDN40 via the HPLMN where PGW100 is located can be used for data communication of communication terminal 800, regardless of the location of the VPLMN where 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 to be capable of both data communication via the first ASN network and data communication via the second ASN network, 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. Since 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 the communication paths available for data communication of communication terminal 800 redundant, providing a communication path that accesses PDN60 via the HPLMN where PGW100 is located and a communication path that accesses PDN60 via the HPLMN where PGW200 is located. This allows the communication path to access PDN60 via HPLMN, which has a shorter communication distance from VPLMN where SGW300 is located, as selected according to the BGP best path selection algorithm, to be used for data communication of the communication terminal 800.Therefore, according to the system 10 shown in Figure 5, the communication terminal 800 can either perform data communication via the first ASN network or data communication via the second ASN network, or both. By pre-registering whether the communication terminal 800 can perform data communication via the first ASN network or both, and determining the communication path used for data communication of the communication terminal 800 in both cases using the method described above, it is possible to access the PDN via the appropriate network according to the user's needs without installing a unique PGW for each user or assigning a unique IP address for each user. Thus, the system 10 shown in Figure 5 can realize an LTE communication service that allows access to the PDN via the appropriate network according to the user's needs and incorporates a CUPS architecture, with fewer resources.

[0221] Figure 6 is an explanatory diagram illustrating another example of the processing flow of System 10. Here, the starting state is described as a user of a communication terminal 800, which is registered with the terminal information management device 50 so that both data communication via the first ASN network and data communication via the second ASN network can be performed, visiting the VPLMN where the SGW300 is located.

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

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

[0224] In S208, database 150 synchronizes the session information of the communication terminal 800, which was registered by PGW-C120 in S204, between database 150 and database 250. In S210, database 150 notifies PGW-U140 of the completion of synchronization, in response to the synchronization of the session information of the communication terminal 800 between database 150 and database 250 in S208. In S212, database 250 notifies PGW-U240 of the completion of synchronization, in response to database 150 synchronizing the session information of the communication terminal 800 between database 150 and database 250 in S208.

[0225] In S214, SGW-U340 transmits the uplink data received from communication terminal 800 to PGW-U140. PGW-U140 then transmits the uplink data from communication terminal 800 to the destination via PDN60.

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

[0227] In an example of the processing flow of system 10 shown in Figure 6, the process in which PGW-C120 sends a session creation response from communication terminal 800 to SGW-C320 in response to PGW-C120 registering the session information of communication terminal 800 in database 150 may be replaced with the process in which PGW-C120 sends a session creation response from communication terminal 800 to SGW300 in response to PGW-U140 receiving a synchronization completion notification from database 150. In other words, S206 shown in Figure 6 may be performed after S210 shown in Figure 6.

[0228] Figure 7 schematically shows an example of the functional configuration of PGW-C120. PGW-C120 comprises a request receiving unit 122, a session information generation unit 126, a registration unit 128, a session information synchronization unit 130, a notification receiving unit 132, a response transmission unit 134, and a communication tunnel establishment unit 136. Note that it is not necessarily required that PGW-C120 include all of these components.

[0229] The request receiving unit 122 receives session creation requests from 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 communication terminal 800 requesting the creation of a session to PDN40. For example, the request receiving unit 122 receives a session creation request from communication terminal 800 requesting the creation of a session to PDN60. The request receiving unit 122 may also receive session creation requests from communication terminal 800 requesting the creation of a session to any other 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 also receives, for example, a session creation request for the communication terminal 800 from the SGW-C320.

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

[0232] The session information generation unit 126 generates session information for the communication terminal 800. For example, the session information generation unit 126 generates session information for the communication terminal 800 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 for the communication terminal 800 based on a session generation request from the communication terminal 800. For example, if the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods, the session information generation unit 126 generates session information for the communication terminal 800 including the first IP address of the PGW-U140. For example, if the communication terminal 800 is registered to be able to perform both data communication via the first ASN network and data communication via the second ASN network, the session information generation unit 126 generates session information for the communication terminal 800 including the second IP address of the PGW-U140.

[0234] The registration unit 128 registers the session information of the communication terminal 800 in the database 150. For example, 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.

[0235] The registration unit 128 may, for example, register session information of the communication terminal 800, including the second IP address of the PGW-U140, in the database 150. The registration unit 128 may also register session information of the communication terminal 800, including the first IP address of the PGW-U140, in the database 150.

[0236] The session information synchronization unit 130 synchronizes the session information of the communication terminal 800, including the second IP address of the PGW-U140, which has been registered in the database 150 by the registration unit 128, 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 notify a synchronization completion notification when it has synchronized the session information between database 150 and database 250. For example, the session information synchronization unit 130 may notify PGW-U140 of the synchronization completion notification. For example, the session information synchronization unit 130 may notify PGW-U240 of the synchronization completion notification. The session information synchronization unit 130 may also notify PGW-C220 of the synchronization completion notification.

[0238] The session information synchronization unit 130 notifies, for example, of the synchronization completion via the network 20. The session information synchronization unit 130 notifies, for example, of the synchronization completion via the router 21 and the network 20.

[0239] The notification receiving unit 132 receives a synchronization completion notification. The notification receiving unit 132 may receive a synchronization completion notification from, for example, the database 150. The notification receiving unit 132 may also receive a synchronization completion notification from, for example, the database 250. The notification receiving unit 132 may also receive a synchronization completion notification from the PGW-C220.

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

[0241] The response transmission unit 134 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800. For example, the response transmission unit 134 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800 that was received by the request reception unit 122.

[0242] The response transmission unit 134 transmits, for example, the session creation response of the communication terminal 800 to the SGW-C320. The response transmission unit 134 transmits, for example, the session creation response of the communication terminal 800 to the SGW-C320 via the network 20. The response transmission unit 134 transmits, for example, the session creation response of the communication terminal 800 to the SGW-C320 via the network 20 and the router 21.

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

[0244] The communication tunnel establishment unit 136 establishes a communication tunnel to generate a session for the communication terminal 800 to a PDN. For example, the communication tunnel establishment unit 136 establishes a communication tunnel to generate a session for the communication terminal 800 to PDN 40. For example, the communication tunnel establishment unit 136 establishes a communication tunnel to generate a session for the communication terminal 800 to PDN 60. The communication tunnel establishment unit 136 may also establish a communication tunnel to generate a session for the communication terminal 800 to any other PDN.

[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 a communication tunnel, for example, by having PGW-U140 establish a communication tunnel between PGW-U140 and SGW-U340. In this case, the communication tunnel establishment unit 136 may instruct PGW-U140 to establish a communication tunnel between PGW-U140 and SGW-U340. The communication tunnel establishment unit 136 also establishes a communication tunnel, for example, by establishing a communication tunnel between PGW-C120 and SGW-C320.

[0247] The communication tunnel establishment unit 136 establishes a communication tunnel, for example, based on the session information of the communication terminal 800. The communication tunnel establishment unit 136 establishes a communication tunnel, for example, based on the session information of the communication terminal 800 generated by the session information generation unit 126. The communication tunnel establishment unit 136 establishes a communication tunnel, for example, based on 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 also establish a 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] If the communication terminal 800 is registered to be capable of performing only data communication via the first ASN network, for example, the communication tunnel establishment unit 136 establishes a communication tunnel based on the session information of the communication terminal 800, including the first IP address of the PGW-U140, if the communication terminal 800 is registered to be capable of performing both data communication via the first ASN network and data communication via the second ASN network. If the communication terminal 800 is registered to be capable of performing both data communication via the first ASN network and data communication via the second ASN network, the communication tunnel establishment unit 136 establishes a communication tunnel based on the session information of the communication terminal 800, including the second IP address of the PGW-U140, which is synchronized between database 150 and database 250.

[0249] Figure 8 schematically shows an example of the functional configuration of the PGW-U140. The PGW-U140 includes a session information acquisition unit 142, a communication tunnel establishment unit 144, a data reception unit 146, and a data transmission unit 148. However, it is not necessarily required that the PGW-U140 include all of these components.

[0250] The session information acquisition unit 142 acquires session information of the communication terminal 800. For example, the session information acquisition unit 142 acquires session information of the communication terminal 800 generated by the PGW-C120.

[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 may, for example, receive a synchronization completion notification from database 150. The session information acquisition unit 142 may, for example, receive a synchronization completion notification from database 250. The session information acquisition unit 142 may, for example, receive a synchronization completion notification from PGW-C120. The session information acquisition unit 142 may also receive a synchronization completion notification from PGW-C220.

[0253] The communication tunnel establishment unit 144 establishes a communication tunnel in order to generate a session for the communication terminal 800 to the PDN. The communication tunnel establishment unit 144 establishes a communication tunnel between the PGW-U140 and the SGW-U340 in order to generate a session for the communication terminal 800 to the PDN.

[0254] The communication tunnel establishment unit 144 establishes a communication tunnel, for example, in accordance with instructions from the PGW-C120. The communication tunnel establishment unit 144 may also establish a communication tunnel autonomously without receiving instructions from the PGW-C120.

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

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

[0257] The communication tunnel establishment unit 144 establishes a communication tunnel based on the session information of the communication terminal 800 acquired by the session information acquisition unit 142, for example. If the communication terminal 800 is registered to be capable of performing only data communication via the network of the first ASN, the communication tunnel establishment unit 144 establishes a communication tunnel based on the session information of the communication terminal 800, including the first IP address of the PGW-U140, if the communication terminal 800 is registered to be capable of performing both 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 a communication tunnel based on the session information of the communication terminal 800, including the second IP address of the PGW-U140, 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 the data communication of the communication terminal 800. The data receiving unit 146 receives data related to the data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 146 receives data related to the 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 the 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 from the communication terminal 800. The data receiving unit 146 receives uplink data from the communication terminal 800 when, for example, PGW-U140 is selected from among multiple PGW-Us that have the same IP address assigned to them as the target for transmitting uplink data from the communication terminal 800.

[0261] The data receiving unit 146 receives, for example, downlink data from the communication terminal 800. The data receiving unit 146 receives downlink data from the communication terminal 800 when, for example, PGW-U140 is selected from among multiple PGW-Us that have the same IP address assigned to them as the target for transmitting downlink data from the communication terminal 800.

[0262] The communication tunnel establishment unit 144 establishes a communication tunnel, for example, when the data reception unit 146 receives uplink data from the communication terminal 800 and the PGW-U 140 does not hold session information for the communication terminal 800, by obtaining session information for the communication terminal 800 from the database 150. The communication tunnel establishment unit 144 also obtains session information for the communication terminal 800 from the database 150 when the data reception unit 146 receives uplink data from the communication terminal 800 for the first time.

[0263] The communication tunnel establishment unit 144 establishes a communication tunnel, for example, when the data reception unit 146 receives downlink data from the communication terminal 800 and the PGW-U 140 does not hold session information for the communication terminal 800, by obtaining session information for the communication terminal 800 from the database 150. The communication tunnel establishment unit 144 also obtains session information for the communication terminal 800 from the database 150 when the data reception unit 146 receives downlink data from the communication terminal 800 for the first time.

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

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

[0266] Figure 9 schematically shows an example of the functional configuration of the SGW-C320. The SGW-C320 comprises a storage unit 322, a route information receiving unit 324, a table generation unit 326, a request receiving unit 330, a request transmission unit 332, a response receiving unit 334, and a response provisioning unit 335. Note that it is not necessarily required that the SGW-C320 include all of these components.

[0267] The storage unit 322 stores various types of information. For example, the storage unit 322 stores a route table.

[0268] The route table includes, for example, communication path information showing the communication path between SGW300 and PGW100. The route table also includes, for example, communication path information showing the communication path between SGW300 and PGW200.

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

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

[0271] The routing information receiving unit 324 receives, for example, communication route information indicating the communication route between SGW300 and PGW100. The routing information receiving unit 324 also receives, for example, communication route information indicating the communication route between SGW300 and PGW200.

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

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

[0274] The request receiving unit 330 receives session creation requests from 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 communication terminal 800 requesting the creation of a session to PDN40. For example, the request receiving unit 330 receives a session creation request from communication terminal 800 requesting the creation of a session to PDN60. The request receiving unit 330 may also receive session creation requests from communication terminal 800 requesting the creation of a session to any other PDN.

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

[0276] The request transmission unit 332 transmits a session creation request for the communication terminal 800. The request transmission unit 332 transmits, for example, the session creation request for the communication terminal 800 that the request reception unit 330 has received.

[0277] The request transmission unit 332 transmits a session creation request for the communication terminal 800, for example, via the network 20. The request transmission unit 332 transmits a session creation request for the communication terminal 800, for example, via the router 23 and the network 20.

[0278] The request transmission unit 332 transmits a session creation request for the communication terminal 800, for example, based on the route table stored in the storage unit 322. If the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the data communication via the first ASN network and data communication via the second ASN network, the request transmission unit 332 transmits a session creation request for the communication terminal 800, including the first IP address of the PGW-U140, to the PGW 100.

[0279] If the communication terminal 800 is registered to be capable of both data communication via the network of the first ASN and data communication via the network of the second ASN, the request transmission unit 332 sends a session creation request for the communication terminal 800, including the second IP address of PGW-U140, to a PGW-C selected as the recipient of the session creation request from among a plurality of PGW-Cs that have been assigned the same IP address based on predetermined PGW selection conditions. In this case, the request transmission unit 332 sends the session creation request to a PGW-C selected as the recipient of the session creation request from among PGW-C120 and PGW-C220 based on the PGW selection conditions. The request transmission unit 332 also sends the session creation request to a PGW-C selected as the recipient of the session creation request via a communication path selected according to the BGP best path selection algorithm.

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

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

[0282] For example, the response receiving unit 334 receives the session generation response of the communication terminal 800 via the network 20. For example, the response receiving unit 334 receives the session generation response of the communication terminal 800 via the network 20 and the router 23.

[0283] The response providing unit 335 provides the session generation response of the communication terminal 800 received by the response receiving unit 334. For example, the response providing unit 335 provides the session generation response of the communication terminal 800 to the SGW-U 340.

[0284] FIG. 10 schematically 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 receiving unit 348, and a data transmitting unit 349. Note that it is not essential for the SGW-U 340 to include all of these configurations.

[0285] The storage unit 342 stores various information. For example, the storage unit 342 stores a routing table.

[0286] For example, the SGW-C 320 and the SGW-U 340 share a storage unit. In this case, the storage unit 322 and the storage unit 342 are the same storage unit. The SGW-C 320 and the SGW-U 340 do not have to share a storage unit. In this case, the storage unit 322 and the 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-C320. The table acquisition unit 344 may store the acquired route table in the storage unit 342.

[0288] The response acquisition unit 345 acquires the session creation response from the communication terminal 800 to the session creation request from the communication terminal 800. The response acquisition unit 345 acquires the session creation response from the communication terminal 800 provided by, for example, the SGW-C320. 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 from the communication terminal 800. The data receiving unit 348 also receives, for example, downlink data from the communication terminal 800.

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

[0292] The data transmission unit 349 transmits, for example, uplink data of the communication terminal 800. The data transmission unit 349 transmits the uplink data of the communication terminal 800 based, for example, on a route table stored in the storage unit 342. The data transmission unit 349 transmits the uplink data of the communication terminal 800 to the PGW 100 if, for example, the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods (data communication via the first ASN network and data communication via the second ASN network).

[0293] If the communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, the data transmission unit 349 transmits the uplink data of the communication terminal 800 to the PGW-U selected as the target for transmitting the uplink data of the communication terminal 800 from among a plurality of PGW-Us to which the same IP address has been assigned based on predetermined PGW selection conditions. In this case, the data transmission unit 349 transmits the uplink data of the communication terminal 800 to the PGW-U selected as the target for transmitting the uplink data of the communication terminal 800 from among PGW-U140 and PGW-U240 based on the PGW selection conditions. The data transmission unit 349 transmits the uplink data of the communication terminal 800 to the PGW-U selected as the target for transmitting the uplink data of the communication terminal 800 via a communication path selected according to the BGP best path selection algorithm.

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

[0295] Figure 11 schematically shows another example of system 10. Figure 11 shows an example in which system 10 provides 5G communication services.

[0296] System 10 may include H-SMF420 and H-UPF440. System 10 may include H-SMF520 and H-UPF540. System 10 may include V-SMF620 and V-UPF640. System 10 may include database 450. System 10 may include database 550. System 10 may include router 24. System 10 may include router 25. System 10 may include router 26. System 10 may include terminal information management device 50. System 10 may include request generation device 70.

[0297] The H-SMF420 has the function of managing sessions. The H-SMF420 may be an example of a first SMF, or an example of a second SMF.

[0298] The H-SMF420 is deployed, for example, in the network of the first ASN. The H-SMF420 is deployed, for example, in the network of the first country. The H-SMF420 is deployed, for example, in the HPLMN. In one example shown in Figure 11, the H-SMF420 is deployed in the HPLMN based in Tokyo, Japan, with ASN 65001.

[0299] The H-SMF420 may be assigned an IP address. In the example of system 10 shown in Figure 11, the H-SMF420 is assigned the IP address AAAA with subnet mask 32.

[0300] The H-UPF440 has the function of relaying data related to data communication of the communication terminal 800. For example, the H-UPF440 has the function of relaying uplink data of the communication terminal 800. For example, the H-UPF440 has the function of relaying downlink data of the communication terminal 800. The H-UPF440 may be an example of a first UPF, an example of a second UPF, or an example of a third UPF.

[0301] The H-UPF440 transmits the uplink data of the communication terminal 800 to the destination via, for example, an external network. The H-UPF440 transmits the uplink data of the communication terminal 800 to the destination via, for example, the DN80. The H-UPF440 transmits the uplink data of the communication terminal 800 to the destination via, for example, the DN90. The H-UPF440 may transmit the uplink data of the communication terminal 800 to the destination via other DNs. The H-UPF440 is connected to an external network via, for example, the N6 interface.

[0302] The DN80 is, for example, a private network. The DN80 may be a public network.

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

[0304] The H-UPF440 transmits the downlink data of the communication terminal 800 to other UPFs via, for example, the network 20. The H-UPF440 transmits the downlink data of the communication terminal 800 to the V-UPF640 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 DNs such as the DN80 and DN90, for example. The network 20 may include the Internet.

[0306] The H-UPF440 is arranged in a network where the H-SMF420 is arranged. In an example shown in FIG. 11, the H-UPF440 is arranged in the HPLMN based in Tokyo, Japan, with an ASN of 65001.

[0307] The H-UPF440 may be assigned an IP address. For example, the H-UPF440 may be assigned multiple IP addresses that are different from each other. For example, the H-UPF440 may be assigned a first IP address and a second IP address that is different from the first IP address. The first IP address of the H-UPF440 may be used to access DN80. The second IP address of the H-UPF440 may be used to access DN90. The H-UPF440 may be assigned three or more IP addresses that are different from each other. In the example of system 10 shown in Figure 11, the H-UPF440 is assigned IP address BBBB with subnet mask 32 as its first IP address and IP address CCCC with subnet mask 32 as its second IP address.

[0308] The H-SMF520 has the function of managing sessions. The H-SMF520 may have the same functions as the H-SMF420. The H-SMF520 may be an example of a first SMF, or an example of a second SMF.

[0309] The H-SMF520 is deployed, for example, on the network of a second ASN different from the first ASN. The H-SMF520 is deployed, for example, on the network of a second country different from the first country. The H-SMF520 is deployed, for example, on an HPLMN. In one example shown in Figure 11, the H-SMF520 is deployed on an HPLMN based in Singapore with ASN 65002.

[0310] The H-SMF520 may be deployed in the network of a first country. For example, if the H-SMF420 is deployed in a network based in Tokyo, Japan, the H-SMF520 may be deployed in a network based in Osaka, Japan.

[0311] An IP address may be assigned to the H-SMF520. For example, the H-SMF520 may be assigned the same IP address as the H-SMF420. For example, the same IP address may be assigned to both the H-SMF420 and H-SMF520 using IP Anycast. In the example of system 10 shown in Figure 11, the H-SMF520 is assigned the IP address AAAA with subnet mask 32.

[0312] The H-UPF540 has the function of relaying data related to data communication of the communication terminal 800. For example, the H-UPF540 has the function of relaying uplink data of the communication terminal 800. For example, the H-UPF540 has the function of relaying downlink data of the communication terminal 800. The H-UPF540 may be an example of a first UPF, an example of a second UPF, or an example of a third UPF.

[0313] The H-UPF540 transmits uplink data from the communication terminal 800 to a destination, for example, via an external network. The H-UPF540 transmits uplink data from the communication terminal 800 to a destination, for example, via DN90. The H-UPF540 may also transmit uplink data from the communication terminal 800 to a destination via other DNs. The H-UPF540 is connected to an external network, for example, via the N6 interface.

[0314] H-UPF540 transmits, for example, downlink data from communication terminal 800 to another UPF via network 20. H-UPF540 also transmits, for example, downlink data from communication terminal 800 to V-UPF640 via network 20.

[0315] The H-UPF540 is deployed in the same network as, for example, the H-SMF520. In one example shown in Figure 11, the H-UPF540 is deployed in HPLMN, which is based in Singapore and has ASN 65002.

[0316] An IP address may be assigned to the H-UPF540. For example, the H-UPF540 may be assigned the second IP address of the H-UPF440. For example, the same IP address may be assigned to both the H-UPF440 and the H-UPF540 using IP Anycast. The H-UPF540 may be assigned multiple IP addresses that are different from each other. In the example of system 10 shown in Figure 11, the H-UPF540 is assigned the IP address CCCC with subnet mask 32.

[0317] The V-SMF620 has the function of managing sessions. The V-SMF620 may be an example of a third SMF.

[0318] The V-SMF620 is located in a third ASN network, which is different from the first and second ASNs. The V-SMF620 may also be located in the first ASN network or in the second ASN network.

[0319] The V-SMF620 may be deployed in the network of country 1, or in the network of country 2. The V-SMF620 may also be deployed in the network of a third country, which is different from country 1 and country 2.

[0320] V-SMF620 is located, for example, at VPLMN. In one example shown in Figure 11, V-SMF620 is located at VPLMN, which is based in Singapore and has ASN 65003.

[0321] The V-SMF620 may be assigned an IP address. In the example of system 10 shown in Figure 11, the V-SMF620 is assigned the IP address DDDD with subnet mask 32.

[0322] The V-UPF640 has the function of relaying data related to data communication of the communication terminal 800. For example, the V-UPF640 has the function of relaying uplink data of the communication terminal 800. For example, the V-UPF640 has the function of relaying downlink data of the communication terminal 800. The V-UPF640 may be an example of a second UPF, or an example of a third UPF.

[0323] For example, V-UPF640 transmits uplink data from communication terminal 800 to other UPFs via network 20. For example, V-UPF640 transmits uplink data from communication terminal 800 to H-UPF440 via network 20. For example, V-UPF640 transmits uplink data from communication terminal 800 to H-UPF540 via network 20.

[0324] V-UPF640 receives downlink data for communication terminal 800 from another UPF via network 20, for example. V-UPF640 receives downlink data for communication terminal 800 from H-UPF440 via network 20, for example. V-UPF640 receives downlink data for communication terminal 800 from H-UPF540 via network 20, for example.

[0325] The V-UPF640 is deployed in the same network as, for example, the V-SMF620. In one example shown in Figure 11, the V-UPF640 is deployed in the VPLMN based in Singapore with ASN 65003.

[0326] The V-UPF640 may be assigned an IP address. In the example of system 10 shown in Figure 11, the V-UPF640 is assigned the IP address EEEE with subnet mask 32.

[0327] Router 24 has the function of relaying data. Router 24 relays, for example, uplink data. Router 24 relays, for example, downlink data.

[0328] Router 24 is located in the same network as, for example, the H-SMF420. Router 24 is located in the network of, for example, the first ASN. Router 24 may be located in a different network than the network in which the H-SMF420 is located.

[0329] Router 24 is, for example, separated from H-SMF420 and H-UPF440. Router 21 may be integrated with either H-SMF420 or H-UPF440.

[0330] Router 25 has the function of relaying data. Router 25 relays, for example, uplink data. Router 25 relays, for example, downlink data.

[0331] Router 25 is located in the same network as, for example, the H-SMF520. Router 25 is located in the network of, for example, the second ASN. Router 25 may be located in a different network from the network in which the H-SMF520 is located.

[0332] Router 25 is, for example, separate from H-SMF520 and H-UPF540. Router 25 may also be integrated with H-SMF520 or H-UPF540.

[0333] Router 26 has the function of relaying data. Router 26 relays, for example, uplink data. Router 26 relays, for example, downlink data.

[0334] Router 26 is located in the same network as, for example, the V-SMF620. Router 26 is located in the same network as, for example, the third ASN. Router 26 may be located in a different network than the one in which the V-SMF620 is located.

[0335] Router 26 is, for example, separate from V-SMF620 and V-UPF640. Router 26 may also be integrated with V-SMF620 or V-UPF640.

[0336] For example, inter-organizational routing information is exchanged between routers 24, 25, and 26 according to BGP. For example, routing information is exchanged between routers 24, 25, and 26 in response to changes in routing information. Routing information may also be exchanged periodically between routers 24, 25, and 26.

[0337] Router 24 may advertise routing information to, for example, Router 26. Router 24 may also advertise routing information to IPX. Router 25 may advertise routing information in the same manner as Router 24.

[0338] In the example of system 10 shown in Figure 11, router 24 advertises ASN=65001, IP address of H-SMF420=AAAA / 32, first IP address of H-UPF440=BBBB / 32, and second IP address of H-UPF440=CCCC / 32. In the example of system 10 shown in Figure 11, router 25 advertises ASN=65002, IP address of H-SMF520=AAAA / 32, and IP address of H-UPF540=CCCC / 32.

[0339] Router 26 advertises routing information to, for example, Router 24 and Router 25. Router 26 may also advertise routing information to IPX. In an example of system 10 shown in Figure 11, Router 26 advertises ASN=65003, IP address of V-SMF620=DDDD / 32, and IP address of V-UPF640=EEEE / 32.

[0340] Router 26 generates a route table based on, for example, the communication path information advertised by Router 24 and Router 25, respectively. In an example of System 10 shown in Figure 11, Router 26 generates a route table that includes the IP address of ASN=65001 and H-SMF420=AAAA / 32, the first IP address of ASN=65001 and H-UPF440=BBBB / 32, the second IP address of ASN=65001 and H-UPF440=CCCC / 32, the IP address of ASN=65002 and H-SMF520=AAAA / 32, and the IP address of ASN=65002 and H-UPF540=CCCC / 32.

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

[0342] The request generation device 70 generates session generation requests for communication terminal 800 that request the creation of a session to a DN. For example, the request generation device 70 generates a session generation request for communication terminal 800 that requests the creation of a session to DN80. For example, the request generation device 70 generates a session generation request for communication terminal 800 that requests the creation of a session to DN90. The request generation device 70 may also generate session generation requests for communication terminal 800 that request the creation of sessions to other DNs.

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

[0344] A session creation request includes, for example, the IP address of the communication terminal 800. A session creation request includes, for example, the IMSI of the communication terminal 800. A session creation request includes, for example, the IP address of the V-SMF620. A session creation request includes, for example, the IP address of the V-UPF640. A session creation request includes, for example, the TEID assigned to the communication tunnel of the V-SMF620. A session creation request includes, for example, the TEID assigned to the communication tunnel of the V-UPF640. A session creation request includes, for example, the IP address of the H-SMF420. A session creation request includes, for example, the first IP address or the second IP address of the H-UPF440. For example, if the communication terminal 800 is registered with the terminal information management device 50 such that only data communication via the network of the first ASN is possible among data communication via the network of the first ASN and data communication via the network of the second ASN, then the session creation request includes the first IP address of the H-UPF440. For example, if a communication terminal 800 is registered with the terminal information management device 50 so that it can perform both data communication over the network of the first ASN and data communication over the network of the second ASN, the session creation request includes the second IP address of the H-UPF440. The session creation request may further include any other information necessary to create a session to the DN.

[0345] In the example of system 10 shown in Figure 11, HPLMN may be established at three or more locations. In this case, the second IP address of H-UPF440 may be assigned to the H-UPF at each of the three or more locations.

[0346] Here, we will describe an example of generating a session to the DN of a communication terminal 800 of a user visiting the VPLMN where the V-SMF620 is located. First, we will describe an example of generating a session of the communication terminal 800 to DN 80. Here, we assume that the communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the network of the first ASN, out of the two data communication methods, is possible.

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

[0348] Since the communication terminal 800 is registered with the terminal information management device 50 so that only data communication via the first ASN network is possible among data communication via the first ASN network and data communication via the second ASN network, the request generation device 70 generates a session creation request for the communication terminal 800, including the first IP address of the H-UPF440. The request generation device 70 transmits the generated session creation request for the communication terminal 800 to the V-SMF620 via the network 20.

[0349] The V-SMF620 sends the session creation request received from the communication terminal 800 to the router 26. If the session creation request from the communication terminal 800 includes the first IP address of the H-UPF440, the router 26 forwards the session creation request from the communication terminal 800 to the router 24 via the network 20. The router 24 forwards the session creation request from the communication terminal 800 to the H-SMF420.

[0350] H-SMF420 generates session information for communication terminal 800 in response to receiving a session creation request from communication terminal 800. For example, H-SMF420 generates session information for communication terminal 800 based on the session creation request from communication terminal 800. If the session creation request from communication terminal 800 includes the first IP address of H-UPF440, the session information for communication terminal 800 includes, for example, the IP address of communication terminal 800, the first IP address of H-UPF440, the TEID assigned to the communication tunnel of H-UPF440, the IP address of V-UPF640, and the TEID assigned to the communication tunnel of V-UPF640. The session information for 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 necessary to generate a session to DN80. The session information of the communication terminal 800, including the first IP address of H-UPF440, may be an example of the first session information of the communication terminal 800.

[0351] H-SMF420 may register the session information of the generated communication terminal 800 in the database 450 corresponding to H-UPF440. H-SMF420 may also provide the session information of the generated communication terminal 800 to H-UPF440.

[0352] H-SMF420 instructs H-UPF440 to establish a communication tunnel between H-UPF440 and V-UPF640 in order to generate a session of communication terminal 800 to DN80. H-SMF420 instructs H-UPF440 to establish a communication tunnel between H-UPF440 and V-UPF640 by, for example, providing H-UPF440 with session information of communication terminal 800. H-UPF440 may establish a communication tunnel between H-UPF440 and V-UPF640 based on the session information of communication terminal 800, in accordance with instructions from H-SMF420.

[0353] H-SMF420 sends the session creation response from communication terminal 800 to router 24 in response to the session creation request from communication terminal 800. Router 24 forwards the session creation response from communication terminal 800 to router 26. Router 26 forwards the session creation response from communication terminal 800 to V-SMF620. Upon receiving the session creation response from communication terminal 800, V-SMF620 creates a session for communication terminal 800 to DN80.

[0354] The session creation response includes, for example, the first IP address of H-UPF440 and the TEID assigned to the communication tunnel of H-UPF440. The session creation response may further include the IP address of H-SMF420 and the TEID assigned to the communication tunnel of H-SMF420. The session creation response may further include any other information necessary to create a session of the communication terminal 800 to DN80.

[0355] Subsequently, V-UPF640 receives the uplink data from communication terminal 800. V-UPF640 transmits the uplink data from communication terminal 800 to router 26. Router 26 forwards the uplink data from communication terminal 800 to router 24 via network 20. Router 24 forwards the uplink data from communication terminal 800 to H-UPF440. H-UPF440 transmits the uplink data from communication terminal 800 to the destination via DN80.

[0356] Next, we will describe an example of generating a session from the communication terminal 800 to DN90. Here, we assume that the communication terminal 800 is registered with the terminal information management device 50 so that it can perform both data communication via the first ASN network and data communication via the second ASN network.

[0357] The request generation device 70 generates a session creation request for the communication terminal 800 in response to receiving an attach request from the communication terminal 800. Since the communication terminal 800 is registered with the terminal information management device 50 so that both data communication over the first ASN network and data communication over the second ASN network can be performed, the request generation device 70 generates a session creation request for the communication terminal 800 that includes the second IP address of the H-UPF440. The request generation device 70 transmits the generated session creation request for the communication terminal 800 to the V-SMF620 via the network 20.

[0358] The V-SMF620 sends the session creation request received from the communication terminal 800 to the router 26. If the session creation request from the communication terminal 800 includes the second IP address of the H-UPF440, the router 26 selects an H-SMF from among several H-SMFs assigned the same IP address to forward the session creation request from the communication terminal 800. Here, we will continue the explanation assuming that the router 26 selects an H-SMF from among the H-SMF420 and H-SMF520 to forward the session creation request from the communication terminal 800.

[0359] Router 26 selects the H-SMF to forward the session creation request of communication terminal 800, for example, by selecting the communication path to which the session creation request of communication terminal 800 will be forwarded. Router 26 also selects the communication path to which the session creation request of communication terminal 800 will be forwarded, for example, by selecting the communication path from Router 26 to the router corresponding to the H-SMF to which the session creation request of communication terminal 800 will be forwarded. Here, we will continue the explanation 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 to which the session creation request of communication terminal 800 will be forwarded, for example, based on its route table. Router 26 selects a communication path to which the session creation request of communication terminal 800 will be forwarded, for example, according to the BGP best path selection algorithm. Router 26 selects the communication path with the shortest communication distance among the communication paths from Router 26 to the router corresponding to each of the multiple H-SMFs that are assigned the same IP address, as the communication path to which the session creation request of communication terminal 800 will be forwarded. Here, we will continue the explanation assuming that Router 26 has selected the communication path from Router 26 to Router 25 as the communication path to which the session creation request of communication terminal 800 will be forwarded.

[0361] Router 26 selects the H-SMF520 as the H-SMF to forward the session creation request from communication terminal 800 by selecting the communication path from Router 26 to Router 25 as the communication path to which the session creation request from communication terminal 800 will be forwarded. Router 26 forwards the session creation request from communication terminal 800 to Router 25 via Network 20. Router 25 forwards the session creation request from communication terminal 800 to H-SMF520.

[0362] In response to receiving a session creation request from the communication terminal 800, the H-SMF520 generates session information for the communication terminal 800. If the session creation request from the communication terminal 800 includes the second IP address of the H-UPF440, the session information for the communication terminal 800 includes, for example, the IP address of the communication terminal 800, the second IP address of the H-UPF440, the TEID assigned to the communication tunnel of the H-UPF440 and the communication tunnel of the H-UPF540, the IP address of the V-UPF640, and the TEID assigned to the communication tunnel of the V-UPF640. The session information for the communication terminal 800 may further include the IP address of the H-SMF420, the TEID assigned to the communication tunnel of the H-SMF420 and the H-SMF520, the IP address of the V-SMF620, and the TEID assigned to the communication tunnel of the V-SMF620. The session information of communication terminal 800 may include other optional information for generating a session to DN90. The session information of communication terminal 800, including the second IP address of H-UPF440, may be an example of the second session information of communication terminal 800.

[0363] H-SMF520, for example, registers the session information of the generated communication terminal 800 in a database 550 corresponding to H-UPF540. Database 550 includes, for example, a message queue for temporarily storing the session information of the communication terminal 800. Database 550 may be an example of a first storage unit or an example of a second storage unit.

[0364] Database 550 is, for example, separate from H-SMF520 and H-UPF540. Database 550 may also be integrated with H-SMF520 or H-UPF540.

[0365] Database 550 is located, for example, on the network where H-SMF520 is located. Database 550 is located, for example, on the network of the second ASN. Database 550 may be located on a different network from the network where H-SMF520 is located.

[0366] Database 550 synchronizes, for example, the session information of the communication terminal 800 registered in database 550 between database 550 and database 450, which corresponds to H-UPF440. Database 550 may synchronize the session information of the communication terminal 800 between database 550 and database 450, for example, in the same way that database 250 synchronizes the session information of the 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] Database 550 notifies H-UPF540 of the completion of a synchronization process, for example, to synchronize the session information of the communication terminal 800 between database 550 and database 450. Database 550 may also notify H-SMF520 of the completion of the synchronization. The completion of the synchronization includes, for example, the session information of the communication terminal 800.

[0368] For example, database 450 notifies H-UPF440 of the synchronization completion. Database 450 may also notify H-SMF420 of the synchronization completion.

[0369] Database 450 is, for example, separate from H-SMF420 and H-UPF440. Database 450 may also be integrated with H-SMF420 or H-UPF440.

[0370] Database 450 is located, for example, on the network where H-SMF420 is located. Database 450 is located, for example, on the network of the first ASN. Database 450 may be located on a different network from the network where H-SMF420 is located.

[0371] H-SMF520 instructs H-UPF540 to establish a communication tunnel between H-UPF540 and V-UPF640 in order to create a session for communication terminal 800 to DN90. H-UPF540 may establish a communication tunnel between H-UPF540 and V-UPF640 based on the session information of communication terminal 800 included in the synchronization completion notice notified from database 550, in accordance with the instructions from H-SMF520.

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

[0373] H-SMF520 sends the session creation response from communication terminal 800 to router 25 in response to the session creation request from communication terminal 800. Router 25 forwards the session creation response from communication terminal 800 to router 26. Router 26 forwards the session creation response from communication terminal 800 to V-SMF620. Upon receiving the session creation response from communication terminal 800, V-SMF620 creates a session for communication terminal 800 to DN90.

[0374] The session generation response includes, for example, the second IP address of H-UPF440 and the TEID assigned to the communication tunnel of H-UPF440 and the communication tunnel of H-UPF540. The session generation response may further include the IP address of H-SMF420 and the TEID assigned to the communication tunnel of H-SMF420 and the communication tunnel of H-SMF520. The session generation response may further include any other information necessary to generate a session of the communication terminal 800 to DN90.

[0375] Subsequently, V-UPF640 receives the uplink data from the communication terminal 800. V-UPF640 sends the uplink data from the communication terminal 800 to router 26. Router 26 selects an H-UPF to forward the uplink data from the communication terminal 800. Router 26 may select an H-UPF to forward the uplink data from the communication terminal 800 from among multiple H-SMFs assigned the same IP address, similar to how it selects an H-SMF to forward the session creation request from the communication terminal 800 from among multiple H-UPFs assigned the same IP address. Here, we will continue the explanation assuming that router 26 has selected H-UPF540 as the H-UPF to forward the uplink data from the communication terminal 800.

[0376] Router 26 forwards the uplink data of communication terminal 800 to router 25 via network 20. Router 25 forwards the uplink data of communication terminal 800 to H-UPF540. H-UPF540 sends the uplink data of communication terminal 800 to the destination via DN90.

[0377] Subsequently, if the communication path between V-UPF640 and H-UPF540 becomes unavailable, such as when H-UPF540 fails or when maintenance work is performed on H-UPF540, router 25 will advertise communication path information. Router 26 will receive the communication path information advertised by router 25 and update its route table. In this case, router 26 may change the H-UPF that forwards the uplink data of communication terminal 800 from H-UPF540 to H-UPF440 based on the updated route table.

[0378] Router 26 forwards the uplink data of communication terminal 800 to router 24 via network 20. Router 24 forwards the uplink data of communication terminal 800 to H-UPF440. H-UPF440 sends the uplink data of communication terminal 800 to the destination via DN90.

[0379] If, at the time V-SMF620 receives a session creation request from communication terminal 800, the communication path between V-UPF640 and H-UPF540 is unavailable, router 26 forwards the session creation request from communication terminal 800 to router 24 via network 20. Router 24 then forwards the session creation request from communication terminal 800 to H-SMF420.

[0380] The H-SMF420 generates session information for the communication terminal 800 in response to receiving a session creation request from the communication terminal 800. The H-SMF420 may generate session information for the communication terminal 800 in the same manner as when the H-SMF520 generates session information for the communication terminal 800 in order to create a session for the communication terminal 800 to DN90.

[0381] H-SMF420 registers the session information of the generated communication terminal 800 in database 450. Database 450 synchronizes the session information of the communication terminal 800 registered in database 450 with database 550. Database 450 may synchronize the session information of the communication terminal 800 with database 450 and database 550 in the same manner as when database 250 synchronizes the session information of the communication terminal 800 with database 250 and database 150. Database 450 may be an example of a session information synchronization unit.

[0382] For example, database 450 notifies H-UPF440 of the synchronization completion. Database 450 may also notify H-SMF420 of the synchronization completion.

[0383] For example, database 550 notifies H-UPF540 of the synchronization completion. Database 550 may also notify H-SMF520 of the synchronization completion.

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

[0385] H-SMF420 sends the session creation response from communication terminal 800 to router 24 in response to the session creation request from communication terminal 800. Router 24 forwards the session creation response from communication terminal 800 to router 26. Router 26 forwards the session creation response from communication terminal 800 to V-SMF620. Upon receiving the session creation response from communication terminal 800, V-SMF620 creates a session for communication terminal 800 to DN90.

[0386] Subsequently, V-UPF640 receives the uplink data from communication terminal 800. V-UPF640 transmits the uplink data from communication terminal 800 to router 26. Router 26 forwards the uplink data from communication terminal 800 to router 24 via network 20. Router 24 forwards the uplink data from communication terminal 800 to H-UPF440. H-UPF440 transmits the uplink data from communication terminal 800 to the destination via DN90.

[0387] Subsequently, if a communication path between V-UPF640 and H-UPF540 becomes available, H-SMF520 instructs H-UPF540 to establish a communication tunnel between H-UPF540 and V-UPF640 in order to generate a session for communication terminal 800 to DN90. H-UPF540 may establish a communication tunnel between H-UPF540 and V-UPF640 based on the session information of communication terminal 800 included in the synchronization completion notice notified from database 550, in accordance with the instructions from H-SMF520.

[0388] Router 25 advertises the communication path information after the communication path between V-UPF640 and H-UPF540 becomes available. Router 26 receives the communication path information advertised by Router 25 and updates its route table. In this case, based on the updated route table, Router 25 may change the H-UPF that forwards the uplink data of the communication terminal 800 from H-UPF440 to H-UPF540.

[0389] Router 26 forwards the uplink data of communication terminal 800 to router 25 via network 20. Router 25 forwards the uplink data of communication terminal 800 to H-UPF540. H-UPF540 sends the uplink data of communication terminal 800 to the destination via DN90.

[0390] According to the system 10 shown in Figure 11, when H-SMF420 receives a session creation request for communication terminal 800 from V-SMF620, if communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods (data communication via the first ASN network and data communication via the second ASN network), H-SMF420 generates session information for communication terminal 800, including the first IP address of H-UPF440. Since the first IP address of H-UPF440 is assigned only to H-UPF440 out of H-UPF440 and H-UPF540, the communication path that accesses DN80 via the HPLMN where H-SMF420 is located can be used for data communication of communication terminal 800, regardless of the location of the VPLMN where V-SMF620 is located. Furthermore, when H-SMF420 receives a session creation request for communication terminal 800 from V-SMF620, if communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, 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, by synchronizing the session information for communication terminal 800 between database 450 and database 550, the communication paths available for data communication of communication terminal 800 can be made redundant, with a communication path accessing DN90 via the HPLMN where H-SMF420 is located and a communication path accessing DN90 via the HPLMN where H-SMF520 is located. This allows the communication path to access DN90 via the HPLMN, which has a shorter communication distance from the VPLMN where the V-SMF620 is located, as selected according to the BGP best path selection algorithm, to be used for data communication of the communication terminal 800.Therefore, according to the system 10 shown in Figure 11, the communication terminal 800 can either perform data communication via the first ASN network or both, and in both cases, the communication path used for data communication of the communication terminal 800 is determined in the manner described above. This allows users to access the DN via the appropriate network according to their needs without having to install a unique UPF for each user or assign a unique IP address to each user.

[0391] Figure 12 is an explanatory diagram illustrating another example of the processing flow of system 10. Here, the starting state is described as a user of a communication terminal 800, which is registered with the terminal information management device 50 so that both data communication over the first ASN network and data communication over the second ASN network can be performed, visiting the VPLMN where the V-SMF620 is located.

[0392] In S302, V-SMF620 transmits the session creation request from the communication terminal 800, received from the request generation device 70, to H-SMF. Here, since the communication path between V-UPF640 and H-UPF540 is unavailable at the time V-SMF620 receives the session creation request from the communication terminal 800, we will continue the explanation assuming that V-SMF620 transmits the session creation request from the communication terminal 800 to H-SMF420.

[0393] In S304, H-SMF420 generates session information for communication terminal 800 based on the session generation 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 sends a session generation response from communication terminal 800 to V-SMF620 in response to the session generation request for communication terminal 800.

[0394] In S308, database 450 synchronizes the session information of the communication terminal 800, which was registered by H-SMF420 in S304, between database 450 and database 550. In S310, database 450 notifies H-UPF440 of the completion of synchronization in response to the synchronization of the session information of the communication terminal 800 between database 450 and database 550 in S308. In S312, database 550 notifies H-UPF540 of the completion of synchronization in response to database 450 synchronizing the session information of the communication terminal 800 between database 450 and database 550 in S308.

[0395] In S314, V-UPF640 transmits the uplink data received from communication terminal 800 to H-UPF440. H-UPF440 then transmits the uplink data from communication terminal 800 to the destination via DN90.

[0396] Subsequently, in S316, after the communication path between V-UPF640 and H-UPF540 becomes available, V-UPF640 transmits the uplink data of communication terminal 800 received from communication terminal 800 to H-UPF540. H-UPF540 transmits the uplink data of communication terminal 800 to the destination via DN90.

[0397] In an example of the processing flow of system 10 shown in Figure 12, the process in which H-SMF420 sends a session creation response for communication terminal 800 to V-SMF620 in response to H-SMF420 registering the session information of communication terminal 800 in database 450 may be replaced with the process in which H-SMF420 sends a session creation response for communication terminal 800 to V-SMF620 in response to H-UPF440 receiving a synchronization completion notification from database 450. In other words, S306 shown in Figure 12 may be performed after S310 shown in Figure 12.

[0398] Figure 13 schematically shows an example of the functional configuration of the H-SMF420. The H-SMF420 comprises a request receiving unit 422, a session information generation unit 426, a registration unit 428, a session information synchronization unit 430, a notification receiving unit 432, a response transmission unit 434, and a communication tunnel establishment unit 436. Note that it is not necessarily required that the H-SMF420 include all of these components.

[0399] The request receiving unit 422 receives session creation requests from communication terminal 800 requesting the creation of a session to a DN. For example, the request receiving unit 422 receives a session creation request from communication terminal 800 requesting the creation of a session to DN80. For example, the request receiving unit 422 receives a session creation request from communication terminal 800 requesting the creation of a session to DN90. The request receiving unit 422 may also receive session creation requests from communication terminal 800 requesting the creation of a session to any other DN.

[0400] The request receiving unit 422 receives, for example, a session creation request from the communication terminal 800 from the V-SMF620. The request receiving unit 422 receives, for example, a session creation request from the communication terminal 800 from the V-SMF620 via the network 20. The request receiving unit 422 receives, for example, a session creation request from the communication terminal 800 from the V-SMF620 via the network 20 and the router 24.

[0401] The session information generation unit 426 generates session information for the communication terminal 800. For example, the session information generation unit 426 generates session information for the communication terminal 800 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, for example, based on a session generation request from the communication terminal 800. If the communication terminal 800 is registered to be able to perform only data communication via the first ASN network, among data communication via the first ASN network and data communication via the second ASN network, the session information generation unit 426 generates session information for the communication terminal 800, including the first IP address of the H-UPF440. If the communication terminal 800 is registered to be able to perform both data communication via the first ASN network and data communication via the second ASN network, the session information generation unit 426 generates session information for the communication terminal 800, including the second IP address of the H-UPF440.

[0403] The registration unit 428 registers the session information of the communication terminal 800 in the database 450. For example, 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.

[0404] The registration unit 428 may, for example, register session information of the communication terminal 800, including the second IP address of the H-UPF440, in the database 450. The registration unit 428 may also register session information of the communication terminal 800, including the first IP address of the H-UPF440, in the database 450.

[0405] The session information synchronization unit 430 synchronizes the session information of the communication terminal 800, including the second IP address of the H-UPF440, which has been registered in the database 450 by the registration unit 428, between database 450 and database 550. The session information synchronization unit 430 may synchronize the session information between database 450 and database 550 in the same manner as when database 250 synchronizes the session information of the communication terminal 800 between database 250 and database 150.

[0406] The session information synchronization unit 430 may notify a synchronization completion notification when it has synchronized the session information between database 450 and database 550. For example, the session information synchronization unit 430 may notify H-UPF440 of the synchronization completion notification. For example, the session information synchronization unit 430 may notify H-UPF540 of the synchronization completion notification. The session information synchronization unit 430 may also notify H-SMF520 of the synchronization completion notification.

[0407] The session information synchronization unit 430 notifies, for example, of the synchronization completion via the network 20. The session information synchronization unit 430 notifies, for example, of the synchronization completion via the router 24 and the network 20.

[0408] The notification receiving unit 432 receives a synchronization completion notification. The notification receiving unit 432 may receive a synchronization completion notification from, for example, the database 450. The notification receiving unit 432 may also receive a synchronization completion notification from, for example, the database 550. The notification receiving unit 432 may also receive a synchronization completion notification from the H-SMF520.

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

[0410] The response transmission unit 434 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800. For example, the response transmission unit 434 transmits the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800 that was received by the request reception unit 422.

[0411] The response transmission unit 434 transmits, for example, the session creation response of the communication terminal 800 to the V-SMF620. The response transmission unit 434 transmits, for example, the session creation response of the communication terminal 800 to the V-SMF620 via the network 20. The response transmission unit 434 transmits, for example, the session creation response of the communication terminal 800 to the V-SMF620 via the network 20 and the router 24.

[0412] The response transmission unit 434 transmits a session generation response for the communication terminal 800, for example, in response to the session information generation unit 426 generating session information for the communication terminal 800. The response transmission unit 434 transmits a session generation response for the communication terminal 800, for example, in response to the registration unit 428 registering the session information for the communication terminal 800 in the database 450. The response transmission unit 434 transmits a session generation response for the communication terminal 800, for example, in response to the session information of the communication terminal 800 being synchronized between the database 450 and the database 550. The response transmission unit 434 transmits a session generation response for the communication terminal 800, for example, in response to the session information synchronization unit 430 synchronizing the session information of the communication terminal 800 between the database 450 and the database 550. The response transmission unit 434 may also transmit a session generation response for the communication terminal 800, for example, 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 generate a session for the communication terminal 800 to a DN. The communication tunnel establishment unit 436 establishes a communication tunnel to generate a session for the communication terminal 800 to DN 80, for example. The communication tunnel establishment unit 436 establishes a communication tunnel to generate a session for the communication terminal 800 to DN 90, for example. The communication tunnel establishment unit 436 may also establish a communication tunnel to generate a session for the communication terminal 800 to any other DN.

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

[0415] The communication tunnel establishment unit 436 establishes a communication tunnel, for example, by having H-UPF440 establish a communication tunnel between H-UPF440 and V-UPF640. In this case, the communication tunnel establishment unit 436 may instruct H-UPF440 to establish a communication tunnel between H-UPF440 and V-UPF640. The communication tunnel establishment unit 436 also establishes a communication tunnel, for example, by establishing a communication tunnel between H-SMF420 and V-SMF620.

[0416] The communication tunnel establishment unit 436 establishes a communication tunnel, for example, based on the session information of the communication terminal 800. The communication tunnel establishment unit 436 establishes a communication tunnel, for example, based on the session information of the communication terminal 800 generated by the session information generation unit 426. The communication tunnel establishment unit 436 establishes a communication tunnel, for example, based on 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 also establish a 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] If the communication terminal 800 is registered to be capable of performing only data communication via the first ASN network, for example, if the communication terminal 800 is registered to be capable of performing data communication via the first ASN network and data communication via the second ASN network, the communication tunnel establishment unit 436 establishes a communication tunnel based on the session information of the communication terminal 800, including the first IP address of the H-UPF440, which is synchronized between database 450 and 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] Figure 14 schematically shows an example of the functional configuration of the H-UPF440. The H-UPF440 includes a session information acquisition unit 442, a communication tunnel establishment unit 444, a data reception unit 446, and a data transmission unit 448. Note that it is not necessarily required that the H-UPF440 include all of these components.

[0420] The session information acquisition unit 442 acquires session information of the communication terminal 800. For example, the session information acquisition unit 442 acquires session information of the communication terminal 800 generated by the H-SMF420.

[0421] The session information acquisition unit 442 acquires session information of the communication terminal 800, for example, by receiving a synchronization completion notification. 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 may, for example, receive a synchronization completion notification from the database 450. The session information acquisition unit 442 may, for example, receive a synchronization completion notification from the database 550. The session information acquisition unit 442 may, for example, receive a synchronization completion notification from the H-SMF 420. The session information acquisition unit 442 may also receive a synchronization completion notification from the H-SMF 520.

[0423] The communication tunnel establishment unit 444 establishes a communication tunnel in order to generate a session for the communication terminal 800 to the DN. The communication tunnel establishment unit 444 establishes a communication tunnel between the H-UPF440 and the V-UPF640 in order to generate a session for the communication terminal 800 to the DN.

[0424] The communication tunnel establishment unit 444 establishes a communication tunnel, for example, in accordance with instructions from the H-SMF420. The communication tunnel establishment unit 444 may also establish a communication tunnel autonomously without receiving instructions from the H-SMF420.

[0425] The communication tunnel establishment unit 444 establishes a communication tunnel, for example, to create a session for communication terminal 800 to DN80. The communication tunnel establishment unit 444 also establishes a communication tunnel, for example, to create a session for communication terminal 800 to DN90. The communication tunnel establishment unit 444 may also establish a communication tunnel to create sessions for communication terminal 800 to other DNs.

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

[0427] The communication tunnel establishment unit 444 establishes a communication tunnel based on the session information of the communication terminal 800 acquired by the session information acquisition unit 442, for example. If the communication terminal 800 is registered to be capable of performing only data communication via the network of the first ASN, the communication tunnel establishment unit 444 establishes a communication tunnel based on the session information of the communication terminal 800, including the first IP address of the H-UPF440, if the communication terminal 800 is registered to be capable of performing both 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 a communication tunnel based on the session information of the communication terminal 800, including the second IP address of the H-UPF440, which is synchronized between the database 450 and the database 550.

[0428] The data receiving unit 446 receives data related to the data communication of the communication terminal 800. The data receiving unit 446 receives data related to the data communication of the communication terminal 800, for example, via the network 20. The data receiving unit 446 receives data related to the 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 the 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 from the communication terminal 800. The data receiving unit 446 receives uplink data from the communication terminal 800 when, for example, H-UPF440 is selected from among multiple H-UPFs that have the same IP address assigned to them as the target for transmitting uplink data from the communication terminal 800.

[0430] The data receiving unit 446 receives, for example, downlink data from the communication terminal 800. The data receiving unit 446 receives downlink data from the communication terminal 800 when, for example, H-UPF440 is selected from among multiple H-UPFs that have the same IP address assigned to them as the target for transmitting downlink data from the communication terminal 800.

[0431] The communication tunnel establishment unit 444 establishes a communication tunnel, for example, when the data reception 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, by obtaining session information for the communication terminal 800 from the database 450. The communication tunnel establishment unit 444 also obtains session information for the communication terminal 800 from the database 450 when the data reception unit 446 receives uplink data from the communication terminal 800 for the first time.

[0432] The communication tunnel establishment unit 444 establishes a communication tunnel, for example, when the data reception 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, by obtaining session information for the communication terminal 800 from the database 450. The communication tunnel establishment unit 444 also obtains session information for the communication terminal 800 from the database 450 when the data reception unit 446 receives downlink data from the communication terminal 800 for the first time.

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

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

[0435] Figure 15 schematically shows an example of the functional configuration of the V-SMF620. The V-SMF620 comprises a storage unit 622, a route information receiving unit 624, a table generation unit 626, a request receiving unit 630, a request transmission unit 632, a response receiving unit 634, and a response provisioning unit 635. Note that it is not necessarily required that the V-SMF620 include all of these components.

[0436] The storage unit 622 stores various types of information. For example, the storage unit 622 stores a route table.

[0437] The route table includes, for example, communication path information showing the communication path between V-SMF620 and H-SMF420. The route table includes, for example, communication path information showing the communication path between V-UPF640 and H-UPF440. The route table includes, for example, communication path information showing the communication path between V-SMF620 and H-SMF520. The route table includes, for example, communication path information showing the communication path between V-UPF640 and H-UPF540.

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

[0439] The routing information receiving unit 624 receives, for example, communication route information advertised by router 24. The routing information receiving unit 624 also receives, for example, communication route information advertised by router 25. The routing 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 V-SMF620 and H-SMF420. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between V-UPF640 and H-UPF440. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between V-SMF620 and H-SMF520. The route information receiving unit 624 receives, for example, communication route information indicating the communication route between V-UPF640 and H-UPF540.

[0441] The table generation unit 626 generates a route table. The table generation unit 626 generates a route table based, for example, on the communication path information stored in the storage unit 622. The table generation unit 626 generates a route table based, for example, on the communication path 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 generation unit 626 may store the generated route table in the storage unit 622. The table generation unit 626 may also provide the generated route table to the V-UPF 640.

[0443] The request receiving unit 630 receives session creation requests from communication terminal 800 requesting the creation of a session to a DN. For example, the request receiving unit 630 receives a session creation request from communication terminal 800 requesting the creation of a session to DN80. For example, the request receiving unit 630 receives a session creation request from communication terminal 800 requesting the creation of a session to DN90. The request receiving unit 630 may also receive session creation requests from communication terminal 800 requesting the creation of a session to another DN.

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

[0445] The request transmission unit 632 transmits a session creation request for the communication terminal 800. The request transmission unit 632 transmits, for example, the session creation request for the communication terminal 800 that the request reception unit 630 has received.

[0446] The request transmission unit 632 transmits a session creation request for the communication terminal 800, for example, via the network 20. The request transmission unit 632 transmits a session creation request for the communication terminal 800, for example, via the router 26 and the network 20.

[0447] The request transmission unit 632 transmits a session creation request for the communication terminal 800, for example, based on the route table stored in the storage unit 622. If the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the data communication via the first ASN network and data communication via the second ASN network, the request transmission unit 632 transmits a session creation request for the communication terminal 800, including the first IP address of the H-UPF440, to the H-SMF420.

[0448] If the communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, the request transmission unit 632 sends a session generation request for the communication terminal 800, including the second IP address of the H-UPF440, to an H-SMF selected as the target of the session generation request from among multiple H-SMFs to which the same IP address has been assigned based on predetermined SMF selection conditions. In this case, the request transmission unit 632 sends the session generation request to an H-SMF selected as the target of the session generation request from among H-SMF420 and H-SMF520 based on the SMF selection conditions. The request transmission unit 632 sends the session generation request to the H-SMF selected as the target of the session generation request via a communication path selected according to the BGP best path selection algorithm.

[0449] The response receiving unit 634 receives the session creation response from the communication terminal 800 to the session creation request from the communication terminal 800. The response receiving unit 634 receives, for example, the session creation response from the communication terminal 800 to the session creation request from the communication terminal 800 sent by the request sending 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, for example, a session creation response from the communication terminal 800 from the H-SMF420. The response receiving unit 634 also receives, for example, a session creation response from the communication terminal 800 from the H-SMF520.

[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 also receives the session creation response from the communication terminal 800, for example, via the network 20 and the router 26.

[0452] The response provider 635 provides the session generation response from the communication terminal 800 that the response receiver 634 has received. For example, the response provider 635 provides the session generation response from the communication terminal 800 to the V-UPF 640.

[0453] Figure 16 schematically shows an example of the functional configuration of the V-UPF640. The V-UPF640 comprises 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. However, it is not necessarily required that the V-UPF640 include all of these components.

[0454] The storage unit 642 stores various types of information. For example, the storage unit 642 stores a route table.

[0455] For example, V-SMF620 and V-UPF640 share a storage unit. In this case, storage unit 622 and storage unit 642 are the same storage unit. V-SMF620 and V-UPF640 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. The table acquisition unit 644 acquires, for example, a route table provided by V-SMF620. The table acquisition unit 644 may store the acquired route table in the storage unit 642.

[0457] The response acquisition unit 645 acquires the session creation response of the communication terminal 800 to the session creation request of the communication terminal 800. The response acquisition unit 645 acquires the session creation response of the communication terminal 800 provided by, for example, the V-SMF620. The response acquisition unit 645 may store the acquired session creation response of 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 from the communication terminal 800. The data receiving unit 648 also receives, for example, downlink data from the communication terminal 800.

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

[0461] The data transmission unit 649 transmits, for example, uplink data of the communication terminal 800. The data transmission unit 649 transmits the uplink data of the communication terminal 800 based, for example, on a route table stored in the storage unit 642. The data transmission unit 649 transmits the uplink data of the communication terminal 800 to the H-UPF440 if, for example, the communication terminal 800 is registered to be able to perform only data communication via the first ASN network out of the two data communication methods (data communication via the first ASN network and data communication via the second ASN network).

[0462] If the communication terminal 800 is registered to be capable of both data communication via the first ASN network and data communication via the second ASN network, the data transmission unit 649 transmits the uplink data of the communication terminal 800 to an H-UPF selected as the target for transmitting the uplink data of the 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, the data transmission unit 649 transmits the uplink data of the communication terminal 800 to an H-UPF selected as the target for transmitting the uplink data of the communication terminal 800 from among H-UPF440 and H-UPF540 based on the UPF selection conditions. The data transmission unit 649 also transmits the uplink data of the communication terminal 800 to an H-UPF selected as the target for transmitting the uplink data of the communication terminal 800 via a communication path selected according to the BGP best path selection algorithm.

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

[0464] Figure 17 schematically shows 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. A program installed on computer 1200 can cause computer 1200 to function as one or more "parts" of the apparatus according to this embodiment, or to cause computer 1200 to execute operations associated with the apparatus according to this embodiment or such one or more "parts", and / or to cause computer 1200 to execute a process or a stage of such process according to this embodiment. Such a program may be executed by CPU 1212 to cause computer 1200 to execute 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, 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 communication 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 and a DVD-RAM drive, etc. The storage device 1224 may be a hard disk drive and a solid-state drive, etc. The computer 1200 also includes legacy input / output units such as a ROM 1230 and a keyboard, which are connected to the input / output controller 1220 via an input / output chip 1240.

[0466] The CPU 1212 operates according to the programs stored in the ROM 1230 and RAM 1214, thereby controlling each unit. The graphics controller 1216 acquires the image data generated by the CPU 1212 and stores it in the frame buffer provided in RAM 1214 or within itself, so that the image data is 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, etc., 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 boot programs and / or hardware-dependent programs of the computer 1200, which are executed by the computer 1200 upon activation. The input / output chip 1240 may also connect various input / output units to the input / output controller 1220 via USB ports, parallel ports, serial ports, keyboard ports, mouse ports, etc.

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

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

[0471] Furthermore, the CPU 1212 may read all or necessary parts of files or databases stored on external recording media such as the storage device 1224, DVD drive 1226 (DVD-ROM 1227), or IC card into the RAM 1214, and perform various types of processing on the data in the RAM 1214. The CPU 1212 may then write the processed data back to the external recording media.

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

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

[0474] In this embodiment, blocks in the flowchart and block diagram may represent a stage in a process in which an operation is performed or a "part" of a device that has the role of performing an operation. A particular stage and "part" may be implemented by a dedicated circuit, a programmable circuit supplied with computer-readable instructions stored on a computer-readable storage medium, and / or a processor supplied with computer-readable instructions stored on a computer-readable storage medium. The dedicated circuit may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. The programmable circuit may include reconfigurable hardware circuits, such as field-programmable gate arrays (FPGAs) and programmable logic arrays (PLAs), which include logical AND, logical OR, exclusive OR, negated AND, negated OR, and other logical operations, flip-flops, registers, and memory elements.

[0475] Computer-readable media may include any tangible device capable of storing instructions to be executed by a suitable device, and as a result, computer-readable media having instructions stored therein will comprise a product containing instructions that can be executed to create means for performing operations specified in a flowchart or block diagram. Examples of computer-readable media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, etc. 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 disk read-only memory (CD-ROM), digital multipurpose disc (DVD), Blu-ray® disc, memory stick, integrated circuit card, etc.

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

[0477] Computer-readable instructions are provided locally or via a wide area network (WAN) such as a local area network (LAN) or the internet to the processor or programmable circuit of a programmable data processing device such as a computer, and may be executed to create means for performing operations specified in a flowchart or block diagram. Here, the computer may be a PC (personal computer), tablet computer, smartphone, workstation, server computer, general-purpose computer, or special-purpose computer, and may also 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 computer in a broad sense. In a distributed computing system, multiple computers execute a program collectively by having each computer execute a part of the program and passing data during program execution between computers as needed.

[0478] Examples of processors include computer processors, central processing units (CPUs), processing units, microprocessors, digital signal processors, controllers, and microcontrollers. A computer may have one or more processors. In a multiprocessor system with multiple processors, each processor executes a portion of the program, and the processors collectively execute the program by passing program execution data between them as needed. For example, in the execution of multitasking, each of the multiple processors may execute a portion of each task in small chunks by switching tasks at each time slice. In this case, which part of a program each processor executes changes dynamically. Which part 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 or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0480] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before" or "prior to," and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," and "next," for convenience, this does not mean that it is essential to perform the operations in that 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 Generation Unit, 108 Registration Unit, 110 Session Information Synchronization Unit, 112 Notification Receiving Unit, 114 Response Transmission Unit, 116 Communication Tunnel Establishment Unit, 118 Data Receiving Unit, 119 Data Transmission Unit, 120 PGW-C, 122 Request Receiving Unit, 126 Session Information Generation Unit, 128 Registration Unit, 130 Session Information Synchronization Unit, 132 Notification Receiving Unit, 134 Response Transmission 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 transmission unit, 420 H-SMF, 422 Request reception unit, 426 Session information generation unit, 428 Registration unit, 430 Session information synchronization unit, 432 Notification reception unit, 434 Response transmission unit, 436 Communication tunnel establishment unit, 440 H-UPF, 442 Session information acquisition unit, 444 Communication tunnel establishment unit, 446 Data reception unit, 448 Data transmission unit, 450 Database, 520 H-SMF, 540 H-UPF, 550 Database, 620 V-SMF, 622 Storage unit, 624 Route information reception unit, 626 Table generation unit, 630 Request reception unit, 632 Request transmission unit, 634 Response reception unit, 635 Response provision unit, 640 V-UPF, 642 Storage unit, 644 Table acquisition unit, 645 Response acquisition unit, 648 Data reception unit, 649Data transmission unit, 800 Communication terminal, 1200 Computer, 1210 Host controller, 1212 CPU, 1214 RAM, 1216 Graphics 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. It is a system, A first PGW (Packet data network gateway) is located on the network of the first ASN (Autonomous System number) and is assigned a first IP (Internet Protocol) address and a second IP address different from the said first IP address, A second PGW is located on a network of a second ASN, which is different from the first ASN, and to which the second IP address is assigned, A first storage unit corresponding to the first PGW, The second storage unit corresponding to the second PGW and Equipped with, The aforementioned first PGW is, A request receiving unit receives a session creation request from a communication terminal requesting the creation of a session from an SGW (Serving Gateway) to a PDN (Packet Data Network), In response to the request receiving unit receiving the session generation request, if the communication 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 the network of the second ASN, then the IP address of the communication terminal, the first IP address of the first PGW, and the TEID (Tunnel Endpoint) assigned to the communication tunnel of the first PGW are used. A session information generation unit generates first session information for the communication terminal, including an IDentifier, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW. If the communication terminal is registered to be capable of both data communication over the network of the first ASN and data communication over the network of the second ASN, the session information generation unit generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first PGW, a TEID assigned to the communication tunnel of the first PGW and the communication tunnel of the second PGW, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW. A registration unit registers the second session information generated by the session information generation unit into the first storage unit. It has, The aforementioned system, A session information synchronization unit synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit. Furthermore, The aforementioned first PGW is, If the communication terminal is registered to be capable of performing only data communication via the network of the first ASN and data communication via the network of the second ASN, in order to generate a session of the communication terminal to the PDN, the first communication tunnel establishment unit establishes a communication tunnel between the first PGW and the SGW based on the first session information. If the communication terminal is registered to be capable of performing both data communication via the network of the first ASN and data communication via the network of the second ASN, the first communication tunnel establishment unit 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. It further possesses, The aforementioned second PGW is, If the communication terminal is registered to enable both data communication via the network of the first ASN and data communication via the network of the second ASN in order to generate a session of the communication terminal to the PDN, the second communication tunnel establishment unit 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. A system that has

2. The aforementioned SGW is further provided, The aforementioned first PGW is, A response transmission unit transmits a session generation response from the communication terminal to the SGW in response to the synchronization of the second session information between the first storage unit and the second storage unit. It further possesses, The aforementioned SGW is, A response receiving unit that receives the session generation response, If the communication terminal is registered to be capable of both data communication via the network of the first ASN and data communication via the network of the second ASN, the data transmission unit transmits the uplink data of the communication terminal to a PGW selected from the first PGW and the second PGW as the target for transmitting the uplink data based on predetermined PGW selection conditions. The system according to claim 1, having the following features.

3. The aforementioned second PGW is, When the second PGW is selected as the target for transmitting the uplink data, the data receiving unit receives the uplink data. It further possesses, The second communication tunnel establishment unit establishes a communication tunnel between the second PGW and the SGW by obtaining 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. The system according to 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. The system according to claim 2, wherein the data transmission unit transmits the uplink data to the PGW selected as the target for transmission of the uplink data via a communication path selected according to the best path selection algorithm of BGP (Border Gateway Protocol).

6. The system according to any one of claims 1 to 5, wherein the first PGW is located in the network of a first country, and the second PGW is located in the network of a second country different from the first country.

7. The system according to claim 6, wherein the network on which the first PGW is located and the network on which the second PGW is located are HPLMN (Home Public Land Mobile Network), and the network on which the SGW is located is VPLMN (Visited PLMN).

8. A PGW located in the network of a first ASN, and to which a first IP address and a second IP address different from the first IP address are assigned, A request receiving unit receives a session creation request from a communication terminal requesting the creation of a session to the PDN from the SGW, In response to the request receiving unit receiving the session generation request, if the communication terminal is registered so that only data communication via the network of the first ASN can be performed among data communication via the network of the first ASN and data communication via the network of a second ASN different from the first ASN, then first session information for the communication terminal is generated, including the IP address of the communication terminal, the first IP address of the PGW, the TEID assigned to the communication tunnel of the PGW, the IP address of the SGW, and the TEID assigned to the communication tunnel of the SGW, and the first If the communication terminal is registered to be capable of both data communication over the ASN network and data communication over the second ASN network, a session information generation unit generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the PGW, the communication tunnel of the PGW, a TEID assigned to the communication tunnel of another PGW located in the network of the second ASN and to which the second IP address is assigned, the IP address of the SGW, and a TEID assigned to the communication tunnel of the SGW. A registration unit registers the second session information generated by the session information generation unit into a first storage unit corresponding to the PGW, A session information synchronization unit synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit corresponding to the other PGW, In order to generate a session of the communication terminal to the PDN, if the communication terminal is registered so that only data communication via the network of the first ASN and data communication via the network of the second ASN are possible, a communication tunnel establishment unit is established between the PGW and the SGW based on the first session information, and if 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, a communication tunnel establishment unit is established between the PGW and the SGW based on the second session information synchronized between the first storage unit and the second storage unit. PGW equipped with

9. It is a system, The first PGW located in the network of the first ASN, A second PGW located in the network of a second ASN, which is different from the first ASN, A first storage unit corresponding to the first PGW, The second storage unit corresponding to the second PGW and 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 the first PGW-U is assigned a first IP address and a second IP address different from the first IP address. The second PGW is separated into second PGW-C and second PGW-U, and the second IP address is assigned to second PGW-U. The first PGW-C is, A request receiving unit receives session generation requests from communication terminals requesting the creation of a session to the PDN from an SGW which is separated into SGW-C (SGW-Control plane function) and SGW-U (SGW-User plane function), In response to the request receiving unit receiving the session generation request, if the communication terminal is registered such that only data communication over the network of the first ASN is executable among data communication over the network of the first ASN and data communication over the network of the second ASN, the communication terminal's IP address includes the IP address of the communication terminal, the first IP address of the first PGW-U, the TEID assigned to the communication tunnel of the first PGW-U, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. A session information generation unit generates session information and, if the communication terminal is registered to enable both data communication via the network of the first ASN and data communication via the network of the second ASN, generates second session information for the communication terminal including the IP address of the communication terminal, the second IP address of the first PGW-U, the TEID 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. A registration unit registers the second session information generated by the session information generation unit into the first storage unit. Includes, The aforementioned system, A session information synchronization unit 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 is, If the communication terminal is registered to be capable of performing only data communication via the network of the first ASN and data communication via the network of the second ASN, in order to generate a session of the communication terminal to the PDN, the first communication tunnel establishment unit establishes a communication tunnel between the first PGW-U and the SGW-U based on the first session information. If the communication terminal is registered to be capable of performing both data communication via the network of the first ASN and data communication via the network of the second ASN, the first communication tunnel establishment unit 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. Includes, The second PGW-U is, If the communication terminal is registered to enable both data communication via the network of the first ASN and data communication via the network of the second ASN in order to generate a session of the communication terminal to the PDN, the second communication tunnel establishment unit 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. A system that includes this.

10. A PGW located in the network of the first ASN, The PGW is separated into PGW-C and PGW-U, and PGW-U is assigned a first IP address and a second IP address different from the first IP address. The aforementioned PGW-C is, A request receiving unit receives session generation requests from communication terminals requesting the creation of a session to the PDN from the SGW which is separated into SGW-C and SGW-U, In response to the request receiving unit receiving the session generation request, if the communication terminal is registered so that only data communication via the network of the first ASN is possible among data communication via the network of the first ASN and data communication via the network of a second ASN different from the first ASN, then the first session of the communication terminal includes the IP address of the communication terminal, the first IP address of the PGW-U, the TEID assigned to the communication tunnel of the PGW-U, the IP address of the SGW-U, and the TEID assigned to the communication tunnel of the SGW-U. A session information generation unit generates information and, if the communication terminal is registered to enable both data communication over the network of the first ASN and data communication over the network of the second ASN, generates second session information for the communication terminal including the IP address of the communication terminal, the second IP address of the PGW-U, the TEID assigned to the communication tunnel of the PGW-U and the communication tunnel of another PGW-U to which the second IP address is assigned, the IP address of the SGW-U and the TEID assigned to the communication tunnel of the SGW-U, A registration unit registers the second session information generated by the session information generation unit into a first storage unit corresponding to the PGW, A session information synchronization unit synchronizes the second session information registered in the first storage unit with the first storage unit and the second storage unit which is located in the network of the second ASN and corresponds to another PGW which is separated into another PGW-C and the other PGW-U. It has, The aforementioned PGW-U is, If the communication terminal is registered to be capable of performing only data communication via the network of the first ASN and data communication via the network of the second ASN, in order to generate a session of the communication terminal to the PDN, a communication tunnel establishment unit is established between the PGW-U and the SGW-U based on the first session information. If the communication terminal is registered to be capable of performing both data communication via the network of the first ASN and data communication via the network of the second ASN, a communication tunnel establishment unit is established 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. PGW has

11. It is a system, The first SMF (Session Management Function) located in the network of the first ASN, A first UPF (User Plane Function) is located in the network where the first SMF is located, and is assigned a first IP address and a second IP address different from the first IP address. A second SMF located in the network of a second ASN, which is different from the first ASN, A second UPF is located in the network where the second SMF is located, and to which the second IP address is assigned, The first storage unit corresponding to the first UPF, The second storage unit corresponding to the second UPF and Equipped with, The first SMF is, A request receiving unit receives a session creation request from a communication terminal requesting the creation of a session to the DN (Data Network) from the third SMF, In response to the request receiving unit receiving the session generation request, if the communication 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 the network of the second ASN, then the IP address of the communication terminal, the first IP address of the first UPF, the TEID assigned to the communication tunnel of the first UPF, the IP address of the third UPF located in the network where the third SMF is located, and the TE assigned to the communication tunnel of the third UPF A session information generation unit generates first session information for the communication terminal, including an ID, and if the communication terminal is registered to be able to perform both data communication over the network of the first ASN and data communication over the network of the second ASN, a session information generation unit generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address of the first UPF, the TEID 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 the TEID assigned to the communication tunnel of the third UPF, A registration unit registers the second session information generated by the session information generation unit into the first storage unit. It has, The aforementioned system, A session information synchronization unit 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, If the communication terminal is registered to enable only data communication via the network of the first ASN and data communication via the network of the second ASN, in order to generate a session of the communication terminal to the DN, the first communication tunnel establishment unit establishes a communication tunnel between the first UPF and the third UPF based on the first session information. If the communication terminal is registered to enable both data communication via the network of the first ASN and data communication via the network of the second ASN, the first communication tunnel establishment unit establishes a communication tunnel between the first UPF and the third UPF based on the second session information synchronized between the first storage unit and the second storage unit. It further possesses, The aforementioned second SMF is, If the communication terminal is registered to enable both data communication via the network of the first ASN and data communication via the network of the second ASN in order to generate a session of the communication terminal to the DN, a second communication tunnel establishment unit establishes 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. A system that has

12. An SMF located in the network of the first ASN, A request receiving unit receives a session creation request from a communication terminal requesting the creation of a session to the DN from another SMF, If, in response to the request receiving unit receiving the session generation request, the communication 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 the network of a second ASN different from the first ASN, then the communication terminal includes the IP address of the communication terminal, the first IP address assigned to the first UPF located in the network where the SMF is located, the TEID assigned to the communication tunnel of the first UPF, the IP address of the second UPF located in the network where the other SMF is located, and the TEID assigned to the communication tunnel of the second UPF. A session information generation unit generates first session information for the communication terminal, and if the communication terminal is registered 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, the session information generation unit generates second session information for the communication terminal, including the IP address of the communication terminal, the second IP address assigned to the first UPF, the communication tunnel of the first UPF, and the TEID assigned to the communication tunnel of the third UPF which 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 the TEID assigned to the communication tunnel of the second UPF. A registration unit registers the second session information generated by the session information generation unit into a first storage unit corresponding to the first UPF, A session information synchronization unit synchronizes the second session information registered in the first storage unit between the first storage unit and the second storage unit corresponding to the third UPF, If the communication terminal is registered to generate a session of the communication terminal to the DN, and only data communication via the network of the first ASN is possible among data communication via the network of the first ASN and data communication via the network of the second ASN, the first UPF establishes a communication tunnel between the first UPF and the second UPF based on the first session information, and if the communication terminal is registered 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, the first UPF establishes a communication tunnel establishment unit that establishes 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. SMF equipped with [unclear].

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