Communication method and device

Abstract

The present application provides a communication method and apparatus. The method may include: a first session management network element obtaining IP address information of a visited network; the first session management network element sending the IP address information to an edge application server discovery network element; the first session management network element and the edge application server discovering the network element as a network element deployed in a home network. When a terminal device accesses the visited network via HR roaming, the IP address information can be used to enable the terminal device to access services in the visited network.

Description

Technical Field

[0001] The present application relates to the field of communications, and more particularly, to a communication method and apparatus. Background Art

[0002] In edge computing (EC) deployment scenarios, some services may be provided by multiple edge application servers (EAS) deployed at the edge of the network. These multiple EASs can provide the same services and content, and most of them have different Internet Protocol (IP) addresses. When a user equipment (UE) requests access to the service, the EC scenario requires it to access an available EAS that is close to the UE. Therefore, the IP address of the appropriate EAS is relatively important.

[0003] In some cases, a UE may leave the coverage of its home public land mobile network (PLMN) (home PLMN, HPLMN) and access a visited public land mobile network (VPLMN) through home routed (HR) roaming, and the VPLMN provides services for the UE. Summary of the Invention

[0004] The present application provides a communication method and apparatus to access services in a VPLMN through the IP address of the VPLMN (such as information used to determine ECS option, such as ECS option or L-DNS server, etc.), and to realize the discovery of the local EAS in the HR roaming scenario.

[0005] On the first aspect, a communication method is provided. The method can be executed by a core network network element, or can also be executed by a component of the core network network element (such as a chip or circuit). There is no limitation on this. For the sake of ease of description, the following is explained using the example of execution by the first session management network element.

[0006] The method may include: a first session management network element obtaining IP address information of a visited network; the first session management network element sending the IP address information to an edge application server discovery network element, the first session management network element and the edge application server discovery network element being network elements deployed in a home network.

[0007] Based on the above technical solution, the first session management network element deployed in the home network can obtain the IP address information of the visited network (such as information used to determine the ECS option, such as the ECS option or L-DNS server, etc.) and send it to the edge application server discovery network element. By obtaining the IP address information of the visited network, when the terminal device accesses the visited network through HR roaming, since the edge application server discovery network element has obtained the IP address information of the visited network, the terminal device can access the services in the visited network through the edge application server discovery network element. For example, after the edge application server discovery network element receives the DNS query message from the terminal device, it can add the ECS option determined based on the IP address information to the DNS query message, or it can forward the DNS query message to the L-DNS server determined based on the IP address information (such as the IP address information is the L-DNS server address information), thereby realizing the discovery of the local EAS in the HR roaming scenario.

[0008] In combination with the first aspect, in certain implementations of the first aspect, the IP address information is information used to determine a Domain Name System (DNS) extended mechanism client subnet option (ECS option), or the IP address information is an ECS option or a local DNS server address.

[0009] In combination with the first aspect, in certain implementations of the first aspect, the first session management network element obtains the IP address information of the visited network, including: the first session management network element obtains the IP address information of the visited network according to indication information, wherein the indication information indicates that the visited network diversion is allowed.

[0010] Based on the above technical solution, when the visited network offloading is allowed, the first session management network element obtains the IP address of the visited network, thereby avoiding the situation where the visited network IP address information is obtained but cannot be used because the visited network offloading is not allowed.

[0011] In combination with the first aspect, in certain implementations of the first aspect, the first session management network element sends IP address information to the edge application server discovery network element, including: the first session management network element sends IP address information to the edge application server discovery network element according to the indication information, wherein the indication information indicates that visited network diversion is allowed.

[0012] Based on the above technical solution, when traffic offloading to the visited network is allowed, the first session management network element sends IP address information to the edge application server discovery network element.

[0013] With reference to the first aspect, in certain implementations of the first aspect, the indication information includes an identifier of the first service, and the indication information indicates that offloading of the first service to the visited network is allowed.

[0014] For example, the identifier of the first service may be: a full domain name (or a full domain name range), an application identifier, an IP address of an application server, and a port number.

[0015] In combination with the first aspect, in some implementations of the first aspect, the first session management network element obtains the IP address information of the visited network, including: the first session management network element receives the IP address information from the second session management network element, and the second session management network element is a network element deployed in the visited network.

[0016] Based on the above technical solution, the first session management network element can receive the IP address information from the second session management network element.

[0017] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the first session management network element sending first request information to the second session management network element, where the first request information is used to request IP address information.

[0018] Based on the above technical solution, the first session management network element may first send a request to the second session management network element to request the IP address information, and then receive the IP address information from the second session management network element.

[0019] In combination with the first aspect, in certain implementations of the first aspect, the method also includes: the first session management network element sends a second request message to the network storage network element, the second request message includes an identifier of the visited network, the second request message is used to request IP address information, and the network storage network element is a network element deployed in the home network; the first session management network element obtains the IP address information of the visited network, including: the first session management network element receives the IP address information of the visited network from the network storage network element.

[0020] Based on the above technical solution, the first session management network element may send a request to the network storage network element to request the IP address information, and then receive the IP address information from the network storage network element.

[0021] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the first session management network element locally configuring the indication information; or the first session management network element receiving the indication information.

[0022] In combination with the first aspect, in some implementations of the first aspect, the indication information includes first indication information and / or second indication information, the first indication information is locally configured by the first session management network element, and the second indication information is received by the first session management network element.

[0023] In combination with the first aspect, in certain implementations of the first aspect, the first session management network element obtains the IP address information of the visited network, including: the first session management network element determines the IP address information of the visited network based on the first correspondence and the identifier of the visited network, and the first correspondence is used to indicate the relationship between the visited network and the IP address information of the visited network.

[0024] Based on the above technical solution, there can be a correspondence between the visited network and the IP address information of the visited network, or the visited network and the IP address information of the visited network are associated, so that the IP address information of the visited network can be determined based on the identifier of the visited network and the correspondence.

[0025] In combination with the first aspect, in certain implementations of the first aspect, the method also includes: the first session management network element determines the indication information based on the second correspondence and the identifier of the visited network, the second correspondence is used to indicate the relationship between the visited network and the indication information, and the indication information is used to indicate whether the visited network diversion is allowed.

[0026] Based on the above technical solution, there can be a correspondence between the visited network and the indication information, or the visited network and the indication information can be associated. In this way, based on the identifier of the visited network and the correspondence, the indication information corresponding to the visited network can be determined, and then it can be known whether the visited network allows diversion.

[0027] On the second aspect, a communication method is provided. The method can be executed by a core network network element, or can also be executed by a component of the core network network element (such as a chip or circuit). There is no limitation on this. For the sake of ease of description, the following is explained as an example of execution by a second session management network element.

[0028] The method may include: a second session management network element obtaining IP address information of a visited network; and the second session management network element sending the IP address information to a first session management network element, wherein the second session management network element is a network element deployed in the visited network and the first session management network element is a network element deployed in the home network.

[0029] Based on the above technical solution, the second session management network element deployed in the visited network can obtain the IP address information of the visited network (such as information used to determine the client subnet option of the Domain Name System (DNS) extension mechanism, such as the client subnet option of the DNS extension mechanism or the local DNS server address) and send it to the first session management network element deployed in the home network. In this way, when a terminal device accesses the visited network through HR roaming, the terminal device can use this IP address information to access services in the visited network.

[0030] In combination with the second aspect, in some implementations of the second aspect, the second session management network element obtains the IP address information of the visited network, including: the second session management network element obtains the IP address information of the visited network according to the indication information, wherein the indication information indicates that the visited network diversion is allowed.

[0031] Based on the above technical solution, when the visited network offloading is allowed, the second session management network element obtains the IP address of the visited network, thereby avoiding the situation where the visited network IP address information is obtained but cannot be used because the visited network offloading is not allowed.

[0032] In combination with the second aspect, in certain implementations of the second aspect, the second session management network element sends IP address information to the first session management network element, including: the second session management network element sends IP address information to the first session management network element according to the indication information, wherein the indication information indicates that visited network diversion is allowed.

[0033] Based on the above technical solution, when traffic offloading to the visited network is allowed, the second session management network element sends IP address information to the first session management network element.

[0034] With reference to the second aspect, in certain implementations of the second aspect, the indication information includes an identifier of the first service, and the indication information indicates that offloading of the first service to the visited network is allowed.

[0035] For example, the identifier of the first service may be: a full domain name (or a full domain name range), an application identifier, an IP address of an application server, and a port number.

[0036] In combination with the second aspect, in some implementations of the second aspect, the method also includes: the second session management network element receives first request information from the first session management network element, the first request information is used to request IP address information; the second session management network element sends IP address information to the first session management network element, including: in response to the first request information, the second session management network element sends IP address information to the first session management network element.

[0037] Based on the above technical solution, the second session management network element may receive a request from the first session management network element, where the request is used to request IP address information. In response to the request, the second session management network element sends the IP address information to the first session management network element.

[0038] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element locally configuring the indication information; or the second session management network element receiving the indication information.

[0039] In combination with the second aspect, in some implementations of the second aspect, the IP address information is information used to determine a domain name system (DNS) extension mechanism client subnet option, or the IP address information is a domain name system (DNS) extension mechanism client subnet option or a local DNS server address.

[0040] On the third aspect, a communication method is provided. The method can be executed by a core network network element, or can also be executed by a component of the core network network element (such as a chip or circuit). There is no limitation on this. For the sake of ease of description, the following is explained using the example of execution by the second session management network element.

[0041] The method may include: the second session management network element obtains indication information, the indication information indicates that the visited network is allowed to be diverted; the second session management network element sends the IP address information of the visited network to the user plane network element according to the indication information, wherein the second session management network element and the user plane network element are network elements deployed in the visited network.

[0042] For example, the user plane network element may be a user plane function (UPF), an edge application server discovery network element, or may be a module that combines the UPF and the edge application server discovery network element.

[0043] Based on the above technical solution, the second session management network element deployed in the visited network can send the IP address information of the visited network (such as information for determining the ECS option, such as the ECS option or the L-DNS server address) to the user plane network element according to the indication information. In this way, when the terminal device accesses the visited network through HR roaming, the IP address information can be used to enable the terminal device to access the services in the visited network. For example, the user plane network element can add the ECS option determined based on the IP address information to the DNS query message, or the user plane network element sends the ECS option or IP address information to the edge application server discovery network element, and the edge application server discovery network element can add the ECS option determined based on the IP address information to the DNS query message, or can forward the DNS query message to the L-DNS server determined based on the IP address information, thereby realizing the discovery of the local EAS in the HR roaming scenario.

[0044] In combination with the third aspect, in some implementations of the third aspect, the second session management network element obtains the indication information, including: the second session management network element locally configures the indication information; or the second session management network element receives the indication information.

[0045] In combination with the third aspect, in certain implementations of the third aspect, the indication information includes an identifier of the second service, and the indication information indicates that offloading of the second service to the visited network is allowed.

[0046] For example, the identifier of the second service may be: a full domain name (or a full domain name range), an application identifier, an IP address of an application server, and a port number.

[0047] In combination with the third aspect, in certain implementations of the third aspect, the indication information includes first indication information and / or second indication information, the first indication information is locally configured by the second session management network element, and the second indication information is received by the second session management network element.

[0048] In combination with the third aspect, in certain implementations of the third aspect, the IP address information is information used to determine a domain name system DNS extension mechanism client subnet option, or the IP address information is a DNS extension mechanism client subnet option or a local DNS server address.

[0049] Fourthly, a communication method is provided. The method can be executed by a core network element, or it can be executed by a component of the core network element (such as a chip or circuit). There is no limitation on this. For the sake of ease of description, the following is an example of execution by a policy control network element.

[0050] The method may include: a policy control network element obtaining indication information, the indication information indicating whether visited network offloading is allowed; and the policy control network element sending the indication information to a first session management network element, wherein the first session management network element is a network element deployed in a home network.

[0051] In combination with the fourth aspect, in certain implementations of the fourth aspect, the method further includes: the policy control network element sending an identifier of a first service to the first session management network element, where the first service is a service allowed to be offloaded in the visited network.

[0052] In combination with the fourth aspect, in certain implementations of the fourth aspect, the indication information includes an identifier of the first service, and the indication information indicates that offloading of the first service to the visited network is allowed.

[0053] In a fifth aspect, a communication method is provided, which can be executed by a core network element, or can also be executed by a component of the core network element (such as a chip or circuit), without limitation.

[0054] The method may include: a first session management network element obtaining IP address information of a visited network; the first session management network element sending the IP address information to an edge application server discovery network element, the first session management network element and the edge application server discovery network element being network elements deployed in a home network; and the edge application server discovery network element receiving the IP address information.

[0055] In combination with the fifth aspect, in certain implementations of the fifth aspect, the edge application server discovers that the network element receives a DNS query message; the edge application server discovers that the network element adds a domain name system extension mechanism client subnet option in the DNS query message, and the domain name system extension mechanism client subnet option is determined based on the IP address information.

[0056] In combination with the fifth aspect, in certain implementations of the fifth aspect, the edge application server discovers that the network element receives a DNS query message; the edge application server discovers that the network element forwards the DNS query message to a local DNS server address, which is determined based on the IP address information.

[0057] In combination with the fifth aspect, in certain implementations of the fifth aspect, the IP address information is information used to determine a domain name system DNS extension mechanism client subnet option, or the IP address information is a domain name system extension mechanism client subnet option or a local DNS server address.

[0058] In a sixth aspect, a communication method is provided, which can be executed by a core network element, or can also be executed by a component of the core network element (such as a chip or circuit), without limitation.

[0059] The method may include: the second session management network element obtains indication information, the indication information indicates that the visited network diversion is allowed; the second session management network element sends the IP address information of the visited network to the user plane network element according to the indication information, wherein the second session management network element and the user plane network element are network elements deployed in the visited network; the user plane network element receives the IP address information.

[0060] In combination with the sixth aspect, in certain implementations of the sixth aspect, the user-side network element receives a DNS query message; the user-side network element adds a domain name system extension mechanism client subnet option to the DNS query message, and the domain name system extension mechanism client subnet option is determined based on the IP address information.

[0061] In combination with the sixth aspect, in certain implementations of the sixth aspect, the user plane network element receives a DNS query message; the user plane network element forwards the DNS query message to a local DNS server address, where the local DNS server address is determined based on the IP address information.

[0062] In combination with the sixth aspect, in certain implementations of the sixth aspect, the user plane network element sends the IP address information to the edge application server discovery network element, and the edge application server discovery network element is a network element deployed in the home network.

[0063] In combination with the sixth aspect, in certain implementations of the sixth aspect, the IP address information is information used to determine a domain name system DNS extension mechanism client subnet option, or the IP address information is a domain name system extension mechanism client subnet option or a local DNS server address.

[0064] In a seventh aspect, a communication device is provided, the device being configured to execute the method of any possible implementation of aspects 1 to 6. Specifically, the device may include units and / or modules, such as a processing unit and / or a communication unit, for executing the method of any possible implementation of aspects 1 to 6.

[0065] In one implementation, the apparatus is a core network element. When the apparatus is a core network element, the communication unit may be a transceiver or an input / output interface; and the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0066] In another implementation, the device is a chip, chip system, or circuit for a core network element. When the device is a chip, chip system, or circuit for a core network element, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; and the processing unit may be at least one processor, processing circuit, or logic circuit.

[0067] In an eighth aspect, a communication device is provided, the device comprising: at least one processor configured to execute a computer program or instruction stored in a memory to perform the method of any possible implementation of aspects 1 to 6. Optionally, the device further comprises a memory configured to store the computer program or instruction. Optionally, the device further comprises a communication interface, and the processor reads the computer program or instruction stored in the memory through the communication interface.

[0068] In one implementation, the device is a core network element.

[0069] In another implementation, the device is a chip, a chip system or a circuit for a core network element.

[0070] In a ninth aspect, the present application provides a processor for executing the methods provided in the above aspects.

[0071] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as processor output, reception, input and other operations, and can also be understood as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0072] In a tenth aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, wherein the program code includes a method for executing any possible implementation of the first to sixth aspects above.

[0073] In the eleventh aspect, a computer program product comprising instructions is provided, which, when run on a computer, enables the computer to execute the method in any possible implementation of the first to sixth aspects above.

[0074] In a twelfth aspect, a communication system is provided, comprising one or more of the aforementioned first session management network element, second session management network element, edge application server discovery network element, and user plane network element. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 A schematic diagram of a network architecture is shown.

[0076] Figure 2 A schematic diagram showing another network architecture is shown.

[0077] Figure 3 It is a schematic diagram of a communication method 300 provided in an embodiment of the present application.

[0078] Figure 4 It is a schematic diagram of another communication method 400 provided in an embodiment of the present application.

[0079] Figure 5 It is a schematic flowchart of a communication method 500 provided in an embodiment of the present application.

[0080] Figure 6 It is a schematic flowchart of another communication method 600 provided in an embodiment of the present application.

[0081] Figure 7 It is a schematic flowchart of another communication method 700 provided in an embodiment of the present application.

[0082] Figure 8 It is a schematic flowchart of another communication method 800 provided in an embodiment of the present application.

[0083] Figure 9 It is a schematic flowchart of another communication method 900 provided in an embodiment of the present application.

[0084] Figure 10 It is a schematic flowchart of another communication method 1000 provided in an embodiment of the present application.

[0085] Figure 11It is a schematic flowchart of another communication method 1100 provided in an embodiment of the present application.

[0086] Figure 12 A schematic block diagram of a communication device 1200 provided in an embodiment of the present application is shown.

[0087] Figure 13 A schematic block diagram of another communication device 1300 provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0088] The technical solution in this application will be described below with reference to the accompanying drawings.

[0089] The technical solutions provided in this application can be applied to various communication systems, such as: fifth generation (5G) or new radio (NR) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, etc. The technical solutions provided in this application can also be applied to future communication systems, such as the sixth generation mobile communication system. The technical solutions provided in this application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), and Internet of Things (IoT) communication systems or other communication systems.

[0090] First combine Figure 1 and Figure 2 The following briefly introduces the network architecture applicable to this application.

[0091] As an example, Figure 1 A schematic diagram of a network architecture is shown.

[0092] like Figure 1 As shown, the network architecture takes home routed (HR) roaming as an example.

[0093] A cellular mobile communication network of a certain standard of an operator can be called a public land mobile network (PLMN). The PLMN to which the user equipment (UE) subscribes can be called a home public land mobile network (PLMN) (home PLMN, HPLMN), which represents the home operator of the subscribed user. When the UE leaves the coverage of the HPLMN due to movement or other reasons, if there is a PLMN that meets the following conditions: 1) it can cover the current location of the UE, 2) its operator has signed a roaming agreement with the operator of the HPLMN of the UE (a roaming agreement is an agreement between operators, the content of which may include but is not limited to: services and billing methods provided to subscribers of the other operator's network, etc., and is not restricted to this), then the UE can access the PLMN, and the PLMN can be called a visited public land mobile network (visited PLMN, VPLMN). The act of UE accessing the VPLMN can be called roaming. Roaming scenarios can be categorized as local breakout (LBO) roaming and home routed (HR) roaming. The main difference between the two lies in whether the session is connected to the UPF of the home network. In the HR roaming scenario, the session (e.g., an HR session) is connected to the UPF of the home network. An HR session is established when a user is in a visited network and connected to the UPF of the home network. The traffic carried in this HR session is sent from the UE to the UPF of the home network and then to the receiving end.

[0094] like Figure 1As shown, the network architecture may include but is not limited to: network slice specific authentication and authorization function (NSSAAF), network slice selection function (NSSF), authentication server function (AUSF), unified data management (UDM), policy control function (PCF), application function (AF), access and mobility management function (AMF), session management function (SMF), user equipment (UE), radio access network equipment, user plane function (UPF), data network (DN), etc.

[0095] Below Figure 1 A brief introduction is given to each network element shown in FIG.

[0096] 1. UE: may also be referred to as terminal equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device.

[0097] The terminal device can be a device that provides voice / data to users, for example, a handheld device or vehicle-mounted device with a wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (PLMNs). The terminal equipment in the network (PLMN), etc., is not limited to this in the embodiments of the present application.

[0098] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0099] In addition, in the embodiments of the present application, the terminal device can also be a terminal device in an IoT system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection.

[0100] It should be noted that the terminal device and the access network device can communicate with each other using a certain air interface technology (such as NR or LTE technology). The terminal devices can also communicate with each other using a certain air interface technology (such as NR or LTE technology).

[0101] In the embodiments of the present application, the device for implementing the function of the terminal device can be the terminal device, or it can be a device that can support the terminal device to implement the function, such as a chip system or chip, which can be installed in the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0102] 2. (Radio) Access Network (R)AN) equipment: This equipment provides access to the communications network for authorized users in a specific area. Specifically, it can include wireless network equipment in 3rd Generation Partnership Project (3GPP) networks as well as access points in non-3GPP networks. For ease of description, the term "AN" is used below.

[0103] AN equipment can adopt different wireless access technologies. There are currently two types of wireless access technologies: 3GPP access technology (for example, the wireless access technology used in the third generation (3rd generation, 3G), fourth generation (4G) or 5G systems) and non-3GPP (non-3GPP) access technology. 3GPP access technology refers to access technology that complies with 3GPP standard specifications. For example, the access network equipment in the 5G system is called the next generation NodeBase station (gNB) or RAN equipment. Non-3GPP access technologies may include air interface technologies represented by access points (APs) in wireless fidelity (WiFi), worldwide interoperability for microwave access (WiMAX), code division multiple access (CDMA), etc. AN equipment can allow terminal devices and the 3GPP core network to interconnect and communicate using non-3GPP technologies.

[0104] AN equipment is responsible for radio resource management, quality of service (QoS) management, data compression and encryption, etc. on the air interface side. AN equipment provides access services to terminal devices and forwards control signals and user data between terminal devices and the core network.

[0105] AN equipment may include, for example, but is not limited to: a macro base station, a micro base station (also known as a small station), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), an AP in a WiFi system, a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP), etc. It may also be a gNB or transmission point (TRP or TP) in a 5G (e.g., NR) system, one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G system, or a network node constituting a gNB or transmission point, such as a distributed unit (DU), or a base station in a next-generation communication 6G system. The embodiments of the present application do not limit the specific technology and specific device form adopted by the AN equipment.

[0106] 3. AMF: Mainly used for access control, mobility management, attachment and detachment functions.

[0107] 4. SMF: Mainly used for user-plane network element selection, user-plane network element redirection, Internet Protocol (IP) address allocation for terminal devices, and session management in mobile networks, such as session establishment, modification and release, and quality of service (QoS) control.

[0108] In this application, for the purpose of distinction, the SMF in the HPLMN is referred to as the home SMF (H-SMF), and the SMF in the VPLMN is referred to as the visited SMF (V-SMF).

[0109] 5. UPF: Primarily responsible for receiving and forwarding user plane data. For example, the UPF can receive user plane data from the DN and send it to the terminal device via the AN. The UPF can also receive user plane data from the terminal device via the AN and forward it to the DN. The UPF directly connected to the DN via the N6 interface in a session is called the protocol data unit (PDU) session anchor (PSA).

[0110] In this application, for the purpose of differentiation, the UPF in the HPLMN is referred to as the home UPF (H-UPF), and the UPF in the VPLMN is referred to as the visited UPF (V-UPF). In addition, for the purpose of differentiation, the PSA in the HPLMN is referred to as the home PSA (H-PSA), and the PSA in the VPLMN is referred to as the visited PSA (V-PSA) (or the local PSA (L-PSA)).

[0111] 6. PCF: A unified policy framework mainly used to guide network behavior and provide policy rule information for control plane network elements (such as AMF, SMF, etc.).

[0112] 7. AF: Mainly used to provide services to the 3GPP network, such as interacting with the PCF for policy control.

[0113] 8. Network slice selection function (NSSF): mainly used for network slice selection.

[0114] 9. UDM: Mainly used for UE contract data management, including storage and management of UE identification, UE access authorization, etc.

[0115] 10. DN: Operator network mainly used to provide data services to UE, such as the Internet, third-party service networks, and IP Multimedia Service (IMS) networks.

[0116] 11. AUSF: Mainly used for user authentication, etc.

[0117] As an example, Figure 2 A schematic diagram showing another network architecture is shown.

[0118] like Figure 2 As shown, the network architecture can be understood as Figure 1Enhancement of the HR roaming architecture shown. The network architecture may include, but is not limited to: SMF (such as V-SMF and H-SMF), UE, UPF (such as V-UPF and H-UPF), PSA (such as L-PSA), domain name system (DNS), PCF (such as H-PCF), edge application server discovery network element (EASDF). In this architecture, the domain name system (DNS) message may terminate at the EASDF of the HPLMN. The DNS message may terminate at the EASDF of the HPLMN, which may indicate that the DNS message is processed by the EASDF of the HPLMN, or that the destination address of the DNS message is the EASDF of the HPLMN, or that the EASDF of the HPLMN receives the DNS message. The edge application server discovery network element may also be called, for example, an edge application (service) discovery function, an application instance discovery function, an edge application instance discovery function, an MEC application (server) discovery function, etc., without limitation.

[0119] The EASDF is primarily used to assist in edge application server (EAS) discovery. Its main functions include: processing DNS messages according to the instructions of the SMF. Processing DNS messages may include, but is not limited to: reporting DNS messages to the SMF, adding the ECS option (Edns-client-subnet option) to the DNS query, forwarding the DNS query to the DNS server, forwarding the DNS response to the UE, etc. EDNS stands for the extended mechanisms for DNS (EDNS). In this application, for distinction, the DNS in the HPLMN is referred to as C-DNS, and the UPF in the VPLMN is referred to as L-DNS.

[0120] For an introduction to other network elements, please refer to Figure 1 The description in , will not be repeated here.

[0121] exist Figure 1 or Figure 2 In the network architecture shown, each network element can communicate with each other through an interface. For example, the UE is connected to the AN device through the radio resource control (RRC) protocol, and the UE and the AN device communicate using the Uu interface. Figure 1 The interfaces shown are not described here in detail.

[0122] It should be understood that the network architecture shown above is only an example, and the network architecture applicable to the embodiments of the present application is not limited thereto. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiments of the present application. In addition, the network architecture shown above may also include other more network elements, such as network storage function network elements ((network function (NF) repository function, NRF), which is not limited. In this application, for the purpose of distinction, the NRF in the HPLMN is referred to as the home NRF (H-NRF), and the NRF in the VPLMN is referred to as the visited NRF (V-NRF).

[0123] It should also be understood that Figure 1 or Figure 2 The AMF, SMF, UPF, PCF, UDM, NSSF, AUSF and other functions or network elements shown in the specification can be understood as network elements used to implement different functions, for example, they can be combined into network slices as needed. These network elements can be independent devices, or they can be integrated into the same device to implement different functions, or they can be network elements in hardware devices, or they can be software functions running on dedicated hardware, or they can be virtualized functions instantiated on a platform (for example, a cloud platform). This application does not limit the specific form of the above network elements.

[0124] It should also be understood that the above naming is defined only to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 6G networks and other future networks. For example, in a 6G network, some or all of the above network elements may continue to use the terminology used in 5G, or may adopt other names.

[0125] In edge computing (EC) deployment scenarios, some services may be provided by multiple EASs deployed at the edge of the network. These multiple EASs can provide the same services and content, and most of them have different IP addresses. In EC scenarios, when a UE accesses the service, it can request access to an available EAS that is close to the UE. Therefore, obtaining the IP address of the appropriate EAS is relatively important.

[0126] As mentioned above, a UE may access a VPLMN through HR roaming, and the VPLMN may provide services to the UE. If HR roaming is required for these services, since the session anchor is in the HPLMN, the application server (AS) IP returned by the remote DNS server is close to the H-UPF, but may be far away from the UE. This results in a long path for the UE to access the AS, resulting in a poor user experience. Therefore, existing edge service discovery mechanisms cannot be used in HR roaming scenarios.

[0127] This application proposes a solution to access services in the VPLMN through the IP address of the VPLMN (such as information used to determine the ECS option, such as the ECS option or L-DNS server, etc.), and to achieve local EAS discovery in the HR roaming scenario.

[0128] For example, the session management network element of the HPLMN obtains the IP address information of the visited network (such as information used to determine the ECS option, such as the ECS option or L-DNS server, etc.), and sends it to the edge application server discovery network element of the HPLMN. In this way, when the terminal device accesses the service in the VPLMN, the edge application server discovery network element can be implemented based on the obtained IP address information. For example, after the edge application server discovery network element of the HPLMN receives a DNS query message from the terminal device, it can add the ECS option determined based on the IP address information to the DNS query or forward the DNS query message to the L-DNS server determined based on the IP address information (such as the IP address information is the L-DNS server address information), etc., thereby realizing the discovery of the local EAS in the HR roaming scenario.

[0129] For another example, the session management network element of the VPLMN obtains information #B, and the information #B indicates that the visited network diversion is allowed. The session management network element of the VPLMN can send the IP address information of the visited network (such as information used to determine the ECS option, such as the ECS option or the L-DNS server address) to the user plane network element of the VPLMN based on the information #B. In this way, when the terminal device accesses the visited network through HR roaming, the IP address information can be used to enable the terminal device to access the services in the visited network. For example, the user plane network element of the VPLMN can add the ECS option to the DNS query message, or the user plane network element of the VPLMN sends the ECS option or the information used to determine the ECS option to the edge application server discovery network element, and the edge application server discovery network element can add the ECS option to the DNS query message, etc., so as to realize the discovery of the local EAS in the HR roaming scenario.

[0130] It should be understood that the term "and / or" in this document simply describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0131] The communication method provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings. Figure 1 or Figure 2 The network architecture shown is not limited.

[0132] Figure 3 FIG3 is a schematic diagram of a communication method 300 provided in an embodiment of the present application. The method 300 may include the following steps.

[0133] 310. A first session management network element obtains IP address information of a visited network. The first session management network element is a network element deployed in a home network.

[0134] The visited network is a network that a terminal device accesses after leaving its home network, such as a virtual private network (VPLMN). The following mainly uses a VPLMN as an example for explanation.

[0135] The home network is the network to which the terminal device subscribes, such as the HPLMN. The following mainly uses the HPLMN as an example for explanation.

[0136] The first session management network element is a network element deployed in the HPLMN. For example, the first session management network element is an H-SMF.

[0137] In one example, IP address information (referred to as information #A for distinction) refers to information used to determine an ECS option, or the IP address information is an ECS option, or the IP address information is an IP address or prefix of a subnet. For example, in step 310, the H-SMF obtains information #A, which is used to determine an ECS option (i.e., the ECS option of the VPLMN). As an example, when information #A is information used to determine an ECS option, the information #A may also be an ECS option. Unless otherwise specified below, the ECS option mentioned below refers to the ECS option of the VPLMN.

[0138] In another example, information #A refers to the local DNS (L-DNS) server address. For example, in step 310, the H-SMF obtains information #A, which is the L-DNS server address.

[0139] It is understandable that the IP address information can also be described as the media access control (MAC) address of the subnet. This application does not limit the representation format of the IP address information.

[0140] For ease of description, the following description uses the ECS option as an example for illustrative purposes. However, the present application is not limited thereto. For example, the ECS option may be replaced with the L-DNS server address. Accordingly, the action of adding the ECS option to the DNS query may be replaced with the action of forwarding the DNS query to the L-DNS server.

[0141] Information #A will not be elaborated on below.

[0142] 320. The first session management network element sends IP address information to the edge application server discovery network element. The edge application server discovery network element is a network element deployed in the home network.

[0143] The edge application server discovers that the network element is a network element deployed in the HPLMN. For example, the edge application server discovers that the network element is the H-EASDF.

[0144] Based on the above technical solution, the first session management network element deployed in the home network can obtain the IP address information of the visited network (such as information used to determine the ECS option, such as the ECS option or L-DNS server) and send it to the edge application server discovery network element. By obtaining the IP address information of the visited network, when the terminal device accesses the visited network through HR roaming, since the edge application server discovery network element has obtained the IP address information of the visited network, the terminal device can access the services in the visited network through the edge application server discovery network element. For example, after the edge application server discovery network element receives the DNS query message from the terminal device, it can add the ECS option determined based on the IP address information to the DNS query message, or it can forward the DNS query message to the L-DNS server determined based on the IP address information (such as the IP address information is the L-DNS server address information), thereby realizing the discovery of the local EAS in the HR roaming scenario.

[0145] Optionally, in step 310, the first session management network element obtains the IP address information of the visited network, including: the first session management network element obtains the IP address information of the visited network according to indication information (recorded as information #B for distinction), and information #B indicates that the visited network is allowed to offload traffic.

[0146] For example, when the H-SMF learns that VPLMN offloading is allowed, the H-SMF obtains the IP address information of the VPLMN (ie, information #A).

[0147] Optionally, in step 320, the first session management network element sends information #A to the edge application server discovery network element, including: the first session management network element sends information #A to the edge application server discovery network element based on information #B, and information #B indicates that visited network diversion is allowed (or information #B indicates that diversion is allowed).

[0148] For example, if the information #B indicates that VPLMN offloading is allowed, the H-SMF learns that VPLMN offloading is allowed, and then the H-SMF sends the information #A to the H-EASDF.

[0149] Information #B is described in detail below.

[0150] Information #B indicates that traffic offloading to the visited network is permitted. Information #B can also be described as indicating (or representing, or indicating) that traffic offloading is permitted (or authorized, or expected). Here, "permit" can indicate authorization or expectation.

[0151] In one example, "allow traffic offloading" indicates that traffic offloading in the VPLMN is allowed. Accordingly, information #B indicating that traffic offloading in the visited network is allowed may be replaced by information #B indicating that traffic offloading in the VPLMN is allowed.

[0152] In another example, traffic offloading allowed indicates whether the HPLMN allows local traffic offloading to the VPLMN. Accordingly, information #B indicating that traffic offloading to the visited network is allowed may be replaced with information #B indicating whether the HPLMN allows local traffic offloading to the VPLMN.

[0153] In another example, allowing traffic offloading means allowing the addition (or use or acquisition) of the ECS option (or allowing the acquisition of the L-DNS server address, or allowing the DNS query to be forwarded to the L-DNS server). Accordingly, information #B indicating that visited network offloading is allowed can also be replaced by information #B indicating that the addition (or use or acquisition) of the ECS option (or allowing the acquisition of the L-DNS server address, or allowing the DNS query to be forwarded to the L-DNS server) is allowed.

[0154] In another example, allowing traffic offloading means adding (or using or obtaining) an ECS option (or obtaining the L-DNS server address, or forwarding the DNS query to the L-DNS server). Accordingly, information #B indicating that visited network offloading is allowed can also be replaced by information #B indicating adding (or using or obtaining) an ECS option (or obtaining the L-DNS server address, or forwarding the DNS query to the L-DNS server).

[0155] The present application does not limit the specific content of "Information #B". The following is a unified description, mainly taking "Information #B" indicating whether to allow offloading in VPLMN as an example for exemplary explanation.

[0156] It can be understood that this application is mainly explained by taking the example of allowing VPLMN diversion, and does not limit all situations to allowing VPLMN local diversion. In other words, in some cases, VPLMN diversion may not be allowed (or not supported). In this case, local diversion may not be performed in the VPLMN.

[0157] This application does not limit the specific naming of information #B. For example, "information #B" in this application can be replaced by "authorization policy", or can be replaced by "diversion policy", or can be replaced by "roaming policy", etc.

[0158] This application does not limit the form of information #B. For example, information #B can be a cell, a parameter, or a table, etc.

[0159] Optionally, the information #B indicates that offloading of the first service to the visited network is permitted. Optionally, the information #B includes an identifier of the first service. For example, the first session management network element may also send the identifier of the first service to the edge application server discovery network element. The identifier of the first service and the information #B may be carried in the same signaling or sent separately, without limitation.

[0160] Among them, allowing the first service to be offloaded in the visited network, for example, it may indicate that it is allowed to add (or use) the ECS option in the DNS query corresponding to the first service, or it may indicate that it is allowed to forward the message corresponding to the first service to the L-DNS server, or it may indicate that the ECS option is added in the uplink message, and the method of adding in the uplink message is not restricted, for example, adding a general packet radio service (GPRS) tunneling protocol (GPRS Tunnelling Protocol for the user plane, GTP-U) message header at the user layer.

[0161] As an example, the identifier of the first service can be any of the following: a fully qualified domain name (FQDN) (or an FQDN range), an application ID (AppID), an IP address, or a port number. In other words, information #B can include one or more of the following: an FQDN (or an FQDN range), an application ID, or an IP address. The following description primarily uses the FQDN as an example. It is understood that the FQDN in the following examples can also be replaced with any of the following: an application ID, an IP address, or a port number.

[0162] For example, information #B includes one or more FQDNs, which indicate the FQDNs corresponding to services that are allowed to be diverted in the visited network (or the FQDNs corresponding to services that are allowed to use the VPLMN ECS option). In one possible implementation, information #B includes two information elements, one information element is used to indicate that diverting in the visited network is allowed, and the other information element includes the one or more FQDNs. The H-SMF can learn from information #B that the services corresponding to the one or more FQDNs are allowed to be diverted in the visited network. In another possible implementation, information #B includes one or more FQDNs, and the H-SMF determines, based on internal logic, that the services corresponding to the one or more FQDNs are allowed to be diverted in the visited network.

[0163] For another example, information #B includes one or more FQDNs, and the one or more FQDNs indicate the FQDNs corresponding to the services that are not allowed to be diverted in the visited network (or indicate the FQDNs corresponding to the services that are not allowed to use the VPLMN ECS option). In one possible implementation, information #B includes two information elements, one information element is used to indicate that diversion in the visited network is not allowed, and the other information element includes the one or more FQDNs. The H-SMF can learn from information #B that the services corresponding to the one or more FQDNs are not allowed to be diverted in the visited network. In another possible implementation, information #B includes one or more FQDNs, and the H-SMF determines based on internal logic that the services corresponding to the one or more FQDNs are not allowed to be diverted in the visited network. In addition, further, the H-SMF can learn from information #B that the services corresponding to other FQDNs (i.e., FQDNs other than the one or more FQDNs) are allowed to be diverted in the visited network.

[0164] For another example, information #B includes one or more FQDN#1s and one or more FQDN#2s. The one or more FQDN#1s represent the FQDNs corresponding to services that are permitted to be offloaded in the visited network, and the one or more FQDN#2s represent the FQDNs corresponding to services that are not permitted to be offloaded in the visited network. In one possible implementation, information #B includes three information elements: one information element indicating that services corresponding to FQDN#1 are permitted to be offloaded in the visited network, another information element including the one or more FQDN#1s, and another information element including the one or more FQDN#2s. Based on information #B, the H-SMF can determine that services corresponding to the one or more FQDN#1s are permitted to be offloaded in the visited network, and services corresponding to the one or more FQDN#2s are not permitted to be offloaded in the visited network. In another possible implementation, information #B includes three information elements: one indicating that the service corresponding to FQDN #2 is not allowed to be offloaded to the visited network; another including the one or more FQDN #1s; and another including the one or more FQDN #2s. Based on information #B, the H-SMF can determine that the service corresponding to the one or more FQDN #1s is allowed to be offloaded to the visited network, but the service corresponding to the one or more FQDN #2s is not allowed to be offloaded to the visited network. In another possible implementation, information #B includes two information elements: one including the one or more FQDN #1s, and another including the one or more FQDN #2s. The H-SMF determines, based on internal logic, that the service corresponding to the one or more FQDN #1s is allowed to be offloaded to the visited network, but the service corresponding to the one or more FQDN #2s is not allowed to be offloaded to the visited network.

[0165] Optionally, information #B corresponds to the PLMN.

[0166] For example, information #B may be associated with a PLMN. By determining the PLMN, the information #B corresponding to (or associated with) the PLMN may be determined. For example, information #B may be in the form of Table 1.

[0167] Table 1

[0168] PLMN identity (ID) Information#B PLMN#1 Information #B1 PLMN#2 Information #B2 PLMN#3 Message #B3

[0169] Taking Table 1 as an example, for example, if the PLMN is determined to be PLMN#2, it can be known that the information #B corresponding to the PLMN is information #B2.

[0170] In one possible scenario, the PLMN ID in Table 1 may be the ID of a VPLMN. For example, if the VPLMN is determined to be PLMN#2, then the information #B corresponding to the VPLMN may be determined to be information #B2. If information #B2 indicates that local traffic diversion for PLMN#2 is permitted, local traffic diversion may be performed in the VPLMN.

[0171] In another possible scenario, the PLMN ID in Table 1 may be the ID of the HPLMN. For example, if the HPLMN is determined to be PLMN#1, then the information #B corresponding to the HPLMN may be obtained as information #B1. If information #B1 indicates that PLMN#1 allows local traffic offload to the VPLMN, local traffic offload may be performed in the VPLMN.

[0172] It should be understood that Table 1 is merely illustrative and not limiting, and any variations of Table 1 are applicable to this application. For example, the PLMN ID in Table 1 can also be replaced with an SMF ID. For example, PLMN#1 can be replaced with one or more SMF IDs (i.e., the IDs of one or more SMFs corresponding to PLMN#1).

[0173] Optionally, the PLMN and information #A have a corresponding relationship, such as denoted as correspondence #A. That is, based on the PLMN and correspondence #A, information #A of the PLMN can be determined. Information #A can be used to determine the ECS option. For example, correspondence #A can be presented in the form of Table 2.

[0174] Table 2

[0175] PLMN ID Information#A PLMN#1 Information #A1 PLMN#2 Information #A2 PLMN#3 Information #A3

[0176] Taking Table 2 as an example, if the PLMN is determined to be PLMN#2, then the information #A corresponding to the PLMN is known to be information #A2. The ECS option can be determined based on this information #A2. For example, if the H-SMF determines that the PLMN is PLMN#2 and that the information #A corresponding to the PLMN is information #A2, the H-SMF can send this information #A2 to the H-EASDF, so that the H-EASDF can determine the ECS option based on this information #A2.

[0177] It should be understood that Table 2 is merely illustrative and not limiting. Any variations of Table 2 are applicable to this application. For example, the PLMN ID in Table 2 can be replaced with an SMF ID. For example, PLMN#2 can be replaced with one or more SMF IDs (i.e., the IDs of one or more SMFs corresponding to PLMN#2). For another example, information #A in Table 2 can be replaced with an ECSoption or L-DNS server address.

[0178] Optionally, the PLMN, information #B, and information #A have a corresponding relationship, such as denoted as corresponding relationship #B. That is, based on the PLMN and corresponding relationship #B, the information #B and information #A corresponding to the PLMN can be determined. The ECS option can be determined through the information #A.

[0179] For example, Tables 1 and 2 are used in combination. For example, if the PLMN is determined to be PLMN #1, then the information #B corresponding to the PLMN can be obtained as information #B1 based on Table 1, and the information #A corresponding to the PLMN can be obtained as information #A1 based on Table 2. The ECS option can be determined based on this information #A1.

[0180] For another example, the corresponding relationship #B may exist in the form of Table 3.

[0181] Table 3

[0182] PLMN ID Information#B Information#A PLMN#1 Information #B1 Information #A1 PLMN#2 Information #B2 Information #A2 PLMN#3 Message #B3 Information #A3

[0183] Taking Table 3 as an example, if the PLMN is determined to be PLMN#2, then based on Table 3, it can be determined that the information #B corresponding to the PLMN is information #B2, and the information #A corresponding to the PLMN is information #A2. The ECS option can be determined based on this information #A2. For example, if the H-SMF determines that the PLMN is PLMN#2 and that the information #A corresponding to the PLMN is information #A2, the H-SMF can send this information #A2 to the H-EASDF, so that the H-EASDF can determine the ECS option based on this information #A2.

[0184] It should be understood that Table 3 is merely illustrative and not limiting. Any variations of Table 3 are applicable to this application. For example, the PLMN ID in Table 3 can be replaced with an SMF ID. For example, PLMN#1 can be replaced with one or more SMF IDs (i.e., the IDs of one or more SMFs corresponding to PLMN#1). For another example, information #A in Table 3 can be replaced with an ECSoption or L-DNS server address.

[0185] Optionally, the method 300 further includes: the first session management network element obtaining information #B.

[0186] For example, the H-SMF can obtain information #B in at least any of the following ways.

[0187] Method 1, H-SMF receives information #B.

[0188] For example, the H-SMF receives information #B from the H-PCF or AF. For example, the H-PCF or AF sends information #B to the H-SMF, and accordingly, the H-SMF receives information #B from the H-PCF or AF. There is no limitation on the conditions for triggering the H-PCF or AF to send information #B to the H-SMF. For example, the triggering condition may be that the H-SMF sends the VPLMN identifier to the H-PCF or AF. Figures 5 to 11 Give examples.

[0189] For another example, H-SMF receives information #B from H-NRF. For example, H-NRF sends information #B to H-SMF, and accordingly, H-SMF receives information #B from H-NRF. There is no limitation on the conditions for triggering H-NRF to send information #B to H-SMF. For example, the triggering condition may be that H-SMF sends the VPLMN identifier to H-NRF. Figures 5 to 11 Give examples.

[0190] For another example, the H-SMF receives information #B from the V-SMF. For example, the V-SMF sends information #B to the H-SMF, and correspondingly, the H-SMF receives information #B from the V-SMF.

[0191] Method 2: H-SMF local configuration information #B.

[0192] For example, the locally configured roaming agreement includes information #B corresponding to the VPLMN. The H-SMF directly obtains the information #B corresponding to the VPLMN according to the locally configured roaming agreement.

[0193] For another example, the locally configured roaming agreement includes one or more information #B, and the H-SMF obtains the information #B according to the locally configured roaming agreement. The one or more information #B may be information #B corresponding to one or more PLMNs. The H-SMF may first determine the VPLMN and then obtain the corresponding information #B according to the VPLMN. It should be noted that the H-SMF may determine the information #B based on the message received from the V-SMF and the local configuration. The message may be an Nsmf_PDUSession_CreateRequest or Nsmf_PDUSession_Update Request message, etc., which is not limited in this application.

[0194] Optionally, information #B may be stored in the H-SMF in the form of Table 1. Taking Table 1 as an example, if the H-SMF determines that the VPLMN is PLMN#2, then the information #B corresponding to the VPLMN may be obtained as information #B2. If information #B2 indicates that local traffic offloading for PLMN#2 is permitted, local traffic offloading may be performed in the VPLMN.

[0195] Optionally, there is a correspondence between the VPLMN and information #A (e.g., correspondence #A). That is, based on the VPLMN and correspondence #A, information #A for the VPLMN can be determined. Taking Table 2 as an example, in one possible scenario, the PLMN ID in Table 2 can be the ID of the VPLMN. For example, if the H-SMF determines that the VPLMN is PLMN #2, then the information #A corresponding to the VPLMN can be determined to be information #A2.

[0196] This application does not limit the way in which the H-SMF determines the VPLMN. As an example, the H-SMF can identify the VPLMN based on the identifier of the network element deployed in the VPLMN (such as the identifier of the V-SMF, or the identifier of other network elements, etc.). In one possible way, the H-SMF receives the identifier of the V-SMF (such as the V-SMF ID, which is not limited in this application), and the H-SMF determines the identifier of the VPLMN based on the identifier of the V-SMF, that is, determines the VPLMN. Another possible way is that the H-SMF receives the identifier of the VPLMN from the V-SMF. In another possible way, the H-SMF receives a message from the V-SMF and determines the identifier of the VPLMN based on the message. The message can be an Nsmf_PDUSession_Create Request or an Nsmf_PDUSession_Update Request message, etc., which is not limited in this application.

[0197] The above two methods are exemplary descriptions, and any method that enables the H-SMF element to obtain information #B is applicable to the embodiments of the present application.

[0198] Optionally, in step 310, the first session management network element obtains the information #A, which includes: the first session management network element itself determines the information #A, or the first session management network element receives the information #A.

[0199] The following description is made by taking the first session management network element as H-SMF as an example.

[0200] Method 1, H-SMF receives information #A from V-SMF.

[0201] For example, the V-SMF may proactively send information #A. For example, by reusing the HR session establishment process, the V-SMF sends an Nsmf_PDUSession_Create Request message to the H-SMF, which includes information #A.

[0202] For another example, the V-SMF may send information #A to the H-SMF based on the request of the H-SMF. Further, optionally, the method 300 further includes: the H-SMF sends request information #1 (i.e., an example of the first request information) to the V-SMF, where the request information #1 is used to request the above-mentioned information #A.

[0203] There are no restrictions on the implementation of request message #1. In one possible embodiment, request message #1 may be message #B, i.e., the H-SMF sends message #B to the V-SMF, where message #B is used to request the aforementioned message #A. In another possible embodiment, request message #1 may be implemented using one or more bits, such as requesting the aforementioned message #A using a field of one or more bits. In another possible embodiment, request message #1 itself has the function of requesting the aforementioned message #A, i.e., upon receiving request message #1, the V-SMF sends message #A to the H-SMF.

[0204] Mode 2: H-SMF receives information #A from H-NRF.

[0205] For example, the H-NRF may send information #A to the H-SMF based on the request of the H-SMF. Further, optionally, the method 300 also includes: the H-SMF sends request information #2 (i.e., an example of the second request information) to the H-NRF, and the request information #2 is used to request the above-mentioned information #A. In the first possible case, after the H-NRF receives the request information #2, it can determine the information #A according to the local configuration. In this case, the H-NRF directly sends a response to the request information #2 to the H-SMF, and the response carries the information #A. In the second possible case, after the H-NRF receives the request information #2, it can receive information #A from the V-NRF.

[0206] There is no limitation on the implementation of request message #2. In one possible manner, the request message #2 may be message #B, i.e., the H-SMF sends message #B to the H-NRF, and the message #B is used to request the above-mentioned information #A. In another possible manner, the request message #2 may be implemented through one or more bits, such as requesting the above-mentioned information #A through the field of the one or more bits. In another possible manner, the request message #2 itself has the function of requesting the above-mentioned information #A, i.e., upon receiving the request message #2, the H-NRF sends the information #A to the H-SMF. In the various possible manners described above, the request message #2 may also include an identifier of the VPLMN, such as a VPLMN ID.

[0207] Method 3: H-SMF itself determines information #A.

[0208] For example, the VPLMN may correspond to one or more information #A.

[0209] The H-SMF may first determine the VPLMN, and then determine the information #A corresponding to the VPLMN based on the correspondence between the VPLMN and the information #A (such as the correspondence #A).

[0210] This application does not limit the way in which the H-SMF determines the VPLMN. As an example, the H-SMF can identify the VPLMN based on the identifier of the network element deployed in the VPLMN (such as the identifier of the V-SMF, or the identifier of other network elements, etc.). In one possible way, the H-SMF receives the identifier of the V-SMF (such as the V-SMF ID, which is not limited in this application), and the H-SMF determines the identifier of the VPLMN based on the identifier of the V-SMF, that is, determines the VPLMN. Another possible way is that the H-SMF receives the identifier of the VPLMN from the V-SMF. In another possible way, the H-SMF receives a message from the V-SMF and determines the identifier of the VPLMN based on the message. The message can be an Nsmf_PDUSession_Create Request or an Nsmf_PDUSession_Update Request message, etc., which is not limited in this application.

[0211] For another example, V-SMF may correspond to one or more information #A.

[0212] The H-SMF may first determine the V-SMF, and then determine the information #A corresponding to the V-SMF based on the correspondence between the V-SMF and the information #A. For example, the H-SMF receives the identifier of the V-SMF (e.g., the V-SMF ID, which is not limited in this application), and the H-SMF determines the information #A corresponding to the V-SMF based on the identifier of the V-SMF.

[0213] The above possible methods are for illustrative purposes only and are not limited thereto. Any method that can enable the H-SMF to determine the information #A is applicable to this application.

[0214] As described above, information #B may include an identifier of the first service, such as an FQDN (or FQDN range), an application identifier, an IP address, or a port number. If the H-SMF is locally configured with information #B and also receives information #B, the H-SMF may determine information #A based on the locally configured information #B and / or the received information #B. The following description primarily uses the FQDN as an example. It will be appreciated that the FQDN may also be replaced by any of the following: an application identifier, an IP address, or a port number.

[0215] Assume that the information #B locally configured by the H-SMF is recorded as the first information #B (i.e., an example of the first indication information), and the information #B received by the H-SMF is recorded as the second information #B (i.e., an example of the second indication information). If the first information #B includes FQDN, the FQDN is represented by FQDN#3; if the second information #B includes FQDN, the FQDN is represented by FQDN#4.

[0216] FQDN#3 may include one or more FQDNs. FQDN#3 includes: FQDNs corresponding to services allowed to be offloaded to the VPLMN (or FQDNs corresponding to services allowed to use the VPLMN ECS option), and / or FQDNs corresponding to services not allowed to be offloaded to the VPLMN (or FQDNs corresponding to services not allowed to use the VPLMN ECS option).

[0217] FQDN#4 may include one or more FQDNs. FQDN#4 includes: FQDNs corresponding to services allowed to be offloaded to the VPLMN (or FQDNs corresponding to services allowed to use the VPLMN ECS option), and / or FQDNs corresponding to services not allowed to be offloaded to the VPLMN (or FQDNs corresponding to services not allowed to use the VPLMN ECS option).

[0218] The following describes several possible situations.

[0219] Case 1: the first information #B includes FQDN#3, and the second information #B includes FQDN#4.

[0220] Based on scenario 1, one possible approach is for the H-SMF to determine that the target FQDN is FQDN#4. For example, information #A may be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#4. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#4), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request edge services (or to request the address of an edge server); if the FQDN included in the DNS query message matches FQDN#4, the ECS option may be added to the DNS query message.

[0221] Based on this situation 1, another possible approach is that the H-SMF determines that the target FQDN is the intersection of FQDN#3 and FQDN#4 (e.g., denoted as FQDN#5). For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#5. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#5), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request an edge service (or to request the address of an edge server); if the FQDN contained in the DNS query message matches FQDN#5, the ECS option can be added to the DNS query message.

[0222] Based on scenario 1, in another possible approach, the H-SMF determines that the target FQDN is FQDN#3. For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#3. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#3), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request edge services (or to request the address of an edge server); if the FQDN included in the DNS query message matches FQDN#3, the ECS option can be added to the DNS query message.

[0223] Based on this scenario 1, another possible approach is that the H-SMF determines that the target FQDN is the union of FQDN#3 and FQDN#4 (e.g., denoted as FQDN#6). For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#6. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#6), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request an edge service (or to request the address of an edge server); if the FQDN included in the DNS query message matches FQDN#6, the ECS option can be added to the DNS query message.

[0224] Based on this situation 1, another possible approach is that the H-SMF determines the target FQDN to be FQDN#7, which is determined by the H-SMF based on FQDN#3 and FQDN#4, and is not limited to any of the above FQDN#3, FQDN#4, FQDN#5, and FQDN#6. For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#7. For example, based on this approach, when the FQDN of a certain service matches the target FQDN (i.e., FQDN#7), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request an edge service (or to request the address of an edge server); if the FQDN contained in the DNS query message matches FQDN#7, the ECS option can be added to the DNS query message.

[0225] Case 2: the first information #B does not include FQDN#3, and the second information #B includes FQDN#4.

[0226] Based on scenario 2, one possible approach is for the H-SMF to determine that the target FQDN is FQDN#4. For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#4. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#4), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request edge services (or to request the address of an edge server); if the FQDN included in the DNS query message matches FQDN#4, the ECS option can be added to the DNS query message.

[0227] Case 3: the first information #B includes FQDN#3, and the second information #B does not include FQDN#4.

[0228] Based on scenario 3, one possible approach is for the H-SMF to determine that the target FQDN is FQDN#3. For example, information #A may be used to determine and / or add an ECS option for the DNS query corresponding to FQDN#3. For example, based on this approach, when the FQDN of a service matches the target FQDN (i.e., FQDN#3), the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request edge services (or to request the address of an edge server); if the FQDN included in the DNS query message matches FQDN#3, the ECS option may be added to the DNS query message.

[0229] Based on this situation 3, another possible way is that the H-SMF determines that the target FQDN includes the FQDN of the service that is not deployed at the edge of the HPLMN, or the H-SMF determines that the target FQDN is all FQDNs. It should be noted that this determination action is optional. For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to the target FQDN (such as the FQDN of the service that is not deployed at the edge of the HPLMN). For example, based on this method, when the FQDN of a certain service matches the target FQDN, the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request edge services (or to request the address of the edge server); if the FQDN contained in the DNS query message matches the target FQDN, the ECS option can be added to the DNSquery message. It can be understood that in this case, the H-SMF may not send the FQDN to the H-EASDF.

[0230] Case 4: the first information #B does not include FQDN#3, and the second information #B does not include FQDN#4.

[0231] Based on this situation 4, one possible approach is that the H-SMF determines that the target FQDN includes the FQDN of the service that is not deployed at the edge of the HPLMN, or the H-SMF determines that the target FQDN is all FQDNs. It should be noted that this determination action is optional. For example, information #A can be used to determine and / or add an ECS option for the DNS query corresponding to the target FQDN (such as the FQDN of the service that is not deployed at the edge of the HPLMN). For example, based on this approach, when the FQDN of a certain service matches the target FQDN, the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request an edge service (or to request the address of an edge server); if the FQDN contained in the DNS query message matches the target FQDN, the ECS option can be added to the DNS query message. It can be understood that in this case, the H-SMF may not send the FQDN to the EASDF.

[0232] In the above four cases, the DNS query corresponding to the FQDN is mentioned to determine and / or add the ECS option. Among them, determining the ECS option means determining the ECS option based on information #A, and adding means adding the ECS option to the DNS query message (or the uplink message).

[0233] It is also understood that the above main information #A uses the ECS option as an example for illustrative purposes, and this application is not limited thereto. For example, the ECS option can also be replaced with the L-DNS server address, and the action of adding the ECS option can also be replaced with the action of forwarding the DNS query to the L-DNS server.

[0234] Figure 4 FIG4 is a schematic diagram of another communication method 400 provided in an embodiment of the present application. The method 400 may include the following steps.

[0235] 410. The second session management network element obtains information #B, where information #B indicates that traffic offloading to the visited network is allowed.

[0236] The second session management network element is a network element deployed in the VPLMN, for example, the second session management network element is a V-SMF.

[0237] Regarding information #B, please refer to the relevant description in method 300, which will not be repeated here.

[0238] 420. The second session management network element sends the IP address information of the visited network to the user plane network element according to information #B.

[0239] The user plane network element is a network element deployed in the VPLMN, for example, the user plane network element is a V-UPF, a V-EASDF, or a module combining UPF and EASDF network elements.

[0240] The IP address information (i.e., information #A) refers to information used to determine the ECS option. Alternatively, the IP address information is the ECS option, or the IP address information is the IP address or prefix of the subnet. Alternatively, information #A may refer to the L-DNS server address. For details about information #A, please refer to the description of method 300 and will not be repeated here.

[0241] Based on the above technical solution, the second session management network element deployed in the visited network can send the IP address information of the visited network (such as information for determining the ECS option, such as the ECSoption or L-DNS server address) to the user plane network element according to the indication information. In this way, when the terminal device accesses the visited network through HR roaming, the IP address information can be used to enable the terminal device to access the services in the visited network. For example, the user plane network element can add the ECS option determined based on the IP address information to the DNS query message, or the user plane network element sends the ECS option or the information for determining the ECS option to the edge application server discovery network element, and the edge application server discovery network element can add the ECS option to the DNS query message, wherein the way in which the user plane network element sends the ECSoption or the information for determining the ECS option to the edge application server discovery network element is not limited, for example, it can be sent through an uplink message, or the DNS query message can be forwarded to the L-DNS server, thereby realizing the discovery of the local EAS in the HR roaming scenario.

[0242] Optionally, the method 400 further includes: the second session management network element obtaining information #B.

[0243] For example, the V-SMF can obtain information #B in at least any of the following ways.

[0244] Method 1, V-SMF receives information #B.

[0245] For example, the V-SMF receives information #B from the H-SMF. For example, the H-SMF sends information #B to the V-SMF, and correspondingly, the V-SMF receives information #B from the H-SMF. Information #B can be sent via Nsmf_PDUSession_Create Response or Nsmf_PDUSession_Update Response, etc., and this application does not limit this.

[0246] For another example, the V-SMF receives information #B from the V-PCF or AF. For example, the V-PCF or AF sends information #B to the V-SMF, and correspondingly, the V-SMF receives information #B from the V-PCF or AF.

[0247] Method 2: V-SMF local configuration information #B.

[0248] For example, the locally configured roaming agreement includes information #B corresponding to the HPLMN. The V-SMF directly obtains the information #B corresponding to the HPLMN based on the locally configured roaming agreement.

[0249] For another example, the locally configured roaming agreement includes one or more information #B. The V-SMF obtains the information #B based on the locally configured roaming agreement. The one or more information #B may be information #B corresponding to one or more PLMNs. The V-SMF may first determine the HPLMN and then obtain the corresponding information #B based on the HPLMN.

[0250] Optionally, information #B may be stored in the V-SMF in the form of Table 1. Taking Table 1 as an example, if the V-SMF determines that the HPLMN is PLMN#2, then the information #B corresponding to the HPLMN may be obtained as information #B2. If information #B2 indicates that PLMN#2 allows VPLMN local offload, local offload may be performed in the VPLMN.

[0251] This application does not limit the way in which the V-SMF determines the HPLMN. As an example, the V-SMF can identify the HPLMN based on the identifier of the network element deployed in the HPLMN (such as the identifier of the H-SMF, or the identifier of other network elements, etc.). In one possible way, the V-SMF receives the identifier of the H-SMF (such as the H-SMF ID, which is not limited in this application) from the AMF, and the V-SMF determines the identifier of the HPLMN based on the identifier of the H-SMF, that is, determines the HPLMN. Another possible way is that the V-SMF receives the identifier of the HPLMN from the AMF.

[0252] The above two methods are exemplary illustrations, and any method that enables V-SMF to obtain information #B is applicable to the embodiments of the present application.

[0253] Optionally, the method 400 further includes: the second session management network element obtaining information #A.

[0254] In one possible approach, the second session management network element obtains the IP address information of the visited network based on information #B, where information #B indicates that traffic offloading to the visited network is permitted. For example, the V-SMF learns that VPLMN traffic offloading is permitted based on information #B, and then obtains information #A. Information #B can also be described as indicating (or representing, or indicating) that traffic offloading is permitted.

[0255] It is understood that the above is an exemplary description and the present application is not limited thereto. For example, the second session management network element may also obtain the IP address information of the visited network based on the request. For example, the V-SMF may determine information #A based on the request of the H-SMF.

[0256] Optionally, the method 400 further includes: the second session management network element determining information #A.

[0257] The following takes the second session management network element as V-SMF as an example.

[0258] Method 1, V-SMF receives information #A from V-NRF.

[0259] For example, the V-NRF may send information #A to the V-SMF based on the V-SMF's request. Further, optionally, method 400 further includes: the V-SMF sends a request message #3 to the V-NRF, where the request message #3 is used to request the above-mentioned information #A. In the first possible scenario, after receiving the request message #3, the V-NRF may determine the information #3 based on the local configuration. In this case, the V-NRF directly sends a response to the request message #3 to the V-SMF, where the response carries the information #A.

[0260] There is no limitation on the implementation of request message #2. In one possible manner, the request message #2 may be message #B, i.e., the H-SMF sends message #B to the H-NRF, and the message #B is used to request the above-mentioned information #A. In another possible manner, the request message #2 may be implemented through one or more bits, such as requesting the above-mentioned information #A through the field of the one or more bits. In another possible manner, the request message #2 itself has the function of requesting the above-mentioned information #A, i.e., upon receiving the request message #2, the H-NRF sends the information #A to the H-SMF. In the various possible manners described above, the request message #2 may also include an identifier of the VPLMN, such as a VPLMN ID.

[0261] Method 2: V-SMF itself determines information #A.

[0262] For example, the HPLMN may correspond to one or more information #A.

[0263] The V-SMF may first determine the HPLMN, and then determine the information #A corresponding to the HPLMN based on the correspondence between the HPLMN and the information #A (such as the correspondence #A).

[0264] This application does not limit the way in which the V-SMF determines the HPLMN. As an example, the V-SMF can identify the HPLMN based on the identifier of the network element deployed in the HPLMN (such as the identifier of the H-SMF, or the identifier of other network elements, etc.). In one possible way, the V-SMF receives the identifier of the H-SMF (such as the H-SMF ID, which is not limited in this application), and the V-SMF determines the identifier of the HPLMN based on the identifier of the H-SMF, that is, determines the HPLMN. Another possible way is that the V-SMF receives the identifier of the HPLMN.

[0265] For another example, H-SMF may correspond to one or more information #A.

[0266] The V-SMF may first determine the H-SMF, and then determine the information #A corresponding to the H-SMF based on the correspondence between the H-SMF and the information #A. For example, the V-SMF receives the identifier of the H-SMF (e.g., the H-SMF ID, which is not limited in this application), and the V-SMF determines the information #A corresponding to the H-SMF based on the identifier of the H-SMF.

[0267] The above possible methods are for illustrative purposes only and are not limited thereto. Any method that can enable the V-SMF to determine the information #A is applicable to this application.

[0268] Optionally, information #B includes an identifier of the second service, and the information #B indicates that the second service is allowed to be diverted in the visited network. Optionally, the second session management network element may also send the identifier of the second service to the user plane network element. The identifier of the second service and information #A may be carried in the same signaling, or may be sent separately, without limitation. As an example, the identifier of the second service may be any of the following: FQDN (or FQDN range), application identifier, IP address, port number. For details, please refer to the relevant description in method 300, which will not be repeated here.

[0269] If the V-SMF has locally configured information #B and has received information #B, the V-SMF may determine information #A based on the locally configured information #B and / or the received information #B. For details, please refer to the description of Cases 1 to 4 in method 300, which will not be repeated here.

[0270] Optionally, the method 400 further includes: after the user plane network element receives the information #A, it may have the following processing methods.

[0271] For example, after receiving the DNS query, the user plane network element adds the ECS option determined based on information #A to the DNS query. For example, after receiving the DNS query, if the user plane network element determines that the DNS query is a DNS query corresponding to the message of the second service, the user plane network element adds the ECS option determined based on information #A to the DNS query.

[0272] For another example, after receiving the DNS query, the user-plane network element forwards the DNS query to the L-DNS server. For example, information #A is the L-DNS server address. After receiving the DNS query, if the user-plane network element determines that the DNS query corresponds to the message of the second service, it forwards the DNS query to the L-DNS server.

[0273] For another example, after receiving the DNS query, the user plane network element requests the EASDF to add the ECS option determined based on information #A to the DNS query. Alternatively, after receiving information #A, the user plane network element sends the information #A to the EASDF for processing.

[0274] For another example, the user plane network element sends information #A to the EASDF, which may be the H-EASDF. For example, the user plane network element adds information #A to the GTP-U message header and sends information #A to the EASDF via the user plane message.

[0275] For another example, the user plane network element determines the ECS option based on information #A and then sends the ECS option to the EASDF, which can be the H-EASDF. For example, the user plane network element adds the ECS option to the GTP-U message header and sends information #A to the EASDF via the user plane message.

[0276] It can be understood that the above are some exemplary explanations and are not limiting.

[0277] For ease of understanding, the following mainly uses information #A as an example for determining the ECS option. Figures 5 to 11 The present application embodiment is exemplified. As described above, information #B can also be described as an authorization policy. In the following examples, it is assumed that the authorization policy is used for illustrative purposes. It is understood that the authorization policy is the information #B described above. The specific steps involved can be referred to above.

[0278] Figure 5This is a schematic flow chart of a communication method 500 provided in an embodiment of the present application. Method 500 can be used to implement a solution such as method 300. For example, method 500 can be used in a scenario where the H-SMF determines information #A based on local configuration, and the H-EASDF adds it to a DNS query. Method 500 may include the following steps.

[0279] 501, H-SMF obtains authorization policy #1.

[0280] Authorization policy #1 is used to indicate (or characterize, or indicate) whether traffic offloading in the VPLMN is allowed (or authorization policy #1 is used to indicate whether traffic offloading is allowed). Regarding authorization policy #1, refer to the description of information #B in method 300 above, which will not be repeated here.

[0281] H-SMF obtains authorization policy #1, which can be achieved through at least one of the following methods:

[0282] The first possible way is that H-SMF locally configures authorization policy #1.

[0283] In a second possible manner, the H-SMF receives the authorization policy #1. For example, after the device is powered on, the H-SMF receives the authorization policy #1 from the V-SMF through other processes (such as a session establishment process).

[0284] Regarding the specific method for the H-SMF to obtain the authorization policy #1, please refer to the method for the first session management network element to obtain the information #B in the above method 300, which will not be repeated here.

[0285] Optionally, the H-SMF may also obtain a correspondence #A, where the correspondence #A may be used to indicate a correspondence between the VPLMN and the information #A. As an example, the authorization policy #1 includes the correspondence #A.

[0286] Optionally, authorization policy #1 also includes target FQDN#1 (or FQDN range), and target FQDN#1 may include one or more FQDNs. The target FQDN#1 includes: the FQDN corresponding to the service allowed to be diverted in the VPLMN (or the FQDN corresponding to the service allowed to use the VPLMN ECS option), and / or the FQDN corresponding to the service not allowed to be diverted in the VPLMN (or the FQDN corresponding to the service not allowed to use the VPLMN ECS option). For example, the target FQDN#1 includes the FQDN corresponding to the service allowed to be diverted in the VPLMN, and when the FQDN of a service matches the target FQDN#1, the service is allowed to use the VPLMN ECS option. For example, the UE sends a DNS query message to request an edge service (or to request the address of an edge server); if the FQDN contained in the DNS query message matches the target FQDN#1, the ECS option can be added to the DNS query message.

[0287] 502. The UE initiates a session establishment process.

[0288] In the HR roaming scenario, the UE can initiate the HR session establishment process. This application does not limit the specific session establishment process. For example, it can be done in the following way: after the AMF receives the session establishment request from the UE, it selects the V-SMF and H-SMF to serve the HR session; after the V-SMF and H-SMF receive the session establishment request, they respectively select the V-UPF and H-UPF to serve the HR session, create an N4 session, and send user plane tunnel information. If the session is successfully established, the network side returns a session establishment response to the UE, and then the message can be transmitted through the HR session.

[0289] Specifically, reference may be made to sections 4.3.2.2.2 and other sections in 3GPP standard TS 23.502, or later session establishment methods, which are not limited in this application.

[0290] It should be understood that step 502 is not limited to executing the complete HR session establishment process. Multiple steps after step 502 can reuse (or reuse) the HR session establishment process, or in other words, multiple steps after step 502 can be executed in the HR session establishment process.

[0291] 503. AMF sends H-SMF ID to V-SMF.

[0292] V-SMF can determine H-SMF based on H-SMF ID.

[0293] One possible implementation method is to reuse the HR session establishment process, and AMF sends an Nsmf interface PDU session establishment session management context request (Nsmf_PDUSession_CreateSMContext Request) message to V-SMF, which carries the H-SMF ID.

[0294] It should be understood that the Nsmf_PDUSession_CreateSMContext Request message is merely an example and is not intended to be limiting.

[0295] 504. V-SMF sends V-SMF ID to H-SMF.

[0296] The H-SMF can determine the VPLMN ID according to the V-SMF ID, that is, determine the VPLMN.

[0297] One possible implementation method is to reuse the HR session establishment process, and the V-SMF sends an Nsmf interface PDU session establishment request (Nsmf_PDUSession_Create Request) message to the H-SMF, which carries the V-SMF ID.

[0298] It should be noted that this step can also be described as the V-SMF sending the V-SMF ID and / or VPLMN ID to the H-SMF. In this case, the H-SMF can directly determine the VPLMN ID.

[0299] In another possible implementation, the H-SMF may determine the VPLMN ID based on the message sent by the V-SMF.

[0300] It should be understood that the Nsmf_PDUSession_Create Request message is merely an example and is not intended to be limiting.

[0301] 505. H-SMF determines information #A based on the V-SMF ID and the corresponding relationship #A.

[0302] One possible implementation is that the authorization policy #1 includes a correspondence #A, the H-SMF determines the VPLMN ID according to the V-SMF ID, and then determines the VPLMN information #A according to the correspondence #A included in the authorization policy #1.

[0303] 506. The H-PCF sends authorization policy #2 to the H-SMF.

[0304] Authorization policy #2 is used to indicate (or characterize, or indicate) whether traffic offloading in the VPLMN is permitted (or authorization policy #1 is used to indicate whether traffic offloading is permitted). Authorization policy #2 sent by the H-PCF can be locally configured by the H-PCF or provided by the AF. For example, the AF can provide authorization policy #2 to the H-PCF via an AF request. Regarding authorization policy #2, refer to the description of information #B in method 300 above and will not be repeated here.

[0305] Optionally, authorization policy #2 also includes target FQDN #2 (or FQDN range), and target FQDN #2 may include one or more FQDNs. Target FQDN #2 includes: the FQDNs corresponding to services that are allowed to be diverted to the VPLMN (or the FQDNs corresponding to services that are allowed to use the VPLMN ECS option), and / or the FQDNs corresponding to services that are not allowed to be diverted to the VPLMN (or the FQDNs corresponding to services that are not allowed to use the VPLMN ECS option). For example, target FQDN #2 includes the FQDNs corresponding to services that are allowed to be diverted to the VPLMN. When the FQDN of a service matches target FQDN #2, the service is allowed to use the VPLMN ECS option. It can be understood that target FQDN #2 here can be the same as or different from target FQDN #1 in step 501, without limitation.

[0306] One possible implementation is to reuse the HR session establishment process and implement it through the session management (SM) policy association process. For example, the PDU session can be established or modified through SM signaling. During the establishment or modification process through SM policy, the H-PCF sends authorization policy #2 to the H-SMF.

[0307] Specifically, one possible implementation method is that after the H-SMF receives the Nsmf_PDUSession_Create Request message from the V-SMF in step 504, it triggers the H-PCF selection. After the H-PCF selection is completed, the SM policy association establishment process (SM policy association establishment) or the SM policy association modification process (SM policy association modification) is triggered. In the SM policy association establishment process, the H-SMF sends an Npcf interface SM policy control establishment request (Npcf_SMPolicyControl_Create Request) message to the H-PCF. The message may include one or more of the following: UE's user permanent identifier (SUPI) or permanent equipment identifier (PEI), PDU session identifier, data network name (DNN), single network slice selection assistance information (S-NSSAI), radio access technology (RAT) type, etc. After receiving this message, the H-PCF determines authorization policy #2 based on local configuration or obtaining the UE's subscription information and / or session subscription information from the UDR, and sends it to the H-SMF via the Npcf interface SM Policy Control Establishment Response (Npcf_SMPolicyControl_Create Response) message. It should be understood that the above is only an exemplary description given for ease of understanding and is not intended to limit this.

[0308] It should be noted that the H-SMF can locally configure the authorization policy. If the H-SMF locally configures authorization policy #1 in step 501, in this case, the H-PCF may not send authorization policy #2 to the H-SMF, that is, there is no need to execute step 506.

[0309] 507, H-SMF selects H-EASDF.

[0310] This application does not limit the specific method of selecting H-EASDF by H-SMF.

[0311] As an example, when selecting an H-EASDF, the H-SMF may refer to one or more of the following information: S-NSSAI, EASDF location, EASDF IP address, PSA IP address, and DNAI. It is understood that when selecting a V-EASDF, the H-SMF may refer to one or more of the above information, or may refer to other unlisted information, and this application is not limited thereto.

[0312] As an example, H-SMF selects H-EASDF, which can be achieved in at least any of the following ways.

[0313] In one approach, H-SMF can select H-EASDF based on local configuration.

[0314] In another embodiment, the H-SMF obtains the H-EASDF from the H-NRF. For example, the H-SMF sends a request message to the H-NRF, and the H-NRF returns information about one or more H-EASDFs (such as addresses and identifiers) to the H-SMF. If the H-NRF returns multiple H-EASDFs to the H-SMF, the H-SMF can select one from them.

[0315] 508. H-SMF determines the DNS processing rule.

[0316] The H-SMF may determine (or formulate) a DNS processing rule based on the information #A determined in step 505. Specifically, the DNS processing rule may include the information #A determined in step 505, which is used by the H-EASDF to determine the ECS option, and then used to add the ECS option to the DNS query.

[0317] Optionally, the H-SMF determines the DNS processing rules based on the authorization policy. For example, if the authorization policy is used to indicate that traffic diversion in the VPLMN is allowed, the H-SMF can determine the DNS processing rules based on information #A. The authorization policy can be the authorization policy #2 received by the H-SMF in step 506, or it can be the authorization policy locally configured by the H-SMF (such as the authorization policy #1 obtained in step 501), or it can be the authorization policy #3 determined by the H-SMF based on the authorization policy #1 and / or authorization policy #2, without limitation.

[0318] In one example, the H-SMF determines a DNS processing rule based on authorization policy #1 in step 501. In one possible scenario, authorization policy #1 includes target FQDN #1. In this case, the DNS processing rule may also include target FQDN #1, instructing the H-EASDF to detect DNS query messages and, when the included FQDN matches the target FQDN #1 in the DNS processing rule, add an ECS option to the DNS query message. In another possible scenario, authorization policy #1 does not include target FQDN #1. In this case, the DNS processing rule may be used to instruct the H-EASDF to add an ECS option to the DNS query message for the FQDN range of services not deployed at the HPLMN edge.

[0319] In another example, the H-SMF determines a DNS processing rule based on authorization policy #2 in step 506. In one possible scenario, authorization policy #2 includes target FQDN #2. In this case, the DNS processing rule may also include target FQDN #2, instructing the H-EASDF to detect the DNS query message and, when the included FQDN matches the target FQDN #2 in the DNS processing rule, add the ECS option to the DNS query message. In another possible scenario, authorization policy #2 does not include target FQDN #2. In this case, the DNS processing rule may be used to instruct the H-EASDF to add the ECS option to the DNS query message for the FQDN range of services not deployed at the HPLMN edge.

[0320] It can be understood that the above examples are illustrative descriptions. For details, please refer to Cases 1 to 4 in method 300, which will not be repeated here.

[0321] 509. H-SMF sends the DNS processing rules to H-EASDF.

[0322] 510. The H-SMF sends the address of the H-EASDF to the UE.

[0323] In one possible implementation, the H-SMF sends the address of the H-EASDF to the UE through the AMF. For example, the H-SMF sends an N1 message (N1 Message) to the UE through the AMF, and the N1 message includes an N1 SM container (container), and the N1 SM container carries the address of the H-EASDF. For example, the H-SMF sends the address of the H-EASDF to the AMF through the Namf_Communication_N1N2MessageTransfer message, and then the AMF sends the address of the H-EASDF to the UE through the non-access stratum (NAS) message. Among them, the UE and the AMF can interact through the N1 interface, and the interaction message can be called a NAS message, for example.

[0324] 511. The UE sends a DNS query to the H-EASDF.

[0325] For example, the UE sends a DNS query message to the H-EASDF via the user plane, the RAN, and the UPF.

[0326] 512, H-EASDF adds the ECS option to the DNS query.

[0327] The H-EASDF may determine the ECS option according to the information #A, and then add the ECS option to the DNS query according to the DNS processing rule received in step 509 .

[0328] In one possible approach, the H-EASDF can directly determine the ECS option based on the information #A received from the H-SMF, and then add the ECS option to the DNS query.

[0329] In another possible way, H-EASDF may request ECS option or information used to determine ECS option from H-SMF; after H-EASDF receives ECS option or information used to determine ECS option from H-SMF, it determines and adds ECS option in DNSquery. Optionally, when H-EASDF requests ECS option from H-SMF, it may carry FQDN included in DNS query. One possible implementation method is that H-EASDF sends Neasdf_DNSContext_NotifyRequest message to H-SMF, which may include FQDN included in DNS query, and receives Neasdf_DNSContext_Notify Response message from H-SMF. H-SMF sends Neasdf_DNSContext_UpdateRequest message to H-EASDF, which includes ECS option or information used to determine ECS option, and receives Neasdf_DNSContext_Update Response message from H-EASDF.

[0330] 513. H-EASDF sends a DNS query including the ECS option to the DNS server.

[0331] After H-EASDF adds the ECS option to the DNS query, it sends a DNS query message (that is, the DNS query message with the ECS option added) to the DNS server.

[0332] 514. The DNS server sends a DNS response to the H-EASDF.

[0333] The DNS server may send a DNS response message to the V-EASDF. The DNS response message may include address information, such as the EAS IP address or FQDN.

[0334] 515. H-EASDF sends a DNS response to the UE.

[0335] After receiving the DNS response message, the H-EASDF may forward the DNS response message to the UE.

[0336] Based on the above method 500, H-SMF determines information #A according to local configuration, and then determines ECS option, which is added to the DNS query by H-EASDF, and then receives the address of the local EAS from the DNS server, thereby realizing the discovery of the local EAS.

[0337] Figure 6 This is a schematic flow chart of another communication method 600 provided in an embodiment of the present application. This method 600 can be used to implement a solution such as method 300. For example, this method 600 can be used in a scenario where the H-SMF passively receives information #A from the V-SMF and, based on an authorization policy, instructs the H-EASDF to add an ECS option. This method 600 can include the following steps.

[0338] 601. UE initiates session establishment process.

[0339] Among them, step 601 is similar to step 502 and will not be repeated here.

[0340] 602. V-SMF sends information #A to H-SMF.

[0341] One possible implementation method is to reuse the HR session establishment process, and the V-SMF sends an Nsmf_PDUSession_Create Request message to the H-SMF. The message includes information #A, and the information #A can be used to determine the ECSoption.

[0342] It should be understood that the Nsmf_PDUSession_Create Request message is merely an example and is not intended to be limiting.

[0343] Optionally, the V-SMF sends a target FQDN#3 (or FQDN range) to the H-SMF. Target FQDN#3 may include one or more FQDNs. For example, target FQDN#3 includes the FQDNs corresponding to services permitted to be diverted to the VPLMN (or the FQDNs corresponding to services permitted to use the VPLMN ECS option), or the FQDNs corresponding to services expected to be diverted to the VPLMN (or the FQDNs corresponding to services expected to use the VPLMN ECS option). When the FQDN of a service matches target FQDN#3, the service is permitted to use the VPLMN ECS option.

[0344] 603. The H-PCF sends the authorization policy to the H-SMF.

[0345] The authorization policy is used to indicate (or characterize or indicate) whether traffic offloading in the VPLMN is allowed (or the authorization policy is used to indicate whether traffic offloading is allowed). For details about the authorization policy, please refer to the description of information #B in method 300 above, which will not be repeated here.

[0346] Optionally, the authorization policy also includes a target FQDN#4 (or FQDN range), which may include one or more FQDNs. Target FQDN#4 includes: FQDNs corresponding to services permitted to be diverted to the VPLMN (or FQDNs corresponding to services permitted to use the VPLMN ECS option), and / or FQDNs corresponding to services not permitted to be diverted to the VPLMN (or FQDNs corresponding to services not permitted to use the VPLMN ECS option). The following description primarily uses the example of target FQDN#4 including FQDNs corresponding to services permitted to be diverted to the VPLMN.

[0347] Among them, step 603 is similar to step 506 and will not be repeated here.

[0348] It should be noted that the H-SMF can configure the authorization policy locally. In this case, step 603 may not be performed.

[0349] 604, H-SMF selects H-EASDF.

[0350] Among them, step 604 is similar to step 507 and will not be repeated here.

[0351] 605, H-SMF determines the DNS processing rule.

[0352] The H-SMF may determine (or formulate) a DNS processing rule based on the information #A determined in step 602. Specifically, the DNS processing rule may include the information #A determined in step 602, which is used by the H-EASDF to determine the ECS option, and further used to add the ECS option to the DNS query.

[0353] Optionally, the H-SMF determines the DNS processing rules based on the authorization policy. For example, if the authorization policy indicates that traffic diversion in the VPLMN is permitted, the H-SMF may determine the DNS processing rules based on the ECS option. The authorization policy may be the authorization policy received by the H-SMF in step 603, or may be the authorization policy locally configured by the H-SMF, without limitation.

[0354] In one possible scenario, the authorization policy includes target FQDN#4, and the H-SMF does not receive FQDN#3 in step 602. In this case, in one possible approach, the DNS processing rule may further include target FQDN#4, for instructing the H-EASDF to detect the DNS query message and, when the included FQDN matches the target FQDN#4 in the DNS processing rule, add the ECS option to the DNS query message.

[0355] In another possible scenario, the authorization policy includes target FQDN#4, and the H-SMF receives FQDN#3 in step 602. In this case, in one possible manner, the DNS processing rule may further include target FQDN#4 to instruct the H-EASDF to detect the DNS query message and, when the included FQDN matches the target FQDN#4 in the DNS processing rule, add the ECS option to the DNS query message. In another possible manner, the DNS processing rule may further include the intersection of target FQDN#3 and target FQDN#4 (e.g., denoted as target FQDN#34) to instruct the H-EASDF to detect the DNS query message and, when the included FQDN matches the target FQDN#34 in the DNS processing rule, add the ECS option to the DNS query message. In another possible manner, the DNS processing rule may further include target FQDN#3 to instruct the H-EASDF to detect the DNS query message and, when the included FQDN matches the target FQDN#3 in the DNS processing rule, add the ECS option to the DNS query message.

[0356] In another possible scenario, the authorization policy does not include target FQDN#4, and the H-SMF receives FQDN#3 in step 602. In this case, the DNS processing rule may further include target FQDN#3, which is used to instruct the H-EASDF to detect the DNS query message and add the ECSoption to the DNS query message when the included FQDN matches the target FQDN#3 in the DNS processing rule.

[0357] In another possible scenario, the authorization policy does not include target FQDN#4, and the H-SMF does not receive FQDN#3 in step 602. In this case, the DNS processing rule is used to instruct to add an ECS option to the DNS query message for the FQDNrange of the service not deployed at the HPLMN edge.

[0358] It can be understood that the above examples are illustrative descriptions. For details, please refer to Cases 1 to 4 in method 300, which will not be repeated here.

[0359] 606. The H-SMF sends the DNS processing rules to the H-EASDF.

[0360] 607. H-SMF sends the address of H-EASDF to V-SMF.

[0361] One possible implementation method is to reuse the HR session establishment process, and the H-SMF sends an Nsmf interface PDU session establishment response (Nsmf_PDUSession_Create Response) message to the V-SMF, which includes the address of the H-EASDF.

[0362] It should be understood that the Nsmf_PDUSession_Create Response message is merely an example and is not intended to be limiting.

[0363] 608. The V-SMF sends the address of the H-EASDF to the UE.

[0364] In one possible implementation, the V-SMF sends the address of the V-EASDF to the UE through the AMF. For example, the V-SMF sends an N1 Message to the UE through the AMF. The N1 message includes an N1 SM container that carries the address of the H-EASDF. For example, the V-SMF sends the address of the H-EASDF to the AMF through the Namf_Communication_N1N2MessageTransfer message, and then the AMF sends the address of the H-EASDF to the UE through a NAS message.

[0365] 609. The UE sends a DNS query to the H-EASDF.

[0366] 610, H-EASDF adds the ECS option to the DNS query.

[0367] 611. H-EASDF sends a DNS query including the ECS option to the DNS server.

[0368] 612. The DNS server sends a DNS response to the H-EASDF.

[0369] 613. H-EASDF sends a DNS response to the UE.

[0370] Among them, steps 609-613 are similar to steps 511-515 and are not repeated here.

[0371] Based on the above method 600, V-SMF sends information #A to H-SMF, H-SMF passively receives information #A from V-SMF, and instructs H-EASDF to add ECS option in the DNS query according to the authorization policy, and then receives the address of the local EAS from the DNS server, thereby realizing the discovery of the local EAS.

[0372] Figure 7 This is a schematic flow chart of another communication method 700 provided in an embodiment of the present application. This method 700 can be used to implement a solution such as method 300. For example, this method 700 can be used in a scenario where the H-SMF proactively requests the aforementioned information #A from the V-SMF and, based on the authorization policy, instructs the H-EASDF to add the ECS option to the DNS query. This method 700 can include the following steps.

[0373] 701. UE initiates a session establishment process.

[0374] Among them, step 701 is similar to step 502 and will not be repeated here.

[0375] 702. The H-PCF sends the authorization policy to the H-SMF.

[0376] The authorization policy is used to indicate (or characterize or indicate) whether traffic offloading in the VPLMN is allowed (or the authorization policy is used to indicate whether traffic offloading is allowed). For details about the authorization policy, please refer to the description of information #B in method 300 above, which will not be repeated here.

[0377] Among them, step 702 is similar to step 506 and will not be repeated here.

[0378] 703. H-SMF sends the authorization policy to V-SMF.

[0379] One possible implementation is to reuse the HR session establishment process. For example, the H-SMF receives the session establishment request message from the V-SMF and sends a session establishment response message to the V-SMF. The session establishment response message carries the authorization policy. It is understood that the authorization policy may be received from the H-PCF in step 702 or may be locally configured.

[0380] Optionally, the authorization policy includes target FQDN#5 (or FQDN range), and target FQDN#5 may include one or more FQDNs. Target FQDN#5 includes: the FQDNs corresponding to services permitted to be diverted to the VPLMN (or the FQDNs corresponding to services permitted to use the VPLMN ECS option), and / or the FQDNs corresponding to services not permitted to be diverted to the VPLMN (or the FQDNs corresponding to services not permitted to use the VPLMN ECS option). For example, if the authorization policy received by the H-SMF from the H-PCF in step 702 or the authorization policy locally configured by the H-SMF includes target FQDN#5, then in step 703, the authorization policy sent by the H-SMF to the V-SMF may include target FQDN#5.

[0381] In a first possible scenario, the authorization policy may also be used to instruct acquisition of information #A, and the information #A may be used to determine an ECS option.

[0382] In a second possible scenario, the authorization policy includes request information #1, where the request information #1 is used to request the above information #A, and the information #A can be used to determine the ECS option.

[0383] In a third possible scenario, the H-SMF sends a request message #1 to the V-SMF. The request message #1 is used to request the above-mentioned information #A, and the information #A can be used to determine the ECS option.

[0384] 704. V-SMF sends information #A to H-SMF.

[0385] One possible implementation method, taking the first possible situation in step 703 as an example, after the V-SMF receives the authorization policy, it learns that offloading in the VPLMN is allowed according to the authorization policy. Then, in response to the authorization policy, the V-SMF sends information #A to the H-SMF. The information #A can be used to determine the ECS option.

[0386] Another possible implementation method, taking the second possible situation in step 703 as an example, after the V-SMF receives the authorization policy, it learns that offloading in the VPLMN is allowed according to the authorization policy. Then, in response to the request information #1 in the authorization policy, the V-SMF sends information #A to the H-SMF, and the information #A can be used to determine the ECS option.

[0387] Another possible implementation method, taking the third possible situation in step 703 as an example, after the V-SMF receives the authorization policy and request information #1, it is learned that offloading in the VPLMN is allowed according to the authorization policy. Then, in response to the request information #1, the V-SMF sends information #A to the H-SMF, and the information #A can be used to determine the ECS option.

[0388] In another possible implementation, the V-SMF may send information #A to the H-SMF according to the internal logic or local configuration of the V-SMF. The information #A may be used to determine the ECS option.

[0389] It can be understood that the above-mentioned implementation methods are exemplary descriptions and the present application is not limited thereto.

[0390] Optionally, the V-SMF sends a target FQDN#6 (or FQDN range) to the H-SMF. Target FQDN#6 may include one or more FQDNs. For example, target FQDN#6 includes an FQDN corresponding to a service permitted to be diverted to the VPLMN (or an FQDN corresponding to a service permitted to use the VPLMN ECS option), or an FQDN expected to be diverted to the VPLMN (or an FQDN corresponding to a service expected to use the VPLMN ECS option). When the FQDN of a service matches target FQDN#6, the service is permitted to use the VPLMN ECS option.

[0391] For example, if the authorization policy in step 703 includes target FQDN#5, the V-SMF may consider the target FQDN#5 included in the authorization policy when determining that the target FQDN#6 is desired (or allowed) to be diverted in the VPLMN.

[0392] 705, H-SMF selects H-EASDF.

[0393] 706. H-SMF determines the DNS processing rule.

[0394] 707 , H-SMF sends the DNS processing rule to H-EASDF.

[0395] Among them, steps 705-707 are similar to steps 604-606 and will not be repeated here.

[0396] 708. The H-SMF sends the address of the H-EASDF to the UE.

[0397] 709. The UE sends a DNS query to the H-EASDF.

[0398] 710, H-EASDF adds the ECS option to the DNS query.

[0399] 711. H-EASDF sends a DNS query including the ECS option to the DNS server.

[0400] 712. The DNS server sends a DNS response to the H-EASDF.

[0401] 713. H-EASDF sends a DNS response to the UE.

[0402] Among them, steps 708-713 are similar to steps 510-515 and will not be repeated here.

[0403] Based on the above method 700, the H-SMF actively requests the above information #A from the V-SMF, and instructs the H-EASDF to add the ECS option according to the authorization policy, thereby realizing the discovery of the local EAS.

[0404] Figure 8 This is a schematic flow chart of another communication method 800 provided in an embodiment of the present application. Method 800 can be used to implement a solution such as method 300. For example, method 800 can be used in a scenario where the H-SMF requests the aforementioned information #A from the H-NRF and, based on the authorization policy, instructs the H-EASDF to add the ECS option to the DNS query. Method 800 can include the following steps.

[0405] 801. UE initiates a session establishment process.

[0406] Among them, step 801 is similar to step 502 and will not be repeated here.

[0407] 802. The H-PCF sends the authorization policy to the H-SMF.

[0408] The authorization policy is used to indicate (or characterize or indicate) whether traffic offloading in the VPLMN is allowed (or the authorization policy is used to indicate whether traffic offloading is allowed). For details about the authorization policy, please refer to the description of information #B in method 300 above, which will not be repeated here.

[0409] Among them, step 802 is similar to step 506 and will not be repeated here.

[0410] 803. H-SMF sends request information #2 to H-NRF.

[0411] Request message #2 is used to request (or obtain) information #A. Optionally, request message #2 includes a VPLMN ID. The form of request message #2 is not limited. For example, request message #2 can be implemented using one or more bits, and these one or more bits are used to request the aforementioned information #A. For the specific implementation of request message #2, please refer to the description of method 300 and will not be repeated here.

[0412] In a possible implementation, the H-SMF sends an Nnrf_NFManagement_NFStatusSubscribe message to the H-NRF, where the message carries request information #2.

[0413] In the first possible scenario, after receiving request #2, the H-NRF can determine information #A based on its local configuration. In this case, the H-NRF directly sends a response to request #2 to the H-SMF, which carries information #A. This means that steps 804-805 are not required.

[0414] In a second possible scenario, after receiving the request message #2, the H-NRF may receive the message #A from the V-NRF. In this scenario, the method 800 may include steps 804-805.

[0415] 804. H-NRF sends request information #3 to V-NRF.

[0416] Request message #3 is used to request (or obtain) information #A. Optionally, request message #3 includes a VPLMN ID. The form of request message #3 is not limited. For example, request message #3 can be implemented using one or more bits, and the one or more bits are used to request the above-mentioned information #A.

[0417] In a possible implementation, the H-NRF sends an Nnrf_NFManagement_NFStatusSubscribe message to the V-NRF, where the message carries request information #3.

[0418] 805, V-NRF sends information #A to H-NRF.

[0419] The V-NRF determines and sends information #A to the H-NRF based on the request information #3 received from the H-NRF. In one possible implementation, the V-NRF sends an Nnrf_NFManagement_NFStatusNotify message to the H-NRF, which carries information #A.

[0420] 806. H-NRF sends information #A to H-SMF.

[0421] In a possible implementation manner, the H-NRF sends an Nnrf_NFManagement_NFStatus Notify message to the H-SMF, where the message includes information #A.

[0422] In the first possible case, if in step 803, the H-NRF determines information #A according to the local configuration, then in step 806, the information #A sent by the H-NRF to the H-SMF may be: the information #A determined by the H-NRF in step 803 according to the local configuration.

[0423] In the second possible case, if steps 804-805 are executed, the information #A sent by the H-NRF to the H-SMF in step 806 may be the information #A received by the H-NRF from the V-NRF in step 805.

[0424] In the third possible scenario, if in step 803, the H-NRF is locally configured with information #A and steps 804-805 are executed, that is, the H-NRF receives information #A from the V-NRF, then the information #A sent by the H-NRF to the H-SMF in step 806 may be the locally configured or received information #A. For example, in this case, the information #A sent by the H-NRF to the H-SMF in step 806 may be: the information #A received by the H-NRF from the V-NRF.

[0425] 807, H-SMF selects H-EASDF.

[0426] 808. H-SMF determines the DNS processing rule.

[0427] 809. H-SMF sends the DNS processing rules to H-EASDF.

[0428] 810. The H-SMF sends the address of the H-EASDF to the UE.

[0429] 811. The UE sends a DNS query to the H-EASDF.

[0430] 812, H-EASDF adds the ECS option to the DNS query.

[0431] 813. The H-EASDF sends a DNS query including the ECS option to the DNS server.

[0432] 814. The DNS server sends a DNS response to the H-EASDF.

[0433] 815. H-EASDF sends a DNS response to the UE.

[0434] Among them, steps 807-815 are similar to steps 705-713 and will not be repeated here.

[0435] Based on the above method 800, the H-SMF requests the above information #A from the H-NRF, and instructs the H-EASDF to add the ECS option according to the authorization policy, thereby realizing the discovery of the local EAS.

[0436] Figure 9 This is a schematic flow chart of another communication method 900 provided in an embodiment of the present application. This method 900 can be used to implement a solution such as method 400. For example, this method 900 can be used in a scenario where the V-SMF obtains an authorization policy from the H-SMF and inserts it into an ECSoption. This method 900 can include the following steps.

[0437] 901. UE initiates a session establishment process.

[0438] Among them, step 901 is similar to step 502 and will not be repeated here.

[0439] 902. The V-SMF sends a session establishment request message to the H-SMF.

[0440] One possible implementation method is to reuse the HR session establishment process, and the V-SMF sends an Nsmf_PDUSession_Create Request message to the H-SMF.

[0441] Optionally, the session establishment request message includes a target FQDN#7 (or FQDN range). Target FQDN#7 may include one or more FQDNs corresponding to services permitted to be offloaded to the VPLMN (or FQDNs corresponding to services permitted to use the VPLMN ECS option), or FQDNs corresponding to services expected to be offloaded to the VPLMN (or FQDNs corresponding to services expected to use the VPLMN ECS option). As an example, target FQDN#7 includes one or more FQDNs corresponding to services permitted to be offloaded to the VPLMN. When the FQDN of a service matches target FQDN#7, the service is permitted to use the VPLMN ECS option.

[0442] 903. The H-PCF sends the authorization policy to the H-SMF.

[0443] The authorization policy is used to indicate (or characterize or indicate) whether traffic offloading in the VPLMN is allowed (or the authorization policy is used to indicate whether traffic offloading is allowed). For details about the authorization policy, please refer to the description of information #B in method 300 above, which will not be repeated here.

[0444] Optionally, the authorization policy also includes a target FQDN#8 (or FQDN range), which may include one or more FQDNs. Target FQDN#8 includes: FQDNs corresponding to services permitted to be diverted to the VPLMN (or FQDNs corresponding to services permitted to use the VPLMN ECS option), and / or FQDNs corresponding to services not permitted to be diverted to the VPLMN (or FQDNs corresponding to services not permitted to use the VPLMN ECS option). The following description primarily uses the example of target FQDN#8 including FQDNs corresponding to services permitted to use the VPLMN ECS option.

[0445] 904, H-SMF selects H-EASDF.

[0446] Among them, steps 903-904 are similar to steps 603-604 and will not be repeated here.

[0447] 905. H-SMF sends the authorization policy to V-SMF.

[0448] For example, after receiving the session establishment request message from the V-SMF, the H-SMF sends a session establishment response message to the V-SMF, and the session establishment response message carries the authorization policy received in step 903. Optionally, the session establishment response message may also include the address of the H-EASDF.

[0449] One possible implementation method is to reuse the HR session establishment process, and the H-SMF sends an Nsmf_PDUSession_Create Response message to the V-SMF, which includes the address and authorization policy of the H-EASDF.

[0450] 906. The V-SMF sends the N4 rule to the V-UPF.

[0451] The N4 rule is used to instruct the V-UPF to add the ECS option to the DNS query.

[0452] The V-SMF may determine to send the N4 rule to the V-UPF based on the authorization policy received in step 905. Specifically, if the V-SMF learns that offloading in the VPLMN is allowed based on the authorization policy received in step 905, the V-SMF sends the N4 rule to the V-UPF.

[0453] Optionally, if the authorization policy includes the target FQDN#8, the N4 rule is used to instruct the V-UPF to add an ECS option to the DNS query whose included FQDN matches the target FQDN#8 included in the authorization policy.

[0454] In one possible implementation, the V-SMF sends an N4 session creation request message to the V-UPF, which carries the N4 rule. Correspondingly, the V-UPF may send an N4 session creation response message to the V-SMF.

[0455] 907. The V-SMF sends the address of the H-EASDF to the UE.

[0456] In one possible implementation, the V-SMF sends the address of the V-EASDF to the UE through the AMF. For example, the V-SMF sends an N1 Message to the UE through the AMF. The N1 message includes an N1 SM container that carries the address of the H-EASDF. For example, the V-SMF sends the address of the H-EASDF to the AMF through the Namf_Communication_N1N2MessageTransfer message, and then the AMF sends the address of the H-EASDF to the UE through a NAS message.

[0457] 908. The UE sends a DNS query to the V-UPF.

[0458] For example, the UE sends a DNS query message to the V-UPF via the user plane and the RAN.

[0459] 909, V-UPF adds the ECS option to the DNS query.

[0460] The V-UPF adds the ECS option to the DNS query according to the N4 rule received in step 906 .

[0461] Optionally, if the N4 rule received in step 906 includes target FQDN#8, the V-UPF may perform a check on the DNS query after receiving it. For example, when the V-UPF receives the DNS query, if the FQDN included in the DNS query matches the target FQDN#8 of the N4 rule, the V-UPF may add the ECS option to the DNS query.

[0462] It should be noted that the ECS option can be added in the DNS query, or in the GTP-U header of the UP message, or in other ways, without limitation. This application mainly uses examples for illustrative purposes.

[0463] It is understood that in step 909, the V-UPF actually processes the DNS message, which is equivalent to performing the functions of the V-EASDF. Therefore, the V-UPF here can be understood as a UPF with DNS message processing functions, or it can also be understood as a combined UPF and EASDF. It should be understood that this application does not limit the specific network element that performs this function; any network element that can implement this function is applicable to the embodiments of this application.

[0464] 910. The V-UPF sends a DNS query including the ECS option to the H-EASDF.

[0465] After the V-UPF adds the ECS option to the DNS query, it sends a DNS query message (i.e., the DNS query with the ECS option added) to the H-EASDF via the user.

[0466] 911, H-EASDF sends a DNS query containing the ECS option to the DNS server.

[0467] 912. The DNS server sends a DNS response to the H-EASDF.

[0468] 913. H-EASDF sends a DNS response to the UE.

[0469] Among them, steps 911-913 are similar to steps 513-515 and are not repeated here.

[0470] Based on the above method 900, V-SMF obtains the authorization policy from H-SMF, and V-UPF inserts the ECS option in the DNS query, so that EASDF receives the address of the local EAS from the DNS server, thereby realizing local EAS discovery in the HR roaming scenario.

[0471] Figure 10 This is a schematic flow chart of another communication method 1000 provided in an embodiment of the present application. Method 1000 can be used to implement a solution such as method 400. For example, method 1000 can be used in a scenario where a V-SMF, based on local configuration, instructs a V-UPF to insert an ECS option into a DNS query. Method 1000 can include the following steps.

[0472] 1001, V-SMF obtains authorization policy #3.

[0473] Authorization policy #3 is used to indicate (or characterize, or indicate) whether traffic offloading in the VPLMN is allowed (or authorization policy #3 is used to indicate whether traffic offloading is allowed). Regarding authorization policy #3, please refer to the description of information #B in method 300 above, which will not be repeated here.

[0474] One possible approach is that V-SMF locally configures authorization policy #3.

[0475] In another possible manner, the V-SMF receives the authorization policy #3 from the H-SMF through other processes (such as a session establishment process) after the device is powered on.

[0476] Regarding the specific method for V-SMF to obtain authorization policy #3, please refer to the method for the second session management network element to obtain information #B in method 400 above, which will not be repeated here.

[0477] Optionally, the V-SMF may also obtain a correspondence #A, where the correspondence #A indicates a correspondence between the VPLMN and the information #A. As an example, the authorization policy #3 includes the correspondence #A.

[0478] Optionally, authorization policy #3 also includes target FQDN #9 (or FQDN range), which may include one or more FQDNs. Target FQDN #9 includes: FQDNs corresponding to services permitted to be diverted to the VPLMN (or FQDNs corresponding to services permitted to use the VPLMN ECS option), and / or FQDNs corresponding to services not permitted to be diverted to the VPLMN (or FQDNs corresponding to services not permitted to use the VPLMN ECS option). For example, target FQDN #9 includes FQDNs corresponding to services permitted to be diverted to the VPLMN. When the FQDN of a service matches target FQDN #9, the service is permitted to use the VPLMN ECS option.

[0479] 1002. The UE initiates a session establishment process.

[0480] Among them, step 1002 is similar to step 502 and will not be repeated here.

[0481] 1003. V-SMF sends rule N4 to V-UPF.

[0482] The N4 rule is used to instruct the V-UPF to add the ECS option to the DNS query.

[0483] The V-SMF may determine to send the N4 rule to the V-UPF based on the authorization policy #3 obtained in step 1001. Specifically, if the V-SMF learns that the traffic is diverted in the VPLMN based on the authorization policy #3 obtained in step 1001, the V-SMF sends the N4 rule to the V-UPF.

[0484] If the configuration structure of authorization policy #3 in the V-SMF is in the form of a set of {PLMN ID--authorization policy}, as shown in Table 1, then the V-SMF can determine the HPLMN ID based on the H-SMF ID and then obtain the authorization policy #3 corresponding to the HPLMN based on Table 1. The H-SMF ID can be sent to the V-SMF by the AMF. For example, reusing the HR session establishment process, the AMF sends the Nsmf_PDUSession_CreateSMContext Request message to the V-SMF, which carries the H-SMF ID.

[0485] Optionally, if the target FQDN#9 is included in the authorization policy #3, the N4 rule is used to instruct the V-UPF to add an ECS option to the DNS query whose included FQDN matches the target FQDN#9 included in the authorization policy #3.

[0486] In one possible implementation, the V-SMF sends an N4 session creation request message to the V-UPF, which carries the N4 rule. Correspondingly, the V-UPF may send an N4 session creation response message to the V-SMF.

[0487] 1004. H-SMF sends the address of H-EASDF to V-SMF.

[0488] One possible implementation method is to reuse the HR session establishment process, and the H-SMF sends an Nsmf_PDUSession_Create Response message to the V-SMF, which includes the address of the H-EASDF.

[0489] Optionally, the message may further include an authorization policy (denoted as authorization policy #4 for distinction), wherein the authorization policy #4 is used to indicate whether traffic diversion in the VPLMN is allowed (or whether traffic diversion is allowed). Furthermore, the authorization policy #4 may further include the target FQDN #10.

[0490] 1005. V-SMF sends the updated N4 rule to V-UPF.

[0491] If the V-SMF receives authorization policy #4 in step 1004, the V-SMF may send the updated N4 rule to the V-UPF. For example, the V-SMF sends an N4 session creation request message to the V-UPF, where the N4 session creation request message includes the updated N4 rule.

[0492] In one possible scenario, authorization policy #4 is used to indicate that traffic offloading in the VPLMN is not allowed. In this case, the V-SMF sends an updated N4 rule to the V-UPF. The updated N4 rule is used to instruct the V-UPF to delete the instruction to add the ECS option for the DNS query in the previous N4 rule; or the updated N4 rule is used to instruct the V-UPF to invalidate the instruction to add the ECS option for the DNS query in the previous N4 rule.

[0493] In another possible scenario, authorization policy #4 is used to indicate that traffic diversion in the VPLMN is permitted. This is described below with reference to several scenarios.

[0494] Case 1) Authorization policy #4 includes target FQDN #10, and V-SMF obtains target FQDN #9 in step 1001.

[0495] In this case, for example, the V-SMF sends an updated N4 rule to the V-UPF, where the updated N4 rule is used to instruct the V-UPF to add the ECS option to target FQDN#10. For another example, the V-SMF sends an updated N4 rule to the V-UPF, where the updated N4 rule is used to instruct the V-UPF to add the ECS option to target FQDN#11, where target FQDN#11 is, for example, the intersection of target FQDN#9 and target FQDN#10, or the union of target FQDN#9 and target FQDN#10.

[0496] Case 2) Authorization policy #4 includes target FQDN #10, and V-SMF does not obtain target FQDN #9 in step 1001.

[0497] In this case, for example, the V-SMF sends an updated N4 rule to the V-UPF, where the updated N4 rule is used to instruct the V-UPF to add an ECS option to the target FQDN#10.

[0498] Case 3) Target FQDN#10 is not included in authorization policy#4.

[0499] In this case, the V-SMF may not need to send the updated N4 rules to the V-UPF.

[0500] It can be understood that the above situations are exemplary descriptions and the present application is not limited thereto.

[0501] 1006. The V-SMF sends the address of the H-EASDF to the UE.

[0502] 1007. The UE sends a DNS query to the V-UPF.

[0503] 1008, V-UPF adds the ECS option to the DNS query.

[0504] 1009. The V-UPF sends a DNS query including the ECS option to the H-EASDF.

[0505] 1010. The H-EASDF sends a DNS query including the ECS option to the DNS server.

[0506] 1011. The DNS server sends a DNS response to the H-EASDF.

[0507] 1012. H-EASDF sends a DNS response to the UE.

[0508] Among them, steps 1006-1012 are similar to steps 907-913 and are not repeated here.

[0509] Based on the above method 1000, the V-SMF instructs the V-UPF to insert the ECSoption into the DNS query according to the local configuration, and then receives the address of the local EAS from the DNS server, thereby realizing local EAS discovery in the HR roaming scenario.

[0510] Figure 11 1 is a schematic flow chart of another communication method 1100 provided in an embodiment of the present application. The method 1100 can be used by the H-SMF to receive an authorization policy, instruct the EASDF to report a DNS query, and instruct the EASDF to add an ECS option. The method 1100 can include the following steps.

[0511] 1101. UE initiates a session establishment process.

[0512] Among them, step 1101 is similar to step 502 and will not be repeated here.

[0513] 1102. V-SMF sends a session establishment request message to H-SMF.

[0514] One possible implementation method is to reuse the HR session establishment process, and the V-SMF sends an Nsmf_PDUSession_Create Request message to the H-SMF.

[0515] Optionally, the session establishment request message includes a target FQDN#12 (or an FQDN range), which may include one or more FQDNs. For example, the target FQDN#12 includes an FQDN corresponding to a service permitted to be offloaded to the VPLMN (or an FQDN corresponding to a service permitted to use the VPLMN ECS option), or an FQDN corresponding to a service desired to be offloaded to the VPLMN (or an FQDN corresponding to a service desired to use the VPLMN ECS option). When the FQDN of a service matches the target FQDN#12, the service is permitted to use the VPLMN ECS option.

[0516] Optionally, the session establishment request message includes information #A.

[0517] 1103. The H-PCF sends the authorization policy to the H-SMF.

[0518] 1104, H-SMF selects H-EASDF.

[0519] 1105. H-SMF determines the DNS processing rule.

[0520] 1106. The H-SMF sends the DNS processing rules to the H-EASDF.

[0521] Among them, steps 1103-1106 are similar to steps 603-606, except that the DNS processing rules in steps 1105-1106 can also be used to instruct H-EASDF to report the received DNS query or the FQDN contained in the DNS query to H-SMF. Specifically, if the DNS processing rule includes an FQDN (such as the target FQDN#12), H-EASDF is instructed to report the received DNS query or the FQDN contained in the DNS query that matches the target FQDN#12 to H-SMF.

[0522] 1107. H-SMF sends the address of H-EASDF to V-SMF.

[0523] 1108. V-SMF sends the address of H-EASDF to UE.

[0524] Among them, steps 1107-1108 are similar to steps 607-608 and are not repeated here.

[0525] It can be understood that steps 1104-1106 and steps 1107-1108 are not limited to the time sequence or logical relationship of execution, and only need to be before step 1109.

[0526] 1109. The UE sends a DNS query to the H-EASDF.

[0527] For example, the UE sends a DNS query message to the H-EASDF via the user plane, the RAN, and the UPF.

[0528] 1110. H-EASDF reports the FQDN included in the DNS query to H-SMF.

[0529] After receiving the DNS query, the H-EASDF reports the FQDN included in the DNS query to the H-SMF according to the DNS processing rule received in step 1106 .

[0530] If the DNS processing rule contains an FQDN (such as target FQDN #12), then the FQDN contained in the DNS query can be matched with the FQDN in the DNS processing rule. Assume that the FQDN contained in the DNS query matches the FQDN in the DNS processing rule.

[0531] 1111, H-SMF sends request information #1 to V-SMF.

[0532] The request information #1 is used to request the above-mentioned information #A.

[0533] After receiving the FQDN reported by the EASDF, the H-SMF requests the V-SMF for the above information #A. The request information #1 may include the FQDN received by the H-SMF in step 1110.

[0534] 1112, V-SMF sends information #A to H-SMF.

[0535] V-SMF determines and returns information #A to H-SMF based on the UE location and reported FQDN.

[0536] The sending of information #A can be triggered by request information #1 or by the V-SMF's own logic / local configuration without restriction.

[0537] 1113, H-SMF sends information #A to H-EASDF.

[0538] H-SMF sends the received information #A to H-EASDF.

[0539] It should be noted that if step 1102 includes information #A, then steps 1110-1113 can be omitted.

[0540] 1114, H-EASDF adds the ECS option to the DNS query.

[0541] 1115. The H-EASDF sends a DNS query including the ECS option to the DNS server.

[0542] 1116. The DNS server sends a DNS response to the H-EASDF.

[0543] 1117. H-EASDF sends a DNS response to the UE.

[0544] Steps 1114-1117 are similar to steps 512-515 and will not be repeated here.

[0545] Based on the above method 1100, H-SMF instructs EASDF to report DNS query, obtains information #A from V-SMF, and instructs EASDF to add ECS option, and then receives the address of local EAS from the DNS server, thereby realizing local EAS discovery in HR roaming scenario.

[0546] It can be understood that the embodiments of this application Figures 5 to 11 The examples are only for the convenience of those skilled in the art to understand the embodiments of the present application, and are not intended to limit the embodiments of the present application to the specific scenarios illustrated. Figures 5 to 11 Obviously, various equivalent modifications or changes can be made, and such modifications or changes also fall within the scope of the embodiments of the present application. Figures 5 to 11 The session establishment process in can also be replaced by the session modification process. Figures 5 to 11 The ECS option in the DNS query can also be replaced with the L-DNS server address. Correspondingly, the action of adding the ECS option in the DNS query can also be replaced with the action of forwarding the DNS query to the L-DNS server.

[0547] It can also be understood that in some of the above embodiments, the message names involved, such as Nsmf_PDUSession_Update Request message, Nsmf_PDUSession_Context Request, etc., are only examples and do not limit the protection scope of the embodiments of the present application.

[0548] It can also be understood that some optional features in the various embodiments of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0549] It can also be understood that the solutions in the various embodiments of the present application can be reasonably combined and used, and the explanations or descriptions of the various terms appearing in the embodiments can be referenced or explained with each other in the various embodiments, without limitation to this.

[0550] It can also be understood that the sizes of the various numerical serial numbers in the embodiments of the present application do not mean the order of execution, but are only distinguished for the convenience of description and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0551] It can also be understood that in the above-mentioned various method embodiments, the methods and operations implemented by the device can also be implemented by components (such as chips or circuits) of the device.

[0552] Corresponding to the methods provided in the above method embodiments, embodiments of the present application also provide corresponding apparatuses, which include modules for executing the corresponding methods in the above method embodiments. The modules may be software, hardware, or a combination of software and hardware. It is understood that the technical features described in the above method embodiments are also applicable to the following apparatus embodiments.

[0553] Figure 12 This is a schematic block diagram of a communication device provided in an embodiment of the present application. The device 1200 includes a transceiver unit 1210 and a processing unit 1220. The transceiver unit 1210 can be used to implement corresponding communication functions. The transceiver unit 1210 can also be referred to as a communication interface or a communication unit. The processing unit 1220 can be used to implement corresponding processing functions, such as determining a diversion point.

[0554] Optionally, the device 1200 also includes a storage unit, which can be used to store instructions and / or data, and the processing unit 1220 can read the instructions and / or data in the storage unit so that the device implements the actions of the device or network element in the aforementioned method embodiments.

[0555] In a first design, the apparatus 1200 may be the first session management network element in the aforementioned embodiment, or may be a component (e.g., a chip) of the first session management network element. The apparatus 1200 may implement steps or processes corresponding to those performed by the first session management network element in the aforementioned method embodiment, wherein the transceiver unit 1210 may be configured to perform operations related to transmission and reception of the first session management network element in the aforementioned method embodiment, and the processing unit 1220 may be configured to perform operations related to processing of the first session management network element in the aforementioned method embodiment.

[0556] In one possible implementation, the transceiver unit 1210 is configured to obtain IP address information of the visited network; the transceiver unit 1210 is configured to send the IP address information to the edge application server discovery network element, where the first session management network element and the edge application server discovery network element are network elements deployed in the home network. Optionally, the processing unit 1220 is configured to determine the IP address information of the visited network.

[0557] Optionally, the transceiver unit 1210 is used to obtain the IP address information of the visited network, including: the transceiver unit 1210 is used to obtain the IP address information of the visited network according to the indication information, wherein the indication information indicates that the visited network offloading is allowed.

[0558] Optionally, the transceiver unit 1210 is used to send IP address information to the edge application server discovery network element, including: the transceiver unit 1210 is used to send IP address information to the edge application server discovery network element according to the indication information, wherein the indication information indicates that visited network offloading is allowed.

[0559] For example, the indication information includes an identifier of the first service, and the indication information indicates that offloading of the first service to the visited network is allowed.

[0560] Optionally, the transceiver unit 1210 is configured to obtain IP address information of the visited network, including: the transceiver unit 1210 is configured to receive IP address information from a second session management network element, where the second session management network element is a network element deployed in the visited network.

[0561] Optionally, the transceiver unit 1210 is further configured to send first request information to the second session management network element, where the first request information is used to request IP address information.

[0562] Optionally, the transceiver unit 1210 is also used to send a second request message to the network storage network element, the second request message includes an identifier of the visited network, the second request message is used to request IP address information, and the network storage network element is a network element deployed in the home network; the transceiver unit 1210 is used to obtain the IP address information of the visited network, including: the transceiver unit 1210 is used to receive the IP address information of the visited network from the network storage network element.

[0563] Optionally, the first session management network element locally configures the indication information; or, the transceiver unit 1210 is further configured to receive the indication information.

[0564] For example, the indication information includes first indication information and / or second indication information, the first indication information is locally configured by the first session management network element, and the second indication information is received by the first session management network element.

[0565] For example, the IP address information is information used to determine a Domain Name System (DNS) extension mechanism client subnet option, or the IP address information is a Domain Name System (DNS) extension mechanism client subnet option or a local DNS server address.

[0566] In the second design, the apparatus 1200 may be the second session management network element in the aforementioned embodiment, or may be a component (e.g., a chip) of the second session management network element. The apparatus 1200 may implement steps or processes corresponding to those performed by the second session management network element in the aforementioned method embodiment. The transceiver unit 1210 may be configured to perform operations related to transmission and reception by the second session management network element in the aforementioned method embodiment, and the processing unit 1220 may be configured to perform operations related to processing by the second session management network element in the aforementioned method embodiment.

[0567] In a first possible implementation, the transceiver unit 1210 is configured to obtain IP address information of a visited network; the transceiver unit 1210 is configured to send the IP address information to a first session management network element, wherein the second session management network element is a network element deployed in the visited network, and the first session management network element is a network element deployed in the home network.

[0568] Optionally, the transceiver unit 1210 is used to obtain the IP address information of the visited network, including: the transceiver unit 1210 is used to obtain the IP address information of the visited network according to the indication information, wherein the indication information indicates that the visited network offloading is allowed.

[0569] Optionally, the transceiver unit 1210 is used to send IP address information to the first session management network element, including: the transceiver unit 1210 is used to send IP address information to the first session management network element according to the indication information, wherein the indication information indicates that the visited network offloading is allowed.

[0570] For example, the indication information includes an identifier of the first service, and the indication information indicates that offloading of the first service to the visited network is allowed.

[0571] Optionally, the transceiver unit 1210 is also used to receive a first request message from the first session management network element, where the first request message is used to request IP address information; the transceiver unit 1210 is used to send IP address information to the first session management network element, including: in response to the first request message, the transceiver unit 1210 is used to send IP address information to the first session management network element.

[0572] Optionally, the second session management network element locally configures the indication information; or, the transceiver unit 1210 is configured to receive the indication information.

[0573] For example, the IP address information is information used to determine a Domain Name System (DNS) extension mechanism client subnet option, or the IP address information is a Domain Name System (DNS) extension mechanism client subnet option or a local DNS server address.

[0574] A second possible implementation method is that the transceiver unit 1210 is used to obtain indication information, where the indication information indicates that the visited network diversion is allowed; the transceiver unit 1210 is used to send the IP address information of the visited network to the user plane network element according to the indication information, wherein the second session management network element and the user plane network element are network elements deployed in the visited network.

[0575] Optionally, the transceiver unit 1210 is configured to obtain indication information, including: local configuration indication information of the second session management network element; or, the transceiver unit 1210 is configured to receive indication information.

[0576] For example, the indication information includes an identifier of the second service, and the indication information indicates that offloading of the second service to the visited network is allowed.

[0577] For example, the indication information includes first indication information and / or second indication information, the first indication information is locally configured by the second session management network element, and the second indication information is received by the second session management network element.

[0578] For example, the IP address information is information used to determine a Domain Name System (DNS) extension mechanism client subnet option, or the IP address information is a Domain Name System (DNS) extension mechanism client subnet option or a local DNS server address.

[0579] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0580] It should also be understood that the device 1200 here is embodied in the form of a functional unit. The term "unit" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. In an optional example, those skilled in the art will understand that the device 1200 may be specifically a user plane network element in the above-mentioned embodiment, and may be used to execute the various processes and / or steps corresponding to the user plane network element in the above-mentioned method embodiments; or, the device 1200 may be specifically a session management network element in the above-mentioned embodiment (such as the first session management network element, and the second session management network element), and may be used to execute the various processes and / or steps corresponding to the session management network element in the above-mentioned method embodiments. To avoid repetition, they will not be described here.

[0581] The apparatus 1200 of each of the above-mentioned solutions has the function of implementing the corresponding steps performed by the network element (such as the user plane network element, or the session management network element (such as the first session management network element, or the second session management network element)) in the above-mentioned method. The functions can be implemented by hardware, or the corresponding software can be implemented by hardware. The hardware or software includes one or more modules corresponding to the above-mentioned functions; for example, the transceiver unit can be replaced by a transceiver (for example, the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor to respectively perform the sending and receiving operations and related processing operations in each method embodiment.

[0582] In addition, the transceiver unit 1210 may also be a transceiver circuit (for example, may include a receiving circuit and a sending circuit), and the processing unit may be a processing circuit.

[0583] It should be pointed out that Figure 12 The device in the embodiment may be a network element or device as described in the preceding embodiments, or may be a chip or chip system, such as a system on chip (SoC). The transceiver unit may be an input / output circuit or a communication interface; the processing unit may be a processor, microprocessor, or integrated circuit integrated on the chip. This is not limited here.

[0584] like Figure 13 As shown, an embodiment of the present application provides another communication device 1300. The device 1300 includes a processor 1310, which is configured to execute computer programs or instructions stored in a memory 1320, or read data / signaling stored in the memory 1320, to perform the methods in the above method embodiments. Optionally, there are one or more processors 1310.

[0585] Alternatively, as Figure 13 As shown, the device 1300 further includes a memory 1320, which is used to store computer programs or instructions and / or data. The memory 1320 can be integrated with the processor 1310, or can be separately provided. Optionally, there are one or more memories 1320.

[0586] Alternatively, as Figure 13 As shown, the device 1300 further includes a transceiver 1330, which is used to receive and / or send signals. For example, the processor 1310 is used to control the transceiver 1330 to receive and / or send signals.

[0587] As a solution, the device 1300 is used to implement the operations performed by the network element in the above various method embodiments.

[0588] For example, the processor 1310 is configured to execute computer programs or instructions stored in the memory 1320 to implement the relevant operations of the user plane network element in each of the above method embodiments. Figure 4 The method performed by the user plane network element in the embodiment shown, or Figures 5 to 11 The method performed by the V-UPF in any one of the illustrated embodiments.

[0589] For another example, the processor 1310 is configured to execute the computer program or instructions stored in the memory 1320 to implement the relevant operations of the first session management network element in each of the above method embodiments. Figure 3 The method performed by the first session management network element in the embodiment shown, or Figures 5 to 11 The method performed by the H-SMF in any one of the illustrated embodiments.

[0590] For another example, the processor 1310 is configured to execute the computer program or instructions stored in the memory 1320 to implement the relevant operations of the second session management network element in each of the above method embodiments. Figure 3 or Figure 4 The method performed by the second session management network element in the embodiment shown, or Figures 5 to 11 The method performed by the V-SMF in any of the illustrated embodiments.

[0591] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0592] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0593] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0594] It should also be noted that the memory described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

[0595] An embodiment of the present application further provides a computer-readable storage medium on which computer instructions for implementing the methods executed by the network element in the above-mentioned method embodiments are stored.

[0596] For example, when the computer program is executed by a computer, the computer can implement the method performed by the user plane network element in each embodiment of the above method.

[0597] For another example, when the computer program is executed by a computer, the computer can implement the method performed by the session management network element (such as the first session management network element, or the second session management network element) in each embodiment of the above method.

[0598] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by the network element in the above-mentioned method embodiments.

[0599] An embodiment of the present application also provides a communication system, including one or more of the aforementioned user plane network element, the first session management network element, the second session management network element, and the edge application server discovery network element.

[0600] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0601] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0602] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium includes, but is not limited to, various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0603] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: include: The second session management network element in the visited network receives indication information from the first session management network element in the home network, where the indication information indicates that traffic offloading in the visited network is allowed; The second session management network element sends the IP address information of the visited network to the user plane network element in the visited network based on the indication information, where the IP address information is information used to determine the client subnet option of the domain name system DNS extension mechanism, or the IP address information is the DNS extension mechanism client subnet option or the local DNS server address.

2. The method according to claim 1, characterized in that The indication information is carried in the Nsmf protocol data unit session establishment response Nsmf_PDUSession_Create Response message.

3. The method according to claim 1, characterized in that The indication information includes an identifier of the service, and the indication information indicates that the service is allowed to be offloaded in the visited network.

4. The method according to claim 3, characterized in that The identifier of the service is a full domain name or IP address.

5. The method according to any one of claims 1 to 4, characterized in that The user plane network element is an edge application server discovery network element.

6. The method according to any one of claims 1 to 4, characterized in that The method is applied to a home routing roaming scenario.

7. The method according to any one of claims 1 to 4, characterized in that The method further comprises: The user plane network element receives the IP address information.

8. The method according to claim 7, characterized in that The method further comprises: The user plane network element receives the DNS query message; The user plane network element adds a domain name system extension mechanism client subnet option to the DNS query message, where the domain name system extension mechanism client subnet option is determined according to the IP address information.

9. The method according to claim 7, characterized in that The method further comprises: The user plane network element receives the DNS query message; The user plane network element forwards the DNS query message to a local DNS server address, where the local DNS server address is determined based on the IP address information.

10. The method according to any one of claims 1 to 4, characterized in that The method further comprises: The first session management network element sends the indication information to the second session management network element.

11. The method according to claim 10, characterized in that The method further comprises: The policy control function network element in the home network sends the indication information to the first session management network element; The first session management network element receives the indication information from the policy control function network element.

12. A communication device, characterized in that: The device is a device in a visited network, and includes a transceiver unit. The transceiver unit is configured to receive indication information from a first session management network element in the home network, wherein the indication information indicates that traffic offloading in the visited network is allowed; The transceiver unit is also used to send the IP address information of the visited network to the user plane network element in the visited network according to the indication information, where the IP address information is information used to determine the client subnet option of the domain name system DNS extension mechanism, or the IP address information is the DNS extension mechanism client subnet option or the local DNS server address.

13. The device according to claim 12, characterized in that The indication information is carried in the Nsmf protocol data unit session establishment response Nsmf_PDUSession_Create Response message.

14. The device according to claim 12, characterized in that The indication information includes an identifier of the service, and the indication information indicates that the service is allowed to be offloaded in the visited network.

15. The device according to claim 14, characterized in that The identifier of the service is a full domain name or IP address.

16. The device according to any one of claims 12 to 15, characterized in that The user plane network element is an edge application server discovery network element.

17. The device according to any one of claims 12 to 15, characterized in that The device is a session management network element in the visited network.

18. A communication device, characterized in that: include: A processor, configured to execute a computer program so as to cause the apparatus to perform the method according to any one of claims 1 to 6.

19. The device according to claim 18, characterized in that The apparatus further comprises a memory for storing the computer program.

20. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is run on a computer, the computer is caused to perform the method according to any one of claims 1 to 6.

21. A computer program product, characterized in that The computer program product comprises instructions for performing the method of any one of claims 1 to 6.

22. A communication system, characterized in that: including a second session management network element and a user plane network element, The second session management network element is configured to execute the method according to any one of claims 1 to 6, The user plane network element is used to execute any one of the methods executed by the user plane network element according to claims 7 to 9.

23. The system according to claim 22, wherein: The system further includes a first session management network element and / or a policy control function network element, The first session management network element is used to execute the method executed by the first session management network element as claimed in claim 10 or 11, and the policy control function network element is used to execute the method executed by the policy control function network element as claimed in claim 11.

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