Method and apparatus for information transmission

Abstract

The present application provides a method and apparatus for information transmission. The method may include: a first session management network element selects an edge application server discovery network element, and the first session management network element and the edge application server discovery network element are network elements deployed in a visited network; the first session management network element sends address information of the edge application server discovery network element. In this way, after a terminal device accesses the visited network through the HR roaming mode, it can access services in the visited network through the edge application server discovery network element selected by the first session management network element.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly, to a method and apparatus for information transmission. Background Art

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

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

[0004] This application provides a method and apparatus for information transmission to enable an edge application server discovery network element deployed in the VPLMN to provide services for a roaming UE, such as enabling the roaming UE to access edge application services in the VPLMN.

[0005] In a first aspect, a method for information transmission is provided. This method can be executed by a core network network element, or alternatively, can be executed by a component (such as a chip or a circuit) of the core network network element. There is no limitation in this regard. For the sake of description, the following takes the execution by the first session management network element as an example for illustration.

[0006] The method may include: The first session management network element selects an edge application server discovery network element. The first session management network element and the edge application server discovery network element are network elements deployed in the visited network. The first session management network element sends the address information of the edge application server discovery network element.

[0007] Based on the above solution, the first session management network element deployed in the visited network can select the edge application server discovery network element and send the address information of the edge application server discovery network element. In this way, when the terminal device accesses the visited network through the HR roaming mode, it can access the services in the visited network through the edge application server discovery network element selected by the first session management network element. In addition, the edge application server discovery network element can be used to assist in edge application server discovery. Therefore, by selecting the edge application server discovery network element through the first session management network element, local traffic splitting can be achieved in the visited network. Specifically, for example, the address of the edge application server discovery network element selected by the first session management network element can be used as the endpoint of the domain name system (DNS) message, and the edge application server discovery network element processes the DNS message to achieve local traffic splitting in the visited network, so that the roaming UE can access the edge application services in the visited network.

[0008] Among them, "using the address of the edge application server discovery network element as the endpoint of the DNS message" can be expressed as, for example, using the address of the edge application server discovery network element as the destination address of the DNS message, or it can also be expressed as sending the DNS message to the edge application server discovery network element, or it can also be expressed as the edge application server discovery network element processing the DNS message.

[0009] Combined with the first aspect, in some implementation manners of the first aspect, the first session management network element selects the edge application server discovery network element, including: the first session management network element selects the edge application server discovery network element according to the indication information, where the indication information indicates that traffic splitting in the visited network is allowed.

[0010] Based on the above solution, if the indication information indicates that traffic splitting in the visited network is allowed, the first session management network element selects the edge application server discovery network element. Furthermore, it can enable the first session management network element to select the edge application server discovery network element according to the indication information, and as much as possible avoid performing the operation of selecting the edge application server discovery network element in the case where traffic splitting in the visited network is prohibited, thus wasting resources.

[0011] Combined with the first aspect, in some implementation manners of the first aspect, the method further includes: the first session management network element receives the indication information from the second session management network element, where the second session management network element is a network element deployed in the home network; or, the first session management network element locally configures the indication information.

[0012] Based on the above solution, the first session management network element can locally configure the indication information, or it can also receive the indication information from other network elements (such as the second session management network element).

[0013] In combination with the first aspect, in some implementations of the first aspect, the first session management network element sends the address information of the edge application server discovery network element, including: the first session management network element sends the address information of the edge application server discovery network element to the terminal device.

[0014] Based on the above solution, directly sending the address information of the selected edge application server discovery network element from the first session management network element to the terminal device can not only achieve local traffic splitting in the visited network, but also reduce the signaling overhead caused by the first session management network element sending it to other core network elements and then those other core network elements sending the address information of the selected edge application server discovery network element to the terminal device.

[0015] In combination with the first aspect, in some implementations of the first aspect, the first session management network element sends the address information of the edge application server discovery network element, including: the first session management network element sends the address information of the edge application server discovery network element to the second session management network element, and the second session management network element is a network element deployed in the home network.

[0016] Based on the above solution, sending the address information of the selected edge application server discovery network element from the first session management network element to the second session management network element can not only achieve local traffic splitting in the visited network, but also facilitate the second session management network element to process the address information of the edge application server discovery 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 receives request information from the second session management network element, and the request information is used to request the address of the edge application server discovery network element, and the second session management network element is a network element deployed in the home network; the first session management network element selects an edge application server discovery network element, including: in response to the request information, the first session management network element selects an edge application server discovery network element.

[0018] Based on the above solution, the first session management network element can select an edge application server discovery network element after receiving the request from the second session management network element.

[0019] In a second aspect, a method for information transmission is provided. This method can be executed by a core network element, or can also be executed by a component (such as a chip or a circuit) of the core network element, and this is not limited. For the sake of convenience of description, the following takes the execution by the second session management network element as an example for illustration.

[0020] The method may include: a second session management network element obtaining address information of an edge application server discovery network element; the second session management network element sending the address information of the edge application server discovery network element to a terminal device; wherein, the edge application server discovery network element is a network element deployed in a visited network, and the second session management network element is a network element deployed in a home network.

[0021] Based on the above solution, the second session management network element deployed in the home network can obtain the edge application server discovery network element deployed in the visited network and send the address information of the edge application server discovery network element to the terminal device. In this way, after the terminal device accesses the visited network through the HR roaming mode, it can access services in the visited network through the edge application server discovery network element. In addition, the edge application server discovery network element can be used to assist in edge application server discovery. Therefore, the edge application server discovery network element in the visited network obtained by the second session management network element can achieve local traffic splitting in the visited network. Specifically, for example, the address of the edge application server discovery network element can be used as the end point of the DNS message, and the edge application server discovery network element processes the DNS message to achieve local traffic splitting in the visited network, so that the roaming UE can access edge application services in the visited network.

[0022] In combination with the second aspect, in some implementation manners of the second aspect, the second session management network element obtaining the address information of the edge application server discovery network element includes: the second session management network element receiving the address information of the edge application server discovery network element from a first session management network element, and the first session management network element is a network element deployed in a visited network.

[0023] Based on the above solution, the second session management network element can receive the address information of the edge application server discovery network element from the first session management network element.

[0024] In combination with the second aspect, in some implementation manners of the second aspect, the second session management network element sends a first request message to the first session management network element, and the first request message is used to request the address of the edge application server discovery network element.

[0025] Based on the above solution, the second session management network element can request the address information of the edge application server discovery network element from the first session management network element.

[0026] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element sends second request information to the network storage network element, the second request information includes the identifier of the visited network, and the second request information is used to request the address of the edge application server discovery network element, and the network storage network element is a network element deployed in the home network; the second session management network element obtains the address information of the edge application server discovery network element, including: the second session management network element receives the address information of the edge application server discovery network element from the network storage network element.

[0027] Based on the above solution, the second session management network element can request the address information of the edge application server discovery network element from the network storage network element.

[0028] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element obtains indication information, and the indication information indicates that the visited network is allowed to be shunted; the second session management network element obtains the address information of the edge application server discovery network element, including: the second session management network element obtains the address information of the edge application server discovery network element according to the indication information.

[0029] Based on the above solution, if the indication information indicates that the visited network is allowed to be shunted, the second session management network element selects the edge application server discovery network element, and further enables the second session management network element to obtain the edge application server discovery network element according to the indication information, and as much as possible avoids performing the operation of obtaining the edge application server discovery network element in the case where the visited network shunting is prohibited, wasting resources.

[0030] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element obtains indication information, and the indication information indicates that the visited network is allowed to be shunted; the second session management network element sends the address information of the edge application server discovery network element to the terminal device, including: the second session management network element sends the address information of the edge application server discovery network element to the terminal device according to the indication information.

[0031] Based on the above solution, if the indication information indicates that the visited network is allowed to be shunted, the second session management network element sends the address information of the edge application server discovery network element to the terminal device, and further enables the second session management network element to send the address information of the edge application server discovery network element to the terminal device according to the indication information, and as much as possible avoids performing the operation of sending the address information of the edge application server discovery network element to the terminal device in the case where the visited network shunting is prohibited, wasting resources.

[0032] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element sends indication information to the first session management network element.

[0033] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second session management network element receives indication information from the policy control network element, where the policy control network element is a network element deployed in the home network; or, the second session management network element locally configures the indication information.

[0034] In a third aspect, a method for information transmission is provided. This method can be executed by a core network element, or can also be executed by a component (such as a chip or a circuit) of the core network element, and this is not limited. For the sake of description, the following takes the execution by the second session management network element as an example for illustration.

[0035] The method may include: the second session management network element obtains indication information, and the indication information indicates that the visited network is allowed to perform traffic splitting; the second session management network element sends the indication information to the first session management network element; where the first session management network element is a network element deployed in the visited network, and the second session management network element is a network element deployed in the home network.

[0036] Based on the above solution, the second session management network element deployed in the home network sends indication information to the first session management network element deployed in the visited network, and the indication information indicates that the visited network is allowed to perform traffic splitting. In this way, the first session management network element deployed in the visited network can learn that the visited network is allowed to perform traffic splitting, and then the first session management network element can perform some operations, such as selecting an edge application server discovery network element, etc., to access services in the visited network.

[0037] In combination with the third aspect, in some implementations of the third aspect, the method further includes: the second session management network element receives address information of the edge application server discovery network element from the first session management network element.

[0038] In combination with the third aspect, in some implementations of the third aspect, the method further includes: the second session management network element sends address information of the edge application server discovery network element to the terminal device.

[0039] In combination with the third aspect, in some implementations of the third aspect, the second session management network element obtaining indication information includes: the second session management network element receives indication information from the policy control network element, where the policy control network element is a network element deployed in the home network.

[0040] Exemplarily, the policy control network element is a policy control network element deployed in the home network.

[0041] In a fourth aspect, a method for information transmission is provided. This method can be executed by a core network element, or can also be executed by a component (such as a chip or a circuit) of the core network element, and this is not limited. For the sake of description, the following takes the execution by the policy control network element as an example for illustration.

[0042] The method may include: a policy control network element obtaining indication information, where the indication information indicates that offloading to a visited network is allowed; the policy control network element sending the indication information to a second session management network element; wherein, the second session management network element and the policy control network element are network elements deployed in a home network.

[0043] Based on the above solution, the policy control network element deployed in the home network sends indication information to the second session management network element deployed in the home network, and the indication information indicates that offloading to a visited network is allowed. In this way, the second session management network element deployed in the home network can learn that offloading to a visited network is allowed, and further, the second session management network element can perform some operations, such as sending an edge application server discovery network element deployed in the visited network to a terminal device, etc., to access services in the visited network.

[0044] In a fifth aspect, there is provided a device for information transmission, and the device is configured to execute the method in any one of the possible implementation manners of the first aspect to the fourth aspect above. Specifically, the device may include units and / or modules for executing the method in any one of the possible implementation manners of the first aspect to the fourth aspect, such as a processing unit and / or a communication unit.

[0045] In one implementation manner, the device is a core network element. When the device is a core network element, the communication unit may be a transceiver, or an input / output interface; 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.

[0046] In another implementation manner, the device is a chip, a chip system or a circuit for a core network element. When the device is a chip, a chip system or a circuit for a core network element, the communication unit may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, etc. on the chip, the chip system or the circuit; the processing unit may be at least one processor, a processing circuit or a logic circuit, etc.

[0047] In a sixth aspect, there is provided a device for information transmission, and the device includes: at least one processor, configured to execute a computer program or instruction stored in a memory to execute the method in any one of the possible implementation manners of the first aspect to the fourth aspect above. Optionally, the device further includes a memory for storing the computer program or instruction. Optionally, the device further includes a communication interface, and the processor reads the computer program or instruction stored in the memory through the communication interface.

[0048] In one implementation manner, the device is a core network element.

[0049] In another implementation manner, the device is a chip, a chip system or a circuit for a core network element.

[0050] In a seventh aspect, the present application provides a processor for executing the methods provided in the above aspects.

[0051] For operations such as sending and obtaining / receiving involved in the processor, if there is no special description, or if it does not conflict with its actual role or internal logic in the relevant description, it can be understood as operations such as the processor outputting and receiving, inputting, etc., and can also be understood as the sending and receiving operations performed by the radio frequency circuit and the antenna. The present application does not make any limitations in this regard.

[0052] In an eighth aspect, a computer-readable storage medium is provided. The computer-readable medium stores program code for a device to execute, and the program code includes methods for executing any of the possible implementation manners in the first aspect to the fourth aspect above.

[0053] In a ninth aspect, a computer program product including instructions is provided. When the computer program product runs on a computer, it causes the computer to execute the methods in any of the possible implementation manners in the first aspect to the fourth aspect above.

[0054] In a tenth aspect, a communication system is provided, including one or more of the foregoing first session management network element, second session management network element, network storage network element, and policy control network element. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of a network architecture is shown.

[0056] Figure 2 A schematic diagram of another network architecture is shown.

[0057] Figure 3 It is a schematic diagram of a method 300 for information transmission provided by an embodiment of the present application.

[0058] Figure 4 It is a schematic diagram of another method 400 for information transmission provided by an embodiment of the present application.

[0059] Figure 5 It is a schematic flowchart of a method 500 for information transmission provided by an embodiment of the present application.

[0060] Figure 6 It is a schematic flowchart of another method 600 for information transmission provided by an embodiment of the present application.

[0061] Figure 7 It is a schematic flowchart of another method 700 for information transmission provided by an embodiment of the present application.

[0062] Figure 8It is a schematic flowchart of another information transmission method 800 provided by an embodiment of the present application.

[0063] Figure 9 It shows a schematic block diagram of an information transmission device 900 provided by an embodiment of the present application.

[0064] Figure 10 It shows a schematic block diagram of another information transmission device 1000 provided by an embodiment of the present application. Detailed implementation manners

[0065] Next, the technical solutions in the present application will be described with reference to the accompanying drawings.

[0066] The technical solutions provided by the present application can be applied to various communication systems, such as: the fifth generation (5G) or new radio (NR) system, long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, etc. The technical solutions provided by the present application can also be applied to future communication systems, such as the sixth generation mobile communication system. The technical solutions provided by the present 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.

[0067] First, in combination with Figure 1 and Figure 2 briefly introduce the network architecture applicable to the present application as follows.

[0068] As an example, Figure 1 it shows a schematic diagram of a network architecture.

[0069] As Figure 1 shown, this network architecture takes home routed (HR) roaming as an example.

[0070] A cellular mobile communication network of a certain operator and a certain standard can be called a Public Land Mobile Network (PLMN). The PLMN subscribed by a User Equipment (UE) can be called a Home Public Land Mobile Network (HPLMN), which represents the home operator of the subscribed user. When the UE leaves the coverage area of the HPLMN due to mobility or other reasons, if there is a PLMN that meets the following conditions: 1) it can cover the current location of the UE, and 2) its operator has signed a roaming agreement with the operator of the UE's HPLMN (the roaming agreement, that is, a certain agreement between operators, the content of which can include, for example, but is not limited to: services provided for subscribed users of the other operator's network and billing methods, etc., and there is no restriction on this), then the UE can access this PLMN, and this PLMN can be called a Visited Public Land Mobile Network (VPLMN). The behavior of the UE accessing the VPLMN can be called roaming.

[0071] Roaming scenarios can be divided into Local Breakout (LBO) roaming and Home Routed (HR) roaming.

[0072] In the HR roaming scenario, the Session Management Function (SMF) in the VPLMN can forward session management (SM) - related information to the SMF in the HPLMN. In the HR roaming scenario, the SMF in the HPLMN can receive the Subscription Permanent Identifier (SUPI) of the terminal device from the SMF in the VPLMN. Regarding the HR roaming scenario, reference can be made to the provisions in the protocol, without restriction.

[0073] Such as Figure 1As shown, the network architecture may include but is not limited to: a network slice specific authentication and authorization function (NSSAAF), a network slice selection function (NSSF), an authentication server function (AUSF), a unified data management (UDM), a policy control function (PCF), an application function (AF), an access and mobility management function (AMF), a session management function (SMF), a user equipment (UE), a radio access network device, a user plane function (UPF), a data network (DN), etc.

[0074] The following briefly introduces Figure 1 each network element shown in

[0075] 1. UE: It can be called a terminal device, an access terminal, a user unit, a user station, a mobile station, a mobile platform, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device.

[0076] A terminal device can be a device that provides voice / data to users. For example, it can be a handheld device with wireless connection function, a vehicle-mounted device, etc. Currently, some examples of terminals are: mobile phone, tablet computer, laptop computer, palm computer, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing devices connected to a wireless modem, wearable device, terminal device in a 5G network or terminal device in a future evolved public land mobile network (PLMN), etc. The embodiments of the present application are not limited thereto.

[0077] By way of example and not limitation, in the embodiments of the present application, the terminal device can also be a wearable device. A wearable device can also be referred to as a wearable intelligent device, which is a general term for devices developed by applying wearable technology to the intelligent design of daily wear, such as glasses, gloves, watches, clothing, shoes, etc. A wearable device is a portable device that is directly worn on the body or integrated into the user's clothes or accessories. A wearable device is not just a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable intelligent devices include those with complete functions and large sizes that can achieve complete or partial functions without relying on a smartphone, such as smart watches or smart glasses, etc., and those that only focus on a certain type of application function and need to cooperate with other devices such as smartphones, such as various smart bracelets and smart jewelry for physical sign monitoring.

[0078] In addition, in the embodiments of the present application, the terminal device may 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, so as to realize an intelligent network of human-machine interconnection and object-object interconnection.

[0079] 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, etc.). The terminal devices can also communicate with each other using a certain air interface technology (such as NR or LTE technology, etc.).

[0080] In the embodiments of the present application, the device for implementing the functions of the terminal device may be the terminal device or a device capable of supporting the terminal device to implement the functions, such as a chip system or a chip, and this device may be installed in the terminal device. In the embodiments of the present application, the chip system may be composed of chips or may include chips and other discrete devices.

[0081] 2. (Wireless) Access Network ((radio) access network, (R) AN) device: It can provide the function of accessing a communication network for authorized users in a specific area. Specifically, it may include wireless network devices in the 3rd generation partnership project (3GPP) network, and may also include access points in the non-3GPP (non-3GPP) network. For the convenience of description below, it is represented by an AN device.

[0082] AN devices can adopt different radio access technologies. There are two types of current radio access technologies: 3GPP access technologies (for example, the radio access technologies adopted in the third generation (3G), fourth generation (4G), or 5G systems) and non-3GPP access technologies. 3GPP access technologies refer to the access technologies that comply with 3GPP standard specifications. For example, the access network devices in the 5G system are called next generation NodeBase stations (gNBs) or RAN devices. Non-3GPP access technologies can 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 devices can allow the interconnection and interoperability between terminal devices and the 3GPP core network using non-3GPP technologies.

[0083] AN devices are capable of being responsible for functions such as radio resource management, quality of service (QoS) management, data compression, and encryption on the air interface side. AN devices provide access services for terminal devices and then complete the forwarding of control signals and user data between terminal devices and the core network.

[0084] The AN device may include, for example, but not limited to: macro base station, micro base station (also known as small cell), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), baseband unit (BBU), AP in the WiFi system, wireless relay node, wireless backhaul node, transmission point (TP) or 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 of antenna panels (including multiple antenna panels) of the base station in the 5G system, or, it may also be a network node constituting the gNB or transmission point, such as a distributed unit (DU), or a base station in the next-generation communication 6G system, etc. The specific technologies and specific device forms adopted by the AN device are not limited in the embodiments of the present application.

[0085] 3. AMF: mainly used for functions such as access control, mobility management, attachment and detachment.

[0086] 4. SMF: mainly used for user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation for the terminal device, and session management in the mobile network, such as session establishment, modification and release, and Quality of Service (QoS) control.

[0087] In this application, for distinction, the SMF in the HPLMN is denoted as the home SMF (H-SMF), and the SMF in the VPLMN is denoted as the visited SMF (V-SMF).

[0088] 5. UPF: mainly used for receiving and forwarding user plane data. For example, the UPF can receive user plane data from the DN and send the user plane data to the terminal device through the AN device. The UPF can also receive user plane data from the terminal device through the AN device and forward it to the DN. The UPF directly connected to the DN through the N6 interface in the session can be called the protocol data unit (PDU) session anchor (PSA).

[0089] In this application, for the sake of distinction, the UPF in the HPLMN is denoted as the home UPF (H-UPF), and the UPF in the VPLMN is denoted as the visited UPF (V-UPF).

[0090] In addition, for the sake of distinction, the PSA in the HPLMN is denoted as the home PSA (H-PSA), and the PSA in the VPLMN is denoted as the visited PSA (V-PSA) (or denoted as the local PSA (L-PSA)).

[0091] 6. PCF: A unified policy framework mainly used to guide network behavior, providing policy rule information for control plane network elements (such as AMF, SMF, etc.).

[0092] In this application, for the sake of distinction, the PCF in the HPLMN is denoted as the home PCF (H-PCF).

[0093] 7. AF: Mainly used to provide services to the 3GPP network, such as interacting with the PCF for policy control, etc.

[0094] 8. Network slice selection function (NSSF): Mainly used for network slice selection.

[0095] 9. UDM: Mainly used for the subscription data management of the UE, including the storage and management of UE identifiers, access authorization of the UE, etc.

[0096] 10. DN: The operator network mainly used to provide data services to the UE. For example, the Internet, a third-party service network, an IP multimedia service (IMS) network, etc.

[0097] 11. AUSF: Mainly used for user authentication, etc.

[0098] As an example, Figure 2 shows a schematic diagram of another network architecture.

[0099] As Figure 2 shown, this 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), DN, PCF (such as H-PCF), edge application server discovery function (EASDF) (such as EASDF in HPLMN, denoted as home EASDF (home SMF, H-EASDF); and EASDF in VPLMN, denoted as visited EASDF (visited EASDF, V-EASDF)). In this architecture, Domain Name System (DNS) messages may terminate at the EASDF of the VPLMN.

[0100] Among them, the edge application server discovery function, for example, may also be referred to as edge application (service) discovery function, application instance discovery function, edge application instance discovery function, MEC application (server) discovery function, etc., without limitation.

[0101] In Figure 1 or Figure 2 In the network architecture shown, the network elements may communicate through interfaces. For example, the UE is connected to the AN device through the Radio Resource Control (RRC) protocol, and the Uu interface is used for communication between the UE and the AN device. Or reference may also be made to Figure 1 the interfaces shown, which will not be elaborated here.

[0102] It should be understood that the network architecture shown above is only an exemplary illustration, and the network architecture applicable to the embodiments of the present application is not limited thereto. Any network architecture capable of implementing 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 function (NF) repository function (NRF), without limitation. In the present application, for distinction, the NRF in HPLMN is denoted as home NRF (home NRF, H-NRF), and the NRF in VPLMN is denoted as visited NRF (visited NRF, V-NRF).

[0103] It should also be understood that Figure 1 or Figure 2Functions or network elements such as AMF, SMF, UPF, PCF, UDM, NSSF, AUSF, etc. shown in the figure can be understood as network elements for implementing different functions. For example, they can be combined into network slices as needed. These network elements can be individual independent devices, or can be integrated into the same device to implement different functions, or can be network elements in hardware devices, or software functions running on dedicated hardware, or virtualized functions instantiated on a platform (such as a cloud platform). The present application does not limit the specific form of the above-mentioned network elements.

[0104] It should also be understood that the above names are only defined for the convenience of distinguishing different functions and should not constitute any limitation to the present application. The present application does not exclude the possibility of using other names in 6G networks and future other networks. For example, in 6G networks, some or all of the above-mentioned network elements may continue to use the terms in 5G, or may use other names, etc.

[0105] In an edge computing (EC) deployment scenario, some services may be provided by multiple edge application servers (EAS) deployed at the network edge. These multiple EASs can provide the same services and content, and most of them have different IP addresses. In the EC scenario, when a UE accesses this service, it can request to access an available EAS that is close to the UE. Therefore, it is relatively important to obtain the IP address of a suitable EAS.

[0106] As described above, a UE may access the VPLMN through HR roaming, and the VPLMN provides services for the UE.

[0107] Considering that when a UE accesses the VPLMN, some services may want to use EC access. Currently, for a UE in HR roaming, during the PDU session establishment phase, only the relevant information of the HPLMN (such as the address information of the edge application server discovery network element in the HLPMN) is provided to the UE, resulting in the inability to discover the edge application server located in the VPLMN for the UE. Therefore, the existing edge service discovery mechanism cannot be used in the HR roaming scenario. Therefore, the present application proposes that local traffic splitting can be performed in the VPLMN.

[0108] EASDF can be used to assist in EAS discovery. As an example, the functions of EASDF include: processing DNS messages according to the instructions of the SMF. Among them, processing DNS messages may include, but is not limited to: reporting DNS messages to the SMF, adding an EDNS client subnet option (Edns-client-subnet option, ECS option) in a DNS query (DNSquery), forwarding the DNS query to a DNS server, forwarding a DNS response (DNS response) to the UE, etc. Among them, EDNS is the DNS extension mechanism (extended mechanisms for DNS, EDNS).

[0109] In view of this, the present application proposes to provide services for roaming UEs through an edge application server discovery network element deployed in the VPLMN, such as enabling roaming UEs to access edge application services in the VPLMN.

[0110] For example, the session management network element of the VLPMN (such as the V-SMF) can select the V-EASDF and send the address of the V-EASDF to the UE or to the H-SMF. In this way, through the V-EASDF selected by the session management network element of the VLPMN (such as the V-SMF), the V-EASDF can be implemented as an endpoint for DNS messages. For example, the V-EASDF processes DNS query messages from the terminal device, or the V-EASDF receives DNS query messages from the terminal device, or the destination address of the DNS query message from the terminal device can be the V-EASDF address, etc., so that the V-SMF can obtain the address information of the local EAS to achieve local traffic splitting in the VPLMN.

[0111] For another example, the session management network element of the HLPMN (such as the H-SMF) can obtain the V-EASDF and send the address of the V-EASDF to the UE. In this way, through the V-EASDF obtained by the session management network element of the HLPMN (such as the H-SMF), the V-EASDF can be implemented as an endpoint for DNS messages. For example, the V-EASDF processes DNS query messages from the terminal device, or the V-EASDF receives DNS query messages from the terminal device, or the destination address of the DNS query message from the terminal device can be the V-EASDF address, etc., so that the H-SMF can obtain the address information of the local EAS to achieve local traffic splitting in the VPLMN.

[0112] Therefore, the present application can be used to solve edge service discovery in a roaming scenario (such as an HR roaming scenario).

[0113] It can be understood that the term "and / or" in this text is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0114] The method for information transmission provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments provided by the present application can be applied to the Figure 1 or Figure 2 network architectures shown above, without limitation.

[0115] Figure 3 It is a schematic diagram of a method 300 for information transmission provided by an embodiment of the present application. The method 300 may include the following steps.

[0116] 310, the first session management network element selects an edge application server discovery network element, and both the first session management network element and the edge application server discovery network element are network elements deployed in the visited network.

[0117] The visited network is the network accessed by the terminal device after leaving the home network, such as the VPLMN. Below, the VPLMN will be mainly used as an example for illustration.

[0118] The first session management network element is a network element deployed in the VPLMN. For example, the first session management network element is the V-SMF.

[0119] The edge application server discovery network element is a network element deployed in the VPLMN. For example, the edge application server discovery network element is the V-EASDF. Below, the V-EASDF will be mainly used as an example for exemplary illustration.

[0120] 320, the first session management network element sends the address information of the edge application server discovery network element.

[0121] Based on the above solution, the first session management network element deployed in the visited network can select an edge application server discovery network element (such as V-EASDF) and send the address information of the edge application server discovery network element. In this way, when the terminal device accesses the visited network through the HR roaming mode, it can access the services in the visited network through the edge application server discovery network element selected by the first session management network element. In addition, the edge application server discovery network element can be used to assist in EAS discovery. Therefore, by selecting the edge application server discovery network element through the first session management network element, local traffic splitting can be achieved in the visited network. Specifically, for example, the address of the edge application server discovery network element selected by the first session management network element can be used as the endpoint of the DNS message, and the edge application server discovery network element processes the DNS message, so that the first session management network element obtains the address information of the local EAS, so as to achieve local traffic splitting in the visited network, enabling the roaming UE to access the edge application services in the visited network.

[0122] Among them, "using the address of the edge application server discovery network element as the endpoint of the DNS message" can be expressed as, for example, using the address of the edge application server discovery network element as the destination address of the DNS message, or it can also be expressed as sending the DNS message to the edge application server discovery network element, or it can also be expressed as the edge application server discovery network element processing the DNS message. This will not be elaborated further below.

[0123] In step 310, the first session management network element selects V-EASDF, which can be implemented by at least any of the following methods.

[0124] Method 1: The first session management network element selects V-EASDF according to the indication information (for distinction, denoted as indication information #A).

[0125] Among them, the indication information #A indicates that VPLMN traffic splitting is allowed. Among them, "allowing VPLMN traffic splitting" can be understood as, for example, allowing the use of the EASDF of the VPLMN (i.e., V-EASDF), or allowing the user plane of the VPLMN to process the service flow.

[0126] For example, the indication information #A can be used to trigger the first session management network element to select V-EASDF. Specifically, if the first session management network element learns from the indication information #A that VPLMN traffic splitting is allowed, the first session management network element can select V-EASDF.

[0127] In this application, the indication information #A is mentioned multiple times. The indication information #A indicates (or represents, or shows) that VPLMN splitting is allowed (or authorized), or it can be described as the indication information #A indicates that local VPLMN splitting is allowed, or it can be described as the indication information #A indicates that splitting is allowed. For the sake of uniformity below, the example of allowing local VPLMN splitting is used for description.

[0128] In one example, allowing local VPLMN splitting can mean that the HPLMN allows local VPLMN splitting. Correspondingly, the indication information #A used to indicate allowing local VPLMN splitting can be replaced with: the indication information #A is used to indicate allowing (or authorizing) the use of V-EASDF.

[0129] In another example, allowing local VPLMN splitting can mean allowing the VPLMN to select V-EASDF. Correspondingly, the indication information #A used to indicate allowing local VPLMN splitting can be replaced with: the indication information #A is used to indicate allowing (or authorizing) the selection of V-EASDF.

[0130] In another example, allowing local VPLMN splitting can mean allowing the address of V-EASDF to be sent. Correspondingly, the indication information #A used to indicate allowing local VPLMN splitting can be replaced with: the indication information #A is used to indicate allowing (or authorizing) the sending of the address of V-EASDF.

[0131] It can be understood that this application mainly uses the example of allowing local VPLMN splitting for illustration, and does not limit that local VPLMN splitting is allowed in all cases. In other words, in some cases, local VPLMN splitting may also be prohibited (or not allowed), and in this case, local splitting may not be performed in the VPLMN.

[0132] This application does not limit the specific naming of the indication information #A. For example, the "indication information #A" in this application can be replaced with "authorization policy", or can be replaced with "splitting policy", or can be replaced with "roaming policy", and so on.

[0133] This application does not limit the form of the indication information #A. For example, the indication information #A can be a cell, or can be a parameter, or can be the text content recorded in the protocol, and so on.

[0134] In Mode 2, the first session management network element selects V-EASDF according to the request information (for distinction, denoted as request information #1) from the second session management network element.

[0135] Among them, the second session management network element is a network element deployed in the home network. For example, the second session management network element is an H-SMF.

[0136] Specifically, the second session management network element sends request message #1 to the first session management network element. In response to the request message #1, the first session management network element selects V-EASDF.

[0137] Among them, the request message #1 is used to request (or obtain) the address of V-EASDF. The implementation of the request message #1 is not limited.

[0138] For example, the request message #1 can be used to trigger the first session management network element to select V-EASDF. Specifically, if the first session management network element receives the request message #1, then in response to the request message #1, the first session management network element selects V-EASDF. In this case, the request message #1 can also be the indication message #A.

[0139] Another example is that the request message #1 can be implemented by one or more bits. For example, assume that 1 bit is used to indicate whether the first session management network element selects V-EASDF. If this bit is set to "0", it means that the first session management network element selects V-EASDF; if this bit is set to "1", it means that the first session management network element does not need to select V-EASDF. For example, if the first session management network element receives a signaling that includes the request message #1 and the bit corresponding to the request message #1 is set to "0", then in response to the request message #1, the first session management network element selects V-EASDF. It should be understood that the above is only an exemplary description and is not limited. In this case, the request message #1 can be carried on the interface signaling between the first session management network element and the second session management network element. For example, this signaling can be an Nsmf interface PDU session update request (Nsmf_PDUSession_Update Request) message, or an Nsmf interface PDU session context request (Nsmf_PDUSession_Context Request) message, etc. This application does not make a limitation.

[0140] Method 3: The first session management network element selects V-EASDF according to the internal logic implementation.

[0141] As an example, the internal logic of the first session management network element indicates that after receiving the session establishment request message, the selection of V-EASDF is performed. In this example, if the first session management network element receives the session establishment request message, then the first session management network element selects V-EASDF.

[0142] Among them, the session establishment request message can be, for example, an Nsmf interface PDU session create session context request (Nsmf_PDUSession_CreateSMContext Request) message sent by the AMF to the first session management network element. This application does not make a limitation.

[0143] It can be understood that the above three methods are for illustrative purposes, and the present application is not limited thereto.

[0144] Optionally, method 300 further includes: the first session management network element obtains indication information #A.

[0145] The first session management network element can obtain indication information #A at least through any of the following methods.

[0146] Method 1, the first session management network element receives indication information #A from the second session management network element.

[0147] For example, taking the first session management network element as V-SMF and the second session management network element as H-SMF as an example, the H-SMF sends indication information #A to the V-SMF. Correspondingly, the V-SMF receives indication information #A from the H-SMF.

[0148] Method 2, the first session management network element locally configures indication information #A.

[0149] For example, the locally configured roaming protocol includes indication information #A corresponding to the HPLMN. The first session management network element directly obtains the indication information #A corresponding to the HPLMN according to the locally configured roaming protocol.

[0150] Another example is that the locally configured roaming protocol includes one or more pieces of indication information #A. The first session management network element obtains the indication information #A according to the locally configured roaming protocol. Among them, the one or more pieces of indication information #A can be indication information #A corresponding to one or more PLMNs. The first session management network element can first determine the HPLMN and then obtain the corresponding indication information #A according to the HPLMN. For example, the indication information #A can exist in the form of Table 1 in the first session management network element.

[0151] Table 1

[0152] PLMN Identity (ID) Indication Information #A PLMN#1 Indication Information #A1 PLMN#2 Indication Information #A2 PLMN#3 Indication Information #A3

[0153] Taking Table 1 as an example, in a possible case, the PLMN ID can be the ID of the HPLMN, and the indication information #Ai (i = 1, 2, 3,...). It is used to indicate whether the HPLMN allows local offloading in the VPLMN. For example, if the first session management network element determines that the HPLMN is PLMN#1, it can know that the indication information #A corresponding to the HPLMN is indication information #A1. If the indication information #A1 is used to indicate that PLMN#1 allows local offloading in the VPLMN, local offloading can be performed in the VPLMN.

[0154] This application does not limit the manner in which the first session management network element determines the HPLMN. As an example, the first session management network element may identify the HPLMN based on the identifiers of the network elements deployed in the HPLMN (such as the identifier of the second session management network element, or the identifiers of other network elements, etc.). In one possible manner, the first session management network element receives the identifier of the second session management network element from the AMF (for example, H-SMF ID, which is not limited in this application), and the first session management network element determines the identifier of the HPLMN based on the identifier of the second session management network element, that is, determines the HPLMN.

[0155] It should be understood that Table 1 is only an exemplary illustration and is not limited thereto. Any variation belonging to Table 1 is applicable to this application. For example, the PLMN ID in Table 1 above may also be replaced with the SMF ID. For example, PLMN#1 may be replaced with one or more SMF IDs (that is, the IDs of one or more SMFs corresponding to this PLMN#1).

[0156] The above two manners are exemplary illustrations. Any manner that can enable the first session management network element to obtain the indication information #A is applicable to the embodiments of this application.

[0157] In step 320, the first session management network element sends the address information of V-EASDF, and at least the following implementation manners are possible.

[0158] Manner 1: The first session management network element sends the address of V-EASDF to the terminal device.

[0159] Through this manner, if there is an available V-EASDF in the VPLMN, the first session management network element selects the V-EASDF and directly sends the address of the V-EASDF to the terminal device. Furthermore, it can be realized that the V-EASDF serves as the endpoint of the DNS message, and local traffic splitting in the VPLMN is achieved.

[0160] As a possible scenario, the first session management network element sends the address of V-EASDF to the terminal device according to the indication information #A. Specifically, if the indication information #A is used to indicate that local traffic splitting in the VPLMN is allowed, the first session management network element sends the address of the V-EASDF to the terminal device.

[0161] Manner 2: The first session management network element sends the address of V-EASDF to the second session management network element.

[0162] In this way, if there is an available V-EASDF in the VPLMN, the first session management network element selects the V-EASDF and sends the address of the V-EASDF to the second session management network element, and then the second session management network element can process it. For example, the second session management network element can send the address of the V-EASDF to the terminal device, and then it can be realized that the V-EASDF is used as the termination point of the DNS message, and local traffic splitting in the VPLMN is achieved.

[0163] As a possible scenario, the first session management network element sends the address of the V-EASDF to the second session management network element according to the indication information #A. Specifically, if the indication information #A is used to indicate that local traffic splitting in the VPLMN is allowed, the first session management network element sends the address of the V-EASDF to the second session management network element.

[0164] As another possible scenario, the first session management network element sends the address of the V-EASDF to the terminal device according to the request information #1 from the second session management network element. Specifically, the second session management network element sends the request information #1 to the first session management network element to request the address of the V-EASDF; the first session management network element selects the V-EASDF and sends a response to the request information #1 to the second session management network element, and the response carries the address of the V-EASDF.

[0165] Figure 4 It is a schematic diagram of another information transmission method 400 provided by the embodiments of this application. The method 400 may include the following steps.

[0166] 410. The second session management network element obtains the address information of the edge application server discovery network element. The second session management network element is a network element deployed in the home network, and the edge application server discovery network element is a network element deployed in the visited network.

[0167] The visited network is, for example, the VPLMN. The home network, that is, the network subscribed by the terminal device, such as the HPLMN. The following mainly takes the HPLMN as an example for description.

[0168] The second session management network element is a network element deployed in the HPLMN. For example, the second session management network element is the H-SMF.

[0169] The edge application server discovery network element is a network element deployed in the VPLMN, such as the V-EASDF.

[0170] 420. The second session management network element sends the address information of the edge application server discovery network element to the terminal device.

[0171] Based on the above solution, the second session management network element deployed in the home network can obtain the edge application server discovery network element (such as V-EASDF) deployed in the visited network, and send the address information of the edge application server discovery network element to the terminal device. In this way, when the terminal device accesses the visited network through the HR roaming mode, it can access the services in the visited network through the edge application server discovery network element. In addition, the edge application server discovery network element can be used to assist in EAS discovery. Therefore, the edge application server discovery network element in the visited network obtained by the second session management network element can achieve local traffic splitting in the visited network. Specifically, for example, the address of the edge application server discovery network element can be used as the endpoint of the DNS message, and the edge application server discovery network element processes the DNS message to achieve local traffic splitting in the visited network, so that the roaming UE can access the edge application services in the visited network.

[0172] Optionally, in step 410, the second session management network element obtains the address information of V-EASDF, which can be implemented by at least any of the following methods.

[0173] Method 1, the second session management network element obtains the address information of V-EASDF from the first session management network element.

[0174] Among them, the first session management network element is a network element deployed in the visited network. For example, the first session management network element is V-SMF.

[0175] As a possible situation, method 400 may further include: the second session management network element sends request information #1 to the first session management network element, and the request information #1 is used to request the address of V-EASDF. The first session management network element sends a response to the request information #1 to the second session management network element, and the response carries the address information of V-EASDF.

[0176] Regarding the request information #1 and the method for the first session management network element to obtain V-EASDF, reference can be made to the description in method 300, which will not be elaborated here.

[0177] Method 2, the second session management network element receives the address information of V-EASDF from the network storage network element.

[0178] Among them, the network storage network element is a network element deployed in the home network. For example, the network storage network element is H-NRF.

[0179] As a possible situation, method 400 may further include: the second session management network element sends request information #2 to the network storage network element, and the request information #2 is used to request the address of V-EASDF. The network storage network element sends a response to the request information #2 to the second session management network element, and the response carries the address information of V-EASDF.

[0180] Among them, there is no restriction on the way for the network storage network element to obtain the address of the V-EASDF. For example, the network storage network element locally configures the V-EASDF. For example, after the network storage network element receives the request message #2 from the second session management network element, it locally reads the address information of the V-EASDF and sends the address information of the V-EASDF to the second session management network element. Another example is that the network storage network element requests the V-EASDF from other core network elements (such as the V-NRF). For example, after the network storage network element receives the request message #2 from the second session management network element, it requests the V-EASDF from the V-NRF, receives the address information of the V-EASDF from the V-NRF, and sends the address information of the V-EASDF to the second session management network element.

[0181] Optionally, method 400 further includes: the second session management network element obtains indication information #A.

[0182] For the description of the indication information #A, reference can be made to the description in method 300, which will not be elaborated here.

[0183] The second session management network element can obtain the indication information #A at least by any one of the following methods.

[0184] Method 1, the second session management network element receives the indication information #A.

[0185] For example, the second session management network element receives the information #A from the policy control network element, where the policy control network element is a network element deployed in the home network. Taking the second session management network element as the H-SMF and the policy control network element as the H-PCF as an example, the H-PCF sends the indication information #A to the H-SMF. Correspondingly, the H-SMF receives the indication information #A from the H-PCF. There is no restriction on the condition for triggering the H-PCF to send the indication information #A to the H-SMF. For example, the triggering condition can be that the H-SMF sends the identifier of the VPLMN to the H-PCF.

[0186] Another example is that the second session management network element receives the information #A from the network storage network element, where the network storage network element is a network element deployed in the home network. Taking the second session management network element as the H-SMF and the policy control network element as the H-NRF as an example, the H-NRF sends the indication information #A to the H-SMF. Correspondingly, the H-SMF receives the indication information #A from the H-NRF. There is no restriction on the condition for triggering the H-NRF to send the indication information #A to the H-SMF. For example, the triggering condition can be that the H-SMF sends the identifier of the VPLMN to the H-NRF. Examples will be given later in combination with Figures 5 to 8 Examples are given.

[0187] Method 2, the second session management network element local configuration indication information #A.

[0188] For example, the locally configured roaming protocol includes indication information #A corresponding to the VPLMN. The second session management network element directly obtains the indication information #A corresponding to the VPLMN according to the locally configured roaming protocol.

[0189] Another example is that the locally configured roaming protocol includes one or more pieces of indication information #A. The second session management network element obtains the indication information #A according to the locally configured roaming protocol. Among them, the one or more pieces of indication information #A can be indication information #A corresponding to one or more PLMNs. The second session management network element can first determine the VPLMN and then obtain the corresponding indication information #A according to the VPLMN. It should be noted that the second session management network element can determine the indication information #A according to the message received from the first session management network element and the local configuration. Among them, the message can be an Nsmf_PDUSession_Create Request or an Nsmf_PDUSession_Update Request message, etc., which is not limited in this application.

[0190] The indication information #A can exist in the form of Table 2 in the second session management network element.

[0191] Table 2

[0192] PLMN ID Indication Information #A PLMN#1’ Indication Information #A1’ PLMN#2’ Indication Information #A2’ PLMN#3’ Indication Information #A3’

[0193] Taking Table 2 as an example, in a possible case, the PLMN ID can be the ID of the VPLMN, and the indication information #Aj’ (j = 1, 2, 3,...). It is used to indicate whether local offloading of the VPLMN is allowed. For example, if the second session management network element determines that the VPLMN is PLMN#2, it can know that the indication information #A corresponding to the VPLMN is indication information #A2’. If the indication information #A2’ is used to indicate that local offloading of PLMN#2’ is allowed, local offloading can be performed in the VPLMN.

[0194] This application does not limit the manner in which the second session management network element determines the VPLMN. As an example, the second session management network element may identify the VPLMN based on the identifiers of the network elements deployed in the VPLMN (such as the identifier of the first session management network element, or the identifiers of other network elements, etc.). In one possible manner, the second session management network element receives the identifier of the first session management network element (for example, V-SMF ID, which is not limited in this application), and the second session management network element determines the identifier of the VPLMN based on the identifier of the first session management network element, that is, determines the VPLMN. In another possible manner, the second session management network element receives the identifier of the VPLMN from the first session management network element. In still another possible manner, the second session management network element receives a message from the first session management network element and determines the identifier of the VPLMN based on the message. Among them, the message may be an Nsmf_PDUSession_Create Request or an Nsmf_PDUSession_Update Request message, etc., which is not limited in this application.

[0195] It should be understood that Table 2 is only an exemplary illustration and is not limited thereto. Any variation belonging to Table 2 is applicable to this application. For example, the PLMN ID in Table 2 above may also be replaced by the SMF ID. For example, PLMN#1’ may be replaced by one or more SMF IDs (that is, the IDs of one or more SMFs corresponding to the PLMN’#1).

[0196] The above two manners are exemplary illustrations. Any manner that can enable the second session management network element to obtain the indication information #A is applicable to the embodiments of this application.

[0197] As a possible scenario, in step 410, the second session management network element obtaining the address information of the V-EASDF may include: the second session management network element obtaining the address information of the V-EASDF based on the indication information #A.

[0198] Specifically, if the second session management network element obtains the indication information #A and learns from the indication information #A that local traffic splitting of the VPLMN is allowed, the second session management network element obtains the address information of the V-EASDF based on the indication information #A. As a possible example, the H-SMF obtains the indication information #A and learns from the indication information #A that local traffic splitting of the VPLMN is allowed, then the H-SMF sends a request message #1 to the V-SMF based on the indication information #A and receives the address information of the V-EASDF from the V-SMF. Or, as another possible example, the H-SMF obtains the indication information #A and learns from the indication information #A that local traffic splitting of the VPLMN is allowed, then the H-SMF sends a request message #2 to the H-NRF based on the indication information #A and receives the address information of the V-EASDF from the H-NRF.

[0199] As another possible scenario, when the second session management network element sends the address information of the V-EASDF to the terminal device in step 420, it may include: the second session management network element sends the address information of the V-EASDF to the terminal device according to the indication information #A.

[0200] Specifically, if the second session management network element obtains the indication information #A and learns from the indication information #A that VPLMN local traffic splitting is allowed, the second session management network element sends the address information of the V-EASDF to the terminal device according to the indication information #A.

[0201] For ease of understanding, the following combines Figures 5 to 8 to give an exemplary illustration of the embodiments of the present application. In the following examples, it is assumed that the first session management network element is V-SMF, the second session management network element is H-SMF, the network storage network element is H-NRF, the policy control network element is H-PCF, and the indication information #A is an authorization policy. The specific steps involved can refer to the above description.

[0202] Figure 5 It is a schematic flowchart of a method 500 for information transmission provided by the embodiments of the present application. The method 500 can be used in a scenario where the V-SMF directly sends the address of the V-EASDF to the UE. The method 500 may include the following steps.

[0203] 501, the UE initiates a session establishment process.

[0204] In the HR roaming scenario, the UE may initiate an HR session establishment process. The present application does not limit the specific session establishment process. For example, it can be in the following manner: after the AMF receives the session establishment request from the UE, it selects the V-SMF and H-SMF that 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 that serve the HR session, create an N4 session, and send user plane tunnel information. If the session establishment is successful, the network side returns a session establishment response to the UE, and then packets can be transmitted through this HR session.

[0205] Specifically, reference can be made to sections such as 4.3.2.2.2 in 3GPP standard TS 23.502, or the session establishment methods that appear later. The present application does not limit this.

[0206] It should be understood that step 501 does not limit the execution of a complete HR session establishment process. Multiple steps after step 501 can reuse (or re-use) the HR session establishment process, or rather, multiple steps after step 501 can be executed in the HR session establishment process.

[0207] 502, The V-SMF sends a session establishment request message to the H-SMF.

[0208] In a possible implementation, reusing the HR session establishment process, the V-SMF sends a Nsmf interface PDU session establishment request (Nsmf_PDUSession_Create Request) message to the H-SMF.

[0209] It should be understood that the Nsmf_PDUSession_Create Request message is only for illustrative purposes and is not limited thereto.

[0210] 503, The H-PCF sends an authorization policy to the H-SMF.

[0211] This authorization policy is used to indicate that local breakout in the VPLMN is allowed. Regarding the authorization policy, refer to the description of indication information #A in the above method 300, which will not be elaborated here.

[0212] In a possible implementation, reusing the HR session establishment process, it is implemented through the session management (SM) policy association process. For example, the PDU session can be established or modified through SM signaling. During the process of establishing or modifying through the SM policy, the H-PCF sends the authorization policy to the H-SMF.

[0213] Specifically, a possible implementation is that after receiving the Nsmf_PDUSession_CreateRequest message, the H-SMF triggers the selection of the H-PCF. After the selection of the H-PCF is completed, it triggers the SM policy association establishment process (SM policy association establishment) or the SM policy association modification process (SM policy association modification). In the SM policy association establishment process, the H-SMF sends an Npcf interface PDU session SM policy control establishment request (Npcf_SMPolicyControl_Create Request) message to the H-PCF. This message may contain one or more of the following: the user permanent identifier (SUPI) or permanent equipment identifier (PEI) of the UE, the PDU session identifier, the data network name (DNN), the single network slice selection assistance information (S-NSSAI), the radio access technology (RAT) type, etc. After receiving this message, the H-PCF determines the authorization policy based on the local configuration or obtains the subscription information of the UE and / or the subscription information of the session from the UDR, etc., and sends it to the H-SMF through the Npcf interface PDU session SM policy control establishment response (Npcf_SMPolicyControl_CreateResponse) message. It can be understood that the above is only an exemplary description for easy understanding and is not limited thereto.

[0214] It should be noted that the H-SMF can configure the authorization policy locally. In this case, the H-PCF may not send the authorization policy to the H-SMF.

[0215] 504, the H-SMF selects the H-EASDF.

[0216] In the first possible scenario, if the authorization policy is used to indicate that local offloading in the VPLMN is allowed, the H-SMF selects the H-EASDF.

[0217] For the second possible scenario, if the authorization policy is used to indicate that local offloading in the VPLMN is allowed, the H-SMF does not select the H-EASDF. Since the H-SMF has received the authorization policy and learned from this policy that local offloading in the VPLMN is allowed, the H-EASDF may not be visible to the UE (i.e., the address of the H-EASDF may not be sent to the UE). Therefore, the action of selecting the H-EASDF can also be skipped (i.e., step 504 is not executed).

[0218] It can be understood that both of the above scenarios are possible. For example, the H-EASDF can be selected or not selected according to the internal logic or local configuration of the H-SMF, etc., and there is no restriction on this.

[0219] It should be understood that if the authorization policy is used to indicate that local offloading in the VPLMN is not allowed, the H-SMF can perform the selection of the H-EASDF and send the address information of the H-EASDF to the UE.

[0220] It can also be understood that for ease of description, Figure 5 only the first possible scenario is shown in [description], but the embodiments of the present application are not limited thereto.

[0221] 505. The H-SMF sends the authorization policy to the V-SMF.

[0222] 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 carries the authorization policy received in step 503 in this session establishment response message.

[0223] In a possible implementation, reusing the HR session establishment process, the H-SMF sends an Nsmf interface PDU session establishment response (Nsmf_PDUSession_Create Response) message to the V-SMF.

[0224] It should be understood that the Nsmf_PDUSession_Create Response message is only for illustrative purposes and is not limited thereto.

[0225] Optionally, if step 504 is executed, that is, the H-SMF selects the H-EASDF, the H-SMF can also send the address information of the H-EASDF to the V-SMF. The address information of the H-EASDF and the authorization policy can be carried in the same signaling, or can also be carried in two signaling, without limitation. In this way, in the case where the V-SMF fails to select the V-EASDF, it is still possible to send the address of the H-EASDF to the UE, thereby ensuring the provision of edge services for the UE and improving the user experience.

[0226] 506, The V-SMF selects the V-EASDF according to the authorization policy.

[0227] That is, in step 310 of the above method 300, when the first session management network element selects the V-EASDF, it may include: the first session management network element selects the V-EASDF according to the authorization policy.

[0228] After receiving the authorization policy, the V-SMF knows that local offloading of the VPLMN is allowed according to the authorization policy, so it can select the V-EASDF.

[0229] This application does not limit the specific manner in which the V-SMF selects the V-EASDF.

[0230] As an example, when the V-SMF selects the V-EASDF, it may refer to one or more of the following information: S-NSSAI, the location of the EASDF, DNAI. It can be understood that when the V-SMF selects the V-EASDF, it may refer to one or more of the above information, or it may also refer to other unlisted information, which is not limited in this application.

[0231] As an example, the V-SMF selects the V-EASDF, and can be implemented at least by any of the following methods.

[0232] One method is that the V-SMF can select the V-EASDF according to the local configuration.

[0233] Another method is that the V-SMF obtains the V-EASDF from the V-NRF. For example, the V-SMF sends a request message to the V-NRF, and the V-NRF returns information of one or more V-EASDFs (such as including address, identifier, etc.) to the V-SMF. If the V-NRF returns multiple V-EASDFs to the V-SMF, the V-SMF can select one of them.

[0234] It can be understood that the method for the V-SMF to select the V-EASDF can follow the method for the SMF to select the EASDF in the non-roaming scenario, or the method for the SMF to select the EASDF that appears later, which is not limited in this regard.

[0235] After the V-SMF completes the selection of the V-EASDF, it can also send security information to the V-EASDF so that the V-EASDF can securely process DNS messages. The specific timing is not limited. For example, the V-SMF can send the security information to the V-EASDF after step 506 and before step 507.

[0236] 507, The V-SMF sends the address of the V-EASDF to the UE.

[0237] That is, in step 320 of the above method 300, when the first session management network element sends the address information of the V-EASDF, it may include: the first session management network element sends the address information of the V-EASDF to the UE. Further, when the first session management network element sends the address information of the V-EASDF to the UE, it may further include: the first session management network element sends the address information of the V-EASDF to the UE according to the authorization policy.

[0238] In a 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 (N1 Message) to the UE through the AMF, and the N1 message includes an N1 SM container (container), and the address of the V-EASDF is carried in the N1 SM container. For example, the V-SMF sends the address of the V-EASDF to the AMF through the Namf_Communication_N1N2MessageTransfer message, and then the AMF sends the address of the V-EASDF to the UE through a 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.

[0239] 508. The UE sends a DNS query to the V-EASDF.

[0240] For example, the UE sends the DNS query to the V-EASDF through the user plane, via the RAN and the UPF.

[0241] 509. The V-EASDF reports the full qualified domain name (FQDN) included in the DNS query to the V-SMF.

[0242] After receiving the DNS query from the UE, the V-EASDF may cache the DNS query and report the FQDN included in the DNS query to the V-SMF.

[0243] The V-EASDF may report the FQDN according to the DNS processing rule received from the V-SMF. For example, the DNS processing rule includes an FQDN range. When the V-EASDF receives a DNS Query, if the FQDN included in the DNS Query matches the FQDN range in the DNS processing rule, then the V-EASDF sends this FQDN to the V-SMF, for example, through the Neasdf_DNSContext_Notify Request message.

[0244] It can be understood that the specific process of reporting the FQDN can refer to the existing process or the method of reporting the FQDN that appears in the future, and this is not restricted.

[0245] 510, the V-SMF sends an ECS option to the V-EASDF.

[0246] Among them, the ECS option can be used to represent the location information of the UE. After receiving the ECS option, the V-EASDF can add the ECS option to the DNS query.

[0247] This application mainly takes the ECS option as an example for illustrative purposes. This application is not limited thereto. For example, the ECS option can also be replaced by the local DNS (local DNS, L-DNS) server address.

[0248] After adding the ECS option to the DNS query, the V-EASDF sends the DNS query to the DNS server. Further, the DNS server can send a response (such as a DNS response) to the V-EASDF. This response can contain address information such as the EAS IP address or FQDN, etc. After receiving the DNS response, the V-EASDF can cache the DNS response and report the address information (such as the EAS IP address or FQDN) contained in the DNS response to the V-SMF. For ease of description, Figure 5 Take the EAS IP as an example for illustration.

[0249] 511, the V-EASDF reports the EAS IP address to the V-SMF.

[0250] The V-EASDF can report the EAS IP according to the DNS processing rules received from the V-SMF. For example, the DNS processing rules contain the EAS IP range. When the V-EASDF receives the DNS Response, if the EAS IP contained in the DNS Response matches the EAS IP range in the DNS processing rules, then the V-EASDF sends this EAS IP to the V-SMF, for example, it can be sent through the Neasdf_DNSContext_Notify Request message.

[0251] It can be understood that the specific process of reporting the EAS IP can refer to the existing process or the method of reporting the EAS IP that appears in the future, and this is not restricted.

[0252] 512, The V-SMF inserts an uplink classifier (UL CL) or a branchpoint (BP), and an L-PSA.

[0253] For example, the V-SMF can dynamically insert the UL CL or BP, and the L-PSA according to the received EAS IP address.

[0254] 513, The V-EASDF sends the cached DNS response to the UE.

[0255] In a possible implementation, the V-SMF sends indication information to the V-EASDF, and the indication information indicates that the V-EASDF sends the cached DNS response to the UE; after receiving the indication from the V-SMF, the V-EASDF sends the cached DNS response to the UE.

[0256] Based on the above method 500, when the V-SMF knows that the VPLMN is allowed to perform local traffic splitting according to the authorization policy, it selects the V-EASDF and directly sends the address of the V-EASDF to the UE, so as to realize the local traffic splitting of the VPLMN in the HR roaming scenario.

[0257] Figure 6 It is a schematic flowchart of another information transmission method 600 provided by an embodiment of the present application. The method 600 can be used in the scenario where the H-SMF sends the address of the V-EASDF to the UE. The method 600 may include the following steps.

[0258] 601, The UE initiates a session establishment process.

[0259] Among them, step 601 is similar to step 501 and will not be elaborated here.

[0260] 602, The H-PCF sends an authorization policy to the H-SMF.

[0261] Among them, step 602 is similar to step 503 and will not be elaborated here.

[0262] 603, The H-SMF sends request information #1 to the V-SMF.

[0263] Among them, the request information #1 is used to request (or obtain) the address of the V-EASDF. The implementation of the request information #1 is not limited. For example, the request information #1 can be an authorization policy, that is, the H-SMF sends an authorization policy to the V-SMF, and the authorization policy is used to obtain the address of the V-EASDF. For another example, the request information #1 can be implemented by one or more bits, and through the field of the one or more bits, it is used to request the address of the V-EASDF.

[0264] One possible implementation is that the H-SMF sends an Nsmf interface PDU session context request (Nsmf_PDUSession_Context Request) message to the V-SMF, and the request information #1 is carried in this message.

[0265] It should be understood that the Nsmf_PDUSession_Context Request message is only for illustrative purposes and is not limited thereto.

[0266] One possible scenario is that the H-SMF sends the request information #1 to the V-SMF, including: the H-SMF sends the request information #1 to the V-SMF according to the authorization policy. Specifically, if the authorization policy is used to indicate that local splitting of the VPLMN is allowed, the H-SMF sends the request information #1 to the V-SMF. In this scenario, in step 410 of the above method 400, the second session management network element obtaining the address information of the V-EASDF may include: the second session management network element obtaining the address information of the V-EASDF according to the authorization policy.

[0267] 604, the V-SMF sends the address of the V-EASDF to the H-SMF.

[0268] That is, in step 410 of the above method 400, the second session management network element obtaining the address information of the V-EASDF may include: the second session management network element receiving the address information of the V-EASDF from the V-SMF.

[0269] For example, the V-SMF selects the V-EASDF according to the request information #1 received in step 603 and returns the address of the V-EASDF to the H-SMF. Among them, the way for the V-SMF to select the V-EASDF can refer to the description of step 506 in method 500 and will not be elaborated here.

[0270] One possible implementation is that the V-SMF sends an Nsmf interface PDU session context response (Nsmf_PDUSession_Context Response) message to the H-SMF, and the address of the V-EASDF is carried in this message.

[0271] After the V-SMF completes the selection of the V-EASDF, it can also send security information to the V-EASDF to enable the V-EASDF to securely process DNS messages. The specific timing is not limited. For example, the V-SMF can send the security information to the V-EASDF after step 604 and before step 608.

[0272] 605, the V-SMF sends DNS processing rules to the V-EASDF.

[0273] Among them, the DNS processing rules may include, for example, the FQDN range of the VPLMN. The FQDN range may include: the FQDN range where the VPLMN deploys edge services, and / or, the FQDN range expected to be shunted in the VPLMN. When the V-EASDF receives a DNS query that matches this FQDN range, it reports to the V-SMF.

[0274] 606. The H-SMF uses the address of the V-EASDF as the DNS server address.

[0275] The H-SMF uses the address of the V-EASDF received in step 604 as the DNS server address and then sends it to the UE.

[0276] 607. The H-SMF sends the address of the V-EASDF to the V-SMF.

[0277] In method 600, the H-SMF can send the address of the V-EASDF to the UE through the V-SMF. That is, in step 420 of the above method 400, the second session management network element sending the address information of the V-EASDF to the terminal device may include: the second session management network element sending the address information of the V-EASDF to the terminal device through the V-SMF.

[0278] A possible implementation is to reuse the HR session establishment process. The H-SMF sends an Nsmf_PDUSession_Create Response message to the V-SMF, and the address of the V-EASDF is carried in the Nsmf_PDUSession_Create Response message.

[0279] It should be understood that the Nsmf_PDUSession_Create Response message is only for illustrative purposes and is not limited thereto.

[0280] 608. The V-SMF sends the address of the V-EASDF to the UE.

[0281] After receiving the address of the V-EASDF from the H-SMF, the V-SMF may not need to resolve it and directly forwards the address of the V-EASDF to the UE.

[0282] A possible implementation is that the V-SMF sends the address of the V-EASDF to the UE through the AMF. For example, the V-SMF sends an N1 SM container to the UE through the AMF, and the address of the V-EASDF is carried in the N1 SM container.

[0283] 609, The UE sends a DNS query to V-EASDF.

[0284] 610, V-EASDF reports the FQDN contained in the DNS query to V-SMF.

[0285] 611, V-SMF sends an ECS option to V-EASDF.

[0286] 612, V-EASDF reports the EAS IP address to V-SMF.

[0287] 613, V-SMF inserts UL CL / BP and L-PSA.

[0288] 614, V-EASDF sends the cached DNS response to the UE.

[0289] Among them, steps 609-614 are similar to steps 508-513, and will not be elaborated here.

[0290] Based on the above method 600, when the H-SMF learns from the authorization policy that the VPLMN is allowed to perform local traffic splitting, it requests the address of V-EASDF from the V-SMF and sends the address of V-EASDF to the UE, thereby realizing the local traffic splitting of the VPLMN in the HR roaming scenario.

[0291] Figure 7 It is a schematic flowchart of another information transmission method 700 provided by the embodiments of the present application. The method 700 can be used in the scenario where the H-SMF sends the address of V-EASDF to the UE. The method 700 may include the following steps.

[0292] 701, The UE initiates a session establishment process.

[0293] Among them, step 701 is similar to step 501, and will not be elaborated here.

[0294] 702, V-SMF selects V-EASDF.

[0295] Among them, the way for V-SMF to select V-EASDF can refer to the description of step 506 in method 500, and will not be elaborated here.

[0296] 703, V-SMF sends the address of V-EASDF to H-SMF.

[0297] That is, in step 410 of the above method 400, for the second session management network element to obtain the address information of V-EASDF, it may include: the second session management network element receives the address information of V-EASDF from the V-SMF.

[0298] One possible implementation is to reuse the HR session establishment process. The V-SMF sends an Nsmf_PDUSession_Create Request message to the H-SMF, and the address of the V-EASDF is carried in this message.

[0299] After the V-SMF completes the selection of the V-EASDF, it can send security information to the V-EASDF so that the V-EASDF can process DNS messages securely. The specific timing is not limited. For example, the V-SMF can send security information to the V-EASDF after step 702 and before step 707.

[0300] 704. The H-PCF sends an authorization policy to the H-SMF.

[0301] This authorization policy is used to indicate that local offloading in the VPLMN is allowed.

[0302] This step 704 is similar to step 503 and will not be elaborated here.

[0303] 705. The H-SMF does not perform H-EASDF selection.

[0304] Since the H-SMF receives the address of the V-EASDF in step 703 and knows from the authorization policy received in step 704 that local offloading in the VPLMN is allowed, the H-SMF can send the address of the V-EASDF to the UE as the address of the DNS server, so there is no need to select the H-EASDF.

[0305] 706. The H-SMF sends the address of the V-EASDF to the V-SMF.

[0306] In method 700, the H-SMF can send the address of the V-EASDF to the UE through the V-SMF. That is, in step 420 of the above method 400, when the second session management network element sends the address information of the V-EASDF to the terminal device, it can include: the second session management network element sends the address information of the V-EASDF to the terminal device through the V-SMF.

[0307] In addition, when the H-SMF sends the address of the V-EASDF to the V-SMF, it can include: the H-SMF sends the address of the V-EASDF to the V-SMF according to the authorization policy. Specifically, if the authorization policy is used to indicate that local offloading in the VPLMN is allowed, the H-SMF can send the address of the V-EASDF to the UE through the V-SMF. That is, in step 420 of the above method 400, when the second session management network element sends the address information of the V-EASDF to the terminal device, it can include: the second session management network element sends the address information of the V-EASDF to the terminal device according to the authorization policy.

[0308] 707, The V-SMF sends the address of the V-EASDF to the UE.

[0309] Among them, step 707 is similar to step 608 and will not be elaborated here.

[0310] 708, The UE sends a DNS query to the V-EASDF.

[0311] 709, The V-EASDF reports the FQDN included in the DNS query to the V-SMF.

[0312] 710, The V-SMF sends an ECS option to the V-EASDF.

[0313] 711, The V-EASDF reports the EAS IP address to the V-SMF.

[0314] 712, The V-SMF inserts UL CL / BP and L-PSA.

[0315] 713, The V-EASDF sends the cached DNS response to the UE.

[0316] Among them, steps 708 - 713 are similar to steps 508 - 513 and will not be elaborated here.

[0317] Based on the above method 700, the V-SMF sends the address of the V-EASDF to the H-SMF, and the H-SMF sends the address of the V-EASDF to the UE as the DNS server address, thereby realizing local traffic splitting of the VPLMN in the HR roaming scenario.

[0318] Figure 8 It is a schematic flowchart of another information transmission method 800 provided by an embodiment of the present application. The method 800 can be used in the scenario where the H-SMF sends the address of the V-EASDF to the UE. The method 800 may include the following steps.

[0319] 801, The UE initiates a session establishment process.

[0320] Among them, step 801 is similar to step 501 and will not be elaborated here.

[0321] 802, The H-PCF sends an authorization policy to the H-SMF.

[0322] This authorization policy is used to indicate that local traffic splitting of the VPLMN is allowed.

[0323] This step 802 is similar to step 503 and will not be elaborated here.

[0324] 803, The H-SMF sends request message #2 to the H-NRF.

[0325] Among them, the request message #2 is used to request (or obtain) the address of the V-EASDF. There is no restriction on the form of the request message #2. For example, the request message #2 can be implemented by one or more bits, and through the field of the one or more bits, it is used to request the address of the V-EASDF.

[0326] In the first possible case, after receiving the request message #2, the H-NRF can determine the address of the V-EASDF according to the local configuration. In this case, the H-NRF directly sends a response to the request message #2 to the H-SMF, and the address of the V-EASDF is carried in the response. That is, steps 804-805 may not be executed.

[0327] In the second possible case, after receiving the request message #2, the H-NRF can receive the address of the V-EASDF from the V-NRF. In this case, method 800 may include steps 804-805.

[0328] 804, The H-NRF sends request message #3 to the V-NRF.

[0329] Among them, the request message #3 is used to request (or obtain) the address of the V-EASDF. There is no restriction on the form of the request message #3. For example, the request message #3 can be implemented by one or more bits, and through the field of the one or more bits, it is used to request the address of the V-EASDF.

[0330] 805, The V-NRF sends the address of the V-EASDF to the H-NRF.

[0331] In the first possible case, if the address of the V-EASDF is stored in the V-NRF, the V-NRF sends the address of the V-EASDF to the H-NRF according to the request of the H-NRF.

[0332] In the second possible case, if the address of the V-EASDF is not stored in the V-NRF, the V-NRF can request the address of the V-EASDF from the V-SMF; the V-SMF selects the V-EASDF according to the request and returns the address of the V-EASDF to the V-NRF; after receiving the address of the V-EASDF, the V-NRF sends the address of the V-EASDF to the H-NRF.

[0333] Furthermore, the H-NRF sends the address of the V-EASDF to the H-SMF. That is, in step 410 of the above method 400, the second session management network element obtains the address information of the V-EASDF, including: the second session management network element receives the address information of the V-EASDF from the H-NRF.

[0334] 806, The H-NRF sends the address of V-EASDF to the H-SMF.

[0335] In the first possible case, if in step 803, the H-NRF determines the address of V-EASDF according to the local configuration, then the address of V-EASDF sent by the H-NRF to the H-SMF in step 806 is: the address of V-EASDF determined by the H-NRF according to the local configuration in step 803.

[0336] In the second possible case, if steps 804 - 805 are executed, then the address of V-EASDF sent by the H-NRF to the H-SMF in step 806 is: the address of V-EASDF received by the H-NRF from the V-NRF in step 805.

[0337] In the third possible case, if in step 803, the H-NRF has the address of V-EASDF configured locally and steps 804 - 805 are executed, that is, the H-NRF has received the address of V-EASDF from the V-NRF, then the address of V-EASDF sent by the H-NRF to the H-SMF in step 806 can be the locally configured one or the received one. For example, in this case, the address of V-EASDF sent by the H-NRF to the H-SMF in step 806 can be: the address of V-EASDF received by the H-NRF from the V-NRF.

[0338] 807, The V-SMF sends the DNS processing rule to the V-EASDF.

[0339] 808, The H-SMF takes the address of V-EASDF as the DNS server address.

[0340] 809, The H-SMF sends the address of V-EASDF to the V-SMF.

[0341] 810, The V-SMF sends the address of V-EASDF to the UE.

[0342] After receiving the address of V-EASDF from the H-SMF, the V-SMF may not need to resolve it and directly forwards the address of V-EASDF to the UE.

[0343] One possible implementation is that the V-SMF sends the address of V-EASDF to the UE through the AMF. For example, the V-SMF sends an N1 SM container to the UE through the AMF, and the address of V-EASDF is carried in the N1 SM container.

[0344] 811, The UE sends a DNS query to the V-EASDF.

[0345] 812, V-EASDF reports the FQDN included in the DNS query to V-SMF.

[0346] 813, V-SMF sends the ECS option to V-EASDF.

[0347] 814, V-EASDF reports the EAS IP address to V-SMF.

[0348] 815, V-SMF inserts UL CL / BP and L-PSA.

[0349] 816, V-EASDF sends the cached DNS response to the UE.

[0350] Among them, steps 807 - 816 are similar to steps 605 - 614, and will not be elaborated here.

[0351] Based on method 800, H-SMF requests the address of V-EASDF from H-NRF according to the authorization policy. H-NRF requests the address of V-EASDF from V-NRF, and after obtaining the address of V-EASDF, sends the address of V-EASDF to H-SMF, and then H-SMF sends the address of V-EASDF to the UE, thereby realizing the local traffic splitting of the VPLMN in the HR roaming scenario.

[0352] It can be understood that in the embodiments of the present application Figures 5 to 8 The examples in are only for facilitating 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 illustrated specific scenarios. Those skilled in the art can clearly make various equivalent modifications or changes according to Figures 5 to 8 the examples, and such modifications or changes also fall within the scope of the embodiments of the present application. For example, the session establishment process in the above Figures 5 to 8 can also be replaced by a session modification process. Another example is that the ECS option in the above Figures 5 to 8 can also be replaced by the L-DNS server address.

[0353] It can also be understood that in some of the above embodiments, the message names involved, such as the 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.

[0354] It can also be understood that, from an architectural perspective, V-EASDF can be co-located with V-UPF. In this deployment scenario, the VPLMN only needs to obtain an authorization policy that allows the VPLMN to perform local traffic splitting. At this time, the V-UPF splits some DNS queries to the L-DNS for processing, and the rest are split to the HPLMN. Alternatively, V-EASDF can also be separately set up with the V-UPF. In this deployment scenario, local traffic splitting can be performed in the VPLMN through the above embodiments.

[0355] It can also be understood that some optional features in the embodiments of the present application can, in some scenarios, be independent of other features, and in some scenarios, can be combined with other features, without limitation.

[0356] It can also be understood that the solutions in the embodiments of the present application can be reasonably combined and used, and the explanations or descriptions of the various terms that appear in the embodiments can be referred to or explained with each other in the various embodiments, without limitation.

[0357] It can also be understood that the magnitudes of the various numerical serial numbers in the embodiments of the present application do not imply the order of execution, but are only for the convenience of description for distinction, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0358] It can also be understood that in the embodiments of the present application, some message names are involved, and their naming does not limit the protection scope of the embodiments of the present application.

[0359] It can also be understood that in the above method embodiments, the methods and operations implemented by the device can also be implemented by the components (such as chips or circuits) that make up the device.

[0360] Corresponding to the methods given in the above method embodiments, the embodiments of the present application also provide corresponding devices, and the devices include modules for executing the corresponding ones of the above method embodiments. The module can be software, hardware, or a combination of software and hardware. It can be understood that the technical features described in the above method embodiments also apply to the following device embodiments.

[0361] Figure 9 It is a schematic block diagram of a device for switching transmission modes provided by an embodiment of the present application. The device 900 includes a transceiver unit 910 and a processing unit 920. The transceiver unit 910 can be used to implement corresponding communication functions. The transceiver unit 910 can also be referred to as a communication interface or a communication unit. The processing unit 920 can be used to implement corresponding processing functions, such as selecting an edge application server discovery network element.

[0362] Optionally, the apparatus 900 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 920 can read the instructions and / or data in the storage unit to enable the apparatus to implement the actions of the device or network element in the foregoing method embodiments.

[0363] In a first design, the apparatus 900 can be the first session management network element in the foregoing embodiments, or a component (such as a chip) of the first session management network element. The apparatus 900 can implement the steps or processes corresponding to the first session management network element in the foregoing method embodiments. Among them, the transceiver unit 910 can be used to perform the operations related to the transceiver of the first session management network element in the foregoing method embodiments, and the processing unit 920 can be used to perform the operations related to the processing of the first session management network element in the foregoing method embodiments.

[0364] In a possible implementation, the processing unit 920 is configured to select an edge application server discovery network element. The first session management network element and the edge application server discovery network element are network elements deployed in the visited network; the transceiver unit 910 is configured to send the address information of the edge application server discovery network element.

[0365] Exemplarily, the processing unit 920 is configured to select an edge application server discovery network element according to indication information, where the indication information indicates that the visited network is allowed to perform traffic splitting.

[0366] Optionally, the transceiver unit 910 is further configured to: receive indication information from a second session management network element, where the second session management network element is a network element deployed in the home network.

[0367] Optionally, the first session management network element locally configures the indication information.

[0368] Optionally, the transceiver unit 910 is further configured to: send the address information of the edge application server discovery network element to a terminal device.

[0369] Exemplarily, the transceiver unit 910 is configured to: send the address information of the edge application server discovery network element to a second session management network element, where the second session management network element is a network element deployed in the home network.

[0370] Optionally, the transceiver unit 910 is further configured to: receive request information from a second session management network element, where the request information is used to request the address of the edge application server discovery network element, and the second session management network element is a network element deployed in the home network; the processing unit 920 is configured to, in response to the request information, the first session management network element selects an edge application server discovery network element.

[0371] In the second design, the device 900 may be the second session management network element in the foregoing embodiments, or a component (such as a chip) of the second session management network element. The device 900 can implement the steps or processes corresponding to those executed by the second session management network element in the foregoing method embodiments. Among them, the transceiver unit 910 is used to execute the operations related to the transceiver of the second session management network element in the foregoing method embodiments, and the processing unit 920 is used to execute the operations related to the processing of the second session management network element in the foregoing method embodiments.

[0372] In a possible implementation, the transceiver unit 910 is used to obtain the address information of the edge application server discovery network element; send the address information of the edge application server discovery network element to the terminal device; wherein, the edge application server discovery network element is a network element deployed in the visited network, and the second session management network element is a network element deployed in the home network.

[0373] Exemplarily, the transceiver unit 910 is used to receive the address information of the edge application server discovery network element from the first session management network element, and the first session management network element is a network element deployed in the visited network.

[0374] Exemplarily, the transceiver unit 910 is used to send a first request message to the first session management network element, and the first request message is used to request the address of the edge application server discovery network element.

[0375] Optionally, the transceiver unit 910 is further used to send a second request message to the network storage network element. The second request message includes the identifier of the visited network, and the second request message is used to request the address of the edge application server discovery network element. The network storage network element is a network element deployed in the home network; the transceiver unit 910 is used to receive the address information of the edge application server discovery network element from the network storage network element.

[0376] Optionally, the transceiver unit 910 is further used to obtain indication information indicating that the visited network is allowed to perform traffic splitting; the transceiver unit 910 is used to obtain the address information of the edge application server discovery network element according to the indication information.

[0377] Optionally, the transceiver unit 910 is further used to obtain indication information indicating that the visited network is allowed to perform traffic splitting; the transceiver unit 910 is used to send the address information of the edge application server discovery network element to the terminal device according to the indication information.

[0378] Optionally, the transceiver unit 910 is further used to send indication information to the first session management network element.

[0379] Optionally, the transceiver unit 910 is further used to receive indication information from the policy control network element, wherein the policy control network element is a network element deployed in the home network.

[0380] Exemplarily, the second session management network element local configuration indication information.

[0381] It should be understood that the specific processes of each unit performing the corresponding steps above have been described in detail in the above method embodiments. For the sake of brevity, they will not be repeated here.

[0382] It should also be understood that the apparatus 900 here is embodied in the form of functional units. 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 of processors, etc.) for executing one or more software or firmware programs, a memory, a combined logic circuit, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art can understand that the apparatus 900 can specifically be the first session management network element in the above embodiments, and can be used to execute each process and / or step corresponding to the first session management network element in the above method embodiments. Or, the apparatus 900 can specifically be the second session management network element in the above embodiments, and can be used to execute each process and / or step corresponding to the second session management network element in the above method embodiments. For the sake of avoiding repetition, they will not be repeated here.

[0383] The apparatus 900 of each of the above solutions has the function of implementing the corresponding steps executed by the core network element (such as the first session management network element or the second session management network element) in the above method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above 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, respectively performing the transceiver operations and related processing operations in each method embodiment.

[0384] In addition, the above transceiver unit 910 can also be a transceiver circuit (for example, it can include a receiving circuit and a sending circuit), and the processing unit can be a processing circuit.

[0385] It should be noted that Figure 9 the apparatus in can be the network element or device in the foregoing embodiments, or can be a chip or a chip system, for example: a system on chip (SoC). Among them, the transceiver unit can be an input / output circuit, a communication interface; the processing unit is a processor, a microprocessor, or an integrated circuit integrated on the chip. There is no limitation here.

[0386] Such as Figure 10As shown in the figure, an embodiment of the present application provides another information transmission device 1000. The device 1000 includes a processor 1010, and the processor 1010 is used to execute the computer programs or instructions stored in the memory 1020, or read the data / signaling stored in the memory 1020 to execute the methods in the above method embodiments. Optionally, the processor 1010 is one or more.

[0387] Optionally, as Figure 10 shown in the figure, the device 1000 further includes a memory 1020, and the memory 1020 is used to store computer programs or instructions and / or data. The memory 1020 can be integrated with the processor 1010 or can be separately provided. Optionally, the memory 1020 is one or more.

[0388] Optionally, as Figure 10 shown in the figure, the device 1000 further includes a transceiver 1030, and the transceiver 1030 is used for receiving and / or sending signals. For example, the processor 1010 is used to control the transceiver 1030 to receive and / or send signals.

[0389] As a solution, the device 1000 is used to implement the operations performed by the core network element in the above method embodiments.

[0390] For example, the processor 1010 is used to execute the computer programs or instructions stored in the memory 1020 to implement the related operations of the first session management network element in the above method embodiments. For example, Figure 3 or Figure 4 the method performed by the first session management network element in the shown embodiment, or Figures 5 to 8 the method performed by the V-SMF in any one of the shown embodiments.

[0391] Another example is that the processor 1010 is used to execute the computer programs or instructions stored in the memory 1020 to implement the related operations of the second session management network element in the above method embodiments. For example, Figure 3 or Figure 4 the method performed by the second session management network element in the shown embodiment, or Figures 5 to 8 the method performed by the H-SMF in any one of the shown embodiments.

[0392] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0393] 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 ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, the RAM may be used as an external cache. By way of example and not limitation, the RAM includes the following various forms: static random access memory (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0394] 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) may be integrated in the processor.

[0395] It should also be noted that the memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.

[0396] The embodiments of the present application also provide a computer-readable storage medium, on which computer instructions for implementing the methods executed by the core network elements in the above method embodiments are stored.

[0397] For example, when the computer program is executed by a computer, the computer can implement the methods executed by the first session management network element or the second session management network element in the above method embodiments.

[0398] The embodiments of the present application also provide a computer program product, including instructions, which when executed by a computer, implement the methods executed by the core network elements in the above method embodiments.

[0399] The embodiments of the present application also provide a system for information transmission, including one or more of the foregoing first session management network element, second session management network element, network storage network element, and policy control network element.

[0400] For the explanations and beneficial effects of the relevant content in any of the above-mentioned devices, reference can be made to the corresponding method embodiments provided above, and details will not be repeated here.

[0401] In several embodiments provided by the present 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 merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0402] 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 processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. 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. 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 wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD), etc.). For example, the foregoing available media include, but are not limited to: USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs, etc., which can store program codes of various kinds.

[0403] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for information transmission, characterized in that, It includes: The first session management network element selects an edge application server discovery network element, and the first session management network element and the edge application server discovery network element are network elements deployed in the visited network; The first session management network element sends the address information of the edge application server discovery network element; Among them, the first session management network element sending the address information of the edge application server discovery network element includes: The first session management network element sends the address information of the edge application server discovery network element to the second session management network element, and the second session management network element is a network element deployed in the home network.

2. The method according to claim 1, wherein The first session management network element selecting the edge application server discovery network element includes: The first session management network element selects the edge application server discovery network element according to the indication information, where the indication information indicates that the visited network is allowed to perform traffic splitting.

3. The method according to claim 2, wherein The method further includes: The first session management network element receives the indication information from the second session management network element, and the second session management network element is a network element deployed in the home network; or The first session management network element locally configures the indication information.

4. The method according to any one of claims 1 to 3, characterized in that, The first session management network element sending the address information of the edge application server discovery network element includes: The first session management network element sends the address information of the edge application server discovery network element to the terminal device.

5. The method according to any one of claims 1 to 3, characterized in that, The method further includes: The first session management network element receives request information from the second session management network element, and the request information is used to request the address of the edge application server discovery network element, and the second session management network element is a network element deployed in the home network; The first session management network element selecting the edge application server discovery network element includes: In response to the request information, the first session management network element selects the edge application server discovery network element.

6. A method for information transmission, characterized in that, It includes: The second session management network element obtains the address information of the edge application server discovery network element; The second session management network element sends the address information of the edge application server discovery network element to the terminal device; Among them, the edge application server discovery network element is a network element deployed in the visited network, and the second session management network element is a network element deployed in the home network; the second session management network element obtaining the address information of the edge application server discovery network element includes: The second session management network element receives the address information of the edge application server discovery network element from the first session management network element, and the first session management network element is a network element deployed in the visited network.

7. The method according to claim 6, wherein The second session management network element sends first request information to the first session management network element, and the first request information is used to request the address of the edge application server discovery network element.

8. The method according to claim 6, characterized in that, The method further includes: The second session management network element sends second request information to the network storage network element, and the second request information includes the identifier of the visited network, and the second request information is used to request the address of the edge application server discovery network element, and the network storage network element is a network element deployed in the home network; The second session management network element obtains the address information of the edge application server discovery network element, including: The second session management network element receives the address information of the edge application server discovery network element from the network storage network element.

9. The method according to any one of claims 6 to 8, characterized in that, The method further includes: The second session management network element obtains indication information indicating that the visited network is allowed to perform traffic splitting. The second session management network element obtains the address information of the edge application server discovery network element, including: The second session management network element obtains the address information of the edge application server discovery network element according to the indication information.

10. The method according to any one of claims 6 to 8, characterized in that The method further includes: The second session management network element obtains indication information indicating that the visited network is allowed to perform traffic splitting. The second session management network element sends the address information of the edge application server discovery network element to the terminal device, including: The second session management network element sends the address information of the edge application server discovery network element to the terminal device according to the indication information.

11. The method according to claim 9, characterized in that The method further includes: The second session management network element sends the indication information to the first session management network element.

12. The method according to claim 10, wherein The method further includes: The second session management network element sends the indication information to the first session management network element.

13. The method according to claim 11 or 12, characterized in that, The method further includes: The second session management network element receives the indication information from the policy control network element, where the policy control network element is a network element deployed in the home network; or The second session management network element locally configures the indication information.

14. An information transmission device, characterized in that, The device includes: a unit for executing the method according to any one of claims 1 to 5, or a unit for executing the method according to any one of claims 6 to 13.

15. An information transmission device, characterized in that, Including: A processor for executing a computer program stored in a memory, so that the device executes the method according to any one of claims 1 to 5, or so that the device executes the method according to any one of claims 6 to 13.

16. The device according to claim 15, characterized in that, The device further includes the memory.

17. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium. When the computer program runs on a computer, the computer is caused to execute the method according to any one of claims 1 to 5, or the computer is caused to execute the method according to any one of claims 6 to 13.

18. A computer program product, characterized in that, The computer program product includes instructions for executing the method according to any one of claims 1 to 5, or the computer program product includes instructions for executing the method according to any one of claims 6 to 13.

19. A system for information transmission, characterized in that, Including a first session management network element and a second session management network element; The first session management network element is used to execute the method according to any one of claims 1 to 5; The second session management network element is used to execute the method according to any one of claims 6 to 13.

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