Communication method and apparatus

Abstract

The application discloses a communication method and device, the method comprises the following steps: a first session management function (SMF) in a first network receives a first session establishment request sent by a terminal device through an access network device, the request is used for requesting to establish a session connection related to the terminal device; in the case that the terminal device requests to perform a first service of a second network, the first SMF establishes a session connection between a first user plane function (UPF) and a first communication device in the second network, and a session connection between the first UPF and the access network device. The first service is within the service range of the second network, the first communication device is a device connected with a server of the first service in the second network, and the service range of the first network includes the service range of the second network. The method of the embodiment of the application takes the first communication device in the second network as the session anchor point of the terminal device in the case that the terminal device accesses the first network to perform the service of the second network, and can guarantee the security of service data.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0002] Existing standards define non-public networks (NPNs), which third-party service providers can deploy to provide services to terminals. There are two deployment methods for NPNs: standalone non-public networks (SNPNs) and public network integrated-non-public networks (PNI-NPNs). SNPNs require the deployment of independent core network equipment, resulting in higher operation and maintenance costs. PNI-NPNs do not require additional core network deployment; specific resources are isolated and dedicated to PNI-NPNs within the operator's public network core network. However, this deployment method relies on the operator's core network, making it difficult for enterprises to achieve autonomous management of the NPN. Therefore, in future network evolution, a distributed subnet deployment method is proposed. Distributed subnet deployments only deploy a subset of functional network elements as needed, with other undeployed network elements provided by the main network core network. This saves on core network operation and maintenance costs, and because the main network core network is deployed locally, it can be autonomously managed by the enterprise, thus enabling agile deployment of subnet network functions (NFs).

[0003] In some cases, such as when a terminal device is about to perform a subnet service, but the terminal device is located both within the coverage area of ​​the main network and outside the coverage area of ​​the subnet, it can only access the network through the main network. In this situation, if the session management function (SMF) and user plane function (UPF) of the main network are used as the session anchor point for the terminal device, the privacy and security of the subnet service data may not be guaranteed. Summary of the Invention

[0004] This application provides a communication method and apparatus. When a terminal device requests to establish a session connection for a first service in a second network, it accesses the first network but uses a first communication device in the second network as a session anchor point, so that the terminal device can ensure data security when performing the first service.

[0005] In a first aspect, this application provides a communication method applied to a first session management function (SMF), the first SMF being located in a first network. The method includes: receiving a first session establishment request sent by a terminal device through an access network device, the first session establishment request being used to request the establishment of a session connection related to the terminal device, the first session establishment request including service information of the terminal device; if it is determined from the service information that the terminal device requests to execute a first service, establishing a session connection between a first user plane function (UPF) and a first communication device, the first UPF being located in the first network, the first service being within the service range of a second network, the first communication device being a device in the second network connected to a server of the first service, the service range of the first network including the service range of the second network; and establishing a session connection between the first UPF and the access network device.

[0006] The terminal device sends a first session establishment request to the first SMF, i.e., the terminal device requests access to the first network. Currently, the terminal device is within the coverage area of ​​the first network. A connection is established between the first UPF and the first communication device, i.e., a connection is established between the first network and the second network. The first communication device connects to the server of the first service, i.e., the first communication device acts as the session anchor point for the terminal device. Finally, a user plane connection is established between the first UPF and the access network equipment, completing the connection establishment between the terminal device and the first network.

[0007] Based on the above embodiments, the terminal device requests to establish a session connection for a first service from the first network. After receiving the first session establishment request from the terminal device, the first SMF in the first network determines the service range of the first service in the second network. The service range includes the coverage area and the service type. Therefore, when establishing the session connection corresponding to the first service, a connection is established between the terminal device and the first UPF in the first network, and then a connection is established between the first UPF and the first communication device. This allows the terminal device to access the first network, while the first communication device in the second network serves as the session anchor point for the terminal device to transmit service data with the server of the first service, ensuring data security during the execution of the first service.

[0008] In one feasible implementation, before establishing a session connection between the first user plane function and the first communication device, the method further includes: sending a first request to the first user plane function and receiving a first response from the first user plane function, wherein the first request is used to request the establishment of a session connection between the first session management function and the first user plane function, and the first response indicates that the session connection between the first session management function and the first user plane function has been established.

[0009] Establish the connection between the first SMF and the first UPF, that is, complete the control plane connection in the first network.

[0010] In one feasible implementation, the first communication device is a second UPF. Establishing a session connection between the first UPF and the first communication device includes: sending a second request to a second SMF, the second request being used to request the establishment of a session connection between the first UPF and the second UPF corresponding to the second SMF; receiving a second response from the second SMF, the second response including the core network tunnel information of the second UPF; sending a first modification request to the first UPF, the first modification request being used to request the addition of the core network tunnel information of the second UPF to the session connection of the first UPF; and receiving a first modification response from the first UPF, the first modification response indicating that the addition of the core network tunnel information of the second UPF is complete.

[0011] In this process, the first SMF establishes a connection between the second SMF and the second UPF through the second SMF, thus completing the control plane connection in the second network. Then, a connection is established between the second UPF and the first UPF, realizing the connection between the first network and the second network.

[0012] In one feasible implementation, before sending the second request to the second SMF, the method further includes: sending a third request to a first network storage function (NRF) for requesting the identification of the second SMF, the third request including an identifier of the second network, the second SMF being located in the second network; and receiving a third response from the first NRF, the third response including information about the second SMF.

[0013] The first SMF first determines the second network corresponding to the first service for which the terminal device requests to establish a session connection, and then queries the address of the second SMF in the second network from the first NRF to determine the second SMF.

[0014] In one feasible implementation, the first communication device is a proxy device, and establishing a session connection between the first UPF and the first communication device includes: sending a fifth request to the second signaling routing function (SRF) in the second network, the fifth request being used to request the establishment of a session connection between the first UPF and the proxy device, the fifth request including the core network tunnel information of the first UPF; and receiving a fifth response, the fifth response indicating that the session connection between the first UPF and the proxy device has been established.

[0015] In this process, the core network information of the first UPF is added to the session connection of the agent device, thus completing the connection between the first network and the second network.

[0016] In one feasible implementation, the fifth request also includes routing information for a proxy management function in the second network, the routing information for which the proxy management function is used to address the proxy management function, and the proxy management function is used to determine the proxy device.

[0017] In one feasible implementation, the agent management function is a policy control function (PCF) or a network element that includes an agent management function (PCF).

[0018] In one feasible implementation, the service information is used to instruct the terminal device to request the execution of a first service; or the service information indicates a target service identifier. The method further includes: sending a first query request to a data management function (UDM) in a first network, the first query request being used to request the acquisition of the terminal device's network service list; receiving a first query response from the UDM, the first query response including the terminal device's network service list, the network service list including the correspondence between multiple service identifiers and multiple networks, the multiple service identifiers including a target service identifier; and determining that the terminal device requests the execution of the first service based on the target service identifier and the network service list.

[0019] In some cases, the service information sent by the terminal device cannot directly determine whether the service belongs to the second network (i.e., the first service). Therefore, it is necessary to query the network service list from the UDM and determine whether it is the first service based on the correspondence between the target service identifier and the network.

[0020] In one feasible implementation, the subscription data also includes area information of the second network. Before establishing a session connection between the first UPF and the first communication device, the method further includes: determining that the terminal device will pass through the coverage area of ​​the second network in the process of acquiring the first service data.

[0021] In some cases, if the terminal device will pass through the coverage area of ​​the second network while obtaining the first service data, the terminal device's connection can be completely switched to the second network. This can ensure the sustainability and reliability of using the first communication device in the second network as the session anchor point for the terminal device to perform the first service.

[0022] In one feasible implementation, the first communication device is a second UPF, and the method further includes: receiving a first release request from a second SMF, the first release request being used to request the release of the session connection between the first SMF and the first UPF; sending a second release request to the first UPF and receiving a second release response from the first UPF, the second release request being used to request the release of the session connection between the first UPF and the first SMF, the second release response indicating that the connection release between the first UPF and the first SMF has been completed; and sending a first release response to the second SMF, the first release response indicating that the connection release between the first UPF and the first SMF has been completed.

[0023] As described above, during the execution of the first service, the terminal device may move from the coverage area of ​​the first network (outside the coverage area of ​​the second network) to the coverage area of ​​the second network. At this time, the terminal device can connect to the second network and release the connection to the first network. Specifically, this includes releasing the connection between the first UPF and the first communication device, the connection between the first UPF and the RAN, and the connection between the first UPF and the first SMF in the first network. The connection between the first UPF and the first communication device can be executed through the first communication device; the connection between the first UPF and the RAN can be triggered when establishing the connection between the second UPF and the RAN; and the release of the connection between the first UPF and the first SMF can be executed by notifying the first SMF.

[0024] In one feasible implementation, establishing a session connection between a first UPF and an access network device includes: sending a second session establishment request to the access network device, the second session establishment request being used to request the establishment of a session connection between the first UPF and the access network device; receiving a second session establishment response from the access network device, the second session establishment response indicating that the session connection between the first UPF and the access network device has been established, the second session establishment response including access network tunnel information of the access network device; sending a second modification request to the first UPF, the second modification request being used to request the addition of the access network tunnel information of the access network device to the session connection of the first UPF; and receiving a second modification response from the first UPF, the second modification response indicating that the addition of the access network tunnel information has been completed.

[0025] The first SMF establishes a session connection between the first UPF and the access network device, which mainly includes the access network device adding the CN tunnel information of the first UPF to its own connection, and the first UPF adding the AN tunnel information of the access network device to its own connection.

[0026] In this embodiment, the terminal device requests a session connection for a first service from the first network. After receiving the first session establishment request from the terminal device, the first SMF in the first network determines that the first service is within the service range of the second network, thus the server of the first service has a closer communication distance with the second network. Therefore, when establishing the session connection corresponding to the first service, a connection is established between the terminal device and the first UPF in the first network, and then a connection is established between the first UPF and the first communication device, enabling the terminal device to access the first network. By using the first communication device in the second network as the session anchor point for the terminal device to transmit service data with the server of the first service, lower communication latency can be ensured between the network elements in the network and the server of the first service.

[0027] Secondly, this application provides a communication method applied to a second SMF located in a second network. The method includes: receiving a first handover request sent by a terminal device through an access network device. The first handover request is used to request the handover of a session connection related to the terminal device to the second network. The first handover request is sent by the terminal device when it is within the coverage area of ​​the second network. The established session connections related to the terminal device include a session connection between a first UPF and a first communication device in the first network, and a session connection between the first UPF and the access network device. The first communication device is a device connected to a server of a first service in the second network. In the session connections related to the terminal device, modifying or establishing a core network connection of the second UPF located in the second network; establishing a session connection between the second UPF and the access network device, and releasing the session connection between the first UPF and the access network device.

[0028] During the above process, when a terminal device enters the coverage area of ​​the second network, it may request to switch the session to the second network. Based on this, the second SMF in the second network modifies or establishes a core network connection for the second UPF. If the terminal device's session connection does not include the second UPF, a core network connection for the second UPF is established, i.e., a connection is established between the second UPF and the second SMF. If the terminal device's session connection already includes the second UPF, since the second UPF is accessed through the first UPF, the core network connection for the second UPF is modified, i.e., the connection between the first UPF and the second UPF is released, and the second UPF is connected to the second SMF.

[0029] In one feasible implementation, the method further includes: triggering the release of the connection between the first UPF and the first SMF, the first SMF being located in the first network.

[0030] In one feasible implementation, triggering the release of the connection between the first UPF and the first SMF includes: sending a first release request to the first SMF, the first release request being used to request the release of the connection between the first SMF and the first UPF; and receiving a first release response from the first SMF, the first release response indicating that the release of the connection between the first SMF and the first UPF has been completed.

[0031] After determining that the terminal device's session connection has switched to the second network, the second SMF can trigger the release of the connection between the first UPF and the first SMF, that is, notify the first SMF to release the connection with the first UPF.

[0032] In one feasible implementation, establishing a session connection between the second UPF and the access network device, and releasing the session connection between the first UPF and the access network device, includes: sending a seventh request to the access network device, the seventh request being used to request the establishment of a session connection between the second UPF and the access network device, the seventh request including core network tunnel information of the second UPF; receiving a sixth response from the access network device, the sixth response indicating that the session connection between the second UPF and the access network device has been established and the session connection between the first UPF and the access network device has been released.

[0033] This process involves establishing user plane connections between the access network device and the second network, and releasing user plane connections between the access network device and the first network. Essentially, it involves deleting and adding core network tunnel information for the first UPF within the access network device's connection settings.

[0034] In one feasible implementation, the method further includes: receiving a second request from a first SMF, the second request being used to request the establishment of a session connection between the second SMF and a second UPF, the first SMF being located in a first network; sending a sixth request to the second UPF and receiving a sixth response from the second UPF, the sixth request being used to request the establishment of a session connection between the second UPF and the second SMF, the sixth response being used to indicate that the session connection between the second SMF and the second UPF has been established; and sending a second response to the first SMF, the second response including core network tunnel information of the second UPF.

[0035] This process mainly involves the terminal device initiating a session connection establishment with the first network. The second SMF establishes a connection between the second SMF and the second UPF according to the request of the first SMF, and sends the CN tunnel information of the second UPF to the first SMF so that the first SMF can update the CN tunnel information of the second UPF into the connection of the first UPF, thus completing the connection establishment between the first UPF and the second UPF, that is, the connection establishment between the first network and the second network.

[0036] Thirdly, this application provides a communication method applied to a proxy device located in a second network. The method further includes: determining that a second proxy connection has been established and a first proxy connection has been released; triggering the release of a first UPF connection in a session connection related to a terminal device, wherein the first UPF connection includes a connection between the first UPF and a first SMF, and a connection between the first UPF and an access network device; wherein the first UPF and the first SMF are located in a first network, the first proxy connection is a connection between the terminal device and the proxy device established based on the first UPF, the second proxy connection is a connection between the terminal device and the proxy device established based on the second UPF, and the terminal device communicates with the access network device.

[0037] This process primarily describes the connection of the first UPF (or first network) in the session connection release of the terminal device triggered by the agent device. This includes the connection between the first UPF and the first SMF, the connection between the first UPF and the agent device, and the connection between the first UPF and the access network device. The connections between the first UPF and the first SMF, and between the first UPF and the agent device, can also be referred to as the core network connection of the first UPF. The connection between the first UPF and the access network device is also referred to as the user plane connection of the first UPF.

[0038] In one feasible implementation, triggering the release of the first UPF connection includes: sending a third release request to the first UPF, the third release request being used to request the release of the first UPF connection, the first UPF connection including the connection between the first UPF and the access network device, the session connection between the first UPF and the proxy device, and the connection between the first UPF and the first SMF; receiving a third release response from the first UPF, the third release response indicating that the release of the first UPF connection has been completed.

[0039] In one feasible implementation, before determining that the establishment of the second proxy connection has been completed and the first proxy connection has been released, the method further includes: receiving a second proxy connection request from a terminal device, the second proxy connection request being used to request the establishment of a second proxy connection between the terminal device and the proxy device in a session connection associated with the terminal device, and releasing the first proxy connection between the terminal device and the proxy device; sending a second proxy connection response to the terminal device, the second proxy connection response indicating that the establishment of the second proxy connection has been completed and the first proxy connection has been released.

[0040] In one feasible implementation, the first proxy connection and the second proxy connection are multipath Fast User Datagram Protocol (MPQUIC) network connections.

[0041] Fourthly, a communication device is provided, the communication device including units or modules for performing any of the possible methods in the first, second or third aspects described above.

[0042] Fifthly, embodiments of this application provide a communication device, which includes at least one processor and a memory; wherein the memory is used to store computer programs or instructions; and at least one processor is used to execute the computer programs or instructions in the memory, such that the methods that may be implemented in any of the first to third aspects described above are executed.

[0043] Sixthly, embodiments of this application provide a communication system, which includes a first device and a second device, wherein the first device is used to perform the method of any one of the first aspects described above, and the second device is used to perform the method of any one of the second aspects described above. Optionally, a third device may also be included, which is used to perform the method of any one of the third aspects described above.

[0044] In a seventh aspect, embodiments of this application provide a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions, which, when executed, cause the computer to perform a method as described above.

[0045] Eighthly, embodiments of this application provide a computer program product, the computer program product including: computer program code, which, when executed by a computer, causes the computer to perform a method as described above.

[0046] Ninthly, embodiments of this application provide a chip coupled to a memory for reading and executing program instructions in the memory, so that the device in which the chip is located implements any of the methods described above. Attached Figure Description

[0047] Figure 1A This application provides an example of a network architecture for a communication system.

[0048] Figure 1B A flowchart illustrating multi-connection session switching is provided in an embodiment of this application;

[0049] Figure 2A A flowchart of a communication method provided in an embodiment of this application;

[0050] Figure 2B A flowchart of a network handover method provided in an embodiment of this application;

[0051] Figure 3A A flowchart illustrating another communication method provided in an embodiment of this application;

[0052] Figure 3B A flowchart illustrating another network switching method provided in this application embodiment;

[0053] Figure 4A A flowchart illustrating yet another communication method provided in an embodiment of this application;

[0054] Figure 4B A flowchart illustrating another network handover method provided in this application embodiment;

[0055] Figure 5 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0056] Figure 6 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0057] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. The terms "system" and "network" in the embodiments of this application can be used interchangeably. Unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship; for example, A / B can represent A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be one or multiple. Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish between network elements and similar items with essentially the same function. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0058] References to "one embodiment" or "some embodiments" in the embodiments described in this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0059] The following detailed embodiments further illustrate the objectives, technical solutions, and beneficial effects of this application. It should be understood that the following are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solutions of this application should be included within the scope of protection of this application.

[0060] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0061] The following describes the scenarios involved in the embodiments of this application.

[0062] The technical solution provided in this application can be applied to various communication systems, such as 5G mobile communication systems, 6G mobile communication systems, future evolution systems, or multiple communication convergence systems, as well as existing communication systems. The application scenarios of the technical solution provided in this application can include various scenarios, such as machine-to-machine (M2M), macro-micro communication, enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (uRLLC), and massive machine-type communication (mMTC). These scenarios may include, but are not limited to, communication scenarios between terminal devices, communication scenarios between network devices, and communication scenarios between network devices and terminal devices. Network devices include access network devices and core network devices. The following descriptions all use the scenario of communication between network devices and terminal devices as examples.

[0063] See also Figure 1A , Figure 1AThis application provides an example of a network architecture for a communication system, including a terminal device, a radio access network (RAN), a main network (core network), and subnets (core networks). The terminal device, also known as user equipment (UE) or a terminal, is represented by UE in the illustration. The UE accesses the core network (CN) through the RAN. The RAN is connected to the signaling routing function (SRF), which routes UE messages to subsequent CN (main network or subnet) functional network elements. The main network is a fully deployed core network with all necessary core network functions. Subnets are deployed on demand; for example, if a subnet only provides session-related services, it may only deploy SMF and UPF, with other network elements managed by the main network elements.

[0064] A User Equipment (UE) is a device with wireless transceiver capabilities that can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water (such as ships); and in the air (such as airplanes, balloons, and satellites). UEs can include, but are not limited to: user equipment, user units, user stations, mobile stations, mobile stations, remote stations, remote terminal equipment, mobile terminal equipment, user terminal equipment, wireless communication equipment, user agents, user devices, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices, processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in the Internet of Things (IoT), home appliances, virtual reality devices, terminal devices in future 5G networks, or terminal devices in future evolved PLMNs, etc.

[0065] The (R)AN component includes (R)AN equipment. This (R)AN equipment is the device in a mobile communication system that connects terminal devices to the wireless network. As a node in the radio access network, the (R)AN equipment can also be referred to as an access network element, base station, radio access network (RAN) node (or device, or network element), access point (AP), network equipment, small tower, etc. The RAN equipment in this application embodiment includes, but is not limited to: next-generation base stations (g nodeB, gNB) in 5G, evolved node B (eNB), 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), wireless fidelity (WiFi) access point, world interoperability for microwave access (WiMAX) base station, transmitting and receiving point (TRP), transmitting point (TP), or mobile switching center, etc. In systems employing different radio access technologies, the names of devices with base station functions may vary. For example, in 5G communication systems, they are called RAN or gNB (5G NodeB); in LTE systems, they are called evolved NodeB (eNB or eNodeB); and in third-generation (3G) communication systems, they are called Node B, etc. In some deployments of AN devices, they can include centralized units (CU) and distributed units (DU). In other deployments, CUs can be further divided into CU-control plane (CP) and CU-user plane (UP). In still other deployments, AN devices can be radio units (RO). In yet another deployment, AN devices can be based on an open radio access network (ORAN) architecture, etc.For example, when the AN device is an ORAN architecture, the AN device in this application embodiment can be an access network element in ORAN, or a module of an access network element, etc. In the ORAN system, CU can also be called open (O)-CU, DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU.

[0066] The network elements in the core network can be divided into two categories: user plane function network elements (also referred to as user plane network elements) and control plane function network elements (also referred to as control plane network elements). The control plane function network elements include access management network elements, network access network elements, session management network elements, data management network elements, policy control network elements, and network slicing and SNPN authentication and authorization function (NSSAAF) network elements in 5G communication systems.

[0067] User plane network elements are responsible for forwarding and receiving user data in terminal devices. They can receive user data from the data network and transmit it to the terminal device through the access network equipment; user plane network elements can also receive user data from the terminal device through the access network equipment and forward it to the data network. The transmission resources and scheduling functions that provide services to the terminal device in the user plane network element are managed and controlled by the SMF network element. In 5G communication systems, this user plane network element can be a user plane function (UPF) network element. In future communication systems, the user plane network element can still be a UPF network element, or it can have other names; this application embodiment does not limit this.

[0068] The access management network element is a control plane network element provided by the operator's network, responsible for access control and mobility management of terminal devices accessing the operator's network. This includes functions such as mobility state management, allocation of temporary user identities, authentication, and user management. In 5G communication systems, this access management network element can be an access and mobility management function (AMF) network element. In future communication systems, the access management network element may still be an AMF network element, or it may have other names; this application does not limit this.

[0069] The session management network element is primarily responsible for session management in mobile networks, such as session establishment, modification, and release. Specific functions include assigning IP addresses to users and selecting user plane network elements that provide packet forwarding capabilities. In 5G communication systems, this session management network element can be a session management function (SMF) network element. In future communication systems, the session management network element may still be an SMF network element, or it may have other names; this application does not limit the specific name.

[0070] The data management network element is used for generating authentication credentials, processing user identifiers (such as storing and managing permanent user identities), and managing access control and subscription information. In 5G communication systems, this data management network element can be a unified data management (UDM) network element. In future communication systems, unified data management can still be a UDM network element, or it can have other names; this application embodiment does not limit this.

[0071] The policy control network element primarily supports providing a unified policy framework to control network behavior, providing policy rules to the control layer network functions, and is also responsible for acquiring user subscription information related to policy decisions. In 4G communication systems, this policy control network element can be a policy and charging rules function (PCRF) network element. In 5G communication systems, this policy control network element can be a policy control function (PCF) network element. In future communication systems, the policy control network element can still be a PCF network element, or it can have other names; this application embodiment does not limit this.

[0072] The storage network element primarily provides registration and discovery functions. It can be used for mutual discovery among network functions (NFs) and communication via an application programming interface (API). In 5G communication systems, this storage network element's policy control network element can be a network repository function (NRF) network element. In future communication systems, the storage network element can still be an NRF network element, or it can have other names; this application's embodiments do not limit this.

[0073] Understandable, Figure 1AThe network elements or functions shown can be network components in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). One possible implementation is that the aforementioned network element or function can be implemented by a single device, multiple devices working together, or a functional module within a single device; this application does not specifically limit this. Furthermore, for ease of description, the term "network element" can be omitted below. For example, in this application's embodiments, the SMF network element and SMF have the same meaning; the word "network element" is omitted for convenience, and so on. Additionally, it should be noted that this application does not limit the names of each network element in the communication system. For example, in communication systems of different standards, each network element can have other names; or, for example, when multiple network elements are integrated into the same physical device, that physical device can also have other names.

[0074] Understandable, Figure 1A This is merely an exemplary network architecture, and the network architecture applicable to the embodiments of this application is not limited to this. Any network architecture capable of implementing the functions of the above-mentioned network elements is applicable to the embodiments of this application.

[0075] The prior art involved in the embodiments of this application is described below.

[0076] 1. The concept of distributed networks

[0077] Existing standards define NPNs, which third-party service providers can deploy to provide services to UEs. For example, NPNs can be deployed in industrial parks to provide highly reliable, low-latency communication services to devices within the park. However, existing NPN technologies have some problems and cannot meet future network requirements. There are two deployment methods for NPNs: SNPN and PNI-NPN. SNPN is an independently deployed non-public network that requires the deployment of independent core network equipment, resulting in high operation and maintenance costs, which are difficult for small and medium-sized enterprises to bear. The other deployment method is PNI-NPN. The non-public network deployed in this way does not require an additional core network. It uses the operator's public network core network and isolates specific resources using methods such as slicing or data network name (DNN) for dedicated PNI-NPN. Because this deployment method relies on the operator's core network, enterprises cannot achieve autonomous management of the NPN and can only rely on the main network core network to provide corresponding functions. PNI-NPN cannot achieve agile deployment for enterprise needs. Therefore, in future network evolution, a distributed network deployment method is proposed.

[0078] In this architecture, the core network can be divided into two parts: a central network deployed by the operator (also known as the main network) and one or more subnets. The central network possesses complete core network functions and provides corresponding management services to the UE. Subnets are deployed locally based on service requirements, such as on the enterprise side. These subnets can deploy functional network elements on demand, and when there are multiple subnets, a UE can simultaneously access services from multiple subnets. Since network elements in the subnets are deployed on demand, missing network elements still require the use of corresponding network elements from the central network to obtain the corresponding services. For a detailed architecture diagram, please refer to the aforementioned documentation. Figure 1A .

[0079] Because the functional network elements of a subnet are deployed locally in a distributed architecture, they can be autonomously managed by the enterprise, enabling agile deployment of subnet network elements (NFs). Functional network elements can be deployed on demand during distributed subnet deployment, thus avoiding the need to deploy complete core network elements as required by SNPN, thereby saving on core network operation and maintenance costs. When a subnet deploys only some functional network elements as needed, the remaining undeployed network elements still need to be provided by the main core network to provide the corresponding services to the UE.

[0080] 2. Evolution of Distributed Non-Access-Stratum (NAS) Signaling Architecture

[0081] In the existing 5G standard architecture, the endpoint for NAS signaling is the AMF (Advanced Management Function), therefore all NAS messages are routed through the AMF. In another architecture, a signaling routing function (SRF) is introduced into the network. This function acts as the entry point to the core network, through which all signaling can be routed. The SRF itself does not terminate NAS; NAS messages are sent to the corresponding network element after routing. Introducing the SRF further simplifies the functionality of the AMF. (See also...) Figure 1A SRFs can be deployed in both the main network and subnets. The RAN selects to send interactive signaling to the SRF of the main network or subnet through the SRF, and then the SRF routes it to other network elements.

[0082] 3. Execution of subnet services

[0083] The service area of ​​a subnet is included within the service area of ​​the main network. This can be understood as the subnet's coverage area being included within the main network's coverage area, and all services provided by the subnet are considered part of the main network's services. Subnet services are typically provided by application servers (or data networks, DNs) deployed within the subnet's scope. The subnet's UPF can connect to the subnet's DN to obtain subnet service data, and the main network's UPF can also connect to the subnet's DN to obtain subnet service data. However, using a subnet UPF to obtain subnet service data ensures that data management for subnet services remains within the subnet's scope, guaranteeing the privacy and security of the service data.

[0084] 4. Dual-steer traffic switch (multi-connection session switching)

[0085] Multi-connection session handover refers to the process of switching from one UE's session to another UE's session in a multi-connection device composed of multiple UEs. Before the handover begins, UE1 conducts session transmission with the core network through RAN1. UE1 and UE2 have a linked relationship in their subscription permanent identifiers (SUPIs) and these identifiers are stored in the UDM.

[0086] See also Figure 1B The flowchart provided in this application embodiment for a multi-connection session switching can specifically include the following steps:

[0087] (0). First, UE2 shares (or obtains) UE1's PDU session ID#1.

[0088] (1).UE2 sends a PDU session establishment request to AMF2, which includes information such as the PDU session ID#1 (the session to be switched) corresponding to UE1, the session switching indication (information), and the PDU session ID#2 (the session to be established).

[0089] (2). After receiving the PDU session establishment request, AMF2 determines that the UE needs to perform a session handover based on the session handover indication. Based on the PDU session ID#1 or UE1's SUPI, AMF2 requests the UDM to query the session information corresponding to UE1, including the SMFID of the currently serving UE1, etc.

[0090] (3). Based on the queried SMF ID, AMF2 sends UE2's SUPI, PDU session ID#2, UE1's SUPI and PDU session ID#1, and a session handover indication to the SMF indicated by the SMF ID.

[0091] (4). The SMF associates the sessions of UE1 and UE2 based on the SUPI and PDU session ID, and performs session switching.

[0092] (5) The network continues to perform the other steps of the UE2 PDU session establishment process.

[0093] (6) Once the session for UE2 is established, the SMF can trigger the release of UE1's PDU session ID#1. At this point, the session handover is complete, and subsequent data is sent to UE2.

[0094] In the above process, to achieve UE session handover, the anchor point SMF and anchor point UPF (i.e., the SMF and UPF communicating with the DN) must remain unchanged. However, for scenarios involving handover between large network subnets, since the large network and subnets deploy different SMFs, this method cannot be used for session handover, resulting in UE session interruption and inability to guarantee service continuity.

[0095] Based on the above description, embodiments of this application provide corresponding technical methods to ensure that the session anchor point and DN communicate with shorter latency. Alternatively, corresponding technical methods are provided to ensure service continuity during session handover.

[0096] Example 1: See below Figure 2A , Figure 2A A flowchart of a communication method provided in an embodiment of this application is shown below. Figure 2A As shown, the method includes the following steps:

[0097] 201. The terminal device sends a first session establishment request through the access network device. The first session request is used to request the establishment of a session connection related to the terminal device. The first session request includes the service information of the terminal device. Correspondingly, the first SMF receives the first session request. The first SMF is located in the first network.

[0098] In this embodiment, the service range of the first network includes the service range of the second network. The service range may include coverage area and service type. That is, the (physical) service range of the first network includes the service range of the second network, or may also include other larger service ranges; the service types that the first network can perform include the service types of the second network, or may also include other more service types. For example, the first network may be the large network described above, and the second network may be a subnet.

[0099] In the following description of the embodiments, the terminal device is referred to as UE, and the access network device is referred to as RAN. The session management network element is referred to as SMF, the user plane network element as UPF, the data management network element as UDM, and the access management network element as AMF, etc. These network elements may have other names in future networks, and this application embodiment does not limit them.

[0100] The UE initiates a first session establishment request to request the establishment of a Protocol Data Unit (PDU) session connection related to service information. The RAN receives the first session establishment request and forwards it to the first SMF in the first network. The first network can be the SMF in the CN that the UE currently accesses through the RAN.

[0101] The first session request sent by the UE may not be directly transmitted to the first SMF. Step 201 may also include the following steps:

[0102] 2011. The terminal device sends first information, which includes network selection information for the first network, routing information for the first SMF, and a first session establishment request. Correspondingly, the access network device receives the first information.

[0103] Before sending the first information, the UE can receive network information broadcast by the RAN, i.e., the networks the UE can access, including the first network but excluding the second network. If the UE wants to access the first network, it can send a session establishment request to the RAN. In addition, the UE sends network selection information (indicating the first network) based on the network corresponding to the service to be performed (which is both a service of the first network and a service of the second network), so that the first information can be sent to the core network corresponding to the first network.

[0104] Optionally, the first network can be the network to which the RAN defaults to routing. Therefore, the first information may not include routing information, and the RAN will by default send the first information to the core network corresponding to the first network.

[0105] 2012. The access network device sends second information, which includes routing information of the first SRF and a first session establishment request. Correspondingly, the first SRF receives the second information.

[0106] The first information also includes routing information for the first SMF. After the first SRF in the first network obtains the routing information of the first SMF forwarded by the RAN, it sends the first session establishment request to the corresponding network element, i.e., the first SMF, according to the route indicated by the routing information. This can improve communication efficiency.

[0107] Optionally, after the first SRF obtains the routing information of the first SMF, the method further includes:

[0108] 2013. The first SRF sends a network element query request, which includes the routing information of the first SRF and is used to request the query of the network element (or network function, NF) corresponding to the routing information; correspondingly, the first NRF in the first network receives the network element query request.

[0109] 2014. The first NRF sends a network element query response, which includes the identifier (ID) of the first SMF. Correspondingly, the first SRF receives the network element query response.

[0110] 2015. After obtaining the identifier of the first SRF, the first SRF forwards the first session establishment request to the first SRF.

[0111] For example, after obtaining the routing information, the first SRF does not directly address the network element corresponding to the routing information. Instead, it queries the NRF to determine that the network element corresponding to the routing information is the first SMF, and then forwards the first session establishment request to the first SMF. This ensures the accuracy of the network element of the determined route.

[0112] 202. When the first SMF determines that the terminal device requests to execute the first service based on the service information, it establishes a session connection between the first user plane function (UPF) and the first communication device. The first UPF is located in the first network, the first service is within the service range of the second network, and the first communication device is a device in the second network that is connected to the server of the first service. The service range of the first network includes the service range of the second network, and the service range includes the coverage area and the service type.

[0113] The first session establishment request is used to request the establishment of UE-related session connections, including control plane connections in the CN and user plane connections between the UPF and RAN in the CN.

[0114] Before initiating a session connection, the first SMF needs to determine that the UE is requesting to execute a first service. This first service is a service of the second network, and the service scope of the first network includes the first service. The second network is a network with a smaller service scope than the first network. The fact that the first service is a service of the second network typically means that the physical / communication distance between the server of the first service and the network element of the second network is closer. Therefore, in this embodiment, the UE accesses the first network through the RAN (i.e., establishes a connection with the first UPF in the first network), the first network connects to the second network (i.e., the first UPF connects to the first communication device in the second network), and communication with the server (or data network, DN) of the first service is achieved through the second network (the first communication device acts as a session anchor point connected to the DN). On the one hand, this ensures lower communication latency between the CN network element and the DN; on the other hand, the data of the first service is managed by the first communication device of the second network, ensuring the privacy and security of the first service data. The first communication device can be the second UPF, or other devices that can serve as anchor points; this embodiment does not limit this.

[0115] Optionally, the terminal device requests to execute a first service based on service information, including: service information that indicates relevant information for the first service. Specifically, this could include an identifier for the first service, a name for the first service, etc., allowing the first SMF to determine that the first service is a service of the second network based on the identifier or name of the first service.

[0116] Optionally, the service information indicates the target service identifier. If the first SMF cannot directly determine whether a service belongs to the second network based on the service identifier, then the method further includes the following steps:

[0117] 2021. The first SMF sends a first query request, which is used to request network information for the service. Correspondingly, the data management function (UDM) in the first network receives the first query request.

[0118] 2022, UDM sends the first query response, which includes network information for the service.

[0119] For example, the first query request is used to request network information for the service, including the following two cases:

[0120] (1) The UDM obtains the network service list of the terminal device included in the terminal device's subscription data according to the first query request. The network service list includes the correspondence between multiple service identifiers and multiple networks, and the multiple service identifiers include the target service identifier. The UDM uses the network service list as the network information of the service and sends it to the first SMF through the first query response.

[0121] (2) The first query request includes a target service identifier. After receiving the target service identifier, the UDM retrieves the service information corresponding to the target service identifier from the stored network service list, including the correspondence between the target service identifier and the second network. The UDM sends the correspondence between the target service identifier and the second network, or the second network, as the network information of the service to the first SMF through the first query response.

[0122] 2023. The first SMF determines the terminal device's request to execute the first service based on the network information of the service.

[0123] After the first SMF obtains the network information of the service from the first query response, there are two possible scenarios:

[0124] (1) The network information of the service is a list of network services.

[0125] This list specifically includes the correspondence between service identifiers and networks. For example, correspondences like (Service 1, Second Network 0) and (Service 2, Second Network 1). The first SMF, based on the network service list and the target service identifier (e.g., Service 2), determines that the network corresponding to the target service identifier is Second Network 1, indicating that the UE is requesting the execution of the first service.

[0126] (2) The network information of the service includes the network corresponding to the target service identifier.

[0127] If the first query request includes a target service identifier, the network information of the service in the first query response may include the network corresponding to the target service identifier. For example, the network information of the service may be directly the second network, or it may be a correspondence between the target service identifier and the second network. After receiving the network information of the service, the first SMF determines that the service identified by the target service identifier is the service of the second network, that is, the UE is requesting to execute the first service.

[0128] Optionally, the first query request is further used to request coverage area information of the second network, and the first query response also includes the coverage area information of the second network. Before establishing a session connection between the first UPF and the first communication device, the method further includes: determining that the terminal device will pass through the coverage area of ​​the second network during the process of acquiring the first service data.

[0129] For example, the subscription data of the UE obtained by the first SMF from the UDM also includes the coverage area information of the second network. The first SMF can obtain the predicted path of the UE to determine whether the UE will pass through the coverage area of ​​the second network.

[0130] For example, the first SMF requests the network data analytics function (NWDAF) to predict the path information of the UE (mainly during the execution of the first service). When the UE may pass through the coverage area of ​​the second network in the future, the second UPF is selected as the anchor point to establish a session connection. If the UE's future path will not pass through the coverage area of ​​the second network, the first UPF in the first network can be directly selected as the anchor point to establish a session connection.

[0131] 203. The first SMF establishes a session connection between the first UPF and the access network device.

[0132] After the first SMF establishes a control plane connection between the first UPF and the first communication device, it can then establish a user plane connection between the first UPF and the RAN. Specifically, this may include the following steps:

[0133] 2031. The first SMF sends a second session establishment request, which is used to request the establishment of a session connection between the first UPF and the access network device, and the access network device communicates with the terminal device. Correspondingly, the access network device receives the second session establishment request.

[0134] The second session establishment request received by the RAN can be an N2 PDU session request. That is, the RAN and the first SMF are connected via the N2 interface. Specifically, the first SMF can send the second session establishment request to the AMF, which then forwards the request to the RAN, including CN tunnel information connecting to the first UPF. The AMF and RAN are connected via the N2 interface. The communication path between the AMF and RAN may also include network elements such as the first SRF.

[0135] 2032. The access network device sends a second session establishment response, indicating that the session connection between the first UPF and the access network device has been established. The second session establishment response includes the access network (AN) tunnel information of the access network device. The first SMF receives the second session establishment response.

[0136] The RAN adds the CN tunnel information of the first UPF to itself, completing the session connection (N2 session) establishment between the first UPF and the RAN. The RAN then sends a second session establishment response to the first SMF, indicating that the N2 session establishment is complete. The second session establishment response may include the RAN's AN tunnel information.

[0137] Optionally, after receiving the second session establishment request, the RAN establishes AN resources for the UE. This includes the RAN reserving air interface resources for the UE, such as frequency bands and bandwidth, and then sending a session establishment completion message to the UE. After receiving the session establishment completion message, the UE can begin sending service data packets to the RAN.

[0138] 2033. The first SMF sends a second modification request, which requests that the access network tunnel information of the access network device be added to the session connection of the first UPF. The first UPF receives the second modification request.

[0139] 2034. The first UPF sends a second modification response, indicating that the access network tunnel information has been added. The first SMF receives the second modification response.

[0140] The first SMF sends a second modification request to the first UPF, requesting that the AN tunnel information of the RAN be added to the session connection of the first UPF, or in other words, that the N3 interface connection between the first UPF and the RAN be established. After receiving the second modification request, the first UPF adds the included AN tunnel information to the session connection of the first UPF to establish the connection between the first UPF and the RAN.

[0141] In this embodiment, the terminal device requests a session connection for a first service from the first network. After receiving the first session establishment request from the terminal device, the first SMF in the first network determines that the first service is within the service range of the second network, thus the server of the first service has a closer communication distance with the second network. Therefore, when establishing the session connection corresponding to the first service, a connection is established between the terminal device and the first UPF in the first network, and then a connection is established between the first UPF and the first communication device, enabling the terminal device to access the first network. By using the first communication device in the second network as the session anchor point for the terminal device to transmit service data with the server of the first service, data privacy and data security during the execution of the first service can be guaranteed.

[0142] Example 2: In the above implementation process, the UE is within the coverage area of ​​the first network. In other cases, while performing the first service, the UE moves to the coverage area of ​​the second network. See also... Figure 2B , Figure 2B A flowchart of a network handover method provided in an embodiment of this application is shown below. Figure 2B As shown, the method includes the following steps:

[0143] 301. The terminal device sends a first handover request through the access network device. The first handover request is used to request the handover of the terminal device's associated session connection to the second network. The first handover request is sent when the terminal device is within the coverage area of ​​the second network. Correspondingly, the second SMF receives the first handover request.

[0144] When a UE accesses or moves to the coverage area of ​​a second network, it sends a first handover request via the RAN to the second SMF in the second network to request the establishment of a UE-related session connection in the second network. Currently, the UE is connected to the first UPF via the RAN, meaning it is connected to the first network. Establishing a UE-related session connection in the second network involves establishing a connection between the RAN and the second UPF in the second network, releasing the connection between the RAN and the first UPF, and thus switching the UE's session connection from the first network to the second network.

[0145] Optionally, step 301 may specifically include the following steps:

[0146] 3010. The terminal device is located within the coverage area of ​​the second network.

[0147] For example, the UE may have received network information broadcast by the RAN, indicating that the network currently covered by the UE's signal includes a second network, thereby determining that the UE has entered the coverage area of ​​the second network.

[0148] 3011. The terminal device sends third information, which includes network selection information of the second network, routing information of the second SMF, and a first handover request. Correspondingly, the access network device receives the third information.

[0149] The first service currently being performed by the UE is a service provided by the second network, therefore, it can send third information to access the second network. The third information includes the network selection information of the second network, so that the RAN can send the routing information of the second SMF and the first handover request, which are in the third information excluding the network selection information of the second network, to the core network of the second network.

[0150] Optionally, the third information includes a session type, which indicates that the session type requested by the first switching request is a session switching.

[0151] As described above, the first handover request does not establish a completely new session connection, but rather switches the UE from accessing the network through the first network to accessing the network through the second network within an existing session connection related to the terminal device. Therefore, the first handover request may also include the identifier of the session connection related to the terminal device (PDU session ID) to determine which session connection the session handover will take place in.

[0152] 3012. The access network device sends fourth information, which includes routing information of the second SRF and a first handover request. Correspondingly, the second SRF receives the second information.

[0153] The third information also includes the routing information of the second SMF. After the second SRF in the second network obtains the routing information of the second SMF forwarded by the RAN, it sends the first handover request to the corresponding network element, i.e., the second SMF, according to the route indicated by the routing information.

[0154] Alternatively, after the second SRF obtains the routing information of the second SMF, it does not communicate directly with the second SMF, but first obtains the identifier of the second SMF from the UDM, and then forwards the first handover request to the second SMF. The specific process is as described in steps 2013 and 2014 above (not shown in the figure), and will not be repeated here.

[0155] 3013. After the second SRF obtains the identifier of the second SMF, it forwards the first handover request to the second SMF.

[0156] 302. Modify or establish the core network connection of the second SMF or the second UPF.

[0157] In this embodiment, the UE's session anchor point is a first communication device in the second network. The first communication device can be a second UPF or a proxy device, etc. When the first communication device is the second UPF, the session connection between the second UPF and the first UPF has already been established in the UE's session connection. In this step, the core network connection of the second UPF is modified, that is, the connection between the second UPF and the first UPF is deleted.

[0158] When the first communication device is a proxy device, the UE's session connection does not include the connection to the second UPF. Therefore, in this step, the connection between the second SMF and the second UPF is established in the UE's session connection.

[0159] 303. The second SMF establishes a session connection between the second UPF and the access network equipment.

[0160] The process of the second SMF establishing a session connection between the second UPF and the RAN is similar to that of the first SMF establishing a session connection between the first UPF and the access network device in the aforementioned embodiment. The RAN modifies the CN tunnel information of the first UPF stored in its own memory to the CN tunnel information of the second UPF. For details, please refer to the relevant description of step 203, which will not be repeated here.

[0161] 304. The second SMF or proxy device releases the relevant connections of the first UPF. The relevant connections of the first UPF include the connection between the first UPF and the first SMF, and the connection between the first UPF and the access network equipment.

[0162] In this embodiment, if the first communication device is the second UPF, the second SMF sends a release request to the first SMF, triggering the release of the relevant connection of the first UPF. If the first communication device is a proxy device, the proxy device sends a release request to the first UPF, triggering the release of the relevant connection of the first UPF. The specific process is described in the following embodiments and will not be repeated here.

[0163] As can be seen, in this embodiment, when the terminal device moves to the coverage area of ​​the second network, it is triggered to send a first handover request to the second network. The first handover request is used to request the switching of the terminal device's associated session connection to the second network, while simultaneously releasing the connection with the first network. In this way, when the terminal device moves from the first network to the second network, the terminal device's session anchor point remains the first communication device, ensuring service continuity. Releasing the connection to the first network reduces overall communication latency.

[0164] It should be noted that before executing the method of this embodiment, a session connection of the terminal device has been established. This session connection includes a session connection between the RAN and the first network, and a session connection between the first network and the second network, with the second network accessing the DN. The method for establishing the session connection of the terminal device can be found in the foregoing. Figure 2A The communication method described, that is, before step 301, may also include the aforementioned steps 201 to 203. For a detailed description, please refer to the foregoing embodiments, which will not be repeated here.

[0165] Example 3: The above examples generally describe the process of establishing a session connection between the first SMF in the first network and the first UPF in the second network. This example describes a specific implementation where the first communication device is the second UPF.

[0166] See also Figure 3A The flowchart is for another communication method provided in the embodiments of this application, such as... Figure 3A As shown, the method includes:

[0167] 401. The terminal device sends a first session establishment request through the access network device. The first session request is used to request the establishment of a session connection related to the terminal device. The first session request includes the service information of the terminal device. Correspondingly, the first SMF receives the first session request. The first SMF is located in the first network.

[0168] For a detailed description of this step, please refer to the description of step 201 in the foregoing embodiments, which will not be repeated here.

[0169] 402. When the first SMF determines that the terminal device requests to execute the first service based on the service information, it establishes a session connection between the first UPF and the second UPF. The first UPF is located in the first network, the first service is within the service range of the second network, and the second UPF is a device in the second network that is connected to the server of the first service. The service range of the first network includes the service range of the second network, and the service range includes the coverage area and the service type.

[0170] In this embodiment of the application, the session anchor point is the second UPF, that is, when the UE performs the first service, the data interaction with the server of the first service is through the second UPF. The first SMF establishes a session connection between the first UPF and the second UPF, including:

[0171] 4021. The first SMF sends a first request, which is used to request the establishment of a session connection between the first SMF and the first UPF. Correspondingly, the first UPF receives the first request.

[0172] 4022. The first UPF sends a first response, indicating that the session connection between the first SMF and the first UPF has been established. Correspondingly, the first SMF receives the first response.

[0173] For example, the connection between the first SMF and the first UPF is an N4 session connection. Correspondingly, the first SMF instructs the first UPF to generate and store an N4 session context, including an N4 session identifier (ID), packet detection rules, and other information, through a first request. The first response sent by the first UPF to the first SMF includes the N4 session ID.

[0174] 4023. The first SMF determines the second SMF, and the second SMF is located in the second network.

[0175] After the first SMF establishes a session connection with the first UPF, it further establishes a connection between the first UPF and the second UPF, so that the UE can connect to the second UPF through the first UPF. The session connection of the second UPF is managed by the second SMF in the second network, therefore the first SMF must first determine the second SMF. For example, the first SMF determines the second SMF by:

[0176] 40231. The first SMF sends a third request, which requests the identification of the second SMF. The third request includes the identifier of the second network. Correspondingly, the first network storage function (NRF) receives the third request. The first NRF is located in the first network.

[0177] 40232. The first NRF sends an eighth request to the second NRF of the second network based on the identifier of the second network. The eighth request is used to request information about the SMF in the second network. The second NRF receives the eighth request.

[0178] 40233. The second NRF sends an eighth response, which includes information about the second SMF. Correspondingly, the first NRF receives the response message.

[0179] 40234. The first NRF sends a third response, which includes information from the second SMF. Correspondingly, the first SMF receives the third response.

[0180] Specifically, the first SMF sends a third request to the first NRF to request the discovery of SMFs in the second network. The third request includes the identifier of the second network. The first NRF can address the second NRF of the second network based on the identifier of the second network, and communicate with the second NRF. The second NRF obtains the information of the second SMF corresponding to itself and sends it to the first SMF.

[0181] Optionally, the second network is a subnet, and the second NRF is the NRF for all (or more) subnets. The second NRF selects the information of the second SMF of a certain subnet corresponding to the identifier of the second network and sends it to the first NRF.

[0182] Information about the second SMF, including the identifier of the second SMF, the address of the second SMF, etc.

[0183] 4024. The first SMF sends a second request to the second SMF. The second request is used to request the establishment of a session connection between the first UPF and the second UPF corresponding to the second SMF. The second request includes the CN tunnel information of the first UPF. Correspondingly, the second SMF receives the second request.

[0184] 4025. The second SMF sends a sixth request to the second UPF, which requests the establishment of a session connection between the second UPF and the second SMF. Correspondingly, the second UPF receives the sixth request.

[0185] After obtaining the information from the second SMF, the first SMF sends a second request to the second SMF to request the establishment of a session connection between the first UPF and the second UPF corresponding to the second SMF. Upon receiving the second request, the second SMF sends a sixth request to its own corresponding second UPF to request the establishment of a session connection between the second UPF and the second SMF. Both the second and sixth requests include the CN tunnel information of the first UPF. When establishing a connection with the second SMF, the second UPF adds the CN tunnel information of the first UPF to its own session connection. The connection established between the second UPF and the second SMF is also an N4 connection. The second SMF instructs the second UPF to establish an N4 session context, including information such as the N4 session ID, through the sixth request.

[0186] 4026. The second UPF sends a sixth response, indicating that the session connection between the second SMF and the second UPF has been established. Correspondingly, the second SMF receives the sixth response.

[0187] After the second UPF establishes a session connection with the second SMF, it sends a sixth response to the second SMF as an instruction. Optionally, the second UPF and the second SMF establish an N4 session connection, and the sixth response includes information such as the N4 session ID.

[0188] 4027. The second SMF sends a second response, which includes the core network tunnel information of the second UPF. The core network tunnel information of the second UPF is used to indicate the address information of the second UPF. Correspondingly, the first SMF receives the second response.

[0189] After confirming the completion of the session connection between the second SMF and the second UPF, the second SMF sends a second response to the first SMF, which includes the core network tunnel information (CN tunnel info) of the second UPF, indicating the address information of the second UPF.

[0190] 4028. The first SMF sends a first modification request, which requests that the core network tunnel information of the second UPF be added to the session connection of the first UPF. Correspondingly, the first UPF receives the first modification request.

[0191] After receiving the second response, the first SMF sends the core network tunnel information of the second UPF to the first UPF through the first modification request. The first UPF establishes an N9 interface with the second UPF based on the core network tunnel information of the second UPF, or in other words, adds the core network tunnel information of the second UPF to the session connection of the first UPF, thereby realizing the connection between the first UPF and the second UPF.

[0192] 4029. The first UPF sends a first modification response, indicating that the core network tunnel information of the second UPF has been added. Correspondingly, the first SMF receives the first modification response.

[0193] After the first UPF adds the core network tunnel information of the second UPF to the session connection, it sends a first session modification response to the first SMF to indicate this. This allows the first SMF to confirm that the first UPF and the second UPF have completed the session connection establishment.

[0194] 403. The first SMF establishes a session connection between the first UPF and the access network device.

[0195] This process can be referred to in the relevant description of step 203 in the foregoing embodiments, and will not be repeated here.

[0196] As can be seen, in this embodiment, the terminal device requests a session connection for a first service from the first network. After receiving the first session establishment request from the terminal device, the first SMF in the first network determines that the first service is within the service range of the second network, thus the server of the first service has a closer communication distance with the second network. Therefore, when establishing the session connection corresponding to the first service, a connection is established between the terminal device and the first UPF in the first network, and then a connection is established between the first UPF and the second UPF in the second network. This allows the terminal device to access the first network, while using the second UPF as the session anchor point for the terminal device to transmit service data with the server of the first service. This ensures lower communication latency between network elements in the network and the server of the first service. Furthermore, managing the data of the first service through network elements in the second network ensures the data security of the first service. Additionally, this process does not require adding equipment to the core network, reducing the implementation difficulty of the method.

[0197] Example 4: Based on the above examples, when a UE moves to the coverage area of ​​a second network while performing the first service, it can refer to... Figure 3B , Figure 3B A flowchart of another network handover method provided in this application embodiment is shown below. Figure 3B As shown, the method includes the following steps:

[0198] 501. The terminal device sends a first handover request through the access network device. The first handover request is used to request the handover of the terminal device's associated session connection to the second network. The first handover request is sent when the terminal device is within the coverage area of ​​the second network. Correspondingly, the second SMF receives the first handover request.

[0199] For a detailed description of this step, please refer to the relevant description of step 301 in the foregoing embodiments, which will not be repeated here.

[0200] 502. Modify the core network connection of the second UPF in the second SMF.

[0201] In this embodiment, the established UE-related session connections include the connection between the RAN and the first UPF, and the (core network) connection between the first UPF and the second UPF. Additionally, the second UPF is also connected to the DN. When the UE is within the coverage area of ​​the second network, the connection between the first UPF and the second UPF needs to be released (or, in other words, the CN tunnel information of the first UPF needs to be deleted from the second UPF). Then, a (user plane) connection is established between the second UPF and the RAN.

[0202] 503. The second SMF establishes a session connection between the second UPF and the access network device, and releases the connection between the first UPF and the access network device.

[0203] The specific process of the second SMF establishing a session connection between the second UPF and the RAN can be found in the relevant description of step 203, and will not be repeated here.

[0204] When establishing a session connection between the second UPF and the RAN, the RAN updates the CN tunnel information of the second UPF to its local machine and deletes the CN tunnel information of the first UPF, thereby releasing the connection between the first UPF and the RAN.

[0205] 504. The second SMF triggers the release of the connection between the first UPF and the first SMF.

[0206] In this embodiment of the application, the release of the relevant connection of the first UPF is triggered by the second SMF, and the process may include the following steps:

[0207] 5041. The second SMF sends a first release request, which is used to request the release of the connection between the first SMF and the first UPF in the session connection of the terminal device. Correspondingly, the first SMF receives the first release request.

[0208] For example, the first release request may include the session connection identifier of the terminal device (the PDU session ID of the UE) so that the first SMF can determine which PDU session the connection in is to be released.

[0209] 5042. The first SMF sends a second release request, which requests the release of the connection between the first SMF and the first UPF. Correspondingly, the first UPF receives the second release request.

[0210] 5043. The first UPF sends a second release response, indicating that the connection release between the first SMF and the first UPF has been completed. Correspondingly, the first SMF receives the second release response.

[0211] 5044. The first SMF sends a first release response, indicating that the first UPF release and the connection release with the first SMF have been completed. Correspondingly, the second SMF receives the first release response.

[0212] As can be seen in this embodiment, when the terminal device moves to the coverage area of ​​the second network, it is triggered to send a first handover request to the second network. The first handover request is used to request the switching of the terminal device's related session connection to the second network, establish a connection between the second UPF and the RAN in the second network, and release the related connection of the first network. In this way, when the terminal device moves from the first network to the second network, the terminal device's session anchor point is always kept at the second UPF, ensuring service continuity. Releasing the connection of the first network can reduce the overall communication latency.

[0213] It should be noted that a session connection of the terminal device has been established before executing the method of this embodiment. The method for establishing a session connection of the terminal device can be found in the foregoing. Figure 3A The communication method described, that is, before step 501, may also include the aforementioned steps 401 to 403. For a detailed description, please refer to the foregoing embodiments, which will not be repeated here.

[0214] Example 5: This example describes a specific implementation method where the first communication device is a proxy device.

[0215] See also Figure 4A The flowchart is for another communication method provided in the embodiments of this application, such as... Figure 4A As shown, the method includes:

[0216] 601. The terminal device sends a first session establishment request through the access network device. The first session request is used to request the establishment of a session connection related to the terminal device. The first session request includes the service information of the terminal device. Correspondingly, the first SMF receives the first session request. The first SMF is located in the first network.

[0217] For a detailed description of this step, please refer to the description of step 201 in the foregoing embodiments, which will not be repeated here.

[0218] 602. When the first SMF determines that the terminal device requests to execute the first service based on the service information, the first UPF establishes a session connection between the first UPF and the proxy device. The first UPF is located in the first network, the first service is within the service range of the second network, and the proxy device is a device in the second network that is connected to the server of the first service. The service range of the first network includes the service range of the second network, and the service range includes the coverage area and the service type.

[0219] In this embodiment, the session anchor is a proxy device, meaning that when the UE performs the first service, the device that interacts with the server of the first service is the proxy device. The first SMF establishes a session connection between the first UPF and the proxy device, including:

[0220] 6021. The first SMF sends a fourth request, which is used to request the establishment of a session connection between the first SMF and the first UPF. Correspondingly, the first UPF receives the fourth request.

[0221] 6022. The first UPF sends a fourth response, indicating that the session connection between the first SMF and the first UPF has been established. Correspondingly, the first SMF receives the first response.

[0222] For a detailed description of establishing the connection between the first SMF and the first UPF, please refer to the description of steps 4021 to 4022 in the foregoing embodiments, which will not be repeated here.

[0223] 6023. The first SRF sends a fifth request, which requests the establishment of a session connection between the first UPF and the agent device. The fifth request includes the core network tunnel information of the first UPF. Correspondingly, the second SRF receives the fifth request.

[0224] The second SRF is located in the second network. The fifth request may include routing information for addressing the network element corresponding to the first service, so as to establish a connection between the proxy device in the first network and the second network.

[0225] Optionally, if the routing information can be routing information for agent management functions, then the method further includes:

[0226] 6024. The second SRF sends a T1 request, which is used to request the establishment of a session connection between the first UPF and the agent device. The T1 request includes the core network tunnel information of the first UPF. Correspondingly, the agent management function receives the T1 request.

[0227] The agent management function in this embodiment is used to manage agent devices in a second network. Optionally, the agent management function is a policy control function (PCF), or a network element that includes the agent management function (PCF) (the agent management function in the figure is represented as PCF).

[0228] 6025. The proxy management function sends a T2 request, which is used to request the establishment of a session connection between the first UPF and the proxy device. The T2 request includes the core network tunnel information of the first UPF. Correspondingly, the proxy device receives the T2 request.

[0229] The T2 request sent by PCF to the agent device may also include configuring forwarding rules so that the agent device can determine to forward the session of the corresponding connection to DN.

[0230] 6026. The proxy device sends a T2 response, indicating that the session connection between the first UPF and the proxy device has been established. This session connection between the first UPF and the proxy device can be referred to as the first proxy connection. After establishing the first proxy connection with the first UPF, the proxy device generates an identifier for the first proxy connection (this identifier corresponds to the UE that initiated the session connection request and the proxy device; if the UE and the proxy device do not update, this identifier may not be updated). The T2 response may include the identifier of the first proxy connection. Correspondingly, the proxy management function receives the T2 response.

[0231] 6027. The proxy management function sends a T1 response, indicating that the session connection between the first UPF and the proxy device has been established. The T1 response may include an identifier of the first proxy connection. Correspondingly, the second SRF receives the T1 response.

[0232] 6028. The second SRF sends a fifth response, indicating that the session connection between the first UPF and the proxy device has been established. The fifth response may include an identifier of the first proxy connection. Correspondingly, the first SRF receives the fifth response.

[0233] 603. The first SMF establishes a session connection between the first UPF and the access network device.

[0234] The specific process of the first SMF establishing a session connection between the first UPF and the RAN can be found in the relevant description of step 203, and will not be repeated here.

[0235] Optionally, the aforementioned T2 response, T1 response, and fifth response may include the Internet Protocol (IP) address of the proxy device. During the process of the first SMF establishing a session connection between the first UPF and the RAN, the first SMF forwards the IP address of the proxy device to the RAN, which then sends it to the UE. In this embodiment, the proxy device is a proxy device supporting a multipath transmission protocol, such as a multipath quick UDP Internet connections (MPQUIC) proxy device or a multipath transmission control protocol (MPTCP) proxy device, or some other future proxy device supporting a multipath transmission protocol. After establishing the connection between the first UPF and the proxy device, and the connection between the first UPF and the RAN, the UE also initiates a multipath connection to the IP address of the proxy device to establish a connection between the UE and the proxy device. This way, even if the path from the first UPF to the proxy device is broken, the session connection can still be maintained through the path between the UE and the proxy device, thereby ensuring service continuity. Therefore, the method further includes the following steps:

[0236] 604. The first SMF registers the session context of the terminal device with the UDM.

[0237] The session context of a registered UE includes the session connection identifier (PDU session ID) associated with the established terminal device, the IP address of the first UPF, and the identifier (connection ID) of the first proxy connection.

[0238] 605. The terminal device triggers the establishment of the first agent connection with the agent device.

[0239] After receiving the AN resource establishment (or configuration) information sent by the RAN, the UE determines that it has accessed the first network. Then, the UE can initiate a first proxy connection request to the proxy device to request the addition of a connection between the UE and the proxy device in the session connection between the proxy device and the first UPF.

[0240] Optionally, the first proxy connection request may include the IP address of the first UPF and the identifier of the first proxy connection. After receiving the first proxy connection request, the proxy device can determine that the first proxy connection request was initiated through the first network based on the IP address of the first UPF. Then, the proxy device establishes a connection with the UE in the first proxy connection, stores the IP address of the first UPF and the identifier of the first proxy connection, and may also store the timestamp of the establishment of the first proxy connection to determine the time of establishment of the first proxy connection.

[0241] Optionally, the proxy device sends a first proxy connection response to the UE, indicating that a new connection has been added between the UE and the proxy device.

[0242] As can be seen, in this embodiment, the terminal device requests a session connection for a first service from the first network. After receiving the first session establishment request from the terminal device, the first SMF in the first network determines that the first service is within the service range of the second network, thus the server of the first service has a closer communication distance with the second network. Therefore, when establishing the session connection corresponding to the first service, a connection is established between the terminal device and the first UPF in the first network, and then a connection is established between the first UPF and the proxy device in the second network. This allows the terminal device to access the first network, while using the proxy device as the session anchor point for the terminal device to transmit service data with the server of the first service. This ensures lower communication latency between network elements in the network and the server of the first service. Simultaneously, managing the data of the first service through network elements in the second network ensures data security. Furthermore, this process establishes an additional multipath connection between the proxy device and the terminal device, ensuring the continuity of data transmission for the first service to a certain extent even if the second network disconnects from the proxy device.

[0243] Example 6: Based on the above examples, when a UE moves to the coverage area of ​​a second network while performing the first service, it can refer to... Figure 4B , Figure 4B A flowchart of another network handover method provided in the embodiments of this application is shown below. Figure 4B As shown, the method includes the following steps:

[0244] 701. The terminal device sends a first handover request through the access network device. The first handover request is used to request the handover of the terminal device's associated session connection to the second network. The first handover request is sent when the terminal device is within the coverage area of ​​the second network. Correspondingly, the second SMF receives the first handover request.

[0245] For a detailed description of this step, please refer to the relevant description of step 301 in the foregoing embodiments, which will not be repeated here.

[0246] 702. The second SMF establishes a core network connection to the second UPF.

[0247] In this embodiment, the established UE-related session connections include the connection between the RAN and the first UPF, and the connection between the first UPF and the proxy device. Additionally, the proxy device is also connected to the DN. That is, it does not include the connection to the second UPF. If the UE has moved to the coverage area of ​​the second network, the second UPF can be added to the UE-related session connections.

[0248] For example, the second SMF establishes a core network connection with the second UPF, that is, it establishes a connection between the second SMF and the second UPF, and a connection between the second UPF and the proxy device. The second SMF sends a connection establishment request, the second UPF executes the connection establishment, and sends a connection establishment response. The connection establishment request sent by the second SMF may include the IP address of the proxy device, so that the second UPF stores the IP address of the proxy device locally, thus completing the session connection establishment with the proxy device.

[0249] Optionally, before the second SMF establishes a connection between the second UPF and the proxy device, the method further includes: the second SMF sending a session context acquisition request to request the IP address of the proxy device. The UDM receives the session context acquisition request and sends a session context acquisition response, which includes the IP address of the proxy device.

[0250] 703. The second SMF establishes a session connection between the second UPF and the access network equipment.

[0251] The specific process of the second SMF establishing a session connection between the second UPF and the RAN can be found in step 203, which describes the process of the first SMF establishing a session connection between the first UPF and the RAN. In this process, the second SMF sends the CN tunnel information of the second UPF to the RAN. The RAN stores the CN tunnel information of the second UPF and deletes the CN tunnel information of the first UPF, thus establishing and releasing the session connection with the second UPF.

[0252] After the RAN completes the session connection establishment with the second SMF, it can send AN resources to the UE to indicate that the session connection between the UE and the second network is complete. At this time, the RAN can send the identifier of the first proxy connection to the UE, indicating that the first proxy connection has now been established and the connection between the second UPF and the proxy device has been established.

[0253] Optionally, before the second SMF sends a session establishment request to the RAN, the method further includes: the second SMF sending a session context acquisition request to request the identification of the first proxy connection. Specifically, the session context acquisition request may include a UE-related session connection identifier (PDU session ID) so that the UDM can obtain the identifier of the session connection associated with the proxy device within the PDU session ID, i.e., the identifier of the first proxy connection. The UDM receives the session context acquisition request and sends a session context acquisition response, which includes the identifier of the first proxy connection. The second SMF receives the session context acquisition response and obtains the identifier of the first proxy connection included in the session context acquisition response.

[0254] 704. The terminal device triggers the establishment of a second agent connection with the agent device.

[0255] After receiving the AN resource establishment (or reconfiguration) information sent by the RAN, the UE determines that it has accessed the second network. Additionally, the UE can receive the identifier of the first proxy connection sent by the RAN, confirming that a connection has been established between the proxy device and the second UPF. The UE can then initiate a second proxy connection request to the proxy device to update the connection between the UE and the proxy device established based on the first UPF in the first proxy connection to a connection established between the UE and the proxy device based on the second UPF, or in other words, to establish a second proxy connection.

[0256] Optionally, the second proxy connection request may include the IP address of the second UPF and the identifier of the first proxy connection. After receiving the second proxy connection request, the proxy device can determine that the second proxy connection request was initiated through the second network (or based on the second UPF) based on the IP address of the second UPF. Then, the proxy device updates the connection with the UE to a connection established based on the second UPF (still using the identifier of the first proxy connection to mark the connection).

[0257] Optionally, the proxy device updates the timestamp each time it establishes or updates its connection with the UE, in order to determine the time when the proxy device establishes a connection with the UE.

[0258] Optionally, the proxy device sends a second proxy connection response to the UE, indicating that the connection between the proxy device and the UE initiated based on the second UPF has been established.

[0259] 705. The agent device triggers the release of the connection with the first UPF.

[0260] The proxy device updates the connection between itself and the UE established through the first UPF to a connection established through the second UPF. This confirms that the connection has switched from the first network to the second network. At this point, the proxy device can release its connection to the first UPF.

[0261] For example, the process may include the following steps:

[0262] 7051. The proxy device sends a third release request, which is used to request the release of the connection of the first UPF in the session connection related to the terminal device. The connection of the first UPF includes the connection between the first UPF and the access network device, the connection between the first UPF and the proxy device, and the connection between the first UPF and the first SMF. The third release request may include an identifier of the first proxy connection. Correspondingly, the first UPF receives the third release request.

[0263] The connection between the first UPF and the agent device, and the connection between the first UPF and the first SMF, can also be referred to as the core network connection of the first UPF. The identifier of the first agent connection is generated when the agent device agrees to establish a connection with the first UPF.

[0264] 7052. The first UPF forwards the third release request to the first SMF. The first SMF receives the third release request.

[0265] After receiving the third release request, the first SMF can determine the corresponding first UPF based on the identifier of the first proxy connection, and then instruct the first UPF to release its own connection.

[0266] 7053. The first SMF sends a fourth release request, which requests the first UPF to release its connection with the first SMF. The first UPF receives the fourth release request.

[0267] 7054. The first UPF sends a fourth release response, indicating that the connection release with the first SMF has been completed. The first SMF receives the fourth release response.

[0268] The connection between the first UPF and the first SMF can be released by the first SMF directly instructing the first UPF to release it. That is, the first UPF releases the N4 session connection with the first SMF.

[0269] 7055. The first SMF sends a fifth release request, instructing the RAN to release the connection between the RAN and the first UPF. The RAN receives the fifth release request.

[0270] 7056. The RAN sends a fifth release response, indicating that the connection release between the RAN and the first UPF has been completed. The first SMF receives the fifth release response.

[0271] The connection between the first UPF and the RAN is established by the first SMF sending a request to the RAN, instructing the RAN to release the user plane connection with the first UPF. In other words, the RAN deletes the CN tunnel information of the first UPF.

[0272] 7057. The first UPF sends a third release response, indicating that the connection release of the first UPF has been completed. The agent device receives the third release response.

[0273] In the above steps, steps 7053-7054 and steps 7055-7056 do not have a strict order; any set of steps can be executed first. The first UPF triggers the sending of the third release response based on the received fourth release response.

[0274] As can be seen in this embodiment, when the terminal device moves to the coverage area of ​​the second network, it is triggered to send a first handover request to the second network. The first handover request is used to request the switching of the terminal device's related session connection to the second network, establish a connection between the second UPF and the RAN in the second network, and release the related connection of the first network. Furthermore, during the release of the first UPF, the terminal device maintains a connection with the proxy device in the second network, ensuring service continuity. Releasing the connection of the first network reduces overall communication latency.

[0275] It should be noted that a session connection of the terminal device has been established before executing the method of this embodiment. The method for establishing a session connection of the terminal device can be found in the foregoing. Figure 4A The communication method described, that is, before step 701, may also include the aforementioned steps 601 to 605. For a detailed description, please refer to the foregoing embodiments, which will not be repeated here.

[0276] Please see Figure 5 , Figure 5 This is a schematic diagram of a communication device provided in an embodiment of this application. This communication device can be used to execute any of the methods described in the foregoing embodiments.

[0277] like Figure 5 As shown, the communication device includes a processing module 1101 and a transceiver module 1102. The processing module 1101 may be one or more processors, and the transceiver module 1102 may be a transceiver or a communication interface. This communication device can be used to implement the functions of the first data plane network element, the control plane network element, and the second data plane network element involved in any of the above method embodiments. These network elements or network functions may be network components in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform). Optionally, the communication device may further include a storage module 1103 for storing the program code and data of the communication device.

[0278] In the first example, the communication device can function as a first device or a chip within a first device, and execute the steps performed by the first session management function (SMF) in embodiments one through six of the above methods. The transceiver module 1102 supports communication between the first SMF and other network elements. The processing module 1101 can be used to support the execution of actions performed by the first SMF in the above method embodiments, excluding sending and receiving.

[0279] Specifically, the transceiver module 1102 is used to receive a first session establishment request sent by the terminal device through the access network device. The first session establishment request is used to request the establishment of a session connection related to the terminal device. The first session establishment request includes the service information of the terminal device.

[0280] Processing module 1101, upon determining that the terminal device requests to execute the first service based on service information, establishes a session connection between the first user plane function (UPF) and the first communication device in conjunction with transceiver module 1102. The first UPF is located in the first network, the first service is within the service range of the second network, and the first communication device is a device in the second network connected to the server of the first service. The service range of the first network includes the service range of the second network, and the service range includes the coverage area and the service type. Processing module 1101, in conjunction with transceiver module 1102, establishes a session connection between the first UPF and the access network device.

[0281] In one feasible implementation, before establishing a session connection between the first user plane function and the first communication device, the transceiver module 1102 is further configured to: send a first request to the first user plane function and receive a first response from the first user plane function, wherein the first request is used to request the establishment of a session connection between the first session management function and the first user plane function, and the first response indicates that the session connection between the first session management function and the first user plane function has been established.

[0282] In one feasible implementation, the first communication device is a second UPF. Establishing a session connection between the first UPF and the first communication device includes: a transceiver module 1102 sending a second request to a second SMF, the second request being used to request the establishment of a session connection between the first UPF and the second UPF corresponding to the second SMF; the transceiver module 1102 receiving a second response from the second SMF, the second response including the core network tunnel information of the second UPF; the transceiver module 1102 sending a first modification request to the first UPF, the first modification request being used to request the addition of the core network tunnel information of the second UPF to the session connection of the first UPF; and the transceiver module 1102 receiving a first modification response from the first UPF, the first modification response indicating that the addition of the core network tunnel information of the second UPF is complete.

[0283] In one feasible implementation, before sending the second request to the second SMF, the transceiver module 1102 is further configured to: send a third request to the first network storage function NRF, the third request being used to request the identification of the second SMF, the third request including the identifier of the second network, the second SMF being located in the second network; and receive a third response from the first NRF, the third response including information about the second SMF.

[0284] In one feasible implementation, the first communication device is a proxy device. Establishing a session connection between the first UPF and the first communication device includes: the transceiver module 1102 sending a fifth request, which is used to request the establishment of a session connection between the first UPF and the proxy device, and the fifth request includes the core network tunnel information of the first UPF; the transceiver module 1102 receiving a fifth response, which indicates that the session connection between the first UPF and the proxy device has been established.

[0285] In one feasible implementation, the fifth request also includes routing information for a proxy management function in the second network, the routing information for which the proxy management function is used to address the proxy management function, and the proxy management function is used to determine the proxy device.

[0286] In one feasible implementation, the agent management function is a policy control function (PCF) or a network element that includes an agent management function (PCF).

[0287] In one feasible implementation, the service information is used to indicate a first service; or the service information indicates a target service identifier. The transceiver module 1102 is further configured to: send a first query request to the data management function UDM in the first network, the first query request being used to request the acquisition of the network service list of the terminal device; the transceiver module 1102 receives a first query response from the UDM, the first query response including the network service list of the terminal device, the network service list including the correspondence between multiple service identifiers and multiple networks, the multiple service identifiers including the target service identifier; and the processing module 1101 determines that the terminal device requests to execute the first service based on the target service identifier and the network service list.

[0288] In one feasible implementation, the subscription data also includes area information of the second network. Before establishing a session connection between the first UPF and the first communication device, the processing module 1101 is further configured to: determine the coverage area of ​​the second network that the terminal device will pass through during the process of acquiring the first service data.

[0289] In one feasible implementation, the first communication device is a second UPF. The transceiver module 1102 is further configured to receive a first release request from the second SMF, the first release request being used to request the release of the session connection between the first SMF and the first UPF; the transceiver module 1102 sends a second release request to the first UPF and receives a second release response from the first UPF, the second release request being used to request the release of the session connection between the first UPF and the first SMF, the second release response indicating that the connection release between the first UPF and the first SMF has been completed; the transceiver module 1102 sends a first release response to the second SMF, the first release response indicating that the connection release between the first UPF and the first SMF has been completed.

[0290] In a second example, the communication device can function as a second device or a chip within a second device, and execute the steps performed by the second session management function (SMF) in embodiments one through six of the above methods. The transceiver module 1102 supports communication between the second SMF and other network elements. The processing module 1101 can be used to support the execution of actions performed by the second SMF in the above method embodiments, excluding sending and receiving.

[0291] Specifically, the transceiver module 1102 is used to receive a first handover request sent by the terminal device through the access network device. The first handover request is used to request the switching of the terminal device's related session connection to the second network. The first handover request is sent by the terminal device when it is in the coverage area of ​​the second network. The terminal device's established related session connections include the session connection between the first UPF and the first communication device in the first network, and the session connection between the first UPF and the access network device. The first communication device is a device in the second network connected to the server of the first service. The processing module 1101 is used to modify or establish the core network connection of the second UPF in conjunction with the transceiver module 1102 in the terminal device's related session connection. The second UPF is located in the second network. The processing module 1101 is also used to establish the session connection between the second UPF and the access network device in conjunction with the transceiver module 1102, and release the session connection between the first UPF and the access network device.

[0292] In one feasible implementation, the processing module 1101 is further configured to trigger the release of the connection between the first UPF and the first SMF in conjunction with the transceiver module 1102, wherein the first SMF is located in the first network.

[0293] In one feasible implementation, triggering the release of the connection between the first UPF and the first SMF includes: the transceiver module 1102 sending a first release request to the first SMF, the first release request being used to request the release of the connection between the first SMF and the first UPF; the transceiver module 1102 receiving a first release response from the first SMF, the first release response indicating that the release of the connection between the first SMF and the first UPF has been completed.

[0294] In a third example, the communication device can function as a third device or a chip within a third device, and execute the steps performed by the proxy device in embodiments one through six of the above methods. The transceiver module 1102 supports communication between the proxy device and other network elements. The processing module 1101 can be used to support actions performed by the proxy device in the above method embodiments, excluding sending and receiving.

[0295] Specifically, processing module 1101 is used to send a third release request to the first UPF in conjunction with transceiver module 1102 when it is determined that the second proxy connection has been established and the first proxy connection has been released. The third release request is used to request the release of the session connection between the first UPF and the proxy device in the session connection related to the terminal device. The first proxy connection is the connection between the terminal device and the proxy device established based on the first UPF, and the second proxy connection is the connection between the terminal device and the proxy device established based on the second UPF. The first UPF is located in the first network, and the second UPF is located in the second network. Transceiver module 1102 is used to receive a third release response from the first UPF. The third release response indicates that the connection release between the first UPF and the access network device has been completed.

[0296] In one feasible implementation, before determining that the establishment of the second proxy connection has been completed and the first proxy connection has been released, the transceiver module 1102 is further configured to: receive a second proxy connection request from the terminal device, the second proxy connection request being used to request the establishment of a second proxy connection between the terminal device and the proxy device in a session connection related to the terminal device, and to release the first proxy connection between the terminal device and the proxy device; the transceiver module 1102 sends a second proxy connection response to the terminal device, the second proxy connection response indicating that the establishment of the second proxy connection has been completed and the first proxy connection has been released.

[0297] In one feasible implementation, the first proxy connection and the second proxy connection are MPQUIC connections.

[0298] Furthermore, a processor may include a controller, an arithmetic logic unit (ALU), and registers. For example, the controller is primarily responsible for instruction decoding and issuing control signals for the operations corresponding to the instructions. The ALU is primarily responsible for performing fixed-point or floating-point arithmetic operations, shift operations, and logical operations, and can also perform address operations and translations. Registers are primarily responsible for storing register operands and intermediate operation results temporarily stored during instruction execution. In specific implementations, the processor's hardware architecture can be an ASIC architecture, a microprocessor without interlocked piped stages architecture (MIPS), an advanced reduced instruction set machine (RISC) machine (ARM) architecture, or a network processor (NP) architecture, etc. The processor can be single-core or multi-core.

[0299] The storage module can be an internal storage module of the chip, such as a register or cache. Alternatively, the storage module can be an external storage module, such as ROM or other types of static storage devices that can store static information and instructions, such as RAM.

[0300] It should be noted that the functions of the processor and interface can be implemented through hardware design, software design, or a combination of both; no restrictions are imposed here.

[0301] Furthermore, it should be noted that the aforementioned transceiver unit and / or processing unit can be implemented through virtual modules. For example, the processing unit can be implemented through software functional units or virtual devices, and the transceiver unit can be implemented through software functions or virtual devices. Alternatively, the processing unit or transceiver unit can also be implemented through physical devices. For example, if the device is implemented using a chip / chip circuit, the transceiver unit can be an input / output circuit and / or a communication interface, performing input operations (corresponding to the aforementioned receiving operation) and output operations (corresponding to the aforementioned sending operation); the processing unit is an integrated processor, microprocessor, or integrated circuit.

[0302] Figure 6 This is a schematic diagram of another communication device provided in an embodiment of this application. Figure 6 As shown, the communication device 1200 may include one or more of the following components: processor 1201, memory 1202 and communication interface 1203. The processor 1201, memory 1202 and communication interface 1203 are interconnected and perform communication between them. The memory 1202 may store one or more computer programs. The one or more computer programs may be configured to implement the methods described in the above embodiments when executed by one or more processors 1201.

[0303] Processor 1201 may include one or more processing cores. Processor 1201 connects to various parts within the communication device 1200 using various interfaces and lines, and performs various functions and processes data of the communication device 1200 by running or executing instructions, programs, code sets, or instruction sets stored in memory 1202, and by calling data stored in memory 1202. Optionally, processor 1201 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). Processor 1201 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. It is understood that the aforementioned modem may also not be integrated into processor 1201, but may be implemented separately through a communication chip.

[0304] The memory 1202 may include random access memory (RAM) or read-only memory (ROM). The memory 1202 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 1202 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), and instructions for implementing the various method embodiments described above. The data storage area may also store data created during the use of the communication device 1200.

[0305] It is understood that the communication device 1200 may include more or fewer structural elements than those shown in the above block diagram.

[0306] This application provides a communication system, which includes a first device corresponding to a first session management function, a second device corresponding to a second session management function, or a third device corresponding to a proxy device.

[0307] This application provides a computer-readable storage medium storing computer instructions that, when executed, cause the computer to perform any of the methods described above.

[0308] This application provides a computer program product, which includes computer program code. When the computer program code is run, it causes the computer to perform any of the methods described above.

[0309] This application provides a chip coupled to a memory for reading and executing program instructions in the memory, so that the device in which the chip is located implements any of the methods described above.

[0310] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not described in detail in a particular embodiment can be found in the relevant descriptions of other embodiments. It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0311] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0312] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0313] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A communication method, characterized in that, Applied to a first session management network element, which is located in a first network, the method includes: The terminal device receives a first session establishment request sent through the access network device. The first session establishment request is used to request the establishment of a session connection related to the terminal device, and the first session establishment request includes the service information of the terminal device. When it is determined from the service information that the terminal device requests to execute the first service, a session connection is established between the first user plane network element and the first communication device. The first user plane network element is located in the first network, the first service is within the service range of the second network, and the first communication device is a device in the second network connected to the server of the first service. The service range of the first network includes the service range of the second network. Establish a session connection between the first user plane network element and the access network device.

2. The method according to claim 1, characterized in that, Before establishing a session connection between the first user plane network element and the first communication device, the method further includes: A first request is sent to the first user plane network element, and a first response is received from the first user plane network element. The first request is used to request the establishment of a session connection between the first session management network element and the first user plane network element, and the first response indicates that the session connection between the first session management network element and the first user plane network element has been established.

3. The method according to claim 1 or 2, characterized in that, The first communication device is a second user plane network element, and the step of establishing a connection between the first user plane network element and the first communication device includes: Send a second request to the second session management network element in the second network. The second request is used to request the establishment of a session connection between the first user plane network element and the second user plane network element corresponding to the second session management network element. Receive a second response from the second session management network element, the second response including the core network tunnel information of the second user plane network element; Send a first modification request to the first user plane network element. The first modification request is used to request that the core network tunnel information of the second user plane network element be added to the session connection of the first user plane network element. A first modification response is received from the first user plane network element, indicating that the core network tunnel information of the second user plane network element has been added.

4. The method according to claim 3, characterized in that, Before sending the second request to the second session management element in the second network, the method further includes: A third request is sent to the first network storage element. The third request is used to request the identification of the second session management element. The third request includes the identifier of the second network. The second session management element is located in the second network. A third response is received from the first network storage element, the third response including information from the second session management element.

5. The method according to claim 1 or 2, characterized in that, The first communication device is a proxy device, and the step of establishing a session connection between the first user plane network element and the first communication device includes: A fifth request is sent to the second signaling routing network element in the second network. The fifth request is used to request the establishment of a session connection between the first user plane network element and the proxy device. The fifth request includes the core network tunnel information of the first user plane network element. A fifth response is received, indicating that the session connection between the first user plane network element and the proxy device has been established.

6. The method according to claim 5, characterized in that, The fifth request also includes routing information of the proxy management network element in the second network. The routing information of the proxy management network element is used to address the proxy management network element, and the proxy management network element is used to determine the proxy device.

7. The method according to claim 6, characterized in that, The agent management network element is a policy control network element, or a network element that includes the agent management network element.

8. The method according to any one of claims 1-7, characterized in that, The service information is used to indicate a first service; or the service information indicates a target service identifier, and the method further includes: Send a first query request to the data management network element in the first network. The first query request is used to request the network service list of the terminal device. The system receives a first query response from the data management network element. The first query response includes a network service list of the terminal device. The network service list includes the correspondence between multiple service identifiers and multiple networks. The multiple service identifiers include the target service identifier. Based on the target service identifier and the network service list, it is determined that the terminal device requests to execute the first service.

9. The method according to any one of claims 1-8, characterized in that, The subscription data also includes the area information of the second network. Before establishing the session connection between the first user plane network element and the first communication device, the method further includes: It is determined that the terminal device will pass through the coverage area of ​​the second network during the process of acquiring the first service data.

10. The method according to any one of claims 1-9, characterized in that, The first communication device is a second user plane network element, and the method further includes: Receive a first release request from the second session management network element, the first release request being used to request the release of the session connection between the first session management network element and the first user plane network element; Send a second release request to the first user plane network element and receive a second release response from the first user plane network element. The second release request is used to request the release of the session connection between the first user plane network element and the first session management network element. The second release response indicates that the connection release between the first user plane network element and the first session management network element has been completed. Send a first release response to the second session management network element, the first release response indicating that the connection release between the first user plane network element and the first session management network element has been completed.

11. A communication method, characterized in that, Applied to a second session management network element, which is located in a second network, the method includes: The terminal device receives a first handover request sent through the access network device. The first handover request is used to request the switching of the terminal device's related session connection to the second network. The first handover request is sent when the terminal device is in the coverage area of ​​the second network. The terminal device's established related session connection includes the session connection between the first user plane network element and the first communication device in the first network, and the session connection between the first user plane network element and the access network device. The first communication device is a device in the second network that is connected to the server of the first service. In the session connection related to the terminal device, the core network connection of the second user plane network element is modified or established, and the second user plane network element is located in the second network; Establish a session connection between the second user plane network element and the access network device, and release the session connection between the first user plane network element and the access network device.

12. The method according to claim 11, characterized in that, The method further includes: Trigger the release of the connection between the first user plane network element and the first session management network element, wherein the first session management network element is located in the first network.

13. The method according to claim 12, characterized in that, The triggering of releasing the connection between the first user plane network element and the first session management network element includes: Send a first release request to the first session management network element. The first release request is used to request the release of the connection between the first session management network element and the first user plane network element. Receive a first release response from the first session management network element, the first release response indicating that the connection release between the first session management network element and the first user plane network element has been completed.

14. A communication method, characterized in that, Applied to a proxy device located in a second network, the method includes: It has been confirmed that the second proxy connection has been established and the first proxy connection has been released; The connection of the first user plane network element in the session connection related to the terminal device is triggered to be released. The connection of the first user plane network element includes the connection between the first user plane network element and the first session management network element, the connection between the first user plane network element and the proxy device, and the connection between the first user plane network element and the access network device. The first user plane network element and the first session management network element are located in the first network. The first proxy connection is the connection between the terminal device and the proxy device established based on the first user plane network element. The second proxy connection is the connection between the terminal device and the proxy device established based on the second user plane network element. The terminal device communicates with the access network device.

15. The method according to claim 14, characterized in that, The triggering of releasing the connection of the first user plane network element includes: A third release request is sent to the first user plane network element. The third release request is used to request the release of the connection of the first user plane network element. The connection of the first user plane network element includes the connection between the first user plane network element and the access network device, the session connection between the first user plane network element and the proxy device, and the connection between the first user plane network element and the first session management network element. Receive a third release response from the first user plane network element, the third release response indicating that the connection release of the first user plane network element has been completed.

16. The method according to claim 14 or 15, characterized in that, Before determining that the second proxy connection has been established and the first proxy connection has been released, the method further includes: Receive a second proxy connection request from a terminal device, the second proxy connection request being used to request the establishment of a second proxy connection between the terminal device and the proxy device in a session connection associated with the terminal device, and to release the first proxy connection between the terminal device and the proxy device; A second proxy connection response is sent to the terminal device, indicating that the establishment of the second proxy connection has been completed and the first proxy connection has been released.

17. The method according to any one of claims 14-16, characterized in that, The first proxy connection and the second proxy connection are multipath Fast User Datagram Protocol (FAP) network connections.

18. A communication device, characterized in that, Includes units or modules for implementing the method as described in any one of claims 1 to 17.

19. A communication device, characterized in that, The communication device includes at least one processor and a memory; The memory is used to store computer programs or instructions; the at least one processor is used to execute the computer programs or instructions in the memory, such that the method of any one of claims 1 to 17 is performed.

20. A communication system, characterized in that, The communication system includes a first session management network element and a second session management network element; Wherein, the first session management network element is used to perform the method as described in any one of claims 1 to 10, and the second session management network element is used to perform the method as described in any one of claims 11 to 13; or the communication system further includes a proxy device for performing the method as described in any one of claims 14 to 17.

21. A chip system, characterized in that, The chip system includes at least one processor, a memory, and an interface circuit. The memory, the interface circuit, and the at least one processor are interconnected via lines. The at least one memory stores instructions. When the instructions are executed by the processor, the method described in any one of claims 1-17 is implemented.

22. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, enables the implementation of the method according to any one of claims 1-17.

23. A computer program product, characterized in that, The computer program product includes instructions that, when executed, implement the method of any one of claims 1-17.

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