Distributed node switching method and device and storage medium

Abstract

The invention provides a distributed node switching method and device and a storage medium, applied to a terminal, the distributed node switching method comprises the following steps: receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session; and updating the IP address of the target PDU session by using the target IP address, wherein the target PDU session is the PDU session influenced by the node of the service terminal in the switching process. According to the invention, the independent target distributed node can be used for serving the terminal, and the time delay and loss of terminal signaling interaction and user plane data forwarding can be reduced.

Description

Technical Field

[0001] The present application relates to the field of communications, and in particular to a distributed node switching method, device and storage medium. Background Art

[0002] A distributed network includes multiple distributed nodes, each of which has complete control and data forwarding functions. Currently, in a distributed network, when a terminal moves from distributed node A to the service area of ​​distributed node B, the anchor point (user plane function that receives user data of the terminal) of the terminal's PDU (Protocol Data Unit) session is still in distributed node A. At this time, it is necessary to determine the target I-UPF (Intermediate-User Plane Function) among the multiple user plane functions corresponding to distributed node B, so as to forward the data sent by the terminal to the anchor point through the target I-UPF. In this solution, the control plane signaling interaction and user plane data transmission of the terminal's PDU session need to cross multiple distributed nodes (greater than or equal to 2), which leads to increased delay and loss in signaling interaction and user plane data forwarding. Summary of the invention

[0003] The present application provides a distributed node switching method, device and storage medium for reducing the delay and loss of terminal signaling interaction and user plane data forwarding.

[0004] In the first aspect, the present application provides a distributed node switching method, which is applied to a terminal, a distributed node switching method; receiving a message carrying the ID of a target PDU session and a target IP address of the target PDU session; using the target IP address to update the IP address of the target PDU session, the target PDU session is a PDU session affected by the node of the service terminal during the switching process.

[0005] In a second aspect, the present application provides a distributed node switching method, which is applied to a source distributed node. The distributed node switching method includes: receiving a switching request from a source wireless access network; and instructing a target distributed node to switch to serving a terminal alone.

[0006] In a third aspect, the present application provides a distributed node switching method, which is applied to a target distributed node. The distributed node switching method includes: selecting a network function for a service terminal; creating a terminal context for the terminal; and establishing a user plane path in the target distributed node for a target PDU session of the terminal.

[0007] In a fourth aspect, the present application provides a switching device for a distributed node, which is applied to a terminal, and the switching device for a distributed node includes:

[0008] A receiving module, used for receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session;

[0009] The update module is used to update the IP address of the target PDU session using the target IP address, where the target PDU session is the PDU session affected by the node of the service terminal during the switching process.

[0010] In a fifth aspect, the present application provides a switching device for a distributed node, which is applied to a source distributed node. The switching device for the distributed node includes:

[0011] A receiving module, used for receiving a handover request from a source wireless access network;

[0012] The instruction module is used to instruct the target distributed node to switch to serving the terminal alone.

[0013] In a sixth aspect, the present application provides a switching device for a distributed node, which is applied to a target distributed node, and the switching device for the distributed node includes:

[0014] A selection module, used to select a network function of a service terminal;

[0015] Create a module to create a terminal context for the terminal;

[0016] An establishing module is used to establish a user plane path at a target distributed node for a target PDU session of a terminal.

[0017] In a seventh aspect, the present application provides a terminal, including a memory, a transceiver, and a processor:

[0018] Memory for storing computer programs;

[0019] a transceiver for transmitting and receiving data under the control of the processor;

[0020] A processor is used to read the computer program in the memory and perform the following operations:

[0021] receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session;

[0022] The target IP address is used to update the IP address of the target PDU session, where the target PDU session is the PDU session affected by the node of the service terminal during the switching process.

[0023] In an eighth aspect, the present application provides a source distributed node, including a memory, a transceiver, and a processor:

[0024] Memory for storing computer programs;

[0025] a transceiver for transmitting and receiving data under the control of the processor;

[0026] A processor is used to read the computer program in the memory and perform the following operations:

[0027] receiving a handover request from a source wireless access network;

[0028] Instructs the target distributed node to switch to serving the terminal alone.

[0029] In a ninth aspect, the present application provides a target distributed node including a memory, a transceiver, and a processor:

[0030] Memory for storing computer programs;

[0031] a transceiver for transmitting and receiving data under the control of the processor;

[0032] A processor is used to read the computer program in the memory and perform the following operations:

[0033] Select the network function of the service terminal;

[0034] Create a terminal context for the terminal;

[0035] A user plane path is established at the target distributed node for the target PDU session of the terminal.

[0036] In a tenth aspect, the present application provides a processor-readable storage medium, the processor-readable storage medium storing a computer program, the computer program being used to cause a processor to execute the distributed node switching method of any one of the first aspect to the third aspect. ;

[0037] In an eleventh aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the distributed node switching method of the first to third aspects described above.

[0038] According to the distributed node switching method, device and storage medium provided in the present application, the distributed node switching method is applied to a terminal; a message carrying the ID of the target PDU session and the target IP address of the target PDU session is received; the IP address of the target PDU session is updated using the target IP address. The target PDU session is the PDU session affected by the node serving the terminal during the switching process. The present application receives the target IP address of the affected PDU session, and updates the IP address of the original target PDU session through the target IP address, thereby enabling the target distributed node to provide subsequent services for the terminal, and can reduce the delay and loss of terminal signaling interaction and user plane data forwarding.

[0039] It should be understood that the contents described in the above summary of the invention are not intended to limit the key or important features of the embodiments of the present application, nor are they intended to limit the scope of the present application. Other features of the present application will become easy to understand through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] Figure 1 A schematic diagram of the service architecture provided for the existing technology;

[0042] Figure 2 A schematic diagram of a preparation stage of a switching process provided by the prior art;

[0043] Figure 3 A schematic diagram of the execution phase of a switching process provided by the prior art;

[0044] Figure 4 A schematic diagram of a registration process provided for the prior art;

[0045] Figure 5 A schematic diagram of a cross-domain mobility switching management method provided by the prior art;

[0046] Figure 6 A schematic diagram of a preparation phase of a cross-domain mobility handover management method provided in the prior art;

[0047] Figure 7 A schematic diagram of the execution phase of a cross-domain mobility handover management method provided by the prior art;

[0048] Figure 8 A schematic diagram of an embodiment of the present application providing a target distributed node to serve a terminal alone;

[0049] Fig. 9 A schematic diagram of a preparation phase of a distributed node switching method provided in an embodiment of the present application;

[0050] Fig.10 A schematic diagram of an execution phase of a distributed node switching method provided in an embodiment of the present application;

[0051] Fig.11 A schematic diagram of a registration process provided in an embodiment of the present application;

[0052] Fig.12 A schematic diagram of an execution phase of another distributed node switching method provided in an embodiment of the present application;

[0053] Fig.13 A schematic diagram of an execution phase of another distributed node switching method provided in an embodiment of the present application;

[0054] Fig.14 A structural block diagram of a first target type of distributed node switching device provided in an embodiment of the present application;

[0055] Fig.15 A structural block diagram of a second distributed node switching device provided in an embodiment of the present application;

[0056] Fig.16 A structural block diagram of a third distributed node switching device provided in an embodiment of the present application;

[0057] Fig.17 A structural block diagram of a fourth distributed node switching device provided in an embodiment of the present application;

[0058] Fig.18 A structural block diagram of a fourth distributed node switching device provided in an embodiment of the present application;

[0059] Fig.19 This is a structural block diagram of the fifth distributed node switching device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0060] In the present application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers 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 mean: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0061] It is understandable that the various steps or operations in the embodiments of the present application are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the various steps may be performed in different orders presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0062] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0063] The technical solution provided in the embodiment of the present application can be applicable to a variety of systems, especially 6G systems. For example, the applicable system can be a global system of mobile communication (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) general packet radio service (GPRS) system, a long term evolution (LTE) system, a LTE frequency division duplex (FDD) system, a LTE time division duplex (TDD) system, an advanced long term evolution (LTE-A) system, a universal mobile telecommunication system (UMTS), a world-wide interoperability for microwave access (WiMAX) system, a 6G new air interface (NR) system, etc. These various systems include terminals and network equipment. The system may also include a core network part, such as an evolved packet system (EPS), a 6G system (6GS), etc.

[0064] In order to understand this solution more clearly, the existing technology of this solution and the problems existing in the existing technology are briefly described as follows:

[0065] 1. Explanation of relevant abbreviations:

[0066] UPF (User Plane Function), AMF (Access and Mobility Management Function), SMF (Session management function), PCF (Policy Control Function), AF (Application Function), NSSF (Network slice selection function), AUSF (Authentication server function), UDM (Unified Data Management), NSACF (The Network Slice Admission Control Function), NSSAAF (Network Slice-Specific Authentication and Authorization Function) and DN (Data Network). In addition, N1, N2, and N4 are all communication interfaces of the corresponding network elements.

[0067] 2. 6G Architecture

[0068] The 6G architecture will be a new network architecture that integrates centralized control mobile communication networks and open Internet, and where centralized and decentralized networks coexist. It is necessary to go beyond centralized control and gradually evolve to a distributed architecture, expand more networks to the edge of the network, and establish distributed homogeneous micro-cloud units with different functional levels. Each micro-cloud unit is self-contained and has all the functions of complete control and data forwarding.

[0069] Here, the distributed network node is the micro cloud unit deployed at the edge of the network, or the edge network.

[0070] 3. Distributed Network Service Mode

[0071] Reference Figure 1 It is a distributed network service mode, including terminal UE, source radio access network (S-RAN), source distributed node, target radio access network (T-RAN) and target distributed node, wherein the source distributed node includes: source session management function (S-SMF), source user plane function (S-UPF) and other network elements. The target distributed node includes: target session management function (T-SMF), intermediate user plane function (I-UPF) and other network elements. Based on Figure 1 In a distributed network scenario, when a UE moves from a source distributed node to the service area of ​​a target distributed node, the source distributed node and the target distributed node need to work together to serve the UE. Specifically, the anchor point (S-UPF) of the PDU (Protocol Data Unit) session is still in the source distributed node, and an I-UPF needs to be inserted in the target distributed node to forward the control plane signaling of the UE's PDU session to the source distributed node. At this time, the control plane signaling interaction and user plane data transmission of the PDU session need to cross multiple distributed nodes, resulting in increased delay and loss in signaling interaction and user plane data forwarding. The more distributed nodes are crossed, the more obvious this disadvantage is.

[0072] 4. A N2 (an interface) handover process provided by 3GPP TS 23.502 4.9.1.3 includes a preparation phase and an execution phase. The preparation phase in the handover process refers to Figure 2 , including the following steps:

[0073] 201. Decide to trigger repositioning via N2.

[0074] 202. Switch request.

[0075] 203. Select T-AMF.

[0076] 204. Create UE context request.

[0077] 205. PDU session update SM context request.

[0078] 206. Select UPF.

[0079] 207, N4 session modification request

[0080] 208. N4 session modification response.

[0081] 209. N4 session establishment request.

[0082] 210. N4 session establishment response.

[0083] 211. PDU session update SM context response.

[0084] 212. PDU session switching response supervision.

[0085] 213. Switch request.

[0086] 214. Switch request confirmation.

[0087] 215. PDU session update SM context request.

[0088] 216. N4 session modification request.

[0089] 217. N4 session modification response.

[0090] 218. N4 session modification request.

[0091] 219. N4 session modification response.

[0092] 220. PDU session update SM context response.

[0093] 221. Create UE context response.

[0094] The execution phase in the switching process refers to Figure 3 , including the following steps: 301, switching command.

[0095] 302. Switch command.

[0096] 303. Uplink RAN ​​state transfer.

[0097] 304. N1N2 message transmission.

[0098] 305. Downlink RAN ​​state transfer.

[0099] 306. Direct data forwarding.

[0100] 307. Indirect data forwarding.

[0101] 308. Switch confirmation.

[0102] 309. Switch notification.

[0103] 310. N2 information notification.

[0104] 311. N2 information notification confirmation.

[0105] 312. PDU session release SM context request.

[0106] 313. PDU session update SM context request.

[0107] 314. N4 session modification request.

[0108] 315. N4 session modification response.

[0109] 316. N4 session modification request.

[0110] 317. N4 session modification response.

[0111] 318. N4 session modification request.

[0112] 319. N4 session modification response.

[0113] 320. PDU session update SM context response.

[0114] 321. Registration process.

[0115] 322. N4 session release request.

[0116] 323. N4 session release response.

[0117] 324. UE context release command.

[0118] 325. UE context release is completed.

[0119] 326. N4 session update request.

[0120] 327. N4 session update response.

[0121] 5. Registration process provided by 3GPP TS23.502 4.2.2 (including mobility registration update process):

[0122] Among them, in the registration process, T-AMF (target access and mobility management function) knows that this is a handover process, and only executes a subset of the registration process in the 3GPP protocol, especially skipping steps 4, 5 and 10 of the context handover between S-AMF (source access and mobility management function) and T-AMF in the registration process, refer to Figure 4 , specifically including the following steps:

[0123] 401, Registration request.

[0124] 402. Select T-AMF.

[0125] 403, Registration request.

[0126] 404. UE context transmission.

[0127] 405. UE context transfer response.

[0128] 406, Identity Request.

[0129] 407, Identity Response.

[0130] 408. Select T-AUSF.

[0131] 409, Authentication / Security Verification.

[0132] 410. Registration status updated.

[0133] 411, Identity request / response.

[0134] 412. N5g EIR equipment identification check acquisition.

[0135] 413. Select T-UDM.

[0136] 414.UECM registration.

[0137] 415. Get SDM.

[0138] 416. SDM subscription.

[0139] 417. UECM deregistration notification.

[0140] 418. SDM cancels subscription.

[0141] 419. AM Strategy Association E established / modified.

[0142] 420. The PDU session updates the SM context.

[0143] 421. UE context modification request.

[0144] 422. UE context modification response.

[0145] 423.UECM registration.

[0146] 424. UECM1 registration notification.

[0147] 425. SDM cancels subscription.

[0148] 426. Accept registration.

[0149] 427. UE policy association is established.

[0150] 428. Registration completed.

[0151] 429. SDM information.

[0152] 430. N2 message.

[0153] 431. SDM update.

[0154] VI. A cross-domain mobility switching management method

[0155] like Figure 5 As shown, the terminal moves from the source distributed node to the target distributed node. Figure 5 There may be more than one user plane function (UPF) described later. Mobile switching across distributed nodes involves three parts: the control plane of the core network, the user plane of the core network, and the radio access network (RAN).

[0156] 1) For the core network control plane:

[0157] First, when a UE moves and switches across distributed nodes, the control plane of the target distributed node performs context management and related control, such as Figure 6 The preparation stage and Figure 7 The execution phase is shown in Figure 1.

[0158] Reference Figure 6 The preparation phase includes the following steps:

[0159] 601. Decision to switch.

[0160] 602. Switching request.

[0161] 603. Target distributed node selection and T-AMF selection.

[0162] 604. Create context request (carrying S-SMF identifier).

[0163] 605.T-SMF selection.

[0164] 606. Switch notification and response.

[0165] 607. Conversation context interaction.

[0166] 608. Switch request and confirmation.

[0167] 609. Session update request and response.

[0168] 610. Create UE context response.

[0169] Reference Figure 7 , the execution phase includes the following steps:

[0170] 701. Switch command.

[0171] 702. Switch command.

[0172] 703. Send RAN status information and DL data forwarding.

[0173] 704. Cell switching.

[0174] 705. Switch confirmation.

[0175] 706. Switch notification.

[0176] 707. Switch notification.

[0177] 708. Release the session context.

[0178] 709. Session context update request and response.

[0179] 710. Release UE context.

[0180] In summary, for the selection of network functions in the control plane of the target distributed node, such as the selection of T-AMF, the selection of the target distributed node needs to be completed first. The S-AMF of the source distributed node locally or calls a new network function (such as a node selection function) to complete the selection of the target distributed node based on the T-RAN identifier, node service information, UE context, etc. The selection of T-AMF and the interaction between S-AMF and T-AMF can be that S-AMF completes the selection of T-AMF locally and interacts; or S-AMF first sends a message to the default AMF of the target distributed node, and the default AMF then performs the selection of T-AMF; or it can be S-AMF, the default AMF of the source distributed node, the default AMF of the target distributed node, and the default AMF of the target distributed node then performs the selection of T-AMF. The interaction of network functions between distributed nodes can be direct interaction or indirect interaction through a centralized node. For example, the information interaction between S-AMF and T-AMF can be direct information interaction or indirect interaction through a centralized node. After receiving the context creation request, T-AMF selects T-SMF, where how to select T-SMF is not within the scope of this application. T-AMF and T-SMF request to create a session context, and the request carries information about the S-session management function. S-SMF selects T-UPF and interacts with the selected T-UPF to establish or modify session-related information and user plane paths, which may include the establishment of inter-domain forwarding paths. After the switch is completed, T-SMF interacts with S-SMF to release the session context maintained at S-SMF, including the user plane path related to S-SMF and S-UPF.

[0181] 2) For the core network user plane:

[0182] like Figure 5 As shown, cross-domain mobility management involves user plane paths. The user plane path after the final switch can be path 1, where the terminal first accesses the T-UPF of the target distributed node through T-RAN, then forwards data through the S-UPF of the source distributed node, and accesses the DN (Data Network); it can also be path 2, where the terminal directly accesses the DN through the T-UPF of the target distributed node. Path 1, a cross-domain user plane path, will involve the above-mentioned inter-domain forwarding path. During the switching process, for downlink data forwarding, if there is a connection between S-RAN and T-RAN (such as an IP connection), path 2 is used for direct forwarding; if there is no connection between S-RAN and T-RAN, indirect forwarding is used using the user plane connection between distributed nodes (path 1).

[0183] 3) For RAN:

[0184] Figure 5The S-RAN and T-RAN before and after the switching may not be the same device and there may be no Xn interface between them (among which: the interface between two base stations in 5G is the Xn interface, which may not be the name in 6G), may not be the same device and there may be an Xn interface between them, or the cell of the same device may change.

[0185] Above Figures 1 to 7 All of them are solutions adopted in the prior art.

[0186] 7. Technical Problem Analysis

[0187] Based on the above existing technologies, there are technical problems including: 1) The UE's PDU session needs to be collaboratively served by multiple distributed nodes, which increases the load of network functions and the complexity of cross-node interaction. 2) The delay and loss of control plane signaling interaction and user plane data transmission across multiple distributed nodes increase.

[0188] Specifically, in a distributed network, when a UE registers with the network, it is at the distributed node granularity, that is, the UE registers with a certain distributed node, and the UE's registration area is part or all of the distributed node service area. When the UE moves out of the service range of the distributed node, the mobility registration update process will be executed, and the network element of the distributed network node currently serving the UE will serve the UE. However, in order to ensure the continuity of the session, in the prior art, the PSA (anchor UPF) will be kept unchanged during switching, resulting in the need for SMFs and UPFs of multiple distributed nodes to serve the UE.

[0189] The invention concept of this application refers to Figure 8 , after the distributed node switching method provided by the present application, a separate target distributed node can be directly used to serve the UE. The distributed node switching method provided by the present application, when the UE moves to the service area of ​​the target distributed node, if the target distributed node can meet the PDU session requirements of the UE, then the T-PSA (target anchor user plane function) is reselected for the PDU session in the target distributed node or the PDU session is re-established for the UE and the PDU session of the original distributed node is released, so as to ensure that the UE is served by a single distributed node (target distributed node) after it moves to the service area of ​​the target distributed node, that is, the switching of the distributed node granularity is completed.

[0190] The following is a specific embodiment of the handover method of the distributed node provided by the present application, wherein, when the service area of ​​the source distributed node of the terminal (UE) moves to the service area of ​​the target distributed node, the handover method of the distributed node provided by the present application is executed. The present application is an interaction between the terminal (UE), the source radio access network (S-RAN), the target radio access network (T-RAN), the source distributed node and the target distributed node, the source distributed node and the S-RAN provide services to the terminal before the movement, and the target distributed node and the T-RAN provide services to the terminal after the movement. In addition, the source distributed node includes: a source access and mobility management function (S-AMF), a source session management function (S-SMF), a source user plane function (S-UPF) and a source anchor user plane function (S-PSA). The target distributed node includes: a target access and mobility management function (T-AMF), a target session management function (T-SMF), a target user plane function (T-UPF) and a target anchor user plane function (T-PSA).

[0191] Embodiment 1: In the N2 (RAN to AMF interface) handover preparation phase, the T-SMF of the target distributed node reselects the T-PSA for the relevant PDU session and re-establishes the user plane path for the UE at the target distributed node, specifically including the following: Fig. 9 The preparation phase shown and Fig.10 The execution phase shown, wherein reference Fig. 9 The preparation phase includes the following steps:

[0192] 901. Decide that N2 triggers repositioning.

[0193] 902. Switching requirements.

[0194] The S-RAN sends a switching request to the S-AMF, where the switching request includes: all PDU session information processed by the S-RAN, and indication information on whether a direct forwarding path from the S-RAN to the T-RAN is available.

[0195] 903. Select target distributed node.

[0196] Among them, the S-AMF can determine the target distributed node based on the current location of the terminal and relevant information of the UE, and the target service distributed node provides services to the terminal.

[0197] 904. Create UE context request.

[0198] Then, the S-AMF sends a Create UE Context Request to the T-AMF of the selected target distributed node.

[0199] 905.T-SMF selection.

[0200] Among them, T-AMF selects T-SMF to serve the UE based on the received create UE context request. Specifically, T-AMF selects T-SMF from each SMF based on the location of the UE and the service scope of each SMF in the target distributed node.

[0201] 906. PDU session creates SM context request.

[0202] Among them, after selecting T-SMF, T-AMF sends a PDU session creation SM (session management) context request to the selected T-SMF.

[0203] 907. PDU session context request.

[0204] Among them, after receiving the PDU session creation SM context request, the T-SMF sends a PDU session context request to the S-SMF, which is used to request the PDU session context of the UE.

[0205] 908. PDU session context response.

[0206] After receiving the PDU session context request, the S-SMF sends a PDU session context response to the T-SMF, and the PDU session context response carries the PDU session context of the UE. In this way, the T-SMF obtains the PDU session context of the UE.

[0207] 909.UPF selection.

[0208] Among them, after receiving the PDU session context of the UE, the T-SMF selects a T-UPF that can provide services for the UE in the target distributed node and reselects the anchor UPF (T-PSA), wherein the T-PSA selects the anchor UPF that serves the UE in the target distributed node.

[0209] Among them, in steps 906 to 909, T-SMF obtains the context of the UE's PDU session from S-SMF, and reselects T-PSA for the PDU session. If the UE's IP is dynamically allocated, T-SMF reallocates the IP address or IP address prefix for the PDU session; if the UE subscribes to a static IP address or prefix, there is no need to reallocate the IP address or IP address prefix for the PDU session, and the PDU session uses the previous IP address.

[0210] 910. N4 session establishment request.

[0211] Among them, after selecting T-UPF, T-SMF sends N4 (a communication interface between SMF and UPF) session establishment request to T-UPF.

[0212] 911. N4 session establishment response.

[0213] Among them, after T-UPF receives the N4 session establishment request, it sends an N4 session establishment response to T-SMF.

[0214] 912. N4 session establishment request.

[0215] Among them, after selecting T-PSA, T-SMF sends an N4 session establishment request to T-PSA.

[0216] 913. N4 session establishment response.

[0217] After T-PSA receives the N4 session establishment request, it sends an N4 session establishment response to T-SMF.

[0218] In steps 910 to 913, T-SMF sends FAR (packet forwarding rule) and PDR (packet detection rule) to T-UPF / T-PSA through N4 session establishment request based on the UE IP of the target PDU session, and establishes a new user plane path for the PDU session. If an indirect forwarding tunnel is used from S-RAN to T-RAN, T-SMF simultaneously sends PDR and FAR about the original IP of the PDU session to T-UPF. At this time, T-UPF needs to allocate three TE IDs (i.e., tunnel endpoint identifiers of S-RAN, T-RAN and T-UPF).

[0219] 914. PDU session creates SM context response.

[0220] Among them, after completing steps 907 to 913, T-SMF completes the PDU session creation SM context and sends a PDU session creation SM context response to T-AMF.

[0221] 915. PDU switching response supervision.

[0222] Among them, the PDU switching response supervision of T-AMF is used to supervise whether the PDU session creation SM context response sent by T-SMF is received.

[0223] 916. Switch request.

[0224] Among them, if T-AMF receives the PDU session creation SM context response sent by T-SMF, it sends a switching request to T-RAN.

[0225] 917. Switch request confirmation.

[0226] After receiving the handover request, T-RAN sends a handover request confirmation to T-AMF.

[0227] 918. PDU session update SM context request.

[0228] Among them, T-AMF sends a PDU session update SM context request to T-SMF.

[0229] 919. N4 session update request.

[0230] The T-SMF sends an N4 session update request to the T-UPF. The N4 session update request carries the tunnel information of the T-RAN to establish a downlink forwarding tunnel from the T-UPF to the T-RAN.

[0231] 920. N4 session update response.

[0232] Among them, T-UPF sends an N4 session update response to T-SMF.

[0233] 921. PDU session update SM context response.

[0234] Among them, T-SMF sends a PDU session update SM context response to T-AMF.

[0235] 922. Create UE context response.

[0236] Among them, after completing steps 906 to 921, T-AMF sends a create UE context response to S-AMF in response to the create UE context request in step 904.

[0237] Specifically, the create UE context response sent by T-AMF to S-AMF carries the IP address newly allocated by T-SMF for the PDU session and the ID of the PDU session.

[0238] Further, if an indirect forwarding tunnel is used from S-RAN to T-RAN, steps 923 to 926 are executed, otherwise steps 923 to 926 do not need to be executed.

[0239] 923. PDU session update SM context request.

[0240] Among them, S-AMF sends a PDU session update SM context request to S-SMF.

[0241] 924. N4 session modification request.

[0242] Among them, the S-SMF sends an N4 session modification request to the S-UPF, and the N4 session modification request carries the tunnel information of the T-UPF to establish a forwarding tunnel from the S-UPF to the T-UPF.

[0243] 925. N4 session modification response.

[0244] Among them, S-UPF sends an N4 session modification response to S-SMF.

[0245] 926. PDU session update SM context response.

[0246] Among them, S-SMF sends a PDU session update SM context response to S-AMF.

[0247] Reference Fig.10 The execution phase specifically includes the following steps:

[0248] 1001. Switch instruction.

[0249] Among them, S-AMF sends a switching instruction message to S-RAN. If T-SMF newly allocates an IP address for the PDU session, the switching instruction carries the IP address newly allocated by T-SMF for the PDU session and the PDU session ID.

[0250] 1002. Switch instruction.

[0251] The S-RAN sends a switching command message to the UE, which includes the IP address newly allocated by the T-SMF for the PDU session and the ID of the PDU session, wherein the UE determines the corresponding PDU session according to the ID of the PDU session, and then uses the newly allocated IP address to update the PDU session IP address stored in the UE.

[0252] 1003. Uplink RAN ​​status transmission.

[0253] At the same time, S-RAN transmits the uplink RAN ​​status to S-AMF.

[0254] 1004. N1N2 message transmission.

[0255] Among them, S-AMF sends N1N2 message transmission message to T-AMF.

[0256] 1005. Downlink RAN ​​status transmission.

[0257] Among them, T-AMF can transmit downlink RAN ​​status message to T-RAN.

[0258] 1006. Direct data forwarding.

[0259] If a direct forwarding path between the S-RAN and the T-RAN is available, the S-RAN forwards data to the T-RAN using direct forwarding.

[0260] 1007. Indirect data forwarding.

[0261] If the direct forwarding path between S-RAN and T-RAN is not available, the indirect data path from S-RAN to S-UPF to T-UPF to T-RAN is used for data forwarding.

[0262] 1008. The UE synchronizes to the new cell.

[0263] In addition, the new cell refers to a cell served by the target distributed node.

[0264] 1009. Switch confirmation.

[0265] Among them, after the UE sends a switching confirmation message to T-RAN, the user plane path from UE to T-RAN to the target distributed node has been activated. After that, user data is forwarded on the new user plane path, and the forwarding uses the new IP allocated by T-SMF for the PDU session.

[0266] 1010. Uplink / downlink user plane data.

[0267] After the user plane path from UE to T-RAN to the target distributed node (UE to T-RAN to T-UPF to T-PSA) has been activated, the transmission of uplink user plane data and downlink user plane data can be achieved through the user plane path (UE to T-RAN to T-UPF to T-PSA).

[0268] 1011. Switch notification.

[0269] Among them, T-RAN sends a switching notification to T-AMF.

[0270] 1012. N2 message notification.

[0271] T-AMF sends N2 information notification to S-AMF.

[0272] 1013. N2 message notification confirmation.

[0273] S-AMF sends N2 information notification confirmation to T-AMF.

[0274] 1014. PDU session release SM context request.

[0275] Among them, S-AMF sends a PDU session release SM context request to S-SMF so that S-SMF releases the UE's PDU session.

[0276] 1015. PDU session update SM context request.

[0277] Among them, T-AMF sends a PDU session update SM context request to T-SMF. The PDU session update SM context request includes: a timer value started in S-AMF, so that T-SMF starts a timer based on the timer value to release the resources of the indirect forwarding tunnel of the original IP of the PDU session in T-UPF.

[0278] 1016. Registration process.

[0279] The registration process is as above Figure 5 , I will not go into details here.

[0280] 1017. N4 session release request.

[0281] Among them, S-SMF sends an N4 session release request to S-UPF.

[0282] 1018. N4 session release response.

[0283] Among them, after the S-UPF deletes the target PDU session information on it, it sends an N4 session release response to the S-SMF.

[0284] 1019. N4 session release request.

[0285] Among them, S-SMF sends an N4 session release request to S-PSA.

[0286] 1020. N4 session release response.

[0287] Among them, S-PSA deletes the target PDU session information thereon and sends an N4 session release response to S-SMF.

[0288] 1021. N4 session release request.

[0289] Among them, T-SMF sends an N4 session release request to T-UPF.

[0290] 1022. N4 session release response.

[0291] Among them, after T-UPF deletes the relevant information about the first IP address of the PDU session, it returns an N4 session release response to T-SMF.

[0292] 1023. PDU session update SM context response.

[0293] Among them, S-SMF sends an update SM context response to S-AMF.

[0294] In steps 1017 to 1022, after the timer times out, the S-SMF releases the user plane path, indirect forwarding tunnel and related SM context of the relevant PDU session of the source distributed node, and the T-SMF releases the resources of the indirect forwarding tunnel in the T-UPF of the target PDU session of the source distributed node. In this embodiment of the present application, the target PDU session refers to the PDU session affected during the switching process.

[0295] 1024. PDU session update SM context response.

[0296] Among them, T-SMF sends a PDU session update SM context response to T-AMF in response to the PDU session update SM context request in step 1015.

[0297] 1025. UE context release command.

[0298] The S-AMF sends a UE context release command to the S-RAN to instruct the S-RAN to release the UE context.

[0299] 1026. UE context release request completed.

[0300] Among them, after S-RAN releases the UE context, it sends a UE context release request completion to S-AMF.

[0301] In an embodiment of the present application, after the timer expires, the release process of steps 1007-1026 can be executed, so that the S-SMF releases the user plane path, indirect forwarding tunnel and related SM context of the relevant PDU session of the source distributed node, and the T-SMF releases the resources of the indirect forwarding tunnel in the T-UPF.

[0302] After that, the user's uplink and downlink data are forwarded based on the user plane path of T-RAN—T-UPF—T-PSA, realizing a single distributed node serving the UE.

[0303] Embodiment 2 includes: according to "a cross-domain mobility switching management method" (refer to Figure 6 and Figure 7 ) method. That is, through Figure 6 preparation stage and Figure 7 During the execution phase, an indirect forwarding tunnel is established (if necessary). Figure 4 ) in which T-SMF reselects T-PSA and establishes a path from T-RAN to T-PSA. Since T-SMF has been selected in the preparation and execution phases, the relevant steps of the mobility registration update process can be omitted ( Figure 4 402 in step 402). Fig.11 , specifically including the following steps:

[0304] 1101. Registration Process( Figure 4 ) in steps 401-416.

[0305] Among them, this step includes Figure 4 401 to 416.

[0306] 1102. PDU session update SM context request.

[0307] Among them, T-AMF sends a PDU session update SM context request to T-SMF.

[0308] 1103. UPF selection.

[0309] After receiving the PDU session context of the UE, the T-SMF selects a T-UPF that can provide services to the UE in the target distributed node and reselects the anchor UPF (T-PSA), where the T-PSA is the anchor UPF that serves the UE in the target distributed node.

[0310] 1104. N4 session establishment request.

[0311] Among them, after selecting T-UPF, T-SMF sends N4 (a communication interface between SMF and UPF) session establishment request to T-UPF.

[0312] 1105. N4 session establishment response.

[0313] Among them, after T-UPF receives the N4 session establishment request, it sends an N4 session establishment response to T-SMF.

[0314] 1106. N4 session establishment request.

[0315] Among them, after selecting T-PSA, T-SMF sends an N4 session establishment request to T-PSA.

[0316] 1107. N4 session establishment response.

[0317] After T-PSA receives the N4 session establishment request, it sends an N4 session establishment response to T-SMF.

[0318] Among them, step 1104 to step 1107 may correspond to step 910 to step 913.

[0319] 1108. N4 session establishment / change request.

[0320] T-SMF sends an N4 session establishment / change request to T-UPF.

[0321] 1109. N4 session establishment / change response.

[0322] The T-UPF sends an N4 session establishment / modification response to the T-SMF. In step 1103, if the selected T-UPF is the same as the T-UPF used when establishing the indirect forwarding path, steps 1104 and 1105 do not need to be performed.

[0323] 1110. PDU session update SM context response.

[0324] Among them, T-SMF sends a PDU session update SM context response to T-AMF in response to the PDU session update SM context request in step 1102.

[0325] 1111. Registration accepted.

[0326] Among them, T-AMF sends a registration acceptance to the UE. Specifically, the tunnel information of T-UPF is sent to T-RAN along with the registration acceptance message. At the same time, the ID (identifier) ​​of the PDU session and the newly allocated IP address of the PDU session are sent to the UE. After receiving it, the UE uses the new IP address to send user data to the user plane path from T-RAN to T-PSA.

[0327] 1112. Registration completed.

[0328] The UE sends a registration complete message to the T-AMF.

[0329] 1113. Uplink / downlink user data.

[0330] After the above steps 1101 to 1112 are completed, the transmission of uplink user data and downlink user data from UE to T-RAN to T-UPF to T-PSA can be realized.

[0331] 1114. PDU session update SM context request.

[0332] Among them, T-AMF sends a PDU session update SM context request to T-SMF.

[0333] 1115. PDU session update SM context request.

[0334] T-SMF sends a PDU session update SM context request to S-SMF.

[0335] 1116. N4 session release request.

[0336] S-SMF sends an N4 session release request to S-PSA to enable S-PSA to release the UE's PDU session.

[0337] 1117. N4 session release response.

[0338] S-PSA sends an N4 session release response to S-SMF.

[0339] 1118. PDU session update SM context response.

[0340] S-SMF sends a PDU Session Update SM Context Response to T-SMF in response to step 1115

[0341] 1119. PDU session update SM context response.

[0342] T-SMF sends a PDU session update SM context response to T-AMF in response to step 1114.

[0343] In steps 1114 to 1119, after receiving the registration completion message from the UE, the T-AMF sends a message to the T-SMF to instruct the T-SMF to send a message to the S-SMF so that the S-SMF releases the path from the S-UPF to the S-PSA.

[0344] 1120. Registration process.

[0345] The registration process includes Figure 4 Steps 427 to 430 in .

[0346] The release of the indirect forwarding tunnel is the same as Fig. 9 and Fig.10 shown.

[0347] After that, the user's uplink and downlink data are forwarded based on the user plane path of T-RAN—T-UPF—T-PSA, realizing a single distributed node serving the UE.

[0348] In this embodiment, T-SMF selects UPF based on PDU session context information. T-SMF sends an N4 message to UPF to establish a user plane path from T-RAN to T-PSA. In addition, the tunnel information of T-UPF is sent to T-RAN along with the registration acceptance message. At the same time, the PDU session ID (identifier) ​​and the newly assigned target IP address of the PDU session are sent to the UE. After receiving it, the UE uses the new target IP address to send user data to the user plane path from T-RAN to T-PSA. After receiving the registration completion message from the UE, T-AMF sends a message to T-SMF to instruct T-SMF to send a message to S-SMF to enable S-SMF to release S-PSA and the path from S-UPF to S-PSA.

[0349] This embodiment can add a small amount of technical features on the basis of the existing technology to realize a single distributed node serving the UE.

[0350] Embodiment 3, after completing Figure 2After the preparation phase shown, refer to Fig.12 In steps 1201 and 1202, the S-AMF in the source distributed node sends a switching command message to the UE through the S-RAN, wherein the switching command message includes: the ID of the target PDU session and the indication identifier, wherein after the terminal receives the indication identifier, the PDU session establishment process is triggered ( Fig.12 Step 1211)

[0351] exist Fig.12 In the process, after receiving the handover command message, the UE initiates the PDU session establishment process to the target distributed node. After the timer (if any) expires, the S-SMF triggers the PDU session release across distributed nodes ( Fig.12 Step 1216. The PDU session establishment request message sent by the terminal can be carried in the switching confirmation message ( Fig.12 Step 1209), refer to Fig.12 The execution phase includes the following steps:

[0352] 1201. Switch instruction.

[0353] 1202. Switch instruction.

[0354] The switching instruction message includes: the ID of the target PDU session and an indication identifier, wherein after the terminal receives the indication identifier, the PDU session establishment process is triggered.

[0355] 1203. Uplink RAN ​​status transmission.

[0356] 1204. N1N2 message transmission.

[0357] 1205. Downlink RAN ​​status transmission.

[0358] 1206. Direct data forwarding.

[0359] 1207. Indirect data forwarding.

[0360] 1208. The UE synchronizes to the new cell.

[0361] 1209. Switch confirmation.

[0362] The handover confirmation may carry a PDU session establishment request, that is, the UE actively initiates a PDU session establishment process to the target distributed node.

[0363] Specifically, after receiving the handover instruction message, the UE triggers a new PDU session establishment process. An indication flag may be added to the handover instruction message to instruct the UE to trigger the PDU session establishment process, or the UE may make a judgment based on its own processing logic.

[0364] 1210. Switch notification.

[0365] Step 1201 to step 1210, corresponding to reference Fig.10 Step 191 to step 1011.

[0366] 1211. PDU session establishment process.

[0367] After executing steps 1201 to 1310, the PDU session establishment process is executed.

[0368] 1212. Uplink / downlink user plane data.

[0369] 1213. N2 message notification.

[0370] 1214. N2 message notification confirmation.

[0371] 1215. Registration process.

[0372] The registration process is as follows: Figure 4 .

[0373] 1216. PDU session released.

[0374] If there is a timer, after the timer times out, the S-SMF triggers the PDU session release process. The PDU session release process is the same as the prior art and will not be described in detail here.

[0375] In this embodiment, after receiving the switching instruction message, the UE initiates a PDU session establishment process to the target distributed node. The S-SMF triggers the release of the PDU session across distributed nodes, releasing the PDU session served by the source distributed node, thereby achieving the technical effect of a single distributed node serving the terminal after switching.

[0376] Embodiment 4, further, referring to Fig.13 After receiving the updated SM context, T-SMF triggers the PDU session establishment process, which specifically includes the following steps:

[0377] 1301. Switch instruction.

[0378] 1302. Switch instruction.

[0379] 1303. Uplink RAN ​​status transmission.

[0380] 1304. N1N2 message transmission.

[0381] 1305. Downlink RAN ​​status transmission.

[0382] 1306. Direct data forwarding.

[0383] 1307. Indirect data forwarding.

[0384] 1308. The UE synchronizes to the new cell.

[0385] 1309. Switch confirmation.

[0386] 1310. Switch notification.

[0387] 1311. N2 message notification.

[0388] 1312. N2 message notification confirmation.

[0389] 1313. PDU session release SM context request.

[0390] 1314. PDU session update SM context request.

[0391] Among them, steps 1401 to 1414 refer to Fig.10 Steps 1001 to 1015 in .

[0392] 1315. T-SMF triggers the PDU session establishment process.

[0393] The PDU session establishment process includes: establishing a PDU session in the target distributed node and sending a timer value to the terminal, the timer value is used to indicate that when the timer expires, the terminal initiates a target PDU session release process, and the target PDU session release process includes: releasing at least one target PDU session served by the source distributed node.

[0394] 1316. PDU session release process.

[0395] The PDU session release process is the same as the prior art and will not be repeated here.

[0396] 1317. Registration process.

[0397] 1318. N4 session release request.

[0398] 1319. N4 session release response.

[0399] 1320. N4 session change / release request.

[0400] 1321. N4 session change / release response.

[0401] 1322. UE context release request.

[0402] 1323. UE context release completed.

[0403] In this embodiment, the SMF triggers the PDU session establishment process, re-establishes the session for the UE, and sends a timer value to the UE. The timer value is greater than or equal to the timer value set for the indirect forwarding tunnel. When the timer times out, the UE initiates a session release process to release the PDU session served by the source distributed node. When the session is released, the resources of the indirect forwarding tunnel are released together. Or after the timer times out, the indirect forwarding tunnel is released, and after the PDU session release timer times out, the PDU session resources are released.

[0404] Based on the above multiple embodiments, the present application provides a distributed node switching method, which is applied to a terminal. The distributed node switching method includes: receiving a message carrying the ID of a target PDU session and a target IP address of a target PDU session; using the target IP address to update the IP address of the target PDU session, and the target PDU session is a PDU session affected by the node serving the terminal during the switching process.

[0405] The message may be a switching instruction message sent by the source distributed node, or a registration acceptance message sent by the target distributed node. Specifically, one way is to execute the first embodiment. Fig. 9 After the preparation phase, the terminal receives a handover instruction message ( Fig.10 Step 1002), the switching instruction message carries the ID of the target PDU session and the target IP address of the target PDU session. In addition, the target PDU session is Fig. 9 and Fig.10 The PDU session affected in the switching process shown. Another way is embodiment 2. Before executing step 1111, the UE receives a registration acceptance message, which carries the ID of the target PDU session and the target IP address of the target PDU session. In this embodiment, the target PDU session is the PDU session affected in the switching process. Further, after the UE uses the target IP address to update the IP address of the target PDU session, the subsequent UE can use the target IP address to communicate through the user plane path established with the target distributed node.

[0406] Furthermore, the switching instruction message carries an indication identifier, and the indication identifier instructs the terminal to trigger a PDU session establishment process.

[0407] For example, in the third embodiment, the switching instruction message ( Fig.12 Step 1202 in the above description carries an indication identifier. After the UE receives the switching instruction message, the PDU session establishment process is triggered according to the indication identifier.

[0408] Further, after the timer times out, the terminal initiates a target PDU session release process, the target PDU session is a PDU session served by the source distributed node, and the timer is started according to the timer value sent by the received target distributed node, and the timer value is sent by the target distributed node to the terminal. The target PDU session release process refers to releasing the PDU session served by the source distributed node.

[0409] For example, in step 1315 and step 1316 in embodiment 4, during the T-SMF triggering PDU session establishment process in step 1315, the target distributed node sends the timer value to the terminal. After the timer times out, the UE initiates the target PDU session release process in step 1316.

[0410] An embodiment of the present application also provides a distributed node switching method, which uses a source distributed node. The distributed node switching method includes: receiving a switching request from a source wireless access network; and instructing a target distributed node to switch to serving a terminal alone.

[0411] Reference Fig. 9 , S-RAN sends a handover request to the S-AMF of the source distributed node, and the source distributed node sends a create UE context request to the T-AMF of the target distributed node, thereby instructing the target distributed node to switch to serve the terminal alone. The target distributed node switches to serve the terminal alone, including Fig. 9 and Fig.10 The relevant steps executed by the target distributed node in .

[0412] Instructing the target distributed node to switch to serve the terminal alone includes: requesting the target distributed node to create a terminal context for the terminal; transmitting the context of the target PDU session to the target distributed node; and sending a switching command to the terminal. Specifically, requesting the target distributed node to create a terminal context for the terminal is as follows: Fig. 9 Step 904, after the target distributed node receives the terminal context creation request of the terminal, it creates a UE context for the UE. The context of the target PDU session is transmitted to the target distributed node, referring to Fig. 9 The context of the target PDU session is carried in the PDU session context response in step 908. Fig. 9 After the steps, the source distributed node sends a handover command to the terminal via S-RAN (refer to Fig.10 , step 1002 in FIG. 1004 ).

[0413] Furthermore, the method further includes: releasing the target PDU session served by the source distributed node. Fig.10 Steps 1017 to 1026, Fig.12 Step 1216 in , and Fig.13 In step 1316, the source distributed node executes the related release process.

[0414] In addition, the present application also provides a distributed node switching method, which is applied to a target distributed node. The distributed node switching method includes: selecting a network function for a service terminal; creating a terminal context for the terminal; and establishing a user plane path for a target PDU session of the terminal in the target distributed node. Fig. 9 Steps 904 to 922 in Fig.11 In steps 1102 to 1110, Fig.12 Step 1211 and Fig.13 1315 of them.

[0415] Wherein, selecting the network function of the service terminal includes: obtaining the context of the target PDU session from the source distributed node (refer to Fig. 9 Steps 907 and 908, the PDU session context response carries the context of the target PDU session); based on the context of the target PDU session, reselect the target anchor user plane function of the service terminal (such as Fig. 9 Step 909).

[0416] Among them, based on the context of the target PDU session, the target anchor user plane function (T-PSA) of the service terminal is reselected, including: if the IP address of the target PDU session is dynamically allocated, the target distributed node reallocates the IP address or IP address prefix to the target PDU session, and sends it to the terminal through the source distributed node, instructing the terminal to update the IP address or IP address prefix of the target PDU session. In an embodiment of the present application, in the process of reselecting the target anchor user plane function of the terminal, the IP address or IP address prefix is ​​reallocated to the target PDU session. This step refers to Fig. 9 Step 909 and Fig.10 Step 1001 and step 1002 in .

[0417] Further, based on the context of the target PDU session, the target anchor user plane function of the service terminal is reselected, including: if the IP address of the target PDU session is dynamically allocated, the target session management function obtains the target IP address or IP address prefix; if the terminal subscribes to a static IP address or IP address prefix, the IP address or IP address prefix of the target PDU remains unchanged. This step refers to Fig. 9 Step 909.

[0418] Select the network function of the service terminal, including: the target access and mobility management function determines the target session management function based on the context of the terminal; the target session management function obtains the session context from the source session management function, and reselects the target user plane function and the target anchor user plane function for the affected target PDU session; the target session management function sends the packet forwarding rules and data packet detection rules about the target IP address to the target user plane function and the target anchor user plane function based on the target IP address of the target PDU session, so as to establish a user plane path from the target wireless access network to the target user plane function to the target anchor user plane function, and the target wireless access network provides services to the terminal after movement, wherein the target IP address is the second IP address of the target PDU session. This step refers to Fig. 9 Steps 910 to 913.

[0419] After the target session management function obtains the session context from the source session management function and reselects the target user plane function and the target anchor user plane function for the affected PDU session, it also includes: if the IP address of the target PDU session is dynamically allocated, the target session management function obtains the target IP address or IP address prefix; if the terminal subscribes to a static IP address or IP address prefix, the IP address or IP address prefix of the target PDU remains unchanged. This step refers to Fig. 9 Step 909.

[0420] In the embodiment of the present application, it also includes: if the source wireless access network uses an indirect forwarding tunnel to the target wireless access network, instructing the source session management function to send the tunnel information of the target user plane function to the source user plane function to establish a forwarding tunnel from the source user plane function of the target PDU session to the target user plane function regarding the first IP address of the target PDU session. This step refers to Fig. 9 Steps 924 and 925 in .

[0421] In the embodiment of the present application, it also includes: if the source wireless access network uses an indirect forwarding tunnel to the target wireless access network, the target session management function sends a packet forwarding rule and a data packet detection rule related to the first IP address of the target PDU session to the target user plane function to establish a forwarding tunnel from the target user plane function to the target wireless access network regarding the first IP address of the target PDU session. This step refers to Fig. 9 Steps 919 and 920 in .

[0422] In the embodiment of the present application, after the target session management function sends the tunnel information of the target wireless access network to the target user plane function, the target access and mobility management function also includes: the target IP address of the target PDU session is sent to the source access and mobility management function. This step refers to Fig. 9 Step 922 in .

[0423] Establishing a user plane path for the target PDU session of the terminal at the target distributed node, including: sending a switching instruction to the terminal at the source access and mobility management function, the switching instruction carries the target IP address and target PDU session identifier of the target PDU session, so that the terminal updates the IP address of the target PDU session according to the target IP address, the target wireless access network receives the switching confirmation sent by the terminal, and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session. This step refers to Fig.10 Step 1002 to step 1010.

[0424] In the embodiment of the present application, after the target wireless access network receives the handover confirmation sent by the terminal and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session, it also includes: the target access and mobility management function sends the timer value started in the source access and mobility management function to the target session management function, so that the target session management function starts the timer based on the timer value. When the timer times out, the source session function releases the PDU session-related resources of the source distributed node, and the target session management function releases the resources of the indirect forwarding tunnel in the target UPF. This step refers to Fig.10 From step 1012 to step 1024.

[0425] In the embodiment of the present application, the switching instruction also carries an indication mark, which is used to instruct the terminal to initiate a PDU session establishment process. The PDU session establishment process includes: establishing a target PDU session at the target distributed node. This step refers to Fig.12 Step 1201 and step 1202.

[0426] Among them, establishing a user plane path for the target PDU session of the terminal in the target distributed node also includes: the target session management function receives the terminal's switching success notification, the target session management function triggers the target PDU session establishment process to the terminal, the target PDU session establishment process includes: establishing a PDU session in the target distributed node, and sending a timer value to the terminal, the timer value is used to indicate that when the timer expires, the terminal initiates a target PDU session release process, and the target PDU session release process includes: releasing at least one target PDU session served by the source distributed node. This step refers to Fig.13 Step 1309 and step 1316.

[0427] In the embodiment of the present application, selecting the network function of the service terminal includes: in the mobility registration update process, sending the target IP address and the target PDU session identifier to the terminal in the registration acceptance message. This step refers to the second embodiment ( Fig.11 ).

[0428] In an embodiment of the present application, a user plane path is established at a target distributed node for a target PDU session of a terminal, including: a target session management function sends a packet forwarding rule and a data packet detection rule related to a target IP address to a target anchor user plane function, so as to establish a user plane path from the terminal to the target wireless access network to the target user plane function to the target anchor user plane function. This step refers to Fig.11 Steps 1106 to 1107

[0429] In the embodiment of the present application, the switching method of the distributed node also includes: the target access and mobility management function sends the tunnel information of the target user plane function to the target wireless access network, and sends the ID and target IP address of the target PDU session to the terminal, so that the terminal updates the IP address of the target PDU session, and the terminal uses the new PDU session IP address to send user data to the user plane path from the target wireless access network to the target anchor user plane function. This step refers to Fig.11 Step 1111 in .

[0430] In the embodiment of the present application, the distributed node switching method further includes: after the target wireless mobility management function receives the registration completion message of the terminal, sending an indication message to the target session management function to instruct the target session management function to send an update session context message to the source session management function, so that the source session management function releases the session resources of the source user plane function of the target PDU session to the source anchor user plane function. This step refers to Fig.11 Steps 1112 to 1119 in .

[0431] Finally, a user plane path is established at the target distributed node for the target PDU session of the terminal, including: under preset conditions, a user plane path is established at the target distributed node for the target PDU session of the terminal, and the preset conditions are that the number of distributed nodes currently serving the terminal exceeds the source threshold, the data transmission delay of the terminal is greater than the target threshold, and the contract data of the terminal specifies that only a single distributed node can provide services to the terminal. It can be understood that when the preset conditions are met, the user plane path is adopted. Figure 1 The method shown uses multiple distributed nodes to collaborate to serve the terminal.

[0432] In an embodiment of the present application, the switching of distributed nodes is achieved by reselecting T-PSA for the PDU session at the target distributed node or reestablishing the PDU session during the switching process, thereby ensuring that the UE is still served by a single distributed node (target distributed node) after the switching, avoiding the transmission of signaling and user data in multiple distributed nodes, simplifying the interaction process, and reducing transmission delay and loss.

[0433] In addition, refer to Fig.14The present application embodiment provides a switching device 140 of a distributed node, which is applied to a terminal. The switching device of the distributed node includes:

[0434] A receiving module 141 is used to receive a message carrying an ID of a target PDU session and a target IP address of the target PDU session;

[0435] The updating module 142 is used to update the IP address of the target PDU session using the target IP address, where the target PDU session is the PDU session affected by the node of the service terminal during the switching process.

[0436] In an optional embodiment, the message may be a switching instruction message sent by a source distributed node, or the message may be a registration acceptance message sent by a target distributed node.

[0437] In an optional embodiment, the switching instruction message carries an indication identifier, and the indication identifier instructs the terminal to trigger a PDU session establishment process.

[0438] In an optional embodiment, it also includes: an initiating module (not shown), which is used for the terminal to initiate a target PDU session release process after the timer expires. The target PDU session is a PDU session served by the source distributed node. The timer is started based on the timer value sent by the received target distributed node. The timer value is sent by the target distributed node to the terminal.

[0439] In addition, refer to Fig.15 The present application also provides a switching device 150 of a distributed node, which is applied to a source distributed node. The switching device 150 of the distributed node includes:

[0440] The receiving module 151 is used to receive a handover request from a source wireless access network;

[0441] The instruction module 152 is used to instruct the target distributed node to switch to serving the terminal alone.

[0442] In an optional embodiment, the indication module 152 is specifically used to: request the target distributed node to create a terminal context of the terminal; transmit the context of the target PDU session to the target distributed node; and send a switching command to the terminal.

[0443] An optional embodiment further includes: a release module (not shown) for releasing the target PDU session served by the source distributed node.

[0444] Reference Fig.16 The present application further provides a switching device 160 for a distributed node, which is applied to a target distributed node. The switching device 160 for a distributed node includes:

[0445] A selection module 161, used to select a network function of the service terminal;

[0446] A creation module 162, used to create a terminal context for the terminal;

[0447] The establishing module 163 is used to establish a user plane path at the target distributed node for the target PDU session of the terminal.

[0448] In an optional embodiment, the selection module 161 is specifically used to: obtain the context of the target PDU session from the source distributed node; and reselect the target anchor user plane function of the service terminal based on the context of the target PDU session.

[0449] In an optional embodiment, when the selection module 161 reselects the target anchor user plane function of the service terminal based on the context of the target PDU session, it is specifically used to: if the IP address of the target PDU session is dynamically allocated, the target distributed node re-allocates the IP address or IP address prefix for the target PDU session, and sends it to the terminal through the source distributed node, instructing the terminal to update the IP address or IP address prefix of the target PDU session.

[0450] In an optional embodiment, the selection module 161 reselects the target anchor user plane function of the service terminal based on the context of the target PDU session, specifically, if the IP address of the target PDU session is dynamically allocated, the target session management function obtains the target IP address or IP address prefix; if the terminal subscribes to a static IP address or IP address prefix, the IP address or IP address prefix of the target PDU remains unchanged.

[0451] In an optional embodiment, the selection module 161 is specifically used to: the target access and mobility management function determines the target session management function based on the context of the terminal; the target session management function obtains the session context from the source session management function, and re-selects the target user plane function and the target anchor user plane function for the affected target PDU session; the target session management function sends packet forwarding rules and data packet detection rules about the target IP address to the target user plane function and the target anchor user plane function based on the target IP address of the target PDU session, so as to establish a user plane path from the target wireless access network to the target user plane function to the target anchor user plane function, and the target wireless access network provides services to the terminal after movement, wherein the target IP address is the second IP address of the target PDU session.

[0452] In an optional embodiment, the source distributed node also includes: a source user plane function, an establishing module 173, which is specifically used to: if an indirect forwarding tunnel is used from the source wireless access network to the target wireless access network, instruct the source session management function to send tunnel information of the target user plane function to the source user plane function to establish a forwarding tunnel from the source user plane function of the target PDU session to the target user plane function regarding the first IP address of the target PDU session.

[0453] In an optional embodiment, the establishment module 163 is also specifically used to: if an indirect forwarding tunnel is used from the source wireless access network to the target wireless access network, the target session management function sends packet forwarding rules and data packet detection rules related to the first IP address of the target PDU session to the target user plane function to establish a forwarding tunnel from the target user plane function to the target wireless access network regarding the first IP address of the target PDU session.

[0454] In an optional embodiment, the source distributed node also includes: a source access and mobility management function; after the target session management function sends the tunnel information of the target wireless access network to the target user plane function, a module 173 is established, which is also specifically used for: the target access and mobility management function sends the target IP address of the target PDU session to the source access and mobility management function, so that the source access and mobility management function sends a switching instruction to the terminal, the switching instruction carries the target IP address and the target PDU session identifier of the target PDU session, so that the terminal updates the IP address of the target PDU session according to the target IP address, the target wireless access network receives the switching confirmation sent by the terminal, and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session.

[0455] In an optional embodiment, module 163 is established and is also specifically used for: after the target wireless access network receives the switching confirmation sent by the terminal and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session, the target access and mobility management function sends the timer value started in the source access and mobility management function to the target session management function, so that the target session management function starts the timer based on the timer value, and when the timer times out, the source session function releases the PDU session-related resources of the source distributed node, and the target session management function releases the resources of the indirect forwarding tunnel in the target UPF.

[0456] In an optional embodiment, the switching instruction further carries an indication mark, and the indication mark is used to instruct the terminal to initiate a PDU session establishment process. The PDU session establishment process includes: establishing a target PDU session at a target distributed node.

[0457] In an optional embodiment, the establishment module 163 is also specifically used for: the target session management function receives the switching success notification of the terminal, the target session management function triggers the target PDU session establishment process to the terminal, the target PDU session establishment process includes: establishing a PDU session in the target distributed node, and sending a timer value to the terminal, the timer value is used to indicate that when the timer expires, the terminal initiates a target PDU session release process, the target PDU session release process includes: releasing at least one target PDU session served by the source distributed node.

[0458] In an optional embodiment, the source distributed node includes: a source session management function; the source distributed node provides services to the terminal before movement through the source wireless access network; the target distributed node includes: a target session management function, a target user plane function and a target anchor user plane function; the selection module 161 is specifically used to: in the mobility registration update process, send the target IP address and the target PDU session identifier to the terminal in the registration acceptance message.

[0459] In an optional embodiment, module 163 is established, which is specifically used for: the target session management function sends packet forwarding rules and data packet detection rules related to the target IP address to the target anchor user plane function to establish a user plane path from the terminal to the target wireless access network to the target user plane function to the target anchor user plane function.

[0460] In an optional embodiment, the target distributed node also includes: a target access and mobility management function, establishing module 163, and is also specifically used for: the target access and mobility management function sends tunnel information of the target user plane function to the target wireless access network, and sends the ID and target IP address of the target PDU session to the terminal, so that the terminal updates the IP address of the target PDU session, and uses the new PDU session IP address to send user data to the user plane path from the target wireless access network to the target anchor user plane function.

[0461] In an optional embodiment, the source distributed node also includes: a source user plane function, establishing module 173, and is also specifically used to: after the target wireless mobility management function receives the registration completion message of the terminal, send an indication message to the target session management function to instruct the target session management function to send an update session context message to the source session management function, so that the source session management function releases the session resources from the source user plane function of the target PDU session to the source anchor user plane function.

[0462] In an optional embodiment, module 163 is established, which is specifically used to: under preset conditions, establish a user plane path at the target distributed node for the target PDU session of the terminal, and the preset conditions are that the distributed nodes currently serving the terminal exceed the source threshold, the data transmission delay of the terminal is greater than the target threshold, and the contract data of the terminal stipulates that only a single distributed node can provide services to the terminal.

[0463] Reference Fig.17 , a terminal is provided, including a memory 171, a transceiver 172 and a processor 173:

[0464] A memory 171, used for storing computer programs;

[0465] a transceiver 172 for transmitting and receiving data under the control of the processor 173;

[0466] The processor 173 is configured to read the computer program in the memory 171 and perform the following operations:

[0467] receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session;

[0468] The target IP address is used to update the IP address of the target PDU session, where the target PDU session is the PDU session affected by the node of the service terminal during the switching process.

[0469] Among them, Fig.17 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors represented by processor 173 and various circuits of memory represented by memory 171 are linked together. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 172 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which transmission medium includes wireless channels, wired channels, optical cables, and other transmission media. Optionally, the measurement processing device may also include a user interface 174. For different user devices, the user interface 174 may also be an interface capable of externally connecting or internally connecting required devices, and the connected devices include but are not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

[0470] The processor 173 is responsible for managing the bus architecture and general processing, and the memory 171 can store data used by the processor 173 when performing operations.

[0471] Optionally, the processor 173 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or a complex programmable logic device (CPLD), and the processor 173 may also adopt a multi-core architecture.

[0472] The processor 173 is used to execute any terminal-related method provided in the embodiments of the present application according to the obtained executable instructions by calling the computer program stored in the memory 171. The processor and the memory can also be arranged physically separately.

[0473] Reference Fig.18 , a source distributed node is provided, including a memory 181, a transceiver 182 and a processor 183:

[0474] A memory 181, used for storing computer programs;

[0475] a transceiver 182 for transmitting and receiving data under the control of the processor 183;

[0476] The processor 183 is used to read the computer program in the memory 181 and perform the following operations:

[0477] receiving a handover request from a source wireless access network;

[0478] Instructs the target distributed node to switch to serving the terminal alone.

[0479] Among them, Fig.18 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors represented by processor 183 and various circuits of memory represented by memory 181 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 182 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which transmission medium may include a wireless channel, a wired channel, an optical cable, and other transmission media. The processor 183 is responsible for managing the bus architecture and general processing, and the memory 181 may store data used by the processor 183 when performing operations.

[0480] The processor 183 may be a CPU, an ASIC, an FPGA or a CPLD, and the processor may also adopt a multi-core architecture.

[0481] The processor 183 is used to execute any method related to the wireless access network provided in the embodiment of the present application according to the obtained executable instructions by calling the computer program stored in the memory 181. The processor and the memory can also be arranged physically separately.

[0482] Reference Fig.19 , providing a target distributed node, including a memory 191, a transceiver 192 and a processor 193:

[0483] A memory 191, used for storing computer programs;

[0484] A transceiver 192, for transmitting and receiving data under the control of a processor 193;

[0485] The processor 193 is used to read the computer program in the memory 191 and perform the following operations:

[0486] Select the network function of the service terminal;

[0487] Create a terminal context for the terminal;

[0488] A user plane path is established at the target distributed node for the target PDU session of the terminal.

[0489] Among them, Fig.19 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors represented by processor 193 and various circuits of memory represented by memory 191 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 192 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which may include a wireless channel, a wired channel, an optical cable, and other transmission media. The processor 193 is responsible for managing the bus architecture and general processing, and the memory 191 may store data used by the processor 193 when performing operations.

[0490] The processor 193 may be a CPU, an ASIC, an FPGA or a CPLD, and the processor may also adopt a multi-core architecture.

[0491] The processor 193 is used to execute any method related to the source core network element provided in the embodiment of the present application according to the obtained executable instructions by calling the computer program stored in the memory 191. The processor and the memory can also be arranged physically separately.

[0492] It should be noted here that the above-mentioned device provided in the present application can implement all the method steps implemented in the above-mentioned method embodiment, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0493] It should be noted that the division of units in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0494] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of each embodiment method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program code.

[0495] The embodiment of the present application provides a processor-readable storage medium, which stores a computer program, and the computer program is used to enable the processor to execute any method related to the terminal provided in the embodiment of the present application. The processor is enabled to implement all the method steps implemented by the terminal in the above method embodiment, and the same technical effect can be achieved. The parts and beneficial effects that are the same as those in the method embodiment will not be specifically described here.

[0496] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO)), optical storage (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drives (SSDs)), etc.

[0497] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0498] The present application is described with reference to the flowcharts and / or block diagrams of the methods, apparatuses, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer executable instructions. These computer executable instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0499] These processor executable instructions may also be stored in a processor readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the processor readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0500] These processor-executable instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0501] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A distributed node switching method, characterized in that: Applied to a terminal, the distributed node switching method includes: receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session; The IP address of the target PDU session is updated using the target IP address, where the target PDU session is a PDU session affected by the node serving the terminal during the switching process.

2. The distributed node switching method according to claim 1, characterized in that: The message may be a switching instruction message sent by a source distributed node, or the message may be a registration acceptance message sent by a target distributed node.

3. The distributed node switching method according to claim 2, characterized in that: The switching instruction message carries an indication identifier, and the indication identifier instructs the terminal to trigger a PDU session establishment process.

4. The distributed node switching method according to claim 1, characterized in that: Also includes: After the timer expires, the terminal initiates a target PDU session release process, where the target PDU session is a PDU session served by a source distributed node. The timer is started based on a timer value received from a target distributed node, where the timer value is sent by the target distributed node to the terminal.

5. A distributed node switching method, characterized in that: Applied to a source distributed node, the switching method of the distributed node includes: receiving a handover request from a source wireless access network; Instructs the target distributed node to switch to serving the terminal alone.

6. The distributed node switching method according to claim 5, characterized in that: The instructing the target distributed node to switch to serving the terminal alone includes: Requesting the target distributed node to create a terminal context for the terminal; Transmitting the context of the target PDU session to the target distributed node; A switching command is sent to the terminal.

7. The distributed node switching method according to claim 5, characterized in that: Also includes: The target PDU session served by the source distributed node is released.

8. A distributed node switching method, characterized in that: Applied to a target distributed node, the switching method of the distributed node includes: Select the network function of the service terminal; Create a terminal context for the terminal; A user plane path is established at the target distributed node for the target PDU session of the terminal.

9. The distributed node switching method according to claim 8, characterized in that: The network function of the selected service terminal includes: Obtaining a context of the target PDU session from a source distributed node; Based on the context of the target PDU session, a target anchor user plane function serving the terminal is reselected.

10. The distributed node switching method according to claim 9, characterized in that: The reselecting, based on the context of the target PDU session, a target anchor user plane function serving the terminal, comprises: If the IP address of the target PDU session is dynamically allocated, the target distributed node re-allocates an IP address or an IP address prefix for the target PDU session, and sends it to the terminal through the source distributed node, instructing the terminal to update the IP address or IP address prefix of the target PDU session.

11. The distributed node switching method according to claim 9, characterized in that: The source distributed node includes: a source session management function; the target distributed node includes: a target access and mobility management function, a target session management function, a target user plane function and a target anchor user plane function; the network function of the selected service terminal includes: The target access and mobility management function determines the target session management function based on the context of the terminal; The target session management function obtains the session context from the source session management function and reselects the target user plane function and the target anchor user plane function for the affected target PDU session; The target session management function sends packet forwarding rules and data packet detection rules about the target IP address to the target user plane function and the target anchor user plane function based on the target IP address of the target PDU session, so as to establish a user plane path from the target wireless access network to the target user plane function to the target anchor user plane function, and the target wireless access network provides services to the terminal after movement, wherein the target IP address is the second IP address of the target PDU session.

12. The distributed node switching method according to claim 9, characterized in that: The reselecting, based on the context of the target PDU session, a target anchor user plane function serving the terminal, comprises: If the IP address of the target PDU session is dynamically allocated, the target session management function obtains the target IP address or IP address prefix; If the terminal subscribes to a static IP address or IP address prefix, the IP address or IP address prefix of the target PDU remains unchanged.

13. The distributed node switching method according to claim 10, characterized in that: The source distributed node further includes: a source user plane function, wherein the target PDU session for the terminal establishes a user plane path at the target distributed node, including: If an indirect forwarding tunnel is used from the source wireless access network to the target wireless access network, the source session management function is instructed to send tunnel information of the target user plane function to the source user plane function to establish a forwarding tunnel from the source user plane function of the target PDU session to the target user plane function regarding the first IP address of the target PDU session.

14. The distributed node switching method according to claim 13, characterized in that: The establishing of a user plane path at the target distributed node for the target PDU session of the terminal also includes: If an indirect forwarding tunnel is used from the source wireless access network to the target wireless access network, the target session management function sends packet forwarding rules and data packet detection rules related to the first IP address of the target PDU session to the target user plane function to establish a forwarding tunnel from the target user plane function to the target wireless access network regarding the first IP address of the target PDU session.

15. The distributed node switching method according to claim 14, characterized in that: The source distributed node further includes: a source access and mobility management function; after the target session management function sends the tunnel information of the target wireless access network to the target user plane function, it also includes: The target access and mobility management function sends the target IP address of the target PDU session to the source access and mobility management function, so that the source access and mobility management function sends a switching instruction to the terminal, and the switching instruction carries the target IP address of the target PDU session and the target PDU session identifier, so that the terminal updates the IP address of the target PDU session according to the target IP address. The target wireless access network receives the switching confirmation sent by the terminal and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session.

16. The distributed node switching method according to claim 15, characterized in that: After the target wireless access network receives the handover confirmation sent by the terminal and activates the user plane path from the terminal to the target wireless access network to the target distributed node regarding the target IP address of the target PDU session, the method further includes: The target access and mobility management function sends the timer value started in the source access and mobility management function to the target session management function, so that the target session management function starts the timer based on the timer value. When the timer expires, the source session function releases the PDU session-related resources of the source distributed node, and the target session management function releases the resources of the indirect forwarding tunnel in the target UPF.

17. The distributed node switching method according to claim 8, characterized in that: The switching instruction also carries an indication mark, and the indication mark is used to instruct the terminal to initiate a PDU session establishment process. The PDU session establishment process includes: establishing the target PDU session at the target distributed node.

18. The distributed node switching method according to claim 8, characterized in that: The establishing of a user plane path at the target distributed node for the target PDU session of the terminal also includes: The target session management function receives a switching success notification from the terminal, and the target session management function triggers a target PDU session establishment process to the terminal, wherein the target PDU session establishment process includes: establishing a PDU session in the target distributed node, and sending a timer value to the terminal, wherein the timer value is used to indicate that when the timer expires, the terminal initiates a target PDU session release process, and the target PDU session release process includes: releasing at least one target PDU session served by the source distributed node.

19. The distributed node switching method according to claim 11, characterized in that: The source distributed node includes: a source session management function; the source distributed node provides services to the terminal before moving through the source wireless access network; the target distributed node includes: a target session management function, a target user plane function and a target anchor user plane function; the network function of selecting the service terminal includes: In the mobility registration update process, the target IP address and the target PDU session identifier are sent to the terminal in a registration accept message.

20. The distributed node switching method according to claim 19, characterized in that: The establishing of a user plane path at the target distributed node for the target PDU session of the terminal includes: The target session management function sends packet forwarding rules and data packet detection rules related to the target IP address to the target anchor user plane function to establish a user plane path from the terminal to the target wireless access network to the target user plane function to the target anchor user plane function.

21. The distributed node switching method according to claim 20, characterized in that: The target distributed node further includes: a target access and mobility management function, wherein the target PDU session for the terminal establishes a user plane path at the target distributed node, and further includes: The target access and mobility management function sends the tunnel information of the target user plane function to the target wireless access network, and sends the ID and target IP address of the target PDU session to the terminal, so that the terminal updates the IP address of the target PDU session, and uses the new PDU session IP address to send user data to the user plane path from the target wireless access network to the target anchor user plane function.

22. The distributed node switching method according to claim 20, characterized in that: The source distributed node further includes: a source user plane function, wherein the target PDU session for the terminal establishes a user plane path at the target distributed node, and further includes: After the target wireless mobility management function receives the registration completion message of the terminal, it sends an indication message to the target session management function to instruct the target session management function to send an update session context message to the source session management function, so that the source session management function releases the session resources from the source user plane function of the target PDU session to the source anchor user plane function.

23. The distributed node switching method according to any one of claims 8 to 22, characterized in that: The establishing of a user plane path at the target distributed node for the target PDU session of the terminal includes: Under preset conditions, a user plane path is established at the target distributed node for the target PDU session of the terminal, and the preset conditions are that the distributed nodes currently serving the terminal exceed the source threshold, the data transmission delay of the terminal is greater than the target threshold, and the contract data of the terminal stipulates that only a single distributed node can provide service to the terminal.

24. A switching device for a distributed node, characterized in that: Applied to a terminal, the switching device of the distributed node comprises: A receiving module, used for receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session; An updating module is used to use the target IP address to update the IP address of the target PDU session, where the target PDU session is a PDU session affected by the node serving the terminal during the switching process.

25. A switching device for a distributed node, characterized in that: Applied to a source distributed node, the switching device of the distributed node comprises: A receiving module, used for receiving a handover request from a source wireless access network; The instruction module is used to instruct the target distributed node to switch to serve the terminal alone.

26. A switching device for a distributed node, characterized in that: Applied to a target distributed node, the switching device of the distributed node comprises: A selection module, used to select a network function of a service terminal; Create a module to create a terminal context for the terminal; An establishing module is used to establish a user plane path at the target distributed node for the target PDU session of the terminal.

27. A terminal, characterized in that: Includes memory, transceiver and processor: The memory is used to store computer programs; The transceiver is used to send and receive data under the control of the processor; The processor is configured to read the computer program in the memory and perform the following operations: receiving a message carrying an ID of a target PDU session and a target IP address of the target PDU session; The IP address of the target PDU session is updated using the target IP address, where the target PDU session is a PDU session affected by the node serving the terminal during the switching process.

28. A source distributed node, characterized in that: Includes memory, transceiver and processor: The memory is used to store computer programs; The transceiver is used to send and receive data under the control of the processor; The processor is configured to read the computer program in the memory and perform the following operations: receiving a handover request from a source wireless access network; Instruct the target distributed node to switch to serving the terminal alone.

29. A target distributed node, characterized in that: Includes memory, transceiver and processor: The memory is used to store computer programs; The transceiver is used to send and receive data under the control of the processor; The processor is configured to read the computer program in the memory and perform the following operations: Select the network function of the service terminal; Create a terminal context for the terminal; A user plane path is established at the target distributed node for the target PDU session of the terminal.

30. A processor-readable storage medium, characterized in that: The processor-readable storage medium stores a computer program, and the computer program is used to enable the processor to execute the distributed node switching method according to any one of claims 1 to 23.

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