Server discovery improvements when application server changes

Abstract

A method and apparatus for changing an application server are disclosed. One method includes: when a server changes to a target application server, obtaining information about the application server change; and deciding to notify the UE to rediscover the target application server or configure a UPF to redirect services to and from the target application server.

Description

Technical Field

[0001] The topics disclosed in this article generally relate to wireless communication, and more specifically, to improvements in server discovery when application servers change. Background Technology

[0002] The following abbreviations are defined herein, and at least some of them are referenced in the following descriptions: 3rd Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), Frequency Division Duplex (FDD), Frequency Division Multiple Access (FDMA), Long Term Evolution (LTE), New Radio (NR), Very Large Scale Integration (VLSI), Random Access Memory (RAM), Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM or Flash Memory), Optical Disc Read-Only Memory (CD-ROM), Local Area Network (LAN), Wide Area Network (WAN), Personal Digital Assistant (PDA), User Equipment (UE), Uplink (UL), Evolved Node B (eNB), Next Generation Node B (gNB), Downlink (DL), Central Processing Unit (CPU), Graphics Processing Unit (GPU), Field Programmable Gate Array (FPGA), Dynamic RAM (DRAM), Synchronous Dynamic RAM (SDRAM), Static RAM (SRAM), Liquid Crystal Display (LCD), Light Emitting Diode (LED), Organic LED (OLED), Orthogonal Frequency Division Multiplexing (OFDM). Using OFDM, Radio Resource Control (RRC), Reference Signals (RS), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Duplex (TDD), Time Division Multiplexing (TDM), User Entity / Equipment (Mobile Terminal) (UE), Universal Mobile Telecommunications System (UMTS), Global Microwave Access Interoperability (WiMAX), Protocol Data Unit (PDU), PDU Session Anchor (PSA), Data Network (DN), Service and Session Continuity (SSC), Data Network (DN), DN Access Identifier (DNAI), Uplink Classifier (UL Classifier or ULCL), User Plane Function (UPF), Branch Point (BP), Session Management Function (SMF), Policy Control Function (PCF), Network Exposure Function (NEF), Application Function (AF), Unified Data Repository (UDR), 5G Core (5GC), Policy and Charging Control (PCC), Access and Mobility Management Function (AMF), Application Server (AS), Edge Application Server (EAS), Edge Data Network (EDN), Core Network Control Plane (CN) CP), Service Routing Information (TRI), Edge Enabled Server (EES), and Edge Enabled Client (EEC).

[0003] An edge platform is deployed to provide local services. Application servers (e.g., Enterprise Application Servers (EAS)) are deployed within the edge platform. The UE accesses the application server via a PDU session through a UPF (which acts as a PSA (PDU session anchor)). A PDU session is established between the UE and the UPF. A single PDU session can support one or more applications.

[0004] Due to UE mobility, server-side load balancing, or other reasons, the application server may change from the source application server to the target application server. After the application server changes, the UE must connect to the target application server. Due to UE mobility, PSA relocation may occur, leading to a change in the application server. On the other hand, application server relocation may not occur due to server-side load balancing, because the target application server can still connect to the UE via the same PSA UPF connected to the source application server.

[0005] Examples of changes to the application server include: Figure 1 As shown. First, a PDU session is established between the UE and the central DN (data network). Service Routing Information (TRI), which is also information included in the AF request to affect service routing in the session, is derived from the AF request and sent to the SMF. For example... Figure 1 As shown, TRI1, TRI2, and TRI3, derived from AF Request 1, AF Request 2, and AF Request 3, are sent from the AF to the Core Network Control Plane (CN CP). The AF can be an EDN CS or EES (centralized or distributed EES) or other network functions providing corresponding functionality for interaction with the CN CP and application servers. When the UE moves to the service area of ​​DNAI1 / EDN1, a new user plane branch using ULCL can be established based on the available TRI1 (for App1) and TRI2 (for App2). When a DNAI change or PSA relocation occurs, notifications will be sent to the AF for AF Request 1 and AF Request 2 with the corresponding application identifiers App1 and App2 (i.e., ...). Figure 1 EDN CS / EES and / or EES1 shown.

[0006] Traditionally, application-layer solutions can be used to discover EAS11 (the application server deployed within DNAI1 / END1 of App1) and EAS12 (the application server deployed within DNAI1 / END1 of App2) for App1 and App2. Specifically, application-layer methods (e.g., EES notifying EEC) can be used to send information about EAS11 and EAS12 to the UE. Accordingly, UEs with existing active applications can use existing mechanisms to exchange user plane data packets with EAS11 and EAS12 within EDN1. New user plane data exchanges initiated between the UE and the application server can be selected to terminate for App1 and App2 within EDN1, for example, by the UE initiating a new DNS query to launch App1 and App2.

[0007] However, the above solutions are at the application layer. When the server changes, there is no network mechanism available for server rediscovery. In other words, if the application does not provide an application-layer solution for server rediscovery when the server changes, the UE cannot rediscover the changed application server. This application aims to provide a method and apparatus for implementing server discovery at the network layer (i.e., a lower layer) when the application server changes. Summary of the Invention

[0008] Methods and apparatus for modifying application servers are disclosed.

[0009] In one embodiment, a method includes: when a server changes to a target application server, obtaining information about the change in the application server; and deciding to notify the UE to rediscover the target application server of the application or configure the UPF to direct services to and from the target application server of the application.

[0010] In one embodiment, the method performed at the SMF includes: when the server changes to the target application server, obtaining information about the application server change; and deciding to notify the UE to rediscover the target application server of the application or configure the UPF to direct services to the target application server of the application and direct services from the target application server of the application.

[0011] In another embodiment, the method further includes obtaining the changed service routing preferences of the application server, and making a decision based on the obtained changed service routing preferences of the application server.

[0012] In some embodiments, when the AF confirms a notification of a user plane management event, it obtains information about the application server changes and the changed service routing preferences from the AF. Alternatively, it obtains this information from information about AF update requests. Further alternatively, it obtains this information from application relocation exposure event notifications subscribed to by the AF.

[0013] In some embodiments, the method further includes notifying the UE to rediscover the target application server of the application. Alternatively, the method further includes configuring the UPF to route services to and from the target application server of the application. Information regarding changes to the application server can be an indication of application server changes or information about the target application server. Information regarding changes to the application server and changes to service routing preferences can be information about changes to the application server of the application's flow and changes to the service routing preferences of the application's flow's application server.

[0014] In one embodiment, a method performed at the AF includes: obtaining information about the application server change when the server changes to the target application server; and sending the information about the application server change to the SMF.

[0015] In another embodiment, the SMF includes a receiver configured to obtain information about the application server change when the server changes to the target application server; and a processor configured to decide whether to notify the UE to rediscover the target application server of the application or to configure the UPF to direct services to and from the target application server of the application.

[0016] In another embodiment, the AF includes a receiver configured to obtain information about the application server change when the server changes to the target application server; and a transmitter configured to send the information about the application server change to the SMF. Attached Figure Description

[0017] A more detailed description of the embodiments briefly described above will be presented by referring to the specific embodiments illustrated in the accompanying drawings. It should be understood that these drawings depict only some embodiments and are not intended to be limiting of the scope; the embodiments will be described and explained with additional features and details using the drawings, wherein:

[0018] Figure 1 The illustration shows an example of server changes due to UE mobility based on application deployment;

[0019] Figure 2 The illustration shows an example of server discovery according to the first embodiment;

[0020] Figure 3 The illustration shows an example of server discovery according to the second embodiment;

[0021] Figure 4 The illustration shows an example of server discovery according to the third embodiment;

[0022] Figure 5 The illustration shows an example of server discovery according to the fourth embodiment;

[0023] Figure 6 The illustration is a schematic flowchart according to an embodiment of the method;

[0024] Figure 7 This is a schematic flowchart illustrating another embodiment of the method; and

[0025] Figure 8 This is a schematic block diagram illustrating an apparatus according to one embodiment. Detailed Implementation

[0026] As those skilled in the art will appreciate, certain aspects of the embodiments can be embodied as a system, apparatus, method, or program product. Therefore, embodiments can take the form of entirely hardware embodiments, entirely software embodiments (including firmware, resident software, microcode, etc.), or embodiments combining software and hardware aspects, which may generally be referred to herein as “circuit,” “module,” or “system.” Furthermore, embodiments can take the form of a program product embodied in one or more computer-readable storage devices that store machine-readable code, computer-readable code, and / or program code, hereinafter referred to as “code.” Storage devices can be tangible, non-transitory, and / or non-transferable. Storage devices may not embody signals. In one embodiment, the storage device employs only signals for accessing the code.

[0027] Some functional units described in this specification may be labeled "modules" to more specifically emphasize their independent implementation. For example, a module may be implemented as a hardware circuit that includes custom very-large-scale integration (VLSI) circuitry or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. Modules may also be implemented in programmable hardware devices such as field-programmable gate arrays, programmable array logic, programmable logic devices, etc.

[0028] Modules can also be implemented in code and / or software for execution by various types of processors. The code identifying a module can, for example, comprise one or more physical or logical blocks of executable code, which can be organized, for example, as objects, procedures, or functions. However, the executable files identifying modules do not necessarily need to be physically located together, but can include different instructions stored in different locations that, when logically joined together, constitute the module and implement the stated purpose of the module.

[0029] In practice, a module of code can contain a single instruction or many instructions, and can even be distributed across several different code segments, different programs, and across several memory devices. Similarly, operational data can be identified and illustrated within the module and can be represented in any suitable form and organized within any suitable type of data structure. This operational data can be collected as a single dataset or can be distributed across different locations, including different computer-readable storage devices. When the module or parts thereof are implemented in software, the software portion is stored on one or more computer-readable storage devices.

[0030] Any combination of one or more computer-readable media may be used. A computer-readable medium may be a computer-readable storage medium. A computer-readable storage medium may be a storage device for storing code. A storage device may be, for example, but not necessarily, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0031] A non-exhaustive list of more specific examples of storage devices will include the following: electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium can be any tangible medium capable of containing or storing programs for use by or in connection with an instruction execution system, apparatus, or device.

[0032] The code used to perform the operations of the embodiments may include any number of lines and may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Python, Ruby, Java, Smalltalk, C++, and conventional procedural programming languages ​​such as the "C" programming language, and / or machine languages ​​such as assembly language. The code may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may make a connection to an external computer (e.g., via the Internet using an Internet service provider).

[0033] Throughout this specification, references to "an embodiment," "embodiment," or similar language mean that a particular feature, structure, or characteristic described together with that embodiment is included in at least one embodiment. Therefore, unless otherwise expressly specified, the phrases "in an embodiment," "in an embodiment," and similar language throughout this specification may, but not necessarily, refer to the same embodiment, but rather mean "one or more, but not all, embodiments." Unless otherwise expressly specified, the terms "comprising," "including," "having," and variations thereof mean "including, but not limited to,". Unless expressly specified, an enumerated list of items does not imply that any or all of the items are mutually exclusive. Unless otherwise expressly specified, the terms "a," "an," and "the" also mean "one or more."

[0034] Furthermore, the features, structures, or characteristics described in the various embodiments can be combined in any suitable manner. In the following description, numerous specific details, such as examples of programming, software modules, user selection, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., are provided to provide a thorough understanding of the embodiments. However, those skilled in the art will recognize that the embodiments can be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the embodiments.

[0035] Various aspects of different embodiments are described below with reference to schematic flowcharts and / or schematic block diagrams of methods, apparatus, systems, and program products according to embodiments. It should be understood that each block of the schematic flowcharts and / or schematic block diagrams, as well as combinations of blocks in the schematic flowcharts and / or schematic block diagrams, can be implemented by code. This code can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce machinery, such that instructions executable via the processor of the computer or other programmable data processing apparatus create means for implementing the functions specified for one or more blocks in the schematic flowcharts and / or schematic block diagrams.

[0036] The code can also be stored in a storage device that can instruct a computer, other programmable data processing device or other device to function in a particular manner, such that the instructions stored in the storage device produce an article of writing including instructions that implement the functions specified in the blocks or some of the schematic flowcharts and / or schematic block diagrams.

[0037] The code may also be loaded onto a computer, other programmable data processing apparatus or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer-implemented process, such that the code executing on the computer or other programmable apparatus provides a process for implementing the functions specified in the boxes or some boxes of the flowchart and / or block diagram.

[0038] The schematic flowcharts and / or block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, systems, methods, and program products according to various embodiments. In this regard, each block in the schematic flowcharts and / or block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function.

[0039] It should also be noted that in some alternative implementations, the functions indicated in the boxes may not occur in the order shown in the diagrams. For example, depending on the functionality involved, two boxes shown successively may be executed substantially simultaneously, or sometimes in reverse order. Other steps and methods that are functionally, logically, or effectively equivalent to one or more boxes or portions thereof in the illustrated diagrams can be envisioned.

[0040] While various arrow and line types may be used in flowcharts and / or block diagrams, they are not intended to limit the scope of the corresponding embodiments. In practice, some arrows or other connectors may be used to indicate the logical flow of only the depicted embodiment. For example, arrows may indicate wait or monitoring periods of unspecified duration between enumeration steps in a depicted embodiment. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented by a system based on dedicated hardware or a combination of dedicated hardware and code that performs the specified function or behavior.

[0041] The descriptions of the elements in each figure may refer to the elements in the preceding figures. The same reference numerals in all figures refer to the same elements, including alternative embodiments of the same elements.

[0042] This application aims to provide a lower-layer (lower than the application layer) solution for server discovery when the application server of an application changes (e.g., deployed in an edge environment). When the application server changes from a source application server to a target application server, the SMF obtains information about the application server change (e.g., an indication of the application server change, or information about the target application server), and preferably the service routing preferences for the changed application server. Based on the obtained information, it decides to notify the UE to rediscover the application's target application server or configure a UPF to route services to and from the application's target application server. The service routing preferences for the changed application server provide preferences from the application side, i.e., whether the UE needs to be aware of the application server change. When multiple PSA UPFs exist for a PDU session, the UPF for routing services can be a ULCL or BP UPF. The ULCL or BP UPF can be an independent UPF and can be quasi-co-located with the PSA UPF. When only one PSA UPF exists for a PDU session (meaning there is no ULCL or BP UPF), the UPF for routing services can also be a PSA UPF or the UPF of the N3 endpoint. Detailed embodiments are described in detail.

[0043] For all embodiments, the service routing process between the AF and the core network includes the following scenarios: (1) the AF requests to affect the service routing of a session identified by the UE address, (2) the AF requests to affect the service routing of a session not identified by the UE address, affecting future PDU sessions, and (3) the AF requests to affect the service routing of a session not identified by the UE address, affecting an ongoing PDU session.

[0044] Figure 2The first embodiment of this application is illustrated. According to the first embodiment, it is assumed that (1) the service provider deploys the service to the EDN (Edge Data Network), and different applications may have different deployments; (2) the AF sends the service routing information of each DNN & NSSAI (or AF-service-ID) and application to the 3GPP network via an AF request with an AF transaction identifier; and (3) when the application server changes, the AF is able to obtain information about the application server change of the application (e.g., information about the target application server of the application).

[0045] like Figure 2 As shown, the following network elements are involved: UE; AMF (Access and Mobility Management Function); UPF (User Plane Function) (in Figure 1 In this context, UPF0 is the PDU session anchor (PSA) used by the UE to connect to the source application server, while UPF1 is the PDU session anchor (PSA) used by the UE to connect to the target application server. Note that ULCL or BP can be added or relocated as independent UPFs, or co-located with PSA UPFs; SMF (Session Management Function); PCF (Policy Control Function); NEF (Network Exposure Function); UDR (Unified Data Repository); AS (Application Server) Figure 2 In this context, AS stands for Target Application Server; and AF stands for Application Function. Figure 2 In the image, for simplicity, PCF / NEF / UDR is shown as a single box.

[0046] In step 201, in the absence of a separate UE address, an AF request with service routing information is sent from the AF to the core network of each application. For example... Figure 2 As shown in the diagram, the Nnef_TrafficInfluence_Create request contains the parameter "AnyUE", which means that no individual UE is specified.

[0047] In step 202, the NEF stores the service routing information in the UDR. Since the AF request does not have a specific UE address (IP address or MAC address), the data key used for storage may be the AF transaction internal ID, S-NSSAI and DNN and / or internal group identifier or SUPI, which means (1) the AF transaction internal ID, and S-NSSAI & DNN; (2) the AF transaction internal ID, S-NSSAI & DNN and internal group identifier; or (3) the AF transaction internal ID, S-NSSAI & DNN and SUPI; or (4) the AF transaction internal ID and internal group identifier or (5) the AF transaction internal ID and SUPI.

[0048] In step 203, a response message is sent in response to the AF request, for example, from NEF to AF.

[0049] In step 204, the UE registers with the 5G system. The UE sends a registration request message to the AMF and receives registration acceptance from the AMF.

[0050] In step 205, the UE initiates the PDU session establishment process by sending a PDU session establishment request to the SMF.

[0051] In step 206, the SMF retrieves the SM policy using the SM policy association establishment process during the PDU session establishment process. If a PDU session is established for an application, service routing information can be retrieved from the PCF (or via the PCF from the UDR) (e.g., for applications with the application ID indicated in step 201).

[0052] In step 207, the PSA UPF selection for the PDU session is performed by the SMF. The SMF selects the UPF (UPF through the selected UPF). Figure 2 The UPF0 in the PDU initiates the N4 session establishment process. The SMF can provide this PDU session with packet detection, enforcement, and reporting rules to be installed on the UPF.

[0053] In step 208, the SMF sends a PDU session establishment acceptance to the UE to complete the establishment of the PDU session. Uplink and downlink data can be transmitted between the UE and the UPF0. Figure 2 (Only uplink data is shown in the image).

[0054] A PDU session can be used for multiple applications. Based on the application detected in step 209 (e.g., an application with the application ID indicated in step 201), the SMF can update the SM policy using the SM policy control update process in step 210. If the application's service routing information is not obtained in step 206, it can be obtained in step 210.

[0055] In step 211, the conditions for AF notification, such as PSA relocation (from UPF0 to UPF1), have been met.

[0056] In step 212, the SMF sends an AF notification (notification of user plane management events) to the AFs that subscribe to SMF notifications. The notification of user plane management events is also called user plane management event notification.

[0057] When the Application Controller (AF) receives a notification of a User Plane Management (PSA) relocation from UPF0 to UPF1, the PSA triggers an application server change. For example, the source application server connecting to UPF0 is changed to the target application server connecting to UPF1.

[0058] The AF can obtain and confirm information about changes to the application server and the changed service routing preferences of the application server. In step 213, the AF sends information about changes to the application server (e.g., information about the target application server of the application) and the changed service routing preferences of the application server to the SMF.

[0059] In step 214, when the service routing preference changed by the application server in step 213 indicates that the service is preferred to be routed within the core network and the UE is unaware of the server change, the SMF makes a decision based on information about the application server change (e.g., information about the target application server of the application) and the application server's changed service routing preference (the service is preferred to be routed within the core network) to configure the UPF to route the service to the target application server of the application and to route the service from the target application server of the application.

[0060] Based on the decision in step 214, in step 215, the SMF uses forwarding rules to update the ULCL or BP UPF, which can be independent or co-located with UPF1, to direct the service to the target application server. Additionally, the SMF can send information about the application's source application server and / or application identifier to UPF1. This information can come from the AF in step 213 or be pre-stored in the SMF.

[0061] When in UE and target application server ( Figure 2 When new packets are exchanged between ASs in the application, ULCL or BP UPF executes to the target application server and the business guidance from which the application originates.

[0062] For uplink traffic from an application originating from the UE, packets containing the destination IP address of the source application server are directed to the target application server. For example, this can be done by replacing the destination IP address of the packet with the IP address of the target application server. Alternatively, a header containing the IP address of the target application server can be added to the uplink traffic packet as the destination IP address.

[0063] For downlink services from the target application server to the UE, packets with the source IP address of the target application server are replaced with the source IP address of the source application server.

[0064] According to the first embodiment, in step 213, SMF obtains information about the application server changes of the application (e.g., information about the target application server of the application) and the service routing preferences of the application server changes, and decides to configure UPF1 to route services to the target application server of the application and to route services from the target application server of the application.

[0065] Figure 3 The second embodiment of this application is illustrated. According to the second embodiment, it is assumed that (1) the service provider deploys the service to the EDN (Edge Data Network), and different applications may have different deployments; (2) the AF requests each DNN & NSSAI (or AF-service-ID) and the service routing information of the application to the 3GPP network via an AF request with an AF transaction identifier; (3) when the application server changes, the AF is able to obtain information about the application server change (e.g., information about the target application server, or an indication of the application server change); and (4) the core network cannot change the IP address of the packet when the application server changes. The above assumptions (1)-(3) of the second embodiment are the same as those of the first embodiment.

[0066] like Figure 3 As shown, the network elements involved include all the network elements described in the first embodiment, as well as the DNS server. Furthermore, the UE according to the second embodiment further includes an "application client" and a "lower layer".

[0067] Steps 301 to 312 are the same as steps 201 to 212. Detailed descriptions of steps 301 to 312 are omitted.

[0068] In step 313, the AF sends information about the application server change (e.g., an indication of the application server change or information about the target application server) and the service routing preferences of the changed application server to the SMF, similar to step 213. The difference is that in step 213, the changed service routing preferences indicate that the service is preferred for routing within the core network, and the UE is unaware of the server change. Conversely, in step 313, the changed service routing preferences indicate that the service is preferred for the UE to rediscover the IP address of the target application server. Furthermore, the information about the application server change can be an indication of the change, but does not include information about the target application server.

[0069] In step 314, when the service routing preference of the application server changed in step 313 indicates that it is preferred to rediscover the application server's IP address through the UE, the SMF makes a decision based on the information about the application server change and the service routing preference of the application server changed (to rediscover the application server's IP address through the UE) to notify the UE of the application server change.

[0070] Based on the decision in step 314, the SMF notifies the UE of the application server change information in step 315. This information may be information about the target application server of the application (e.g., the IP address or FQDN of the target application server), or an indication of the application server change (e.g., a trigger for the UE to re-initiate a DNS query for the application). Additionally, the SMF may also send information about the source application server and / or the application identifier to the UE. This information and / or the application identifier may originate from the AF in step 313, or may be pre-stored in the SMF.

[0071] In step 316, the UE rediscovers the target application server of the application based on the information received in step 315.

[0072] If the information is the IP address of the target application server of the application, then the UE exchanges service data with the target application server of the corresponding application.

[0073] If the information includes the FQDN of the target application server of the application, the UE uses the received FQDN of the target application server of the corresponding application to re-initiate the DNS query for the corresponding application to the DNS server.

[0074] If the information includes a trigger for the UE to initiate a DNS query for an application, the UE disables the old DNS query results for the corresponding application and re-initiates a new DNS query for the corresponding application to the DNS server.

[0075] Whether and how lower-level layers and application clients interact within the UE can be determined by the implementation method.

[0076] If the target application server is an additional service flow for the application, a new exchange can be established between the UE and the target application server. If the target application server is to replace the source application server, the lower layer can disable the connection between the UE and the source application server, and the application client can re-initiate a DNS query or begin establishing a connection between the UE and the target application server triggered by the disconnection between the UE and the application's source application server. Optionally, if the target application server is to replace the source application server, new interactions can be added between the lower layer and the application client to establish a connection between the UE and the target application server.

[0077] According to the second embodiment, in step 313, the SMF obtains information about the changes in the application server and the changes in the service routing preferences of the application server, and decides to configure the UE to rediscover the target application server of the application.

[0078] Figure 4 The figure illustrates a third embodiment of this application. According to the third embodiment, it is assumed that (1) the service provider deploys the service to the EDN (Edge Data Network), and different applications may have different deployments; (2) the AF sends the service routing information of each DNN & NSSAI (or AF-service-ID) and application to the 3GPP network via an AF request with an AF transaction identifier; (3) when the application server changes, the AF can obtain information about the application server change; (4) the PDU session has been established; and an AF request with the service routing information is sent to the core network (i.e., Nnef_TrafficInfluence_Create has been executed); (5) the application server change is triggered by the application, for example, for load balancing among application servers within the EDN. The above assumptions (1)-(3) of the third embodiment are the same as the assumptions (1)-(3) of the first or second embodiment.

[0079] like Figure 4 As shown, the network elements involved include all the network elements described in the second embodiment, except that the UE according to the third embodiment is not further limited.

[0080] First, as stated in the above assumption (4), step 4001 indicates that it has been connected with the PSA UPF ( Figure 4 The UPF0 in the middle has established a PDU session and has sent an AF request with information affecting service routing to the core network using Nnef_TrafficInfluence_Create.

[0081] The application server for an application may change from a source application server to a target application server due to load balancing, for example, within an EDN application server. The Application Firewall (AF) can obtain information about the application server change (e.g., an indication of the application server change or information about the target application server) and the changed service routing preferences. In step 401, the AF uses an AF update request message (Nnef_TrafficInfluence_Update request) to notify the core network of the application server change information and the changed service routing preferences. Figure 4As illustrated in the diagram, the Nnef_TrafficInfluence_Update request requires an "AF transaction ID" to associate the update with the AF request created in step 4001. Figure 4 In this process, the AF update request message is sent to the core network, and the NEF updates the information contained in the AF update request message received in the UDR and notifies the subscribed PCFs of the update information.

[0082] In step 402, SMF uses the Npcf_SMPolicyControl_UpdateNotify service operation to obtain information about the changes to the application server and the changed service routing preferences of the application server.

[0083] Steps 403-405 are optional. Changing the application server from the source application server to the target application server may or may not result in PSA relocation (UPF change). Figure 4 As illustrated in the diagram, assume an established PDU session uses UPF0 to connect to the source application server. The target application server can also connect to UPF0. Under this condition, PSA relocation (UPF change) is not satisfied. On the other hand, the target application server might connect to another UPF, such as UPF1. Under this condition, PSA relocation is satisfied.

[0084] In optional step 403, the conditions for AF notification, such as PSA relocation (from UPF0 to UPF1), have been met.

[0085] In optional step 404, the SMF sends a notification to the AF that subscribes to the SMF notification (e.g., the UPF changes from UPF0 to UPF1).

[0086] In optional step 405, the AF confirms the notification.

[0087] In step 406, the SMF makes a decision on server discovery for the application based on the information obtained in step 402.

[0088] If the changed service routing preferences obtained in step 402 indicate that the service is preferred for routing within the core network (and the UE is unaware of the server change), then step 407 is executed. Step 407 and... Figure 2 Step 215 is the same as in [previous step], and a detailed description of step 407 is omitted. Please note that... Figure 4As illustrated, in step 407, the SMF updates UPF1 using forwarding rules to redirect the service to the target application server. This means that a PSA relocation from UPF0 to UPF1 was satisfied in optional step 403, and ULCL or BP UPF is quasi-co-located with UPF1. If PSA relocation is not performed in optional step 403, the SMF will update UPF0 using forwarding rules to redirect the service to the target application server (if an ULCL or BP UPF exists for the PDU session, the SMF will update the ULCL or BP, which can be independent or quasi-co-located with UPF0).

[0089] If the changed service routing preferences of the application server obtained in step 402 indicate that it is preferred to rediscover the application server's IP address through the UE, then steps 408 and 409 are executed. Steps 408 and 409 are related to... Figure 3 Steps 315 and 316 are the same. Detailed descriptions of steps 408 and 409 are omitted.

[0090] According to the third embodiment, in step 401, the SMF obtains information about the application server changes and the service routing preferences of the application server changes, and decides to configure UPF1 or UPF0 to route services to the application's target application server and route services from the application's target application server, or configure the UE to rediscover the application's target application server.

[0091] Figure 5 The figure illustrates the fourth embodiment of this application. According to the fourth embodiment, it is assumed that (1) the service provider deploys the service to the EDN (Edge Data Network), and different applications may have different deployments; (2) when the application server changes, the AF can obtain information about the application server change; and (3) the AF can provide the core network with application relocation exposure capabilities.

[0092] like Figure 5 As shown, the network elements involved include all the network elements described in the third embodiment.

[0093] The fourth embodiment differs from the third embodiment in how the SMF obtains information about changes to the application server. According to the fourth embodiment, the AF exposes application relocation capabilities to the core network, and the SMF subscribes to and receives notifications from the AF when the application server changes.

[0094] In step 501a, the AF sends information for application relocation exposure capabilities to the core network during the service routing process of a future PDU session. For example... Figure 5As illustrated in the diagram, the Nnef_TrafficInfluence_Create request includes "AnyUE" in its parameters, meaning that no individual UE is specified. For example, in... Figure 5 In this process, information for applying relocation exposure capabilities is sent to the NEF, and the NEF stores this information in the UDR. A response message can be sent from the NEF to the AF to receive information about applying relocation exposure capabilities.

[0095] In step 501b, in the UE and PSA UPF (e.g., Figure 5 Establish a PDU session between the UPF0 shown in the diagram.

[0096] During the PDU session establishment process, in step 501c or 501d, the SMF can use the SM policy association to establish or modify the process to retrieve information from the PCF (or via the PCF from the UDR) for applying the relocation exposure capability.

[0097] In step 502a, the AF can use a service routing update message to send information for applying relocation exposure capabilities to the core network (e.g., NEF) for existing PDU sessions. In step 502b, the SMF can use the Npcf_SMPolicyControl_UpdateNotify service operation to obtain information for applying relocation exposure capabilities.

[0098] Steps 501a-501d are performed for the SMF to receive information on application relocation exposure capabilities for future PDU sessions, while steps 502a-502b are performed for the SMF to receive information on application relocation exposure capabilities for existing PDU sessions. Therefore, it is possible to perform only steps 501a-501d or only steps 502a-502b. In other words, it is not necessary to perform both steps 501a-501d and steps 502a-502b.

[0099] In step 503, the SMF subscribes to application relocation exposure events from the AF based on the information about the application relocation exposure capability obtained in steps 501a-501d or steps 502a-502b.

[0100] In step 504a, the conditions for AF notification, such as PSA relocation (from UPF0 to UPF1), have been met.

[0101] In step 504b, the SMF sends a notification to the AF to inform the AF of the PSA relocation (from UPF0 to UPF1). The AF acknowledges the notification.

[0102] If, based on steps 504a-504b or a decision from the application side, such as load balancing within the application servers in the EDN, the conditions for application server changes have been met, then AF obtains information about the application server changes and the service routing preferences for the application server changes. Because load balancing within the application servers may trigger application server changes (which will not cause PSA relocation), steps 504a-504b may not be executed.

[0103] In step 505, the AF uses the Naf_EventExposure_AppRelocationInfo_Notify service operation to notify the core network (i.e., SMF) of the application server changes and the application server's changed service routing preferences.

[0104] Steps 506-509 are the same as steps 406-409. Detailed description of steps 506-509 is omitted.

[0105] According to the fourth embodiment, in step 505, the SMF obtains information about the application server changes and the service routing preferences of the application server changes, and decides to configure ULCL or BP (UPF1 or UPF0 or independent ULCL or BP) to guide services to the application's target application server and guide services from the application's target application server, or configure the UE to rediscover the application's target application server.

[0106] In all the embodiments described above, the service routing preferences changed by the application server are obtained by the AF and sent to the SMF. However, the AF may not be able to obtain the changed service routing preferences from the application server and send them to the SMF. Furthermore, even if the AF obtains the changed service routing preferences from the application server, the AF may not send them to the SMF. Under these conditions, the SMF may be pre-configured with the changed service routing preferences from the application server.

[0107] In another embodiment, the SMF does not receive service routing preferences changed by the application server from the AF, nor is it pre-configured with service routing preferences that have changed by the application server. Under this condition, when the application server changes (e.g., when the SMF obtains information about the application server change), the SMF can, based on the information about the application server change, decide to notify the UE to rediscover the target application server of the application or configure the UPF to route services to and from the target application server of the application. For example, when the information about the application server change is an indication of the application server change (in other words, the SMF does not know the information about the target application server), the SMF can decide to notify the UE to rediscover the target application server of the application because, without information about the target application server, the UPF cannot route services to and from the target application server of the application.

[0108] In all the above embodiments, the information regarding application server changes is application-specific. That is, each application has its own unique information regarding application server changes, and the service routing preferences for those changes are also application-specific. In other words, both the information regarding application server changes and the service routing preferences for those changes are application-specific. On the other hand, an application has one or more flows. Therefore, both the information regarding application server changes and the service routing preferences for those changes can be granular at each flow of the application, or at a subset of flows. In this case, the exchange of service routing information between the AF and the core network that affects the session can include relevant service filters to identify the application's flows.

[0109] Figure 6 This is a schematic flowchart illustrating an embodiment of method 600 according to this application. In some embodiments, method 600 is performed by a network function such as SMF. In some embodiments, method 600 may be performed by a processor that executes program code, such as a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0110] Method 600 may include obtaining information about the application server change when the server changes to the target application server 602; and deciding to notify the UE to rediscover the target application server of the application or configure the UPF to direct the service to the target application server of the application and direct the service from the target application server of the application 604.

[0111] Figure 7This is a schematic flowchart illustrating an embodiment of method 700 according to this application. In some embodiments, method 700 is performed by a network function such as AF. In some embodiments, method 700 may be performed by a processor that executes program code, such as a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0112] Method 700 may include: obtaining information about the application server change when the server changes to the target application server; and sending the information about the application server change to the SMF.

[0113] Figure 8 This is a schematic block diagram illustrating an apparatus according to one embodiment.

[0114] refer to Figure 8 Network functions (e.g., SMF or AF) include a processor, memory, and a transceiver. The processor implements functions, processes, and / or methods. The memory is connected to the processor to store information used to drive the processor. The transceiver is connected to the processor to transmit and / or receive messages or information. Needless to say, a transceiver can be implemented as a transmitter for transmitting information and a receiver for receiving information.

[0115] Memory can be located inside or outside the processor and connected to the processor via various known devices.

[0116] In the above embodiments, the components and features of the embodiments are combined in a predetermined manner. Unless otherwise expressly stated, each component or function should be considered optional. Each component or feature may be implemented without being associated with other components or features. Furthermore, embodiments can be configured by associating some components and / or features. The order of operations described in the embodiments may be changed. Some components or features of any embodiment may be included in another embodiment or replaced with components and features corresponding to another embodiment. It is apparent that claims not expressly referenced in the claims are combined to form embodiments or included in new claims.

[0117] The embodiments can be implemented by hardware, firmware, software, or a combination thereof. In the case of hardware implementation, depending on the hardware implementation method, the exemplary embodiments described herein can be implemented using one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0118] The embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects as illustrative rather than restrictive. The scope of the invention is therefore indicated by the appended claims rather than by the foregoing description. All variations falling within the equivalent meaning and scope of the claims should be included within their scope.

Claims

1. A method performed by a Session Management Function (SMF), the method comprising: In response to a server change from the source application server to the target application server, obtain information about the application server change from the application function AF; as well as Configure the User Plane Function (UPF) to direct services to and from the target application server of the application, such that when new packets are exchanged between the User Equipment (UE) and the target application server of the application: For uplink service data packets from the UE's application, the destination IP address of the source application server is replaced with the destination IP address of the target application server, and For data packets of downlink services from the target application server to the UE, the source IP address of the target application server is replaced with the IP address of the source application server.

2. The method according to claim 1, further comprising: Obtain the changed service routing preferences of the application server, and configure the UPF based on the obtained changed service routing preferences of the application server.

3. The method according to claim 2, wherein, In response to the AF receiving a notification that the target application server has changed its user plane management event and the AF confirming the notification of the user plane management event, the AF sends the information about the application server change and the application server's changed service routing preferences.

4. The method according to claim 2, wherein, Obtain the information about the application server changes and the application server's changed service routing preferences from the AF update request.

5. The method according to claim 2, wherein, Based on the application relocation exposure event notification received from the subscription, the information about the application server changes and the application server's changed service routing preferences are obtained.

6. The method of claim 1, further comprising: Instruct the UE to rediscover the target application server of the application.

7. The method according to claim 1, wherein, The information regarding changes to the application server of the application includes indications of such changes or information about the target application server.

8. The method according to claim 2, wherein, The information regarding changes to the application server for the application and the changes to the service routing preferences of the application server include information regarding changes to the application server for the application's flow and the changes to the service routing preferences of the application server for the application's flow.

9. A Session Management Function (SMF), comprising: At least one memory; and at least one processor, said at least one processor being coupled to said at least one memory and configured to cause said SMF to perform a method comprising: In response to a server change from the source application server to the target application server, obtain information about the application server change from the application function AF; as well as Configure the User Plane Function (UPF) to direct services to and from the target application server of the application, such that when new packets are exchanged between the User Equipment (UE) and the target application server of the application: For uplink service data packets from the UE's application, the destination IP address of the source application server is replaced with the destination IP address of the target application server, and For data packets of downlink services from the target application server to the UE, the source IP address of the target application server is replaced with the IP address of the source application server.

10. The SMF according to claim 9, wherein, The processor is configured to enable the SMF to obtain the changed service routing preferences of the application server, and to configure the UPF based on the obtained changed service routing preferences of the application server.

11. The SMF according to claim 10, wherein, In response to the AF receiving a notification that the target application server has changed its user plane management event and the AF confirming the notification of the user plane management event, the AF sends the information about the application server change and the application server's changed service routing preferences.

12. The SMF according to claim 10, wherein, Obtain the information about the application server changes and the application server's changed service routing preferences from the AF update request.

13. The SMF according to claim 10, wherein, Based on the application relocation exposure event notification received from the subscription, the information about the application server changes and the application server's changed service routing preferences are obtained.

14. The SMF of claim 9, further comprising a transmitter configured to instruct the UE to rediscover the target application server of the application.

15. The SMF according to claim 9, wherein, The information regarding changes to the application server of the application includes indications of such changes or information about the target application server.

16. The SMF according to claim 10, wherein, The information regarding changes to the application server and the changes to the service routing preferences of the application server include information regarding changes to the application server's flow and the changes to the service routing preferences of the application server's flow.

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