Method and apparatus for providing local data network information to a terminal in a wireless communication system

Abstract

The present disclosure relates to a 5G or pre-5G communication system provided to support a higher data transmission rate beyond a 4G communication system such as LTE. A method according to one embodiment of the present disclosure is a method for providing local data network information from a session management function (SMF) entity to a terminal in a wireless communication system, the method including the steps of: determining, based on first information, to add a protocol data unit (PDU) session anchor user plane function (PSA-UPF) for a PDU session according to mobility of the terminal; establishing a PDU session with the PSA-UPF determined to be added; configuring a PDU path for downlink and uplink between the PSA-UPF and the terminal; and transmitting a PDU session modification command indicating addition of the new PSA-UPF to the terminal, wherein the first information can include at least one of policy and charging control (PCC) information and local data network (DN) configuration information received from a policy control function (PCF) entity.

Description

Technical Field

[0001] The present invention relates to a wireless communication system, and more specifically, to a method and apparatus for providing local data network information based on the movement of a terminal in a cellular wireless communication system (e.g., a 5G system). Background Technology

[0002] Since the commercialization of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems to meet the growing demand for wireless data services. Accordingly, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE systems".

[0003] To achieve higher data rates, 5G communication systems are being considered for implementation in extremely high frequency (mmWave) bands (e.g., the 60 GHz band). To reduce path loss and increase transmission distance in the mmWave band, various technologies are being considered for 5G communication systems, including beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO.

[0004] In addition, in order to improve the system network in 5G communication systems, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and interference cancellation are being developed.

[0005] In addition, advanced coding and modulation (ACM) schemes such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) are being developed for 5G communication systems, as well as advanced access technologies such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA).

[0006] Meanwhile, in order to evolve from the existing 4G LTE system to the 5G system, 3GPP, which is responsible for cellular mobile communication standards, has named the new core network architecture 5G Core (5GC) and is currently in the process of standardization.

[0007] Compared to the Evolved Packet Core (EPC), which is the core of the existing 4G network, 5GC supports the following differentiated functions.

[0008] First, network slicing functionality is introduced in 5GC. As required by 5G, 5GC should support various types of terminals and services, such as enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine-type communication (mMTC). These terminals / services place different demands on the core network. For example, eMBB services require high data rates, while URLLC services require high stability and low latency. The proposed network slicing scheme is a technology that meets the requirements of these diverse services.

[0009] Network slicing is a method of creating multiple logical networks by virtualizing a single physical network, and each Network Slice Instance (NSI) can have different characteristics. Therefore, various service requirements can be met by using Network Functions (NFs) with characteristics suitable for each NSI. By assigning NSIs with characteristics appropriate to the services requested by each terminal, various 5G services can be effectively supported.

[0010] Secondly, 5GC can facilitate support for network virtualization paradigms by separating mobility management and session management functions. In existing 4G LTE, services from the network can be provided to all terminals through signaling exchange with a single core device called a Mobility Management Entity (MME), which is responsible for registration, authentication, mobility management, and session management functions. However, in 5G, with the explosive increase in the number of terminals and the segmentation of mobility and service / session characteristics to be supported based on terminal type, it is inevitable that the scalability of adding entities for each required function will be reduced if all functions are supported by a single device such as an MME. Therefore, to improve scalability in terms of the functional / implementation complexity and signaling load of the core device responsible for the control plane, various functions are being developed based on an architecture that separates mobility management and session management functions.

[0011] Meanwhile, edge computing technologies for sending data to wireless communication systems using edge servers have been discussed in recent years. Edge computing technologies can include, for example, multi-access edge computing (MEC) or fog computing. Edge computing technology can refer to technologies used to provide data to electronic devices (terminals or user equipment) via a separate server (edge ​​server or MEC server) installed in a geographically proximate location (e.g., inside or near a base station). For example, an application requiring low latency in at least one application installed in an electronic device can send or receive data via an edge server installed in a geographically proximate location, without using a server located on an external data network (DN) (e.g., the Internet). Summary of the Invention

[0012] [Technical Issues]

[0013] In a 5G core network supporting edge computing, application server relocation may occur when the Local PDU Session Anchoring User Plane Function (Local PSA-UPF) entity for the local data network (local DN) is added, modified, or deleted. Therefore, when the Local PSA-UPF is added, modified, or deleted, the Session Management Function (SMF) entity of the 5G core network should notify the terminal of control information regarding the upper network layer. Then, when the terminal receives the control information for the upper network layer from the SMF entity, it performs the appropriate operation accordingly.

[0014] However, the 5G core network does not provide the operation to perform this process. Furthermore, the terminal cannot perform any operation when receiving control information about the upper network layer from an SMF entity.

[0015] Therefore, this disclosure provides a process for notifying the terminal of control information about the upper network layer from the 5G core network when adding / changing / deleting a local PSA-UPF.

[0016] Furthermore, this disclosure provides an apparatus and method that processes control information about the upper network layer received by a terminal from the 5G core network in response to the addition / change / deletion of a local PSA-UPF.

[0017] [Solution to the problem]

[0018] According to embodiments of this disclosure, a method for providing local data network information to a terminal by a Session Management Function (SMF) entity in a wireless communication system may include: determining, based on first information and the terminal's mobility, a PDU Session Anchored User Plane Function (PSA-UPF) to be added for a Protocol Data Unit (PDU) session; establishing a PDU session with the PSA-UPF that has been determined to be added; configuring PDU paths for downlink and uplink between the PSA-UPF and the terminal; and sending a PDU session modification command to the terminal indicating the addition of the new PSA-UPF.

[0019] The first information may include at least one of policy and charging control (PCC) information or local data network (DN) configuration information received from a policy control function (PCF) entity.

[0020] According to another embodiment of this disclosure, as a method for a terminal to receive local data network information from a Session Management Function (SMF) entity in a wireless communication system, the method may include: sending and receiving PDUs using a Protocol Data Unit (PDU) session configured by the terminal; receiving a PDU session modification command from the SMF entity, the PDU session modification command indicating the addition of a new PDU Session Anchored User Plane Function (PSA-UPF); receiving a Router Advertisement (RA) message sent by the SMF through the new PSA-UPF; reconfiguring the new PSA-UPF; and performing upper-layer control based on the reconfiguration of the new PSA-UPF.

[0021] [Beneficial effects of the invention]

[0022] According to this disclosure, when a local PSA-UPF is added (or changed / removed), the terminal's upper-layer network context needs to be released. In this case, the SMF provides the terminal with information about the local DN, allowing the terminal to control the upper-layer context. Furthermore, by defining this procedure, the wireless communication network can provide the terminal with control information about the upper-layer network layer in response to the addition / change / removal of the local PDU Session Anchored User Plane Function (local PSA-UPF) entity. Moreover, due to the addition / change / removal of the local PSA-UPF from the wireless communication network, the terminal can receive control information about the upper-layer network layer and take appropriate actions. Attached Figure Description

[0023] Figure 1 This is a diagram illustrating the architecture of a 5G system represented using reference points in a wireless communication system.

[0024] Figure 2 This is a diagram illustrating the architecture of network entities in a wireless communication system according to various embodiments of the present disclosure.

[0025] Figure 3 This is a diagram illustrating another architecture of a 5G core network supporting edge computing according to embodiments of the present disclosure.

[0026] Figure 4 This is an illustrative diagram used to explain the situation where a UE moves by using a network topology according to this disclosure.

[0027] Figures 5A and 5B are illustrative diagrams illustrating the internal configuration of a UE and the establishment of a PDU session with a wireless communication network and a data network, according to embodiments of the present disclosure.

[0028] Figure 5C is an illustrative diagram illustrating a local DN binding context according to an embodiment of the present disclosure.

[0029] Figure 6This is a signal flow diagram illustrating how the SMF provides control information about the upper-layer network context and information about the PDU session and local DN to the UE according to embodiments of this disclosure.

[0030] Figures 7A and 7B are signal flow diagrams illustrating the situation where the SMF provides local DN notification and upper-layer network context control information to the UE according to an embodiment of the present disclosure.

[0031] Figures 8A and 8B are signal flow diagrams illustrating the operation of each node providing corresponding information to the UE when changing the local PSA in response to an AF request in the network, according to embodiments of the present disclosure.

[0032] Figures 9A and 9B are illustrative diagrams illustrating the process of providing local DN information and upper-layer network context control information to a UE, and the operations within the UE, according to embodiments of the present disclosure.

[0033] Figure 10 It is a block diagram of NF based on this disclosure. Detailed Implementation

[0034] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Descriptions of well-known functions and structures incorporated herein may be omitted in the description of this disclosure to avoid obscuring the subject matter. Furthermore, the terms described below are defined in consideration of their function in this disclosure, and these terms may vary according to the intent of users, operators, or custom. Therefore, their meanings should be determined based on the entire contents of this specification. In the following description, the term "base station" refers to a primary agent that allocates resources to a terminal and may be at least one of an eNode B, Node B, BS, Radio Access Network (RAN), Access Network (AN), RAN node, Radio Access Unit, Base Station Controller, or Network Node. The term "terminal" may refer to at least one of a User Equipment (UE), Mobile Station (MS), Cellular Telephone, Smartphone, Computer, or Multimedia System with communication capabilities. In this disclosure, the term "downlink (DL)" refers to the wireless transmission path through which a base station transmits signals to a terminal, while the term "uplink (UL)" refers to the wireless transmission path through which a terminal transmits signals to a base station. Furthermore, while LTE or LTE-A systems are used as examples to describe embodiments of this disclosure, these embodiments can be applied to other communication systems with similar technical backgrounds or channel configurations. Moreover, those skilled in the art will understand that embodiments of this disclosure can be applied to other communication systems without significant modifications departing from the scope of this disclosure.

[0035] In the following description of this disclosure, session management will be described based on the movement of the UE in a wireless communication system. Furthermore, in this disclosure, processes related to the relocation of the UE to an application server accessed by the UE in an edge computing system may also be applied based on the movement of the UE.

[0036] Figure 1 This is a diagram illustrating the architecture of a 5G system represented using reference points in a wireless communication system.

[0037] refer to Figure 1 The 5G system architecture can include various components (i.e., network functions (NFs)). Among them, the Authentication Server Function (AUSF) entity 160, the (core) Access and Mobility Management Function (AMF) entity 120, the Session Management Function (SMF) entity 130, the Policy Control Function (PCF) entity 140, the Application Function (AF) entity 150, the Unified Data Management (UDM) entity 170, the Data Network (DN) 180, the User Plane Function (UPF) entity 110, the (radio) Access Network ((R)AN) 20, and the terminal (i.e., user equipment (UE)) 10 are... Figure 1 As shown in the image.

[0038] Figure 1 Each device shown can be implemented as a server or equipment, or as a network slice instance as described above. When implemented as a network slice instance, two or more identical or different network slice instances can be implemented on one server or equipment, and one network slice instance can be implemented on two or more servers or equipment.

[0039] The above NF can support the following functions.

[0040] AUSF 160 can process and store data used for UE authentication.

[0041] The AMF 120 can provide each UE with connectivity and mobility management functions, and a UE can essentially connect to one AMF. Specifically, the AMF can support functions such as signaling between CN nodes for mobility between 3GPP access networks, termination of the Radio Access Network (RAN) CP interface (i.e., N2 interface), termination of NAS signaling N1, NAS signaling security (NAS encryption and integrity protection), AS security control, registration management (registration area management), connectivity management, idle mode UE reachability (including paging retransmission control and enforcement), mobility management control (subscription and policies), support for intra-system and inter-system mobility, support for network slicing, SMF selection, lawful eavesdropping (for AMF events and L1 system interface), session management (SM) messaging between the UE and the SMF, transparent proxy for routing SM messages, access authentication, access authorization including roaming authorization checks, SMS messaging between the UE and the Short Message Service Function (SMSF), Security Anchor Function (SAF), and / or Security Context Management (SCM). Some or all of these features of AMF 120 can be supported in a single AMF instance as an AMF operation.

[0042] DN 180 can mean, for example, carrier services, Internet access, or third-party services. DN 180 can send downlink protocol data units (PDUs) to UPF 110, or it can receive PDUs sent from UE 10 via UPF 110.

[0043] The PCF 140 can provide the ability to receive information about packet flows from the application server and determine policies for mobility management, session management, and so on. Specifically, the PCF 140 can support functions such as supporting a unified policy framework for controlling network behavior, providing policy rules so that control plane functions (such as AMF and SMF) can enforce policy rules, and implementing a front-end to access relevant reservation information for making policies in the User Data Store (UDR).

[0044] SMF 130 provides session management functions, and when a UE has multiple sessions, each session can be managed by a different SMF. Specifically, SMF 130 can support functions such as session management (e.g., session establishment, modification, and release, including tunnel maintenance between UPF and AN nodes), UE IP address allocation and management (including selective authentication), establishing service controls to route services to appropriate destinations in the UPF, termination of interfaces for policy-oriented control functions, enforcement of policy and Quality of Service (QoS) control portions, lawful eavesdropping (for SM events and L1 system interfaces), termination of the SM portion of NAS messages, downlink data notification, initiation of AN-specific SM information (sent to the AN via N2 through the AMF), determination of session SSC mode, and roaming functions. As described above, some or all of the functions of SMF 130 can be supported within a single SMF instance operating as an SMF.

[0045] The UDM 170 can store user reservation data, policy data, etc. The UDM 170 can include two parts: the application front-end (FE) (not shown) and the user data storage library (UDR) (not shown).

[0046] The FE can include the UDM-FE, responsible for location management, reservation management, and credential processing, and the PCF-FE, responsible for policy control. The UDR can store the data required for the functions provided by the UDM-FE and the policy configuration files required by the PCF. Data stored in the UDR can include user reservation data, including reservation identifiers, security credentials, access and mobility-related reservation data, as well as session-related reservation data and policy data. The UDM-FE can access the reservation information stored in the UDR and can support functions such as authentication credential processing, user identification processing, access authentication, registration / mobility management, reservation management, and SMS management.

[0047] The UPF 110 can transmit downlink PDUs received from DN 180 to UE 10 via (R)AN 20, and uplink PDUs received from UE 10 via (R)AN 20 to DN 180. Specifically, the UPF 110 can support functions such as: anchor points for intra-RAT / inter-RAT mobility, external PDU session points interconnected with the data network, packet routing and forwarding, user plane portion of packet inspection and policy rule enforcement, lawful interception, service usage reporting, uplink classifier supporting service flow routing toward the data network, branch points supporting multi-homed PDU sessions, QoS processing for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement), uplink service authentication (Service Data Flow (SDF) to QoS flow mapping), transport-level packet marking in uplink and downlink, and downlink packet buffering and downlink data notification triggering, etc. Some or all of the features of UPF 110 can be supported in a single UFP instance as a UPF operation.

[0048] AF 150 can interact with the 3GPP core network to provide services (e.g., supporting functions including: application impact of access on service routing and network capability exposure, and interaction with policy control frameworks).

[0049] AN 20 can be collectively referred to as a new radio access network that supports evolved E-UTRA (e-UTRA) and new radio (NR) access technologies (e.g., gNB), wherein the evolved E-UTRA (e-UTRA) is an evolved version of 4G radio access technology.

[0050] The gNB can support the following functions, such as radio resource management functions (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources for the UE in uplink / downlink (scheduling)), Internet Protocol (IP) header compression, encryption and integrity protection of user data streams, selection of AMF 120 when connecting to UE 10 if the route to AMF 120 is uncertain based on the information provided to UE 10, routing of user plane data to UPF 110, routing of control plane information to AMF 120, connection establishment and release, scheduling and transmission of paging messages (generated from AMF), scheduling and transmission of system broadcast messages (generated from AMF or Operation and Maintenance (O&M)), configuration of mobility and scheduling measurements and measurement reports, transport-level packet marking in uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UE in inactive mode, NAS message distribution function, NAS node selection function, radio access network sharing, dual connectivity, and tight interoperability between NR and E-UTRA.

[0051] UE 10 can mean user equipment. User equipment can be referred to by terms such as terminal, mobile device (ME), and mobile station (MS). Furthermore, user equipment can be portable devices, such as laptops, cellular phones, personal digital assistants (PDAs), smartphones, and multimedia devices, or non-portable devices, such as personal computers (PCs) and in-vehicle devices. In the following text, it will be referred to as user equipment (UE) or terminal.

[0052] For clarity, the Network Exposure Function (NEF) entity and the NF Repository Function (NRF) entity are... Figure 1 Not shown in the figure, but all NFs shown in Figure 5, which will be described later, can perform interoperability with NEF and NRF as needed.

[0053] A description of NRF is given. NRF( Figure 1 (Not shown in the image) can support service discovery functionality. When a second NF discovery request is received from a first NF instance, the NRF can perform a discovery operation on the second NF and provide the first NF instance with information about the discovered second NF instance. It can also maintain records of available NF instances and the services they support.

[0054] at the same time, Figure 1 A reference model for a UE accessing a DN using a PDU session is shown for ease of description, but this disclosure is not limited thereto.

[0055] UE 10 can access two (i.e., local and central) data networks simultaneously using multiple PDU sessions. Here, two SMFs can be selected for different PDU sessions. However, each SMF can have the ability to control the local UPF and central UPF within the PDU session.

[0056] In addition, UE 10 can simultaneously access two (i.e., local and central) data networks provided within a single PDU session.

[0057] In 3GPP systems, the conceptual link between NFs in a 5G system is defined as a reference point. The following illustrates the links included in... Figure 1 The reference point in the 5G system architecture is shown.

[0058] -N1: Reference point between UE and AMF

[0059] -N2: Reference point between (R)AN and AMF

[0060] -N3: Reference point between (R)AN and UPF

[0061] -N4: Reference point between SMF and UPF

[0062] -N5: Reference point between PCF and AF

[0063] -N6: Reference point between UPF and data network

[0064] -N7: Reference point between SMF and PCF

[0065] -N8: Reference point between UDM and AMF

[0066] -N9: Reference point between the two core UPFs

[0067] -N10: Reference point between UDM and SMF

[0068] -N11: Reference point between AMF and SMF

[0069] -N12: Reference point between AMF and AUSF

[0070] -N13: Reference point between UDM and Authentication Server Function (AUSF).

[0071] -N14: Reference point between the two AMFs

[0072] -N15: Reference point between PCF and AMF in non-roaming situations, and reference point between PCF and AMF in the access network during roaming situations.

[0073] Figure 2This is a diagram illustrating the architecture of network entities in a wireless communication system according to various embodiments of the present disclosure.

[0074] The network entity disclosed herein is a concept encompassing network functions according to system implementations. Terms such as “part” or “device” as used herein refer to a unit for processing at least one function or operation, which may be implemented using hardware, software, or a combination thereof. Furthermore, as described above, each function may be implemented in a single device or server, or may be implemented using two or more servers or devices.

[0075] exist Figure 2 In the middle, the components are basically the same as Figure 1 The components are the same, but there are the following differences.

[0076] and Figure 1 In comparison, Figure 2 The newly added NEF 190 provides an apparatus for securely exposing services and capabilities provided by 3GPP network functions, such as those for third-party, internal exposure / re-exposure, application functions, and edge computing. The NEF 190 can receive information from other network functions (based on their exposed capabilities). The NEF 190 can store the received information as structured data using a standardized interface to a data storage network function. The stored information can be re-exposed by the NEF 190 to other network functions and application functions, and can be used for other purposes, such as analysis.

[0077] also, Figure 2 The image shows three different UPF types: 210, 220, and 230, as well as the new DN 240. (See image for details.) Figure 1 The first UPF 210, connected to AN 20, can be connected to the third UPF 230 via N9 for connection to the new DN 240. Furthermore, the first UPF 210 can be connected to the existing DN 180 via the second UPF 220.

[0078] Figure 2 The configuration shown illustrates one of the architectures of a 5G core network that supports edge computing. Figure 2 The control plane functional entities of the 5G core network shown above are the same as those mentioned above. Figure 1The control plane functional entities are identical, and the same reference symbols represent the same parts. A 5G core network architecture is shown, in which UE 10 communicates with the Edge Application Server (EAS) via a first UPF 210 acting as an uplink classifier (ULCL) / branch point (BP). UE 10 can connect to a second UPF 220 via the first UPF 210, which serves as a User Protocol Data Unit (PDU), and then connect to the data network (DN) 180. Here, the second UPF 220 can be... Figure 2 The first PDU session in the process is anchored to the user plane function (PSA-UPF).

[0079] Furthermore, the first UPF 210 can connect to the third UPF 230, and simultaneously to the second UPF 220. Here, the third UPF 230, acting as the second PSA-UPF, can connect to DN 240 at a geographically close location to the UE. An edge application server (EAS) 241 providing edge computing services resides on the regional closed data network 240, and the UE 10 can communicate with EAS 241 to provide edge computing services. SMF 130 can establish N4 sessions with the first UPF 210, the second UPF 220, and the third UPF 230, and send rules for forwarding traffic for each of the UPFs 210, 220, and 230 to control individual UPFs 210, 220, and 230. Furthermore, SMF 130 can send a 3-tuple of information, including the destination IP address, destination port number, and protocol number, to ULCL / BP UPF 210. The first UPF 210 operates as ULCP, enabling UE 10 to connect to the third UPF 230, which acts as a locally disabled second PSA-UPF. It can also determine whether to route UE 10's services to the local data network or the first PSA-UPF 220. In this architecture, to enable UE 10 to communicate with EAS 241 via the nearby local PSA-UPF 230, the 5G core network can perform procedures for adding / changing / removing ULCL / BP 210 and the local PSA-UPF 230.

[0080] Meanwhile, in traditional 3GPP 5G core networks, the relocation of the PDU Session Anchored User Plane Function (PSA-UPF) does not consider data path latency. That is, in traditional 3GPP 5G core networks, the Session Management Function (SMF) internally determines PSA-UPF relocation using topology information. Various embodiments of this disclosure can provide a method and an application for a 5G core network to determine whether to relocate the PSA-UPF in response to a request from an application function requiring low latency service, taking into account data path latency.

[0081] According to various embodiments of this disclosure, the 5G core network and applications consider data path latency to determine PSA-UPF relocation. When a handover occurs due to a UE receiving services from one or more applications leaving a service area where the currently connected application is deployed, performing PSA-UPF relocation could change the UE's IP address and potentially cause service interruption.

[0082] According to various embodiments of this disclosure, considering the latency requested by the application, if the latency requested by the application is satisfied by the existing data path in the area where the UE has already moved, service interruption can be minimized by not performing PSA-UPF relocation.

[0083] According to various embodiments of this disclosure, when the UE moves and provides service via a newly modified path, or when the latency requested by the application is not met, service that meets the latency requested by the application can be provided by reconfiguring the path using a new PSA-UPF.

[0084] Figure 3 This is a diagram illustrating another architecture of a 5G core network supporting edge computing according to embodiments of the present disclosure.

[0085] As mentioned above, for Figure 3 The control plane functions of the 5G core network shown are assigned the same reference symbols as those in the diagram. Figure 1 and Figure 2 The same components are described in the document. Therefore, additional descriptions of the same components will be omitted.

[0086] According to this disclosure Figure 3 The 5G core network architecture is illustrated, in which UE 10 communicates with EAS 321 included in DN 320 without using ULCL / BP. In this network architecture, in order for UE 10 to access EAS 321 via PSA-UPF 310 approaching UE 10 after UE movement, the process for PSA-UPF relocation can be performed using Service and Session Continuity (SSC) Mode 2 or SSC Mode 3.

[0087] Figure 4 This is an illustrative diagram used to explain the situation where a UE moves by using a network topology according to this disclosure.

[0088] according to Figure 4 The diagram shown illustrates a network configuration in which the local data network has a separate IP range within an IPv4 ULCL environment.

[0089] refer to Figure 4Configuration, specific applications (apps) in UE 10 Figure 4 (Not shown) can connect to the first data network 410, for example, a data network with an IP address set to "10.10.10.*". When UE 10 connects to the first data network 410 in this way, it can connect via PSA-UPF#1 (411), which serves as the UPF for connecting to the first data network 410, ULCL / BP 401, and RAN 20 connected to ULCL / BP 401. Furthermore, when UE 10 connects to the Internet, it can connect via ULCL / BP 401, which is the UPF for connecting to the Internet, and the corresponding RAN 20. Here, when UE 10 connects to the first data network 410, the UE can have "10.10.10.xx" as the data network access identifier (DNAI) as described above.

[0090] like Figure 4 As shown, when the UE moves to the second RAN 21, it can connect to the data network with the IP address set to "10.10.20.*" via ULCL / BP 402, which serves as both the new UPF and the new PSA-UPF#2 (421). As another example, although the UE 10 moves to the second RAN 21, it can still connect to the previous PSA-UPF#1 (411) via ULCL / BP 402, which serves as the new UPF.

[0091] It is possible that UE 10 connects via ULCL / BP402 as a new UPF and new PSA-UPF#2 (421). In this case, before the DNAI change, UE 10 is connected to the first local data network 410, and the application (app) of UE 10 is connected to EAS#1 (413), so that UE 10 can create a TCP context. Furthermore, when the DNAI changes due to the movement of UE 10 as described above, the SMF ( Figure 4 (Not shown) A procedure for adding an additional PSA can be performed. After the DNAI change, the application of UE 10 should connect to the IP address (e.g., "10.10.20.1") of EAS#1 (423) of the second local data network 420. However, the TCP context of UE 10 is preserved, and the application of UE 10 cannot connect to EAS#1 (423) of the second local data network 420 because the application is unaware of the local network change and the existing TCP context is still preserved.

[0092] A more detailed explanation follows.

[0093] exist Figure 4In the network configuration diagram, UE 10 can move from its location at the first local DN 410 to its location at the second local DN 420. In this case, as... Figure 4 As shown, UE 10's first PSA-UPF 411 can remain unchanged. That is, UE 10 can maintain PSA-UPF#1 (411). In this case, UE 10's IP address is retained, but in the application layer session that UE 10 will connect to via the first local PSA-UPF#1 (411), when the PSA-UPF 411 used for the first local DN 410 is released, the context of UE 10 should be removed. However, in the current ULCL or local PSA-UPF deletion operation, no information is provided to UE 10 to notify it. In this case, when UE 10 connects to the second local DN 420 and attempts to access the same EAS, the upper-layer context of the first local DN 410 remains in UE 10. As a result, UE 10 cannot access the EAS of the second local DN 420. More specifically, this upper-layer context can be the DNS (Domain Name System or Domain Name Server) information for the fully qualified domain name (FQDN) used for the EAS. The DNS address of the EAS received from the first local DN could be, for example, "10.10.10.1". This DNS process can be cached in the DNS client of UE 10 for the lifetime of the DNS record. Even when UE 10 is affected by mobility or SMF ( Figure 4 When a connection is established to the second local DN (not shown), and a DNS query is made to the same EAS#1, a connection is established to address "10.10.10.1" due to information cached in the DNS client of UE 10. In this case, it is impossible to send or receive data services to or from EAS#1 (423) in the second local DN.

[0094] As another example, this is the case where a connection-oriented upper-layer session is established between the first local DN 410 and EAS#1 (413). For example, a TCP connection (413) for UE 10 can be established between the first local DN 410 and EAS#1. In this case, due to the movement of UE 10 or the local determination of the SMF, when the SMF removes PSA-UPF411 connected to the first local DN 410 and connects the session with PSA-UPF#2 (421) to the second local DN 420, the TCP connection, as one of the upper-layer network contexts of UE 10, is maintained without being disconnected from the previous session. Therefore, UE 10 cannot connect to the IP address (e.g., "10.10.20.1") of EAS#1@LDN2 (423) located in the second local DN 420.

[0095] To address this issue, this disclosure adopts the internal structure of the UE as shown in Figures 5A and 5B.

[0096] Figures 5A and 5B are illustrative diagrams illustrating the internal configuration of a UE and the establishment of a PDU session with a wireless communication network and a data network, according to embodiments of the present disclosure.

[0097] Figures 5A and 5B are shown separately because it is difficult to represent both the UE configuration and the network configuration in one figure. Furthermore, it can be seen from Figures 5A and 5B that components included in a particular part (e.g., the UE's communication processor or modem 1010) may include the NAS control plane 1011.

[0098] First, referring to FIG. 5A, UE 10 may include a communication processor or modem 1010 and an application processor (AP) 1030. Hereinafter, the communication processor or modem 1010 may be referred to as a "communication processor" or a "modem," and both may correspond to reference numeral 1010 in FIG. 5A and FIG. 5B. Furthermore, it should be noted that all unnecessary elements have been omitted in FIG. 5A and FIG. 5B in describing the invention. For example, elements necessary for wireless communication, such as memory, power supply, and antenna, may be further included. Additionally, for user convenience, UE 10 may include various circuits or logic. For example, various circuits, logic, and / or modules, such as RF transceiver circuitry, display modules, touchscreens, speakers, and microphones, may be further included.

[0099] Application processor 1030 can essentially run at least one application. Figure 5A illustrates two different applications 1034 and 1035 running. Within application processor 1030, a TCP / IP stack 1020 can be included in the operating system (OS) kernel. For ease of description, it will be referred to as the "TCP / IP stack." Layer 4 contexts 1021 and 1022 can be included within the TCP / IP stack 1020. Layer 4 contexts 1021 and 1022 can be, for example, sockets. Sockets 1021 and 1022 can be connected to the corresponding applications 1031 and 1032 via a socket application programming interface (API).

[0100] Furthermore, the communication processor 1010 and the application processor 1030 can be connected via network interfaces 1031, 1032, and 1033. In Figure 5A, three different network interfaces 1031, 1032, and 1033 are shown, and the first network interface 1031 is shown as being connected to sockets 1021 and 1022.

[0101] UE 10 can connect to the 5G core network 500 through access network 20, such as a base station. Thus, when UE 10 connects to the 5G core network 500, a PDU session can be established between UE 10 and the PSA-UPF of the 5G core network 500. Figure 5A illustrates the scenario where N PDU sessions 521, 522, and 523 can be configured in a single UE.

[0102] Furthermore, UE 10 can ultimately receive services from the 5G core network 500, or it can receive data services from at least one of the data networks 510, 514, and 515 via the 5G core network 500. Figure 5A illustrates the case where the first data network 510 is an edge computing data network. However, data network 510 can also be a local data network (local DN).

[0103] Next, referring to Figure 5B, the TCP / IP stack 1020 of UE 10 may include a modem control interface 1021 for connecting to a modem, a URSP manager 1022, a DNS client 1023, a context manager 1024, and an interface manager 1025. Furthermore, in addition to the components described in Figure 5B, additional components may be included in the TCP / IP stack 1020 of UE 10 as needed.

[0104] The communication processor 1010 may include the NAS control plane 1011.

[0105] Furthermore, as mentioned above, the 5G core network 500 may include AMF 120, SMF 130, PCF 140, UDM 170, and NEF 190. Additionally, the above-mentioned... Figure 1 The UDR 504 described herein. The 5G core network 500 can be connected to the external AF 150 via NEF 190.

[0106] Although the configuration of UE 10 is shown separately in Figures 5A and 5B, those skilled in the art can identify the overall configuration of the UE from the diagrams in Figures 5A and 5B. It should be noted that the schematic diagrams in Figures 5A and 5B are configurations of the network interface and upper-layer context. Furthermore, in the following description, Figures 5A and 5B will be collectively referred to as Figure 5.

[0107] In Figure 5, User Equipment (UE) 10 is described as consisting of an Application Processor (AP) and a Communication Processor (CP) as described above. However, in UE 10, the Application Processor and the Communication Processor can be implemented as a single chip. In this case, both the Application Processor and the Communication Processor can be included in a single processor. For example, even when a process physically exists, the logical functions performed by the AP and the logical functions performed by the CP can be the same. Applications of UE 10 can reside in the AP, and such applications can send / receive requests / responses to / from mobile operating systems (e.g., Android, Linux, Tizen, BSD Unix, iOS) by invoking network-related system calls and system library calls via socket interface 1041.

[0108] Furthermore, as described above, the TCP / IP stack 1020 resides in the mobile operating system running on the AP, and the TCP context can be managed by a kernel socket for TCP context management. Additionally, the mobile operating system can communicate with the CP 1010 through at least one of network interfaces 1031, 1032, and 1033. Furthermore, the AP 1030 may include a URSP manager 1022 for URSP processing, a DNS client 1023, a context manager 1024 for upper network layer context management, and an interface manager 1025 for network interface management. Moreover, these managers 1022, 1023, 1024, and 1025 can be connected to the CP 1010 via a modem control interface (modem control I / F) 1021 for control purposes. The CP 1010 can interact with the base station by implementing the functions provided by the 3GPP air interface. Furthermore, the module for controlling the NAS control plane 1011 can reside in the CP 1010, and the NAS control plane 1011 can interact with the AMF120 of the 5G core network 500. Session-related NAS control messages can be passed to the SMF 130 via the AMF 120.

[0109] When the PDU session type is IP, the Protocol Data Unit (PDU) sent through the network interface of UE 10 is an IP data packet. This IP data packet can reach the PSA-UPF 501 of the 5G core network 500 through the PDU session (521 in Figure 5). The PSA-UPF 501 can then send the received IP data packet to the data network 510, which is an IP network.

[0110] In this disclosure, it is assumed that the data network is an edge computing data network. Edge application servers (ESA) 511 and 512 and a domain name server (DNS) 513 may reside in the data network 501. ESAs 511 and 512 and DNS 513 may communicate with UE10. UDM, UDR, NEF, AF, AMF, SMF, and PCF residing in the 5G core network 500 perform operations related to... Figure 1 The network functions described herein are the same, so repeated descriptions will be omitted here.

[0111] Figure 5 illustrates the relationship between the UE 10's network interface and the PDU session based on a one-to-one connection assumption. When the UE 10's application requests a TCP connection, a TCP session is established. This process can be accomplished using methods such as the "connect" system call. Once a TCP session is successfully established in the operating system, the TCP context can be bound to the interface with the UE's source IP address.

[0112] If the network interface is disconnected, all context corresponding to the TCP session bound to that interface is removed. Due to this behavior, if SSC Mode 2 operation is performed, the SMF 130 can release the first PDU session and establish a second PDU session for PSA-UPF relocation. During this process, all TCP context of the first PDU session bound to UE 10 is removed, thus session continuity cannot be guaranteed.

[0113] Furthermore, for SSC Mode 3 operation, SMF 130 can instruct the establishment of a second session for PSA-UPF relocation, and UE 10 can establish a second PDU session and temporarily exchange data services through the first and second PDU sessions. In this case, while the first network interface corresponding to the first PDU session is maintained in UE 10, a second network interface is generated corresponding to the establishment of the second PDU session. Subsequently, when the first PDU session is released, the network interface used for the first PDU session is disconnected, and all TCP contexts bound to that network interface are removed. Therefore, the upper-layer context of the first PDU session cannot maintain continuity.

[0114] In the operation disclosed herein, when a first local DN is generated or released, the SMF 130 sends information about the local DN to the UE 130 via NAS signaling (e.g., a PDU session change message). Upon receiving this information, based on a policy determined by the SMF 130 and the information received from the local DN, the UE 10 can forward the relevant information to the upper-layer network context manager, DNS client, and URSP manager 1022 residing in the AP 1030 of the UE 10. Furthermore, if there is a command to be executed in the upper-layer network layer related to the local DN, the UE 10 can forward this information along with it. When the UE's modem (CP) 1010 receives information corresponding to the upper layer, it forwards the information and instructions to the AP 1030, and the corresponding manager in the AP 1030 can perform this operation. For example, when the SMF 130 generates a new local DN and sets a DNS server address for the corresponding local DN, the AP 1030 receives this information and can forward it to the DNS client 1023. Alternatively, when SMF 130 creates a new local DN and notifies the corresponding IP address range to CP 1010 of UE 10, CP 1010 of UE 10 can transmit the corresponding IP address range to AP 1030, allowing the upper-layer context manager 1024 to record it. Subsequently, when the local PSA-UPF used for the corresponding local DN is removed, SMF 130 can notify CP 1010 of UE 10 of the local PSA-UPF removal information. SMF 130 can then send a request to CP 10 of UE 10 to release the upper-layer context 1024 bound to the corresponding local DN. Upon receiving this, CP 1010 of UE 10 will notify the upper-layer context manager 1024 of AP 1030 of the information received from SMF 130, and the upper-layer context manager 1024 of AP 1030 can release the upper-layer context (e.g., TCP context information) managed in the mobile operating system. This process can be referred to as "re-evaluating URSP".

[0115] Figure 5C is an illustrative diagram illustrating a local DN binding context according to an embodiment of the present disclosure.

[0116] Figure 5C is another representation of the configuration diagram of UE 10 described in Figures 5A and 5B, and also explains the local DN binding context described in this disclosure. The descriptions of components not described separately are the same as in Figures 5A and 5B. Components with different reference numerals in Figure 5C are newly numbered components used to describe this disclosure and can be understood from the same viewpoint as in Figures 5A and 5B.

[0117] In Figure 5C, UE application 1 (1034) has a TCP connection to EAS#1 (552) of local DN 551 and creates a Layer 4 context #1 (1021) in the higher-level OS. Furthermore, UE application 2 (1035) has a connection to AS#1 (553) located in central DN 542. The Layer 4 context 1021 of the UE with the connection to EAS#1 (552) of local DN 541 can be an example of a local DN binding context. In the operations described in this disclosure, the upper-layer network context information can be the local DN binding context. Specifically, it can be said that the operation of controlling the upper-layer network context due to notification from local DN 541 corresponds to the operation of controlling the local DN binding context, and the operation for the local DN binding context can include, for example, removing or maintaining the Layer 4 context #1 shown in Figure 5C, or refreshing DNS cache information received from the DNS server 551 configured for local DN 541.

[0118] <First Embodiment>

[0119] The first embodiment of this disclosure proposes a scheme in which, when the SMF 130 determines to add a BP / ULCL and a local PSA-UPF, the SMF 130 notifies the UE 10 of information about the local DN to be added via a PDU session change message. The SMF 130 can transmit control information for the upper-layer network context, as well as information about the PDU session and the local DN.

[0120] Figure 6 This is a signal flow diagram illustrating how the SMF provides control information about the upper-layer network context and information about the PDU session and local DN to the UE according to embodiments of this disclosure.

[0121] Reference Figure 6 Previously, the configuration information for a local DN could include at least one of the following.

[0122] (1) DNS server address, domain name operated by the DNS server

[0123] (2) Identifier of local DN

[0124] (3) Instructions for adding / relocating / deleting local DNs: This instruction indicates that a local DN is added when the SMF 130 determines to add a local PSA-UPF, and that a local DN is deleted when the SMF 130 deletes a local PSA-UPF.

[0125] (4) Information regarding the IP address range of the local DN to be added.

[0126] (5) The server IP address used for the service to be routed to the local DN, or the destination IP address, destination port number, and the upper-layer protocol number of the IP, for example, the protocol number indicating TCP or UDP.

[0127] Next, the upper-layer network context control information related to the local DN may include at least one of the following.

[0128] (1) Should the previous DNS cache information of the local DN be deleted?

[0129] (2) Context control information for upper-layer protocols. For example, reserved indications for upper-layer protocols (e.g., TCP context, HTTP context).

[0130] (3) Instructions for the reassessment of URSP: Instructions to release the binding between URSP and application services and to evaluate URSP rules.

[0131] (4) Refresh instruction for PDU sessions bound to application services: Instructs to release the binding of the PDU session to a specific application service and delete the corresponding context.

[0132] In addition, SMF 130 can receive AF service control information, including DNAI (Service Bootstrapping Execution Control Information Affected by AF), from PCF 140. When SMF 130 detects a change in DNAI due to the movement of UE 10, it can determine additional PSA addition and LDN addition information.

[0133] When the SMF 130 determines to add another PSA, the SMF 130 can perform the ULCL and local PSA addition process.

[0134] During operation 610 (procedure 0), UE 10 may have a previously established PDU session and can be connected to UPF 602 as PSA1 via RAN 20 and tunnel.

[0135] In operation 612 (procedure 1), SMF 130 can determine UPF 603 corresponding to PSA2 as the new PSA based on the UE mobility event, and generate N4 using the new PSA2. Furthermore, upon receiving (or detecting) a UE mobility event, SMF 130 can determine the "Local DN Notification Control Information," "UE Upper Layer Context Control Information (i.e., Local DN Binding Context Information)," and guidance for local processing services based on the PCC rules and / or local DN configuration received from PCF 140. SMF 130 can send the early notification requested by AF. SMF 130 can then wait for a response to this notification.

[0136] In operation 614 (procedure 2), SMF 130 can select a new local PSA-UPF 603 and establish an N4 session with the local PSA-UPF 603.

[0137] In operation 616 (procedure 3), SMF 130 can select ULCL / BP UPF 601 and generate uplink forwarding rules for ULCL / BP UPF 601, PSA1 602, and PSA2 603. SMF 130 can forward service rules pointing to PSA1 602 and PSA2 603 to ULCL UPF 601. In other words, SMF 130 can send an AF service impact post-notification to the AF. Then, SMF 130 can wait for a response.

[0138] In operation 618 (procedure 4), the SMF 130 can update the N4 session using PSA1 602. Similarly, for DL ​​services, the SMF 130 can provide tunnel information from ULCL-BP 601 to PSA1 602.

[0139] Subsequently, in operation 620, PSA1 602 can send a downlink PDU to the first UPF 601. The first UPF 601 can then forward the received downlink PDU to UE 10. Furthermore, in operation 622, UE 10 can send an uplink PDU to be delivered to PSA1 602 using the appropriate tunnel. The order of operations 620 and 622 can be changed when the tunnel information is known to both UE and PSA1 602 in advance. That is, if the tunnel information is mutually known, operation 620 can be performed after operation 622.

[0140] In operation 624 (procedure 5), the SMF 130 can update the N4 session using PSA2 603. Therefore, for DL ​​services, the SMF130 can provide tunnel information from ULCL-BP 601 to PSA2 603.

[0141] In operation 626 (procedure 6A), when SMF 130 needs to notify UE 10 of L-PSA configuration information, SMF 130 can send a PDU session modification command to UE 10.

[0142] Local DN configuration information can be configured directly in SMF 130 or in PCF 140. When SMF 130 receives Policy and Charging Control (PCC) information for UE 10 from PCF 140 through the SMPolicyAssociation creation or modification process, it can also receive local DN configuration information, which may include 3-tuple information, DNS address, and local DN subnet address.

[0143] If the SMF 130 determines to add / change / delete a local PSA-UPF, the SMF 130 can log it as a local DN event and deliver it to the UE 10.

[0144] SMF 130 can receive local DN binding control information from AF requests or PCF 140. Based on this information, SMF 130 can transmit at least one of the following information to UE 10.

[0145] (1) Add L-PSA,

[0146] (2) The list of added 3-tuples,

[0147] (3) The added subnet address,

[0148] (4) DNS address,

[0149] (5) Existing DNS refresh instructions,

[0150] (6) Upper-layer network context preservation indication

[0151] (7) URSP Business Reassessment Instructions

[0152] Once this information is received, UE 10 can perform the operations specified in the LDN information. That is, it can maintain the upper-layer context and reassess URSP services. Subsequently, in operation 628 (procedure 6B), SMF 130 can send N2 SM information to RAN 20 via N11 and AMF 120. In other words, SMF 130 can transmit new CN tunnel information (ULCL / BP tunnel information) to RAN 20.

[0153] Meanwhile, during operation 630, UE 10 can still send uplink PDUs to PSA1602 through the first UPF 601 using the previous tunnel.

[0154] In operation 632 (procedure 7), in the case of IPv6 multi-homed (MH), the SMF 130 can send a Router Advertisement (RA) (new IP prefix, routing rules) message to the UE10 via PSA2 603. The SMF 130 can also send a follow-up notification to the AF.

[0155] In operation 634 (procedure 8), in the case of IPv6 MH, SMF 130 can send RA (original IP prefix, routing rules) via PSA1 602 to reconfigure the previous IP prefix.

[0156] Therefore, in operation 636, UE 10 can send the uplink PDU to the first UPF 601 to be delivered to PSA1 602. Then, the first UPF 601 can forward it to PSA2 603.

[0157] Subsequently, in operation 640, UE 10 can perform upper-layer control, such as URSP re-evaluation, or upper-layer context retraining or refresh.

[0158] <Second Embodiment>

[0159] The second embodiment of this disclosure defines UE and system operations when the SMF 130 performs a process of detecting DNAI changes caused by the movement of UE 10 and removing the local PSA. During this process, the SMF 130 may determine to notify the local DN configuration information and transmit upper-layer network context control information along with the local DN configuration change notification to the UE 10.

[0160] The process according to the second embodiment can be performed as follows. The following description will use the above... Figure 6 The components are given.

[0161] In step 1, UE 10 has a PDU session with the added local PSA (for the process of deleting PSA1 and maintaining PSA2).

[0162] In step 2, in the case of IPv6 MH, SMF 130 can reconfigure the UE IPv6 prefix for PSA1 602 and PSA2 603.

[0163] In step 3, SMF 130 can determine to remove the local PSA based on various reasons. When SMF 130 needs to notify UE 10 of L-PSA configuration information, SMF 130 can send a PDU session modification command to UE 10. The LDN configuration information used for transmission may include information about LDN removal, LDN identifier, list of removed 3-tuples, removed subnet addresses, removed DNS addresses, existing DNS refresh indications, upper layer network context preservation indications, and URSP service reassessment indications.

[0164] In step 4, SMF 130 can update the PSA2 CN tunnel information to RAN 20. If there is an additional UPF between RAN 20 and ULCL 601 (corresponding to a cascaded UPF), the CN tunnel information for that UPF can be updated.

[0165] In step 5, SMF 130 can update the AN tunnel information for PSA2 603 in the N4 session. If there is an additional UPF between RAN 20 and ULCL 601 (corresponding to a cascaded UPF), the CN tunnel information for that UPF can be updated.

[0166] In step 6, the SMF 130 can release N4 of PSA1 602. In the case of IPv6 MH, the SMF 130 can release the IPv6 prefix.

[0167] In step 7, if steps 4 / 5 above are performed, SMF 130 can release the N4 session corresponding to ULCP / BP 601.

[0168] <Third Embodiment>

[0169] The third embodiment of this disclosure is the process by which the SMF 130 delivers local DN notifications and upper-layer network context control information to the UE based on the operator's policy of local DN.

[0170] Figures 7A and 7B are signal flow diagrams illustrating the situation where the SMF provides local DN notification and upper-layer network context control information to the UE according to an embodiment of the present disclosure.

[0171] Mobile communication operators can pre-configure local DN information in the operator policy information of PCF 140. The operator policy information set in PCF 140 can include information about the local DN for each DNAI (operator-configured local DN information).

[0172] Operator policy information may include at least one of the following:

[0173] -Local DN identifier: DNAI

[0174] - Local DN service area: Tracking area or cell list

[0175] - IP address range, for example, 10.10.10.*

[0176] - Whether to operate local DNS

[0177] - Local DNS address and local DNS domain name

[0178] -Service provider identifier or sponsor identifier

[0179] - If service continuity is required when moving the local DN.

[0180] - Whether to notify the UE of local DN information

[0181] PCF 140 can generate PCC rules by including local DN control information in the AF service boot execution control information based on configuration information about the local DN, and can send local DN notification control information to SMF 130. The local DN notification control information may include at least one of the following information.

[0182] - Local DN identifier (e.g., Data Network Access Identifier (DNAI))

[0183] - Whether to notify the UE of local DN information

[0184] - Local DN binding control information: Local DN binding control information may include Layer 4 (TCP) context save / refresh information and DNS cache refresh information.

[0185] -UE upper-level network context refresh indication when leaving the local DN

[0186] -Local DN configuration information

[0187] SMF 130 can receive PCC rules and perform local PSA and ULCL append operations when UE 10 enters the DNAI area. Therefore, UE 10 can operate based on local DN control information.

[0188] SMF 130 can transmit local DN addition notifications to UE 10 and can also transmit upper network layer control information.

[0189] The signal flow and related operations according to this disclosure will then be described with reference to Figures 7A and 7B. Figures 7A and 7B can be executed sequentially. For example, the signal flow of Figure 7B can continue after the flow of Figure 7A is completed. As another example, Figure 7B can be executed independently of Figure 7A. The following description will be given based on the case where Figures 7A and 7B are executed sequentially.

[0190] In procedures 701 and 702, UE 10 can send a PDU session establishment request (PDUSession_CreateSMcontext request) message to SMF 130 via AMF 120. In order to establish the first PDU session, UE 10 can send information to SMF 130 such as whether it supports local DN control functions and whether it supports upper-layer network context control functions.

[0191] When a PDU session request is received from UE 10, in procedure 703, SMF 130 can receive reservation information from UDM 170 to identify the reservation information of UE 10.

[0192] When obtaining the reservation information of UE 10, in procedure 704, SMF 130 may send a PDU session establishment context response (PDUSession_CreateSMcontext response) message to AMF 120.

[0193] In procedure 705, SMF 130 can establish a connection with PCF 140 for receiving SM policies and can receive PCC rules for the PDU session of UE 10 from PCF 140. The PCC rules may include service bootstrapping execution control information affected by AF. The service bootstrapping execution control rules affected by AF may include at least one of the following information.

[0194] (1) DNAI (Data Network Access Identifier)

[0195] (2) Whether local routing is supported: It can more specifically indicate whether IPv6 multihoming or ULCL is supported.

[0196] (3) IP address reservation indication (or network interface reservation indication)

[0197] (4) Upper-layer context hold instruction or upper-layer network refresh instruction

[0198] (5) Is application-layer relocation possible?

[0199] (6) N6 routing information

[0200] (7) Local DN control information

[0201] When SMF 130 adds a local PSA-UPF for connecting to the local DN, the local DN control information may include whether to notify UE 10 of local DN information and the information to be notified to UE 10.

[0202] In process 706, SMF 130 may select a first PSA-UPF 791, which is capable of supporting SSC support provided by the UE and service guidance execution control information affected by AF received from PCF 130.

[0203] In procedures 707 and 708, SMF 130 can determine the establishment of a PDU session and send a PDU session establishment response message to UE 10 via AMF 120.

[0204] In procedures 709 and 710, SMF 130 can receive RAN tunnel information provided by RAN 20 from AMF 120 and can configure tunnel information for downlink services of PSA-UPF1 791.

[0205] The PDU session establishment process has been described above. Next, we will describe the case of newly added local PSA (triggered by local PSA insertion).

[0206] In procedure 711, when UE 10 detects that it has exited its current registered area, it can send a registration request message to AMF 120 via the RAN. Alternatively, when UE 10 performs a handover to another base station according to a command from base station 20, AMF 120 can detect the handover from base station 20 during the handover process. Or, when UE 10 sends a service request in an idle state (Connection Management Idle (CM-IDLE) state), AMF 120 can detect that UE 10 has been moved. To update the PDU session, AMF 120 can send a PDUSession_Update_SMContext request, including the location information of UE 10, to SMF 120.

[0207] In procedure 712, when PCF 140 receives a request for AF service guidance from AF or when the AF service guidance rules within the operator change, PCF 140 can send policy and charging control (PCC) rules, including service guidance execution control information affected by AF, to SMF 130. The service guidance execution control information affected by AF may include the information in procedure 705 above, such as local DN control information and upper-layer network context control information.

[0208] In process 713, when a location change of UE 10 is detected due to the movement of UE 10 (process 711), SMF 130 can determine whether it has moved to a DNAI pre-set in SMF 130 or registered via PCC rules. Alternatively, when receiving service control implementation information affected by AF from PCC, SMF 130 can determine whether the location of the corresponding UE is included in the location mapped to the DNAI. When SMF 130 determines to perform ULCL / BP and local PSA-UPF addition, SMF 130 can execute the process corresponding to stage C of Figure 7.

[0209] Next, stage C will be described. Stage C can be a procedure added (inserted) by ULCL / BP and local PSA-UPF.

[0210] In procedure 714, SMF 130 can establish an N4 session with PSA2 792.

[0211] In procedure 715, SMF 130 can establish an N4 session with ULCL / BP UPF 793.

[0212] In procedure 716, SMF 130 can modify the N4 session of PSA1 for downlink services. That is, the tunnel information pointing to RAN 20 can be updated using the tunnel information of ULCL / BP UPF 793 generated in procedure 715. Afterward, downlink services from PSA1 791 are redirected to ULCL / BP 793.

[0213] In procedure 717, SMF 130 can update the N4 session with PSA2 792.

[0214] In procedure 718, SMF 130 can detect a change in the location of UE 10 via the triggering conditions in procedure 713, namely, the location information of UE 10 from AMF 120, and determine whether a corresponding DNAI change has been made. Alternatively, SMF 130 can receive PCC rules from PCF 140 that include service guidance execution control information affected by AF. The PCC rules may include local DN control information, which includes local DN configuration information and the UE's upper-layer network context control information. When a new local UPF connected to the local DN is added, the local DN control information may instruct that the UE's upper-layer network context control information be delivered to the UE along with the local DN configuration information. When SMF 130 receives this local DN control information and determines that a local PSA-UPF has been added, it can determine to send a PDU session modification command message to UE 10 via AMF 120 to pass the local DN configuration information and upper-layer network context control information to UE 10.

[0215] In procedure 719, SMF 130 may send an N1N2MessageTransfer message to AMF 120, which includes a PDU session modification command message. This message may include a PDU session identifier, local DN configuration information, and upper-layer network context control information, which may be information used to modify the PDU session.

[0216] The local DN configuration information can be the same as the local DN information described in the first embodiment above. Furthermore, the upper-layer network context control information can be the same as the upper-layer network context control information described in the first embodiment above.

[0217] When SMF 130 determines to add ULCL / BP, in order to send CN tunnel information to RAN 20 for establishing tunnels between ULCL / BP and PSA1 and between ULCL / BP and PSA2, the CN tunnel information may be further included in the N1N2MessageTransfer message sent to AMF 120.

[0218] In process 720, AMF 120 may send all or at least some of the information received from SMF 130 as an N2 message (i.e., the content included in N1N2MessageTransfer) to RAN 20.

[0219] In procedure 721, the RAN N2 message includes the configuration of tunnel information for uplink services received from the RAN for local ULCL / BP. RAN 20 can perform an AN-specific resource modification procedure on UE 10 and send a PDU session modification command message included in the N2 message to the UE. RAN 20 can then receive a response from UE 10.

[0220] In procedure 722, RAN 20 can send the newly created tunnel information for PSA2792 and the response message received from UE 10 corresponding to the PDU session modification command to AMF 120.

[0221] In process 723, AMF 120 can transmit the information received from RAN 10 to SMF 130 and receive a response thereto.

[0222] In procedure 724, in the case of IPv6 multihoming, SMF 130 can assign a new IP prefix to PSA2 792 to UE 10 and deliver it to UE 10.

[0223] In procedure 725, in the case of IPv6 multihoming, SMF 130 can reconfigure the existing IP prefix information of PSA1 791 in UE 10.

[0224] <Fourth Embodiment>

[0225] The fourth embodiment provides a procedure and corresponding node operations for transmitting local DN information and upper-layer network context information to the UE during a process of changing the local PSA due to an AF request.

[0226] Figures 8A and 8B are signal flow diagrams illustrating the operations of each node providing corresponding information to the UE when changing the local PSA in response to an AF request in the network, according to embodiments of the present disclosure. In the following description, Figures 8A and 8B will be collectively referred to as Figure 8 unless it is necessary to distinguish between them. Similarly, the operation in Figure 8B can be performed after the operation in Figure 8A. As another example, the operation in Figure 8B can be performed after another operation without the operation in Figure 8A.

[0227] In procedure 801, UE 10 can establish a PDU session with SMF 120. SMF 120 can select PSA-UPF0 802 in this procedure (procedure 801-1). More detailed procedures for this are described in procedures 701 to 710 of the third embodiment, and therefore, a repeated description thereof will be omitted. Furthermore, SMF 120 can determine to add ULCP / BP and local PSA-UPF1 (procedure 801-2). This is described in procedures 711 to 725 of the third embodiment, and therefore, a repeated description will be omitted.

[0228] In process 802, the source EES 807 can act as the source AF and send an AF request to the PCF 805. In Figure 8, in... Figures 1 to 3 PCF 140 and NEF 190, as described in the figure, are shown as a single node. This is for ease of configuration drawing, although they perform different operations. Therefore, in the following description, the node indicated by label 895 will be described as PCF 895 when it operates as PCF and as NEF 895 when it operates as NEF. As a method of transmitting AF requests to PCF 895, AF requests can be stored in UDR (not shown in Figure 8) by NEF 895, and PCF 895, which has received a UDR information change notification, can receive it. Upon receiving an AF request, taking into account the operator policy of the local DN in the third embodiment described above, PCF 895 can send service boot execution control information affected by the AF, including local DN control information and UE upper-layer network context control information, to SMF 130. Both local DN control information and UE upper-layer network context control information can be transmitted to SMF 130.

[0229] In procedure 803, SMF 130 can receive the PCC rules for the PDU session of UE 10 from PCF 895. The PCC rules may include service boot execution control information affected by AF. The service boot execution control rules affected by AF may include at least one of the following information.

[0230] (1) DNAI (Data Network Access Identifier)

[0231] (2) Information about the service area mapped to DNAI

[0232] (3) Whether local routing is supported: It can more specifically indicate whether IPv6 multihoming or ULCL is supported.

[0233] (4) IP address reservation indication (or network interface reservation indication)

[0234] (5) Upper-layer context hold instruction or upper-layer network refresh instruction

[0235] (6) Is application-layer relocation possible?

[0236] (7) N6 routing information

[0237] (8) Local DN control information

[0238] When SMF 130 adds a local PSA-UPF for connecting to the local DN, the local DN control information may include whether to notify UE 10 of local DN information and the information to be notified to UE 10.

[0239] In procedure 804, when UE 10 detects that it has exited its current registration area, UE 10 can send a registration request message to AMF 120 via RAN 20. Alternatively, when UE 10 performs a handover to another base station according to a command from a base station, AMF 120 can detect the handover from the base station during the handover process. Or, when UE 10 sends a service request in an idle state (Connection Management Idle (CM-IDLE) state), AMF 120 can detect that UE 10 has been moved. AMF 120 can send a PDU Session_Update_SMContext request, including the location information of UE 10, to SMF 130 to update the PDU session.

[0240] In procedure 805, SMF 120 may determine whether to relocate the local PSA based on the PCC rules received in procedure 803 or the location information of UE 10 received in procedure 804. For example, suppose the information about the local DN is set as follows.

[0241] 1) Information about local DN 1

[0242] -Local DN Identifier: DNAI-A

[0243] - Service Area: TA1, TA2

[0244] -Relevant local PSA-UPF: PSA-UPF#1

[0245] - IP subnet address: 10.10.10.*

[0246] - Local DNS address: 10.10.10.10.200

[0247] - Local DNS domain name: local1.example.com

[0248] 2) Information about local DN 2

[0249] -Local DN identifier: DNAI-B

[0250] - Service Area: TA3, TA4

[0251] -Relevant local PSA-UPF: PSA-UPF#2

[0252] - IP subnet address: 10.10.20.*

[0253] - Local DNS address: 10.10.20.200

[0254] - Local DNS domain name: local2.example.com

[0255] SMF 130 can also receive local DN control information from PCF 895. This local DN configuration information can be configured directly in the SMF, or it can be configured in PCF 140 and then received by SMF 130 from PCF 140. This information may include the following operator policies. This operator information can be pre-configured locally in SMF 130.

[0256] - When generating a DNAI, should the UE be notified of the local DN configuration information?

[0257] - When the DNAI is changed, should the UE be notified of the local DN change information?

[0258] - When removing DNAI, should the UE be notified of local DN removal information?

[0259] SMF 130 can identify the relevant DNAI based on the location information of UE 10 received from AMF 120, and can determine that the local PSA-UPF has been relocated to PSA-UPF#2 804, which supports DNAI. This determination implies a change in the local DN, and SMF 130 can determine whether to notify the UE of local DN configuration information, local DN change information, or previous local DN control information based on the local DN control information policy received from PCF 895. When the local DN changes, SMF 130 can execute a PDU session modification procedure to pass the local DN configuration information to UE 10.

[0260] In addition, along with local DN control information, PCF 805 can include the upper-layer network context information of UE 10 in the PCC rule and transmit it to SMF 120. The configuration information used for this may include the following information.

[0261] - When the DNAI is changed, the UE upper-layer network context is maintained or refreshed.

[0262] - When DNAI is removed, the UE upper-layer network context is retained or refreshed.

[0263] For example, if local DN1 and local DN2 are in different IP address ranges as described above, PCF 895 can send a policy indicating an upper-layer network context refresh to SMF 130 when the DNAI is changed. Upon receiving such a policy, SMF 130 can select an indication corresponding to the policy and send it to UE 10 via a PDU session modification command message. For example, SMF 130 can transmit an upper-layer network context refresh indication to UE 10. Alternatively, when the DNAI is changed, SMF 130 can determine the refresh context by checking the range of IP addresses in the local DN information and send an upper-layer context refresh indication to UE 10.

[0264] SMF 130 can determine whether a previously generated local PSA-UPF is released in response to a DNAI change. In this case, SMF 130 can transmit an upper-layer network context refresh indication along with local DN deletion information to UE 10. The local DN deletion information may include the local DN identifier and an indication that it has been deleted.

[0265] If the conditions for user event notification are met, SMF 130 can determine whether a PSA-UPF relocation that satisfies the AF request can be performed at the current location of UE 10, and send a corresponding notification to AF (source EES) 897. The early notification from AF may include at least one of the following.

[0266] -Can the IP address be maintained?

[0267] - Should PSA relocation be performed?

[0268] -Information about the expected PDB when repositioning the PSA

[0269] - Target DNAI information in the case of DNAI alteration

[0270] The source EES 897 can receive early notifications of user plane events from the SMF 130. Based on the received information, the source EES 897 can determine whether to relocate the application context. The source EES 897 can determine to relocate the application context when the following conditions are met. When the conditions are not met, the source EES 897 can determine not to relocate the application context.

[0271] When source EES 897 determines to relocate the application context, procedures 816 and 817 can be executed.

[0272] When the source EES 897 determines that PSA relocation should be performed, it can send a positive response via the AppRelocationInfo message. When the source EES 897 determines that PSA-UPF relocation is not required, it can send a negative response to the SMF 130.

[0273] When the source EES 897 determines that it should respond to PSA relocation, the EES 897 may respond by including at least one of the following information in the AppRelocationInfo message.

[0274] - Positive response to PSA repositioning

[0275] - Indicates AF will be changed

[0276] - The notification address of the target AF to be notified

[0277] -UE upper-layer network context preservation indication

[0278] The SMF 130 can receive a response message to an early notification from the source EES(AF)897. Upon receiving a positive result via the response message, the SMF 130 can select a new PSA-UPF1 and establish an N4 session.

[0279] SMF 130 can deliver a follow-up notification to the source EES(AF)897.

[0280] A post-notification message sent from source EES 897 to AF may include at least one of the following information.

[0281] -Target DNAI

[0282] -UE IP address

[0283] - Whether to provide upper-level context persistence information

[0284] - Whether to notify the UE of local DN information

[0285] - Local DN binding information control information (e.g., whether to delete or maintain the L4 context bound to the local DN, or whether to delete DNS cache information).

[0286] Upon receiving the post-notification, the source EES 897 can perform an application context transfer as in procedures 823 and 824. In procedure 814-2, the source EES 897 can pass the context relocation response information to the UE 10's edge enabler client (EEC).

[0287] Subsequently, in procedure 815-1, source EES 897 responds to SMF 130 by including at least one of the following information in the AppRelocation Info.

[0288] - Was AppRelocation successfully performed?

[0289] -Target DNAI

[0290] -UE's reservation information (GPSI, etc.)

[0291] The SMF 130 can receive responses to subsequent notifications.

[0292] In procedure 816, SMF 130 performs an update procedure for the N4 session.

[0293] In procedure 817, SMF 130 can deliver a PDU session modification message to UE 10 via AMF 120 as defined in procedure 805. As described in the first embodiment, the PDU session modification message may include local DN information and upper-layer network context control information, and can be delivered to UE 10.

[0294] In procedure 818, for IPv6 multihoming, SMF 130 can assign a new IPv6 prefix to be used in PSA2 894 and send it to UE 10.

[0295] In procedure 819, for IPv6 multihoming, SMF 130 can reconfigure the UE IPv6 settings for PSA0 892.

[0296] In procedure 820, SMF 130 can release the N4 session previously connected to the local PSA-UPF1 893 of UE 10.

[0297] <Fifth Embodiment>

[0298] The fifth embodiment defines how the local DN information and upper-layer network context control information sent from the SMF 130 to the UE via the AMF 120 are used in the UE.

[0299] Figures 9A and 9B are illustrative diagrams illustrating the process of providing local DN information and upper-layer network context control information to a UE, and the operations within the UE, according to embodiments of the present disclosure.

[0300] In the description of Figures 9A and 9B, the same reference symbols used in Figure 8 will be used for the same elements as in Figure 8.

[0301] In procedure 901, UE 10 can request SMF 130 to establish a new PDU session. SMF 130 can select PSA-UPF0 892, create a tunnel between PSA-UPF0 892 and RAN 20, and send a confirmation message for the PDU session establishment request to UE 10. As shown in Figure 5, since UE 10 has established a new PDU session, a network interface corresponding to the new PDU session can be created, and mapping can be performed between them. That is, a network interface corresponding to the new PDU session can be generated between CP 1010 and AP1030 in UE 10, and mapping can be performed between the new network interface and the established PDU session. Furthermore, applications corresponding to the mapping between them can be mapped together.

[0302] In procedure 902, UE 10 can establish a TCP connection with a server residing in the central DN connected to PSA-UPF0 802. A TCP context can be created in the upper layer of UE 10. In Figure 9, this is indicated by label (A).

[0303] In process 903, according to the various embodiments described above, SMF 130 can determine to perform local PSA-UPF and ULCL / BP addition, select local PSA-UPF 1893, and pass information including a 3-tuple (destination IP address, destination port number, and protocol number) to ULCL / BP 891 for use towards the local PSA-UPF. SMF 130 can send information about the local DN to UE 10. Once received, UE 10 can store the information about the local DN. Since the local DN information has been described in detail in the first embodiment, its description is omitted here. The information included therein may include the local DN identifier in the local DNS, subnet address, local DNS address, EAS address, and the 3-tuple address sent by SMF to ULCL, etc.

[0304] In procedure 904, UE 10 may invoke a DNS query procedure for EAS#1 FQDN upon request from the application layer. The DNS query procedure may be handled by a local DNS server located in local DN1 or a DNS server located in the central DN. Therefore, UE 10 obtains the IP address of EAS#1 where local DN#1 is located.

[0305] In procedure 905, UE 10 can establish a TCP connection by making a TCP connection request to the destination IP address of EAS#1 found by the DNS query procedure. The TCP connection thus created is represented by label (B) in Figure 9.

[0306] In procedure 906, when SMF 130 detects a DNAI change due to UE 10's movement or receives a PCC rule including service guidance execution control information affected by AF, SMF 130 can determine to perform local PSA relocation and execute a procedure to change the local PSA-UPF. During this procedure, SMF 130 can transmit a local DN addition notification to UE 10 to indicate that a second local DN has been newly added. Additionally, SMF 130 can notify UE 10 that the previously connected local DN1 has been deleted. Here, the upper-layer context control information for local DN1 can be delivered along with information indicating that local DN1 has been removed. The upper-layer context control information may include an upper-layer context refresh indication for local DN2. When the upper-layer network context control information includes context information refresh information corresponding to local DN2, UE 10 can remove the upper-layer context information corresponding to local DN2. For example, the TCP context associated with EAS1 of local DN1 created in procedure 904 above can be released. Furthermore, DNS cache refresh information is included in the upper-layer control information. DNS cache refresh instructions can include the domain name FQDN or the IP subnet address of local DN1 provided by the local DN. When the upper layer, i.e., AP 1030 in the UE, receives the included information, it can delete the DNS cache information corresponding to the included subnet address. Alternatively, it can delete the DNS cache information or domain name information corresponding to the target FQDN.

[0307] In procedure 907, the application recognizes that the TCP connection with EAS#1 has been lost and can attempt to re-establish the connection. Here, when the corresponding DNS cache information is deleted, the address information of EAS#1 FQDN can be re-requested and received from the DNS server.

[0308] In procedure 908, if EAS#1 resides in local DN2, a TCP session can be established with local DN2 via local PSA-UPF2 894, based on the application's request.

[0309] In procedure 909, when UE 10 leaves the DNAI-B area or receives an AF request, SMF 130 can remove the local PSA-UPF2 894. SMF 130 can deliver the local DN information for DNAI-B to UE 10 based on a determination of the policy that the local DN information in UE 10 should be changed from the PCC rule, or by SMF 130's own determination. The information sent to UE 10 is about removing the local DN, and in cases where the local DN needs to be removed, upper-layer network context control information can also be sent. The higher-layer network context control information may include requests for higher-layer network context refresh and DNS cache deletion for the local DN2. Upon receiving this request, the UE's AP removes the TCP context and erases the DNS cache.

[0310] Meanwhile, each of the first to fifth embodiments described above can be executed independently, but two or more embodiments can be operated together. For example, the first embodiment describes the process of adding BP / ULCL and local PSA-UPF; the second embodiment describes the process of detecting DNAI changes and removing local PSA; the third embodiment describes a method for delivering local DN notifications and upper-layer network context control information to the UE based on operator policies; the fourth embodiment describes a process for delivering local DN information and upper-layer network context information to the UE during the process of changing local PSA based on AF requests; and the fifth embodiment describes a method for transmitting local DN information and upper-layer network context control information to the UE for use in the UE.

[0311] Therefore, the first and fifth embodiments can be used together, as can the second and fifth embodiments. Furthermore, since a local PSA-UPF is added according to the first embodiment, the second embodiment can be used when another local PSA is removed. Additionally, the first, second, and fifth embodiments can be used together.

[0312] Furthermore, the first and third embodiments can be executed sequentially, for example, when the first embodiment is applied after the third embodiment is applied, or when the third embodiment is applied after the first embodiment is applied.

[0313] As another example, when the first embodiment is executed based on the fourth embodiment, the second embodiment can be executed together, thereby enabling the execution of the fifth embodiment.

[0314] In this way, when different embodiments are used together, some overlapping operations can be omitted in a particular embodiment, or all operations can be performed.

[0315] Figure 10 It is a block diagram of the NF entity according to this disclosure.

[0316] refer to Figure 10 The NF entity may include transceiver 1101, controller 1102, and memory 1103. The NF entity may be a specific AF among the RAN, AMF, UPF, SMF, UDM, PCF, AUSF, AF, and DN mentioned above.

[0317] Transceiver 1101 can provide an interface for communicating with other network entities. For example, when the NF is AMF 120, transceiver 1101 can send signals / messages / information to and from RAN 20, AUSF 160, SMF 130, PCF 140, and another AMF. Furthermore, when the NF is SMF 130, transceiver 1101 can send signals / messages / information to and from AMF 120, UDM 170, UPF 110, and PCF 140.

[0318] Controller 1102 can control the operation of the corresponding NF mentioned above. For example, it can control the reference. Figure 6 The operation of each NF as described in Figure 9. Controller 1102 can be implemented using one or more processors.

[0319] The memory 1103 can store the data required by the corresponding NF, and can also store information included in the various messages / signals described in this disclosure.

[0320] Specific examples have been provided in the foregoing disclosure to aid in understanding this disclosure. However, this disclosure is not limited thereto and can be modified in various ways based on the content disclosed herein.

[0321] [Industrial Applicability]

[0322] This disclosure may be applied when a UE adds, modifies, or deletes a PDU session in a wireless communication system.

Claims

1. A method for a Session Management Function (SMF) entity in a wireless communication system to provide Local Data Network (DN) information to a terminal, the method comprising: Receive policy and charging control (PCC) rules from the policy control function (PCF), wherein the PCC rules include local DN information; Based on the PCC rules, the relocation of the PDU session anchor PSA for the Protocol Data Unit (PDU) session is determined; as well as A PDU session modification command is sent to the terminal. The PDU session modification command includes a Domain Name System (DNS) refresh instruction and the local DN information.

2. The method according to claim 1, in, The local DN information includes fully qualified domain name or IP address information.

3. The method according to claim 1, wherein, The relocation of the PSA includes at least one of adding, changing, or removing the PSA.

4. The method according to claim 1, wherein, The relocation of the PSA is determined due to the mobility of the terminal or by triggering the application function AF.

5. The method according to claim 1, wherein, The local DN information includes the 3-tuple information, DNS address, and subnet address of the local DN.

6. A method for a terminal in a wireless communication system to receive local data network (DN) information from a session management function (SMF) entity, the method comprising: PDUs are sent and received by using a PDU session with the terminal configured using the first protocol data unit (PDU) session anchoring PSA. The session management function (SMF) receives a PDU session modification command, which includes a Domain Name System (DNS) refresh instruction and the local DN information. as well as Reconfigure the second PSA.

7. The method according to claim 6, in, The local DN information includes fully qualified domain name or IP address information.

8. A Session Management Function (SMF) entity capable of providing Local Data Network (DN) information to terminals in a wireless communication system, comprising: A transceiver is configured to communicate with other network entities. The memory is configured to store configuration information; as well as At least one processor, The processor is configured as follows: Receive policy and charging control (PCC) rules from the policy control function (PCF), wherein the PCC rules include the local DN information; Based on the PCC rules, determine the relocation of the PDU session anchor PSA for the Protocol Data Unit (PDU) session; and A PDU session modification command is sent to the terminal. The PDU session modification command includes a Domain Name System (DNS) refresh instruction and the local DN information.

9. The SMF entity according to claim 8, in, The local DN information includes fully qualified domain name or IP address information.

10. The SMF entity according to claim 8, wherein, The relocation of the PSA includes at least one of adding, changing, or removing the PSA.

11. The SMF entity according to claim 8, wherein, The relocation of the PSA is determined due to the mobility of the terminal or by triggering the application function AF.

12. The SMF entity according to claim 8, wherein, The local DN information includes the 3-tuple information, DNS address, and subnet address of the local DN.

Images