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

Abstract

After 4G communication systems such as LTE, 5G or pre-5G communication systems are provided to support higher data transmission rates. [Solution] A method for providing local data network information to a terminal in a session management function device of a wireless communication system, comprising the steps of determining the addition of a PDU session anchor-user plane to a protocol data unit session based on first information due to the mobility of the terminal, forming a PDU session with the PSA-UPF determined to be added, setting up PDU paths for downlink and uplink between the PSA-UPF and the terminal, and sending a PDU session change command to instruct the terminal to add a new PSA-UPF, wherein the first information includes at least one of policy and charging control information and local data network configuration information received from the policy control function device.

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication system, and more particularly to a method and apparatus for providing local data network information according to terminal movement in a cellular wireless communication system, such as 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 increasing demand for wireless data traffic. For this reason, 5G or pre-5G communication systems are also called Beyond 4G Network or Post-LTE systems.

[0003] In order to achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (such as the 60 GHz band). In order to mitigate the path loss of propagation in ultra-high frequency bands and increase the propagation distance, beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antennas, analog beam-forming, and large scale antenna technologies are being discussed for the 5G communication system.

[0004] Furthermore, to improve the system's network, technologies being developed for the 5G communication system include advanced small cells, improved small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device to device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and receive interference cancellation.

[0005] In addition, the 5G system includes advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced connection technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and SCMA (sparse code multiple access).

[0006] Meanwhile, 3GPP (registered trademark), which is responsible for cellular mobile communication standards, is working on standardizing a new core network structure called 5G Core (5GC) in order to evolve from the existing 4G LTE system to the 5G system.

[0007] 5GC supports the following differentiated features for the Evolved Packet Core (EPC), the existing network core for 4G:

[0008] First, 5GC will introduce the network slice function. As a requirement for 5G, 5GC must support a variety of terminal types and services. For example, there are enhanced Mobile Broadband (eMBB), ultra reliable low latency communications (URLLC), and massive machine type communications (mMTC). Each of these terminals / services has different requirements for the core network. For example, eMBB services require high data rates, while URLLC services require high stability and low latency. The network slice approach is a technology proposed to meet such diverse service requirements.

[0009] Network Slice is a method of constructing multiple logical networks by virtualizing one physical network, and each Network Slice Instance (NSI) can have different characteristics. Therefore, by having a network function (NF) that matches each NSI's characteristics, various service requirements can be met. By assigning an NSI that matches the characteristics of the service required for each terminal, multiple 5G services can be supported efficiently.

[0010] Secondly, 5GC can facilitate support for the network virtualization paradigm by separating mobility management functions and session management functions. In the existing 4G LTE, all terminals have been provided with services in the network through signaling exchange with a single core device called the Mobility Management Entity (MME), which is responsible for registration, authentication, mobility management, and session management functions. However, in 5G, the number of terminals is exploding, and the mobility and traffic / session characteristics to be supported are subdivided depending on the type of terminal, so if a single device such as the MME were to support all functions, the scalability of adding an entity for each required function would be poor. Therefore, various functions are being developed based on a structure that separates mobility management functions and session management functions to improve scalability in terms of the function / implementation complexity and signaling load of the core equipment responsible for the control plane.

[0011] Meanwhile, a technology for applying edge computing technology, which transmits data using an edge server, to a wireless communication system has been discussed recently. The edge computing technology may include, for example, multi-access edge computing (MEC) or fog computing. The edge computing technology refers to a technology for providing data to an electronic device (terminal or user device) through a separate server (hereinafter, edge server or MEC server) installed in a location geographically close to the electronic device, for example, inside or near a base station. For example, an application that requires low latency among at least one application installed in the electronic device may transmit and receive data through an edge server installed in a geographically close location, rather than through a server located in an external data network (DN) (e.g., the Internet). Summary of the Invention [Problem to be solved by the invention]

[0012] In a 5G core network supporting edge computing, if a local PDU Session Anchor User Plane Function (local PSA-UPF) device for a local data network (local DN) is added / modified / deleted, an application server may move. In this way, when a local PSA-UPF is added / modified / deleted, the Session Management Function (SMF) device of the 5G core network must notify the terminal of control information related to the upper network layer. In addition, when the terminal receives control information related to the upper network layer from the SMF device, it performs appropriate operations accordingly.

[0013] However, the 5G core network does not provide an operation for performing such a procedure, and the terminal cannot perform an operation for receiving control information related to a higher network layer from the SMF device.

[0014] Therefore, the present invention provides a procedure for notifying a terminal of control information regarding a higher network layer in a 5G core network when a Local PSA-UPF is added / modified / deleted.

[0015] In addition, the present invention provides a processing device and method for a terminal receiving control information related to a higher network layer due to addition / modification / deletion of a Local PSA-UPF from a 5G core network. [Means for solving the problem]

[0016] According to an embodiment of the present invention, a method is provided for providing local data network information to a terminal in a Session Management Function (SMF) device of a wireless communication system, the method comprising: determining addition of a PDU Session Anchor-User Plane Function (PSA-UPF) to a protocol data unit (PDU) session based on first information according to mobility of the terminal; forming a PDU session with the PSA-UPF determined to be added; setting up PDU paths for downlink and uplink between the PSA-UPF and the terminal; and transmitting a PDU Session Modification Command to the terminal to instruct the terminal to add a new PSA-UPF, The first information may 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) device.

[0017] A method according to another embodiment of the present invention is a method for receiving local data network information from a Session Management Function (SMF) device in a terminal of a wireless communication system, the method including: transmitting / receiving a PDU using a protocol data unit (PDU) session established in the terminal; receiving a PDU Session Modification Command from the Session Management Function (SMF) device, the PDU Session Modification Command instructing addition of a new PDU Session Anchor-User Plane Function (PSA-UPF); receiving a Router Advertisement (RA) message sent by the SMF via the new PSA-UPF; re-configuring the new PSA-UPF; and performing the upper layer control based on the reconfiguration of the new PSA-UPF. Effect of the Invention

[0018] According to the present invention, when adding (or modifying / deleting) the local PSA-UPF, the upper layer network context of the terminal needs to be released. In this case, the SMF provides information about the local DN to the terminal so that the terminal can control the upper layer context. In addition, by defining such a procedure, the wireless communication network can provide the terminal with control information regarding the upper network layer due to addition / modification / deletion of a local PDU Session Anchor User Plane Function (Local PSA-UPF) device. In addition, the terminal can receive control information regarding the upper network layer due to addition / modification / deletion of the Local PSA-UPF from the wireless communication network and perform appropriate operations. [Brief description of the drawings]

[0019] [Figure 1]1 is a diagram showing an example of a 5G system architecture using reference point representation in a wireless communication system. [Diagram 2] 1 illustrates a configuration of a network entity in a wireless communication system according to various embodiments of the present invention. [Diagram 3] 1 is a diagram illustrating another structure of a 5G core network supporting edge computing according to an embodiment of the present invention. [Figure 4] 1 is an exemplary diagram for explaining a case where a terminal moves according to the present invention using a network topology; [Figure 5a] An exemplary diagram to explain the internal configuration of a terminal and a case of setting up a PDU session with a wireless communication network and a data network according to one embodiment of the present invention. [Figure 5b] An exemplary diagram to explain the internal configuration of a terminal and a case of setting up a PDU session with a wireless communication network and a data network according to one embodiment of the present invention. [Figure 5c] FIG. 13 is an exemplary diagram illustrating a local DN binding context according to one embodiment of the present invention. [Figure 6] 11 is a signal flow chart showing a case where an SMF provides a UE with control information regarding an upper layer network context together with information regarding a PDU session local DN according to one embodiment of the present invention. [Figure 7a] 1 is a signal flowchart when an SMF provides local DN announcement and upper layer network context control information to a terminal according to one embodiment of the present invention. [Figure 7b] 1 is a signal flowchart when an SMF provides local DN announcement and upper layer network context control information to a terminal according to one embodiment of the present invention. [Figure 8a] 11 is a signal flowchart regarding the provision of information to a terminal and the operation of each node accordingly when changing a local PSA in response to an AF request in a network according to an embodiment of the present invention. [Figure 8b]11 is a signal flowchart regarding the provision of information to a terminal and the operation of each node accordingly when changing a local PSA in response to an AF request in a network according to an embodiment of the present invention. [Figure 9a] 11 is an exemplary diagram illustrating a procedure for providing local DN information and upper layer network context control information to a terminal and an operation in the terminal according to one embodiment of the present invention. [Figure 9b] 11 is an exemplary diagram illustrating a procedure for providing local DN information and upper layer network context control information to a terminal and an operation in the terminal according to one embodiment of the present invention. [Figure 10] FIG. 2 is a block diagram of an NF according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, when it is determined that a detailed description of related known functions or configurations may obscure the gist of the present invention, the detailed description will be omitted. In addition, the terms used below are defined in consideration of the functions of the present invention, and may be changed according to the intention or practice of a user or operator. Therefore, the definitions should be based on the entire contents of this specification. Hereinafter, a base station is a subject that performs resource allocation for a terminal, and may be at least one of eNode B, Node B, BS (Base Station), RAN (Radio Access Network), AN (Access Network), RAN node, radio access unit, base station controller, or node on a network. A terminal may include UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or multimedia system capable of performing a communication function. In the present invention, downlink (DL) refers to a radio transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a radio transmission path of a signal transmitted from a terminal to a base station. In addition, although the embodiments of the present invention will be described below using an LTE or LTE-A system as an example, the embodiments of the present invention may be applied to other communication systems having similar technical backgrounds or channel configurations. Furthermore, the embodiments of the present invention may be applied to other communication systems through partial modifications within the scope of the present invention as determined by a person skilled in the art.

[0021] In the following, a description will be given of a session management procedure according to a movement of a terminal in a wireless communication system. In addition, the present invention may also be applied to a procedure for relocation of an application server to which a terminal is connected according to a movement of the terminal in an edge computing system.

[0022] FIG. 1 is a diagram showing an example of a 5G system architecture using reference point representation in a wireless communication system.

[0023] Referring to FIG. 1, the 5G system architecture may include various components (i.e., network functions (NFs)). FIG. 1 illustrates some of the components, such as an authentication server function (AUSF) device 160, a core access and mobility management function (AMF) device 120, a session management function (SMF) device 130, a policy control function (PCF) device 140, an application function (AF) device 150, a unified data management (UDM) device 170, a data network (DN) 180, a user plane function (UPF) device 110, a (radio) access network ((R)AN) 20, and a terminal, i.e., a user equipment (UE) 10.

[0024] Each of the devices illustrated in FIG 1 may be implemented as one server or device, and may also be implemented as a network slice instance as described above. When implemented as a network slice instance, it may be implemented as two or more identical or different network slice instances in one server or device, and one network slice instance may be implemented in two or more servers or devices.

[0025] Each of the above NFs can support the following functions:

[0026] The AUSF 160 may process and store data for authentication of the UE.

[0027] The AMF 120 can provide functionality for UE-based connection and mobility management, and essentially one UE can be connected to one AMF. Specifically, the AMF 120 provides CN inter-node signaling for mobility between 3GPP access networks, termination of the radio access network (RAN) CP interface (i.e., the N2 interface), termination of NAS signaling (N1), NAS signaling security (NAS ciphering and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE reachability (including control and execution of paging retransmissions), mobility management control (subscription and policy), intra-system and inter-system mobility support, support for network slicing, SMF selection, lawful intercept (for AMF events and interface to the LI system), delivery of session management (SM) messages between the UE and the SMF, a transparent proxy for SM message routing, access authentication, and the like. It may support functions such as authentication, access authorization including roaming permission check, provision of SMS message delivery between the UE and a Short Message Service Function (SMSF) device, security anchor function (SAF) and / or security context management (SCM). Some or all of the functions of the AMF 120 may be supported within a single AMF instance operating in one AMF.

[0028] The DN 180 may be, for example, an operator service, an Internet connection, or a third party service. The DN 180 may transmit a downlink protocol data unit (PDU) to the UPF 110, or may receive a PDU transmitted from the UE 10 via the UPF 110.

[0029] The PCF 140 may provide a function of receiving information about packet flows from an application server and determining policies for mobility management, session management, etc. Specifically, the PCF 140 may support functions such as supporting a unified policy framework for controlling network operations, providing policy rules so that control plane functions (e.g., AMF, SMF, etc.) can enforce the policy rules, and implementing a front end for accessing related subscription information for policy decisions in a user data repository (UDR).

[0030] The SMF 130 provides a session management function, and when a UE has multiple sessions, each session may be managed by a different SMF. Specifically, the SMF 130 may support functions such as session management (e.g., session establishment, modification, and release, including tunnel maintenance between the UPF and AN nodes), UE IP address allocation and management (optionally including authentication), UP function selection and control, traffic steering configuration for routing traffic to an appropriate destination in the UPF, interface termination toward policy control functions, policy and quality of service (QoS) control portion enforcement, lawful intercept (for SM events and interfaces to the LI system), termination of the SM portion of NAS messages, downlink data notification, initiator of AN-specific SM information (transmitted to the AN via the N2 via the AMF), SSC mode determination of a session, and roaming functions. As described above, some or all of the functions of the SMF 130 may be supported within a single SMF instance operating in one SMF.

[0031] The UDM 170 may store user subscription data, policy data, etc. The UDM 170 may include two parts: an application front end (FE) (not shown) and a user data repository (UDR) (not shown).

[0032] The FE may include a UDM FE responsible for location management, subscription management, credential processing, etc., and a PCF-FE responsible for policy control. The UDR may store data required for functions provided by the UDM-FE and policy profiles required by the PCF. Data stored in the UDR may include user subscription data and policy data including subscription identifiers, security credentials, access and mobility related subscription data, and session related subscription data. The UDM-FE may access the subscription information stored in the UDR and support functions such as authentication credential processing, user identification handling, access authentication, registration / mobility management, subscription management, and SMS management.

[0033] The UPF 110 can transmit downlink PDUs received from the DN 180 to the UE 10 via the (R)AN 20, and can transmit uplink PDUs received from the UE 10 to the DN 180 via the (R)AN 20. Specifically, the UPF 110 can support an anchor point for intra / inter radio access technology (RAT) mobility, an external PDU session point for interconnection to a data network, packet routing and forwarding, packet inspection, and the user plane portion of policy rule enforcement, lawful intercept, traffic usage reporting, an uplink classifier to support routing of traffic flows to the data network, a branching point to support multi-homed PDU sessions, QoS handling for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement), validation of uplink traffic (SDF mapping between service data flow (SDF) and QoS flow), transport level packet marking in the uplink and downlink, downlink packet buffering, and downlink data notification triggering functions. Some or all of the functionality of the UPF 110 may be supported within a single UFP instance operating in one UPF.

[0034] The AF 150 can interoperate with the 3GPP core network for service provision (e.g., supporting functions such as application influence on traffic routing, access to network capability exposure, and interoperation with a policy framework for policy control).

[0035] (R)AN20 can collectively refer to new radio access networks that support both evolved E-UTRA, an evolved version of 4G radio access technology, and new radio (NR) technologies (e.g., gNB).

[0036] The gNB provides functions for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources (i.e., scheduling) to UEs in uplink / downlink), internet protocol (IP) header compression, encryption and integrity protection of user data streams, selection of AMF 120 at UE 10 attachment if routing to AMF 120 is not determined from information provided to the UE 10, user plane data routing to UPF 110, control plane information routing to AMF 120, connection setup and release, scheduling and transmission of paging messages (originating from AMF), scheduling and transmission of system broadcast information (originating from AMF or operating and maintenance (O&M)), measurement and measurement report configuration for mobility and scheduling, transport level packet marking in uplink, session management, network slicing, and network management functions. It can support features such as slicing, QoS flow management and mapping to data radio bearers, support for inactive mode UEs, NAS message distribution function, NAS node selection function, radio access network sharing, dual connectivity, and tight interworking between NR and E-UTRA.

[0037] The UE 10 refers to user equipment. The user equipment may be referred to as a terminal, mobile equipment (ME), mobile station (MS), etc. The user equipment may be a portable device such as a notebook computer, a mobile phone, a personal digital assistant (PDA), a smartphone, a multimedia device, etc., or may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device. In the following description, it will be referred to as user equipment (UE) or terminal.

[0038] In FIG. 1, for clarity of explanation, a network exposure function (NEF) device and an NF repository function (NRF) device are not illustrated, but all NFs illustrated in FIG. 5 described below can interact with the NEF and NRF as necessary.

[0039] Consider the NRF. The NRF (not shown in FIG. 1) may support a service discovery function. When receiving a second NF discovery request from a first NF instance, after performing a discovery operation of the second NF, it may provide information of the discovered second NF instance to the first NF instance. It may also maintain available NF instances and the services they support.

[0040] Meanwhile, for convenience of explanation, FIG. 1 illustrates a reference model in which a UE accesses one DN using one PDU session, but the present invention is not limited thereto.

[0041] The UE 10 can simultaneously access two (i.e., local and central) data networks using multiple PDU sessions. In this case, two SMFs can be selected for different PDU sessions. However, each SMF can have the ability to control both the local UPF and the central UPF within a PDU session.

[0042] The UE 10 can also simultaneously access two (i.e., local and central) data networks provided within a single PDU session.

[0043] In the 3GPP (registered trademark) system, a conceptual link connecting NFs in a 5G system is defined as a reference point. Next, the reference points included in the 5G system architecture shown in Figure 1 are illustrated.

[0044] -N1: Reference point between UE and AMF -N2: Reference point between (R)AN and AMF -N3: Reference point between (R)AN and UPF -N4: Reference point between SMF and UPF -N5: Reference point between PCF and AF -N6: Reference point between UPF and data network -N7: Reference point between SMF and PCF -N8: Reference point between UDM and AMF -N9: Reference point between two core UPFs -N10: Reference point between UDM and SMF -N11: Reference point between AMF and SMF -N12: Reference point between AMF and AUSF -N13: Reference point between UDM and authentication server function (AUSF) -N14: Reference point between two AMFs -N15: reference point between PCF and AMF in non-roaming scenario, reference point between PCF and AMF in visited network in roaming scenario

[0045] FIG. 2 illustrates an example of a configuration of a network entity in a wireless communication system according to various embodiments of the present invention.

[0046] The network entity of the present invention is a concept including a network function depending on the implementation of a system. The terms "module" and "device" used below refer to a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software. In addition, each function may be implemented in one device or server as described above, or may be implemented to perform one function using two or more different servers or devices.

[0047] The components in Figure 2 are roughly the same as those in Figure 1, but there are some differences as follows: In contrast to FIG. 1, the additional NEF 190 in FIG. 2 can provide a means to securely expose services and capabilities provided by 3GPP network functions, e.g., for 3rd party, internal exposure / re-exposure, application functions, Edge Computing. The NEF 190 can receive information from other network functions (based on the exposed capabilities of the other network functions). The NEF 190 can store the received information as structured data using a standardized interface to the data storage network function. The stored information can be re-exposed by the NEF 190 to other network functions and application functions and used for other purposes, such as analysis.

[0048] 2 illustrates three different UPFs 210, 220, and 230 and a new DN 240. As in FIG. 1, the first UPF 210 connected to AN20 can be connected to the third UPF 230 for connecting to the new DN 240 using N9. Also, the first UPF 210 can be connected to the existing DN 180 via the second UPF 220.

[0049] The configuration illustrated in FIG. 2 illustrates one of the structures of a 5G core network supporting edge computing. The control plane function device of the 5G core network illustrated in FIG. 2 is the same as that of FIG. 1 described above, and the same reference numerals are given to the same components. The first UPF 210 is an uplink classifier (ULCL) / branching point (BP), and illustrates a 5G core network structure in which a terminal 10 communicates with an edge application server (EAS). The terminal (UE) 10 can connect a user protocol data unit (PDU) to the second UPF 220 via the first UPF 210 that serves as a ULCL / BP UPF and connect to a data network (DN) 180. In this case, the second UPF 220 is a first PDU Session Anchor User Plane Function (PSA-UPF) in FIG. 2.

[0050] Also, the first UPF 210 may be connected to the second UPF 220 and the third UPF 230 at the same time. In this case, the third UPF 230 may be connected to a DN 240 located locally close to the UE as a second PSA-UPF. An edge application server (EAS) 241 providing an edge computing service is located in the locally close data network 240, and the terminal 10 may provide the edge computing service by communicating with the EAS 241. The SMF 130 may generate an N4 session with the first UPF 210, the second UPF 220, and the third UPF 230, transmit a rule for forwarding traffic to each of the UPFs 210, 220, and 230, and control each of the UPFs 210, 220, and 230. In addition, the SMF 130 can transmit 3-tuple information including a destination IP address, a destination port number, and a protocol number to the first UPF 210 operating as a ULCP so that the terminal 10 connects to the third UPF 230, which is a second PSA-UPF that is locally closer, and can determine whether to route the traffic of the terminal 10 to a local data network or to the first PSA-UPF 220. In this structure, the 5G core network can perform a procedure of adding / changing / removing the ULCL / BP 210 and the Local PSA-UPF 230 so that the terminal 10 communicates with the EAS 241 via the local PSA-UPF 230 that is closer.

[0051] Meanwhile, in the conventional 3GPP 5G core network, the relocation of PSA-UPF (PDU session anchor-user plane function) is not considered in terms of data path delay. That is, in the conventional 3GPP 5G core network, the session management function (SMF) determines the relocation of PSA-UPF by itself using topology information. Various embodiments of the present invention may provide a method in which the 5G core network and the application determine whether to relocate PSA-UPF by considering the delay time of the data path based on the request of the application function requiring a low latency service.

[0052] According to various embodiments of the present invention, the 5G core network and the application decide the PSA-UPF movement in consideration of the data path delay. When a handover occurs in which a terminal provided with services by one or more applications leaves the service area in which the currently connected application is located, and the PSA-UPF movement is performed, the IP address of the terminal may be changed, causing a service interruption.

[0053] According to various embodiments of the present invention, by taking into account the delay requested by an application, if the delay requested by the application can be met through an existing data path in the local area to which the terminal has moved, service interruption can be minimized by not performing PSA-UPF relocation.

[0054] According to various embodiments of the present invention, when a terminal moves and a service is provided via a newly changed route, or when the delay requested by an application is no longer met, a route can be reconfigured with a new PSA-UPF to provide a service that meets the delay time requested by the application.

[0055] FIG. 3 is a diagram illustrating another structure of a 5G core network supporting edge computing according to an embodiment of the present invention.

[0056] As described above, the control plane functions of the 5G core network shown in FIG 3 are assigned the same reference numerals as those in FIG 1 and FIG 2. Therefore, additional description of the same components will be omitted.

[0057] 3 illustrates a 5G core network structure in which the UE 10 communicates with the EAS 321 included in the DN 320 without using the ULCL / BP. In this network structure, the UE 10 can perform a procedure for relocation of the PSA-UPF using Service and Session Continuity (SSC) Mode 2 or SSC Mode 3 to access the EAS 321 via the PSA-UPF 310 close to the UE 10 due to movement.

[0058] FIG. 4 is an exemplary diagram for explaining a case where a terminal moves according to the present invention using a network topology. FIG. 4 illustrates a network configuration diagram having separate IP ranges for each Local Data Network in an IPv4 ULCL environment.

[0059] Considering the configuration of FIG. 4, a specific application (not shown in FIG. 4) in the terminal 10 may be in a state of being connected to the first data network 410, for example, a data network with an IP address set to "10.10.10.*". In this way, when the terminal 10 connects to the first data network 410, it can be connected via the PSA-UPF#1 411, which is a UPF for connecting to the first data network 410, the ULCL / BP 401, and the RAN 20 connected to the ULCL / BP 401. Also, when the terminal 10 connects to the Internet, it can be connected via the ULCL / BP 401, which is a UPF for connecting to the Internet, and the corresponding RAN 20. At this time, when the terminal 10 connects to the first data network 410, the terminal can have "10.10.10.xx" as a data network access identifier (DNAI), as described above.

[0060] 4, if the terminal moves to the second RAN 21, it can connect to the data network with the IP address set to "10.10.20.*" via the new UPF, ULCL / BP 402, and the new PSA-UPF#2 421. As another example, even if the terminal 10 moves to the second RAN 21, it can still connect to the previously connected PSA-UPF#1 411 via the new UPF, ULCL / BP 402.

[0061] A case may occur in which the terminal 10 connects via a new PSA-UPF#2 421 via a new UPF, ULCL / BP 402. In this case, the terminal 10 is connected to the first local data network 410 before the DNAI change, and the application of the terminal 10 is connected to the EAS#1 413, so the terminal 10 can generate a TCP context. Also, as described above, when the DNAI of the terminal 10 is changed due to movement, the SMF (not shown in FIG. 4) can perform an additional PSA addition procedure. After the DNAI change, the application of the terminal 10 must connect to the IP address of the EAS#1 423 of the second local data network 420, for example, "10.10.20.1". However, since the TCP context of the terminal 10 is maintained, the application of the terminal 10 is not aware of the change in the local network and the existing TCP context is still maintained, so the application of the terminal 10 does not know of the change in the local network and the EAS#1 423 of the second local data network 420 does not know of the change in the local network and the existing TCP context is still maintained. 423 and not connected.

[0062] This will be explained in more detail as follows: In the network configuration diagram of FIG. 4, the terminal 10 can move from where the first local DN 410 is located to where it connects to the second local DN 420. In this case, as illustrated in FIG. 4, the first PSA-UPF 411 of the terminal 10 may not be changed. That is, the terminal 10 can maintain the PSA-UPF#1 411. In this case, the IP address of the terminal 10 is maintained, but the application layer session in which the terminal 10 is connected via the first local PSA-UPF#1 411 must have its context of the terminal 10 removed when the PSA-UPF 411 for the first local DN 410 is released. However, the current ULCL or local PSAIn the UPF deletion operation, there is no information to inform the terminal 10 of this. In this case, if the terminal 10 attempts to connect to the second local DN 420 and connect to the same EAS, the upper hierarchical context for the first local DN 410 remains in the terminal 10. Therefore, the terminal 10 cannot connect to the EAS of the second local DN 420. To further consider this as an example, such an upper hierarchical context can be Domain Name System (DNS) information for the fully qualified domain name (FQDN) of the EAS. The DNS address of the EAS received from the first local DN can be, for example, "10.10.10.1". Such a DNS procedure can be cached in the DNS Client of the terminal 10 for the lifetime of the DNS record. Even if the terminal 10 connects to a second local DN due to movement or a decision by the SMF (not shown in FIG. 4), when performing a DNS query for the same EAS#1, the connection will be made to the address "10.10.10.1" according to the information cached in the DNS client of the terminal 10. In this case, sending and receiving data traffic to and from the EAS#1 423 in the second local DN is not possible.

[0063] Another example is a case where a connection-oriented upper layer session is connected to the first local DN 410 and EAS#1 413. For example, a TCP connection of the terminal 10 can be connected between the first local DN 410 and EAS#1 413. In this situation, when the SMF removes the PSA-UPF 411 connected to the first local DN 410 due to the movement of the terminal 10 or the local decision of the SMF, and connects a session of the PSA-UPF#2 421 to the second local DN 420, the TCP connection, which is one of the upper layer network contexts of the terminal 10, is maintained without being released from the previous session. As a result, the terminal 10 cannot connect to the IP address of the LDN2 423 of the EAS#1 located in the second local DN 420, for example, "10.10.20.1".

[0064] In order to solve this problem, the present invention assumes a terminal internal structure as shown in Figs. 5a and 5b. 5a and 5b are exemplary diagrams illustrating the internal configuration of a terminal and a case of setting up a PDU session with a wireless communication network and a data network according to one embodiment of the present invention.

[0065] 5a and 5b show the terminal configuration and the network configuration separately because it is difficult to show them all in one drawing. Also, it can be seen from Fig. 5a and 5b that a component included in a particular component, for example, a terminal communication processor or modem 1010, includes a NAS control plane 1011.

[0066] First, referring to FIG. 5a, the terminal 10 may include a communication processor or modem 1010 and an application processor (AP) 1030. In the following, the communication processor or modem 1010 may correspond to the reference numeral 1010 in FIG. 5a and FIG. 5b, where all parts are referred to as a "communication processor" or described as a "modem". It should be noted that all unnecessary elements are omitted in describing the present invention in FIG. 5a and FIG. 5b. For example, the terminal 10 may further include elements necessary for wireless communication, such as a memory, a power source, an antenna, etc. In addition, the terminal 10 may include various circuits or logic for user convenience. For example, the terminal 10 may further include various circuits, logic, and / or modules, such as an RF transceiver circuit, a display module, a touch screen, a speaker, a microphone, etc.

[0067] The application processor 1030 can basically run at least one application. In FIG. 5a, two different applications are 1034 , 1035 In the example shown, a TCP / IP stack in OS Kernel 1020 is driven. The application processor 1030 may include a TCP / IP stack in OS Kernel 1020 in an operating system kernel. Hereinafter, for convenience of explanation, this will be referred to as a "TCP / IP stack." The TCP / IP stack 1020 may include fourth layer contexts 1021 and 1022. The fourth layer contexts 1021 and 1022 may be, for example, sockets. The sockets 1021 and 1022 may be connected to corresponding applications 1031 and 1032 via a socket application interface (API).

[0068] Furthermore, the communication processor 1010 and the application processor 1030 can be connected to each other via network interfaces 1031, 1032, and 1033. Fig. 5a illustrates three different network interfaces 1031, 1032, and 1033, and illustrates a form in which the first network interface 1031 is connected to the sockets 1021 and 1022.

[0069] The terminal 10 can be connected to the 5G core network 500 via an access network 20 such as a base station. In this manner, when the terminal 10 is connected to the 5G core network 500, a PDU session can be formed between the terminal 10 and the PSA-UPF of the 5G core network 500. FIG. 5a illustrates a case in which N PDU sessions 521, 522, and 523 can be set in one terminal.

[0070] In addition, the terminal 10 may ultimately receive a service within the 5G core network 500, and may also receive a data service via at least one of the data networks 510, 514, and 515 via the 5G core network 500. In FIG. 5a, the first data network 510 is an edge computing data network. However, the data network 510 may be a local data network (local DN).

[0071] 5b, the TCP / IP stack 1020 of the terminal 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. The TCP / IP stack 1020 of the terminal 10 may further include additional components as necessary in addition to the components described in FIG.

[0072] The communications processor 1010 may include a NAS control plane 1011 .

[0073] As described above, the 5G core network 500 may include the AMF 120, the SMF 130, the PCF 140, the UDM 170, and the NEF 190. Additionally, the UDR 504 described above in FIG. 1 is further illustrated. The 5G core network 500 may be connected to an external AF 150 via the NEF 190.

[0074] The configuration of the terminal 10 is illustrated separately in Figures 5a and 5b, but those skilled in the art can confirm the overall configuration of the terminal from the drawings illustrated in Figures 5a and 5b, and it should be noted that the drawings illustrated in Figures 5a and 5b are configurations for the network interface and upper layer context.

[0075] In addition, hereinafter, FIGS. 5a and 5b will be collectively referred to as FIG. In FIG. 5, the terminal (UE; User Equipment) 10 is illustrated as being configured with an application processor (AP) and a communication processor (CP) as described above. However, the terminal 10 may be configured with the application processor and the communication processor in one chip. In this case, the application processor and the communication processor may all be included in one processor. For example, even if one physical process exists, the function performed by the AP and the logical function performed by the CP may be the same. An application of the terminal 10 exists in the AP, and such an application may make requests and responses to a mobile operating system (e.g., Android, Linux, Tigen, BSD-based Unix, and iOS) by network-related system calls and system library calls via a socket interface 1041.

[0076] As described above, the mobile operating system driven by the AP includes a TCP / IP stack 1020, and the TCP Context can be managed by a kernel socket for managing the TCP context. The mobile operating system can communicate with the CP 1010 through at least one of the network interfaces 1031, 1032, and 1033. The AP 1030 can include a manager (URSP Manager) 1022 for processing URSPs, a DNS client 1023, an upper network layer context manager (Context Manager) 1024, and a manager (Interface Manager) 1025 for managing network interfaces. The managers 1022, 1023, 1024, and 1025 can be connected to the CP 1010 through a modem control interface (Modem Control I / F) 1021 and used for control purposes. The CP 1010 can implement a function provided by a 3GPP (registered trademark) air interface to interface with a base station. In addition, the CP 1010 includes a module for controlling the NAS control plane 1011, and the NAS control plane 1011 can work with the AMF 120 of the 5G core network 500. A NAS control message related to the session can be provided to the SMF 130 via the AMF 120.

[0077] A protocol data unit (PDU) transmitted through a network interface of the terminal 10 is an IP datagram if the PDU session type is IP. Such an IP datagram can reach the PSA-UPF 501 of the 5G core network 500 through a PDU session (521 in FIG. 5). The PSA-UPF 501 can deliver the received IP datagram to the data network 510, which is an IP network.

[0078] In the following, it is assumed that the data network is an edge computing data network. Edge Application Servers (ESA) 511, 512 and Domain Name Server (DNS) 513 may exist in the data network 501. Such ESAs 511, 512 and DNS 513 may communicate with the terminal 10. UDM, UDR, NEF, AF, AMF, SMF, and PCF existing in the 5G core network 500 perform the same functions as the network functions described in FIG. 1, and therefore will not be described here.

[0079] In Figure 5, the relationship between the network interface of terminal 10 and the PDU session is illustrated assuming a 1:1 connection. A TCP session is created when an application of terminal 10 requests a TCP connection. This process can be performed by requesting the creation of a TCP session by a method such as a "connect" system call. When a TCP session is successfully created in the operating system, the TCP Context can be bound to an interface that has the source IP address of the terminal.

[0080] If the network interface goes down, all contexts corresponding to the TCP sessions bound to the interface are removed. As a result of this operation, if SSC Mode2 operation is performed, SMF 130 can release the first PDU session and generate a second PDU session to move the PSA-UPF. In this process, all TCP contexts connected to the first PDU session of terminal 10 are removed, and session continuity cannot be guaranteed.

[0081] Also, when operating in SSC Mode3, the SMF 130 instructs the terminal 10 to generate a second session for the movement of the PSA-UPF, and the terminal 10 generates a second PDU session, so that the first PDU session and the second PDU session can temporarily exchange data traffic simultaneously. In this situation, when the second PDU session is generated while the first network interface corresponding to the first PDU session is maintained in the terminal 10, a second network interface corresponding to the first PDU session is generated. Then, when the first PDU session is released, the network interface for the first PDU session goes down, and the TCP context bound to this network interface is completely removed. Therefore, the upper layer context of the first PDU session cannot maintain continuity.

[0082] In the operation proposed in the present invention, when a first local DN is created or released, the SMF 130 transmits information about the local DN to the terminal 10 via NAS signaling, for example, via a PDU session change message. The terminal 10 that receives this can transmit information related to the upper network context manager, DNS client, URSP manager 1022, etc. that exists in the AP 1030 of the terminal 10 via the information received from the local DN according to a policy determined by the SMF 130. In addition, if there is a command to be performed in the upper network layer in relation to the local DN, the terminal 10 can also transmit such information. When the terminal modem (CP) 1010 receives such information corresponding to the upper layer, it transmits such information and instructions to the AP 1030, and the corresponding manager in the AP 1030 can perform this. For example, if the SMF 130 generates a new local DN and sets a DNS server address for the corresponding local DN, the AP 1030 that receives such information can transmit the information to the DNS client 1023. Alternatively, when the SMF 130 generates a new local DN and notifies the CP 1010 of the terminal 10 of the corresponding IP address range, the CP 1010 of the terminal can transmit and record the IP address range corresponding to the AP 1030 to the upper layer context manager 1024. After that, when the local PSA-UPF for the corresponding local DN is removed, the SMF 130 can notify the CP 1010 of the terminal 10 of local PSA-UPF removal information. As a result, the SMF 130 can additionally transmit information requesting the release of the upper layer context 1024 connected to the corresponding local DN. That is, the CP 1010 of the terminal that receives this notifies the upper layer context manager 1024 of the AP 1030 of the information received from the SMF, and the upper layer context manager 1024 of the AP 1030 can release the upper layer context (e.g., TCP context information) managed in the mobile operating system.This process can be described as "re-evaluating the URSP."

[0083] FIG. 5c is an exemplary diagram illustrating a local DN binding context according to an embodiment of the present invention.

[0084] Figure 5c is another representation of the configuration diagram of the terminal 10 described in Figures 5a and 5b, and in particular provides an additional explanation of the Local DN binding context described in this specification. The explanation of components that are not described separately is the same as in Figures 5a and 5b. Parts with different reference numbers in Figure 5c are newly numbered for the purpose of explaining the present invention, and can be understood in the same perspective as Figures 5a and 5b.

[0085] In FIG. 5c, the terminal application 1 1034 has a TCP connection with the EAS#1 552 of the Local DN 551, and a Layer 4 Context#1 1021 in the High Layer OS is generated. Also, the terminal application 2 1035 is located in the Central DN 542. AS The Layer 4 Context 1021 of the terminal connected to the EAS #1 552 of the Local DN 541 can be an example of a local DN binding context. During the operation of the present invention, higher layer network context information can be a Local DN binding context. In particular, an operation of controlling a higher layer network context according to the knowledge of the local DN 541 can be said to correspond to an operation of controlling a local DN binding context, and a Local DN binding context operation can include, for example, removing or maintaining Layer Context #1 shown in FIG. 5c, or refreshing DNS cache information received from the DNS 551 server configured for the Local DN 541.

[0086] <First Example> The first embodiment of the present invention proposes a method for the SMF 130 to inform the terminal 10 of information on the local DN to be added via a PDU session modification message when the SMF 130 decides to add a BP / ULCL and a local PSA-UPF. The SMF 130 can deliver control information on the upper layer network context together with information on the PDU session local DN.

[0087] FIG. 6 is a signal flow diagram illustrating a case where the SMF provides the UE with control information regarding the upper layer network context together with information regarding the PDU session local DN according to one embodiment of the present invention.

[0088] Before referring to FIG. 6, the configuration information regarding the local DN may include at least one of the following information: (1) DNS server address and the domain name where the DNS server operates (2) Identifier for Local DN (3) A classifier indicating local DN addition / movement / deletion: This classifier indicates local DN addition when SMF 130 decides to add a local PSA-UPF, and indicates local DN deletion when SMF 130 deletes a local PSA-UPF. (4) Information about the IP address range of the local DN to be added (5) The server IP address or destination IP address, destination port number, and IP higher-level protocol number for traffic to be routed to the Local DN, e.g., a protocol number indicating TCP or UDP

[0089] Next, the upper layer network context control information associated with the local DN may include at least one of the following information: (1) Whether to delete previous DNS cache information for the local DN (2) Context control information for higher-layer protocols, such as the maintenance instructions for higher-layer protocols (e.g., TCP context or HTTP context) (3) Re-evaluation instructor for URSP: Instructs to release the binding of the URSP to the application traffic and to evaluate the URSP rules. (4) Refresh indicator for application traffic's PDU session binding: Instructs that specific application traffic should release the binding to the PDU session and delete the context.

[0090] In addition, the SMF 130 can receive AF Influenced Traffic Steering Enforcement Control Information (AFTC) including the DNAI from the PCF 140. When the SMF 130 detects a change in the DNAI due to the movement of the terminal 10, it can determine additional PSA addition and LDN addition information.

[0091] When the SMF 130 decides to add an Additional PSA, the SMF 130 can perform the ULCL and Local PSA addition procedures.

[0092] In the operation of step 0 (610), the terminal 10 may be in a state where an existing PDU session exists and a tunnel is connected via the UPF 602, which is PSA1, and the RAN 20.

[0093] In operation 612 of step 1, the SMF 130 may determine a UPF 603 corresponding to a new PSA, PSA2, based on the UE mobility event, and may generate a new PSA2 and N4. When the SMF 130 receives (or detects) a UE mobility event, it may also determine "Local DN announcement control information", "UE upper layer context control information (i.e., Local DN binding context information)", and steering for locally processed traffic based on the PCC rule and / or the local DN configuration received from the PCF 140. The SMF 130 may send an Early Notification requested by the AF. Then, the SMF 130 may wait for a response to the announcement.

[0094] In operation 614 of step 2, the SMF 130 may select a new local PSA-UPF 603 and create an N4 session with the local PSA-UPF 603.

[0095] In step 3 616 operation, the SMF 130 can select a ULCL / BP 601UPF and generate an uplink forwarding rule (UL Forwarding Rule) for the ULCL / BP 601UPF and PSA1 602 and PSA2 603. The SMF 130 can convey the traffic rule toward PSA1 602 and PSA2 603 to the ULCL UPF 601. That is, the SMF 130 can send an AF Traffic Influence Late Notification to the AF. The SMF 130 can then wait for a response.

[0096] In step 4 618 operation, the SMF 130 may update the N4 session with the PSA1 602. The SMF 130 may also provide the PSA1 602 with tunnel information regarding the ULCL-BP 601 for DL ​​traffic.

[0097] Thereafter, the PSA1 602 can transmit a downlink PDU to the first UPF 601 in operation 620. Thus, the first UPF 601 can provide the received downlink PDU to the terminal 10. In addition, the terminal 10 can transmit an uplink PDU to be provided to the PSA1 602 in operation 622 using the corresponding tunnel. The order of the operations 620 and 622 can be changed if tunnel information is known in advance between the terminal and the PSA1 602. That is, if the tunnel information is known between them, the operation 620 can be performed after the operation 622.

[0098] In operation 624 of step 5, the SMF 130 can update the N4 session with the PSA2 603. This enables the SMF 130 to provide the PSA2 603 with tunnel information regarding the ULCL-BP 601 for DL ​​traffic.

[0099] In the operation of 626 of procedure 6A, if the SMF 130 needs to notify the terminal 10 of the L-PSA setting information, the SMF 130 can transmit a PDU Session Modification Command to the terminal 10.

[0100] The Local DN setting information may be set in the SMF 130 itself or in the PCF 140. When the SMF 130 receives Policy and Charging Control (PCC) information for the terminal 10 from the PCF 140 through the SMPolicyAssociation creation or modification procedure, the SMF 130 may also receive the Local DN setting information, which may include 3-Tuple information, a DNS address, and a subnet address of the Local DN.

[0101] When the SMF 130 decides to add / change / delete to the Local PSA-UPF, the SMF 130 can record this as information about a Local DN event and transmit it to the terminal 10.

[0102] The SMF 130 may receive an AF request or Local DN Binding control information from the PCF 140. Based on this information, the SMF 130 may transmit at least one of the following information to the terminal 10:

[0103] (1) L-PSA added, (2) Added 3-tuple enumeration, (3) Added subnet address, (4) DNS address, (5) Existing DNS Refresh indicators, (6) a higher-level network context maintenance commander; (7) Information on URSP Traffic Re-evaluation Instructors

[0104] The terminal 10 that receives such information can perform the operation specified in the LDN information. That is, it can perform upper context maintenance and URSP traffic re-evaluation. After that, the SMF 130 can transmit the N2 SM information via N11 to the RAN 20 via the AMF 120 in the 628 operation, which is procedure 6B. That is, the SMF 130 can transmit the new CN tunnel information (ULCL / BP tunnel information) to the RAN 20.

[0105] Meanwhile, in operation 630, the terminal 10 can still send uplink PDUs to PSA1 602 via the first UPF 601 using the previous tunnel.

[0106] In the operation of 632 of step 7, in the case of IPv6 Multi-Homing (MH), the SMF 130 can transmit a Router Advertisement (RA) (new IP prefix, routing rule) message to the terminal 10 via the PSA2 603. The SMF 130 can also send a Late Notification to the AF.

[0107] In the operation of step 8 634, if it is an IPv6 MH, the SMF 130 can transmit an RA (original IP prefix, routing rule) for reconfiguring the previous IP prefix via the PSA1 602.

[0108] This allows the terminal 10 to transmit an uplink PDU to the first UPF 601 for transmission to PSA1 602 in operation 636. The first UPF 601 can then provide it to PSA2 603.

[0109] Thereafter, in operation 640, the terminal 10 may perform upper layer control, such as URSP reevaluation, upper layer context retrain, or refresh.

[0110] <Second Example> The second embodiment of the present invention defines the operation of the terminal and the system during the procedure of removing the local PSA when the SMF 130 detects the DNAI change due to the movement of the terminal 10. In this procedure, the SMF 130 can determine the announcement of the local DN setting information and transmit the upper layer network context control information to the terminal 10 together with the announcement of the local DN setting change.

[0111] The procedure according to the second embodiment can be performed as follows: The following description will be given using the components of FIG.

[0112] In the first stage, the terminal 10 has a PDU session with a Local PSA added (a procedure for removing PSA1 and maintaining PSA2).

[0113] In the case of IPv6 MH in the second stage, the SMF 130 can reconfigure the UE IPv6 prefix for PSA1 602 and PSA2 603.

[0114] In the third step, the SMF 130 may determine the removal of the Local PSA based on various reasons. If the terminal 10 needs to be notified of the L-PSA setting information, the SMF 130 may transmit a PDU Session Modification Command to the terminal 10. Information included in the LDN setting information may include information on LDN removal, LDN identifier, removed 3-tuple list, removed subnet address, removed DNS address, existing DNS refresh indicator, upper network context maintenance indicator, and URSP traffic Traffic Re-evaluation indicator.

[0115] In step 4, the SMF 130 can update the PSA2 CN tunnel information to the RAN 20. If there is an additional UPF between the RAN 20 and the ULCL 601 (this case may correspond to a case where the UPF is cascaded (cascading UPF)), the SMF 130 can update the CN tunnel information related to that UPF.

[0116] In step 5, the SMF 130 can update the AN tunnel information for the N4 session for PSA2 603. If there is an additional UPF between the RAN 20 and the ULCL 601 (this case may correspond to a cascading UPF), the CN tunnel information for that UPF can be updated.

[0117] In step 6, the SMF 130 can release N4 of the PSA1 602. In the case of an IPv6 MH, the SMF 130 can release the IPv6 prefix.

[0118] In step 7, if steps 4 and 5 described above are performed, SMF 130 can release the N4 session corresponding to ULCP / BP 601.

[0119] <Third Example> The third embodiment of the present invention is a procedure for providing a method in which the SMF 130 delivers local DN announcement and upper layer network context control information to a terminal based on an operator policy for the local DN.

[0120] 7a and 7b are signal flow diagrams illustrating an embodiment of the present invention in which the SMF provides local DN public and upper layer network context control information to a terminal.

[0121] A mobile communication operator can pre-configure configuration information for a local DN in operator policy information of the PCF 140. The operator policy information configured in the PCF 140 can include information on a local DN for each DNAI (operator configured local DN information).

[0122] Examples of the business policy information include at least one of the following information: ●Local DN identifier: DNAI ●Service area for Local DN: Tracking Area or Cell list IP address range, e.g. 10.10.10.* ●Whether to operate a local DNS ● Local DNS address and domain name for Local DNS - Service provider identifier or sponsor identifier ●Whether to provide service continuity when moving the local DN ● Whether to notify the terminal of Local DN information

[0123] The PCF 140 may generate a PCC rule including local DN control information in AF traffic steering enforcement control information based on the configuration information for the local DN, and transmit the local DN announcement control information to the SMF 130. The local DN announcement control information may include at least one of the following information:

[0124] Local DN Identifier (e.g., DNAI (Data Network Access Identifier) ●Whether to publicize Local DN information on the device ● Local DN binding control information: Local DN binding control information may include Layer 4 (TCP) context maintenance / refresh information and DNS cache refresh information. When leaving the local DN, the terminal's upper network context refresh command is issued ●Local DN setting information

[0125] The SMF 130 receives the PCC rule and can perform local PSA and ULCL addition operations when the terminal 10 enters the DNAI area. Therefore, the terminal 10 can operate according to the Local DN control information.

[0126] The SMF 130 can transmit a local DN additional notification to the terminal 10 and transmit upper network layer control information.

[0127] The signal flow and its operation according to the present invention will be discussed with reference to the attached Figures 7a and 7b. Figures 7a and 7b may be performed sequentially. For example, after the flow of Figure 7a is completed, the signal flow of Figure 7b may be performed continuously. As another example, Figure 7b may be performed independently of Figure 7a. In the following description, an example will be described in which Figures 7a and 7b are performed sequentially.

[0128] In steps 701 to 702, the terminal 10 can transmit a PDU session creation request (PDUSession_CreateSMcontext Request) message to the SMF 130 via the AMF 120. When generating a first PDU session, the terminal 10 can transmit information including whether or not the Local DN control function is supported and whether or not the upper layer network context control function is supported to the SMF 130.

[0129] The SMF 130, which receives a PDU session request from the terminal 10 in step 703, may receive subscriber information from the UDM 170 to confirm the subscriber information regarding the terminal 10.

[0130] The SMF 130, which has obtained the subscriber information regarding the terminal 10 in step 704, may send a PDU session create context response (PDUSession_CreateSMcontext Response) message to the AMF 120.

[0131] In step 705, the SMF 130 creates a connection with the PCF 140 for receiving an SM policy, and can receive a PCC rule for the PDU session of the terminal 10 from the PCF 140. The PCC rule can include AF-influenced Traffic Steering Enforcement Control Information. The AF-influenced Traffic Steering Enforcement Control rule can include at least one of the following information:

[0132] (1)DNAI (Data Network Access Indentifier) (2) Whether or not Local Routing is supported: Whether or not Local Routing is supported can be further specified as whether or not IPv6 Multihoming is supported or whether or not ULCL is supported. (3) IP address maintenance commander (or network interface maintenance commander) (4) Upper layer context maintenance indicator or upper layer network refresh indicator (5) Is application layer relocation possible? (6) N6 routing information (7) Local DN control information

[0133] The local DN control information may include whether or not to notify the terminal 10 of information regarding the local DN and information that should be notified to the terminal 10 when adding a local PSA-UPF so that the SMF 130 can connect to the local DN.

[0134] In step 706, the SMF 130 determines whether the terminal provides SSC support and whether the AF request received from the PCF 130 is the first PSA-UPF that can support traffic steering enforcement control. 791 can be selected.

[0135] In steps 707 to 708, the SMF 130 can decide to generate a PDU session and transmit a PDU session generation response message to the terminal 10 via the AMF 120.

[0136] In steps 709 to 710, the SMF 130 receives the RAN tunnel information provided by the RAN 20 from the AMF 120, and can set tunnel information related to the downlink traffic of the PSA-UPF1 791.

[0137] Above we have discussed the PDU Session Establishment Procedure. Below we will discuss the case where a new local PSA is added (Triggering of local PSA insertion).

[0138] In step 711, if the terminal 10 detects the departure of the current registration area, the terminal 10 may transmit a registration request message to the AMF 120 via the RAN. Alternatively, if the terminal 10 performs a handover to another base station by a command of the base station 20, the AMF 120 may detect the occurrence of handover from the base station 20 during the handover process. Alternatively, if the terminal 10 transmits a service request in an idle state (CM-IDLE; Connection Management IDLE state), the AMF 120 may detect that the terminal 10 has moved. The AMF 120 may transmit a PDUSession_Update_SMContext request for updating the PDUSession to the SMF 120, including the location information of the terminal 10.

[0139] In step 712, when the PCF 140 receives a request for AF traffic steering from the AF or when the AF traffic steering rule within the operator is changed, the PCF 140 may transmit a Policy and Charging Control (PCC) rule including AF request traffic steering enforcement control information to the SMF 130. The AF request traffic steering enforcement control information may include the information in the above-mentioned step 705, for example, local DN control information and upper layer network context control information.

[0140] In step 713, when the SMF 130 detects a change in the location of the terminal 10 due to the movement of the terminal 10 (step 711), it can identify (determine) whether the terminal 10 has moved to a DNAI that is pre-configured in the SMF 130 or registered via a PCC rule. Alternatively, when the SMF 130 receives AF request traffic control enforcement information from the PCC, it can identify (determine) whether the location of the terminal is included in the locations mapped to the DNAI. When the SMF 130 identifies (determines) the addition of a ULCL / BP and a local PSA-UPF, the SMF 130 can perform a procedure corresponding to Phase C in FIG. 7.

[0141] Below we discuss Phase C, which can be a Procedure for ULCL / BP and local PSA-UPF insertion.

[0142] In step 714, the SMF 130 may create an N4 session with the PSA2 792.

[0143] In step 715, the SMF 130 can create an N4 session with the ULCL / BP UPF 793.

[0144] In step 716, the SMF 130 can change the N4 session of the PSA1 for downlink traffic. That is, the SMF 130 can change the tunnel information toward the RAN 20 in step 716. 715 The tunnel information of the ULCL / BP UPF 793 generated in the ULCL / BP UPF 793 can then be updated. After that, the downlink traffic from the PSA1 791 will be directed to the ULCL / BP 793.

[0145] In step 717, the SMF 130 may update the PSA2 792 and the N4 session.

[0146] In step 718, the SMF 130 may detect the change in the location of the UE 10 through the trigger condition in step 713, i.e., the location information of the UE 10 from the AMF 120, and identify (determine) whether to change the corresponding DNAI. Alternatively, the SMF 130 may receive a PCC rule including AF request traffic steering enforcement control information from the PCF 140. The PCC rule may include local DN control information including local DN setting information and upper layer network context control information of the UE. The local DN control information may include local DN control information instructing the UE to transmit the upper layer network context control information of the UE together with the local DN setting information when a new local UPF connected to the local DN is added. When the SMF 130 receives such local DN control information and determines to add a local PSA-UPF, it may determine to transmit a PDU session modification command message (PDU Session Modification Command) to the UE 10 via the AMF 120 in order to transmit the local DN setting information and the upper layer network context control information to the UE 10.

[0147] In step 719, the SMF 130 can transmit an N1N2MessageTransfer message including a PDU session update command message to the AMF 120. This message can include a PDU session identifier, local DN setting information, and upper layer network context control information, which can be information for modifying the PDU session.

[0148] The local DN setting information may be the same as the local DN information described in the first embodiment. Also, the upper layer network context control information may be the same as the upper layer network context control information described in the first embodiment.

[0149] When the SMF 130 decides to add a ULCL / BP, it can convey the CN tunnel information to the AMF 120 together with the N1N2MessageTransfer message to convey the CN tunnel information to the RAN 20 for tunnel setup between the ULCL / BP and PSA1, or between the ULCL / BP and PSA2.

[0150] In procedure 720, the AMF 120 may transmit to the RAN 20 all or at least a part of the information contained in the information N1N2MessageTransfer received from the SMF 130 in the N2 message.

[0151] In step 721, among the contents included in the RAN N2 message, tunnel information for uplink traffic for the Local ULCL / BP received by the RAN can be set. The RAN 20 can perform an AN-specific resource modification procedure to the terminal 10 and deliver a PDU session modification command message included in the N2 message to the terminal. The RAN 20 can then receive a response thereto from the terminal 10.

[0152] In procedure 722, the RAN 20 can convey to the AMF 120 the newly created tunnel information for PSA2 792 and a response message to the PDU session modification command received from the terminal 10.

[0153] In step 723, the AMF 120 may convey the information received from the RAN 10 to the SMF 130 and receive a response therefrom.

[0154] In step 724, the SMF 130 can assign a new IP prefix for the PSA2 792 to the terminal 10 in case of IPv6 multihoming and transmit it to the terminal 10.

[0155] In step 725, the SMF 130 can reconfigure the existing IP prefix information for the PSA1 791 in the terminal 10 in case of IPv6 multihoming.

[0156] <Fourth Example> The fourth embodiment provides a procedure for transmitting local DN information and upper layer network context information to a terminal during a procedure for changing a local PSA in response to an AF request, and the operation of each node.

[0157] Figures 8a and 8b are signal flow charts relating to the provision of information to a terminal when changing a local PSA in response to an AF request in a network according to an embodiment of the present invention, and the operation of each node accordingly. In the following, unless there is a need to distinguish between Figures 8a and 8b, they will be collectively referred to as Figure 8. Also, the operation of Figure 8b may be performed after the operation of Figure 8a. As another example, the operation of Figure 8b may be performed after performing another operation without performing the operation of Figure 8a.

[0158] In step 801, the terminal 10 can generate a PDU session together with the SMF 120. In this process, the SMF 120 can select a PSA-UPF0 802 (step 801-1). A more detailed procedure for this procedure is described in steps 701 to 710 of the third embodiment, so a duplicated explanation will be omitted. In addition, the SMF 120 can decide to add a ULCP / BP and a local PSA-UPF1 (step 801-2). This procedure is described in steps 711 to 725 of the third embodiment, so a duplicated explanation will also be omitted.

[0159] In step 802, the Source EES 807 operates as a Source AF and can transmit an AF request to the PCF 805. In FIG. 8, the PCF 140 and the NEF 190 in the above-mentioned FIGS. 1 to 3 are illustrated as one node. This is for convenience of the diagram configuration, although they perform different operations. Therefore, in the following description of the reference numeral 895, when it operates as a PCF, it will be described as PCF 895, and when it operates as an NEF, it will be described as NEF 895. A method of transmitting an AF request to the PCF 895 is as follows. The AF request can be received by the PCF 895 that stores the AF request in a UDR (not shown in FIG. 8) via the NEF 895 and receives a notice of the change in UDR information. The PCF 895 that receives the AF request can transmit the AF request traffic steering execution control information to the SMF 130 by including local DN control information and terminal upper layer network context control information in the AF request traffic steering execution control information, taking into consideration the operator policy for the local DN described in the third embodiment. It can be transmitted to SMF 130 including Local DN control information and terminal upper layer network context control information.

[0160] In step 803, the SMF 130 may receive a PCC rule for the PDU session of the terminal 10 from the PCF 895. The PCC rule may include AF-influenced Traffic Steering Enforcement Control Information. The AF-influenced Traffic Steering Enforcement Control rule may include at least one of the following information:

[0161] (1)DNAI (Data Network Access Indentifier) (2) Information on the service area mapped to DNAI (3) Whether or not Local Routing is supported: Whether or not Local Routing is supported can be further specified as whether or not IPv6 Multihoming is supported or whether or not ULCL is supported. (4) IP address maintenance commander (or network interface maintenance commander) (5) Upper layer context maintenance indicator or upper layer network refresh indicator (6) Is application layer relocation possible? (7) N6 routing information (8) Local DN control information

[0162] The local DN control information may include whether or not to notify the terminal 10 of information regarding the local DN and information that should be notified to the terminal 10 when adding a local PSA-UPF so that the SMF 130 can connect to the local DN.

[0163] If the terminal 10 detects the departure of the current registration area in step 804, the terminal 10 may transmit a registration request message to the AMF 120 via the RAN 20. Alternatively, if the terminal 10 performs a handover to another base station by a command from the base station, the AMF 120 may detect the occurrence of handover from the base station during the handover process. Alternatively, if the terminal 10 transmits a service request in an idle state (CM-IDLE; Connection Management IDLE state), the AMF 120 may detect that the terminal 10 has moved. The AMF 120 transmits the SMF 120 a PDUSession_Update_SMContext request including the location information of the terminal 10 to update the PDUSession. 130 can be communicated to.

[0164] In step 805, the SMF 120 can determine whether to perform local PSA relocation based on the PCC rule received in the above step 803 or the location information of the terminal 10 received in step 804. For example, assume that information regarding the local DN is set as follows:

[0165] 1) Information about Local DN1 ●Local DN identifier: DNAI-A ●Service Area:TA1, TA2 ●Associated local PSA-UPF:PSA-UPF#1 ●IP subnet address:10.10.10.* ●Local DNS address:10.10.10.200 ●Local DNS doman name:local1.example.com

[0166] 2) Information about Local DN2 ●Local DN identifier:DNAI-B ●Service Area:TA3, TA4 ●Associated local PSA-UPF:PSA-UPF#2 ●IP subnet address:10.10.20.* ●Local DNS address:10.10.20.200 ●Local DNS doman name:local2.example.com

[0167] The SMF 130 can also receive local DN control information from the PCF 895. The above-described local DN setting information can be set in the SMF itself, or can be set in the PCF 140 and received by the SMF 130 from the PCF 140. This information can include operator policies such as the following. Such operator information may be pre-configured locally in the SMF 130.

[0168] -Whether to notify the terminal of local DN setting information when generating DNAI - Whether to notify the terminal of local DN change information when DNAI is changed - Whether to notify the terminal of local DN removal information when DNAI is removed

[0169] The SMF 130 can identify (determine) the associated DNAI through the location information of the terminal 10 received by the AMF 120, and decide to move the local PSA-UPF to the PSA-UPF#2 804 that supports the DNAI. Such a decision means a change of the local DN, and the SMF 130 can decide to announce the local DN setting information to the terminal, or to announce the local DN change information, or to announce the previous local DN control information, according to the local DN control information policy received from the PCF 895. If the local DN is changed, the SMF 130 can perform a PDU session change procedure to send the local DN setting information to the terminal 10.

[0170] In addition, the PCF 805 can include the upper layer network context information of the terminal 10 together with the local DN control information in the PCC rule and transmit it to the SMF 120. The setting information for this can include the following information.

[0171] - When DNAI is changed, the terminal is instructed to maintain or refresh the upper layer network context When DNAI is removed, the terminal is instructed to maintain or refresh the upper layer network context

[0172] For example, if local DN1 and local DN2 are in different IP address ranges as in the above example, PCF 895 can transmit a policy to SMF 130 instructing a refresh of the upper layer network context when the DNAI is changed. SMF 130 that receives such a policy can select and transmit an indicator corresponding to the policy to the terminal 10 via a PDU session change command message. For example, SMF 130 can transmit an upper layer network context refresh indicator to the terminal 10. Alternatively, SMF 130 can determine to refresh the context based on the IP address range of the local DN information when the DNAI is changed, and transmit the indicator including the upper layer context refresh indicator to the terminal 10.

[0173] The SMF 130 may determine that the DNAI has been changed and that the previously created local PSA-UPF should be released. In this case, the SMF 130 may transmit the deletion information for the local DN together with a higher layer network context refresh indicator to the terminal 10. The local DN deletion information may include an identifier for the local DN and a distinguisher indicating that it has been deleted.

[0174] If the conditions for user event announcement are met, the SMF 130 determines whether a PSA-UPF relocation that satisfies the AF request can be performed at the current location of the terminal 10, and transmits an announcement of this to the AF (Source EES) 897. The AF Early announcement can include at least one of the following contents:

[0175] -Whether the IP address can be maintained -Whether to do PSA-Relocation or not -Information about expected PDB when PSA is moved - If the DNAI is changed, the destination DNAI information to be changed

[0176] The Source EES 897 can receive an Early notification for a user plane event from the SMF 130. The Source EES 897 can determine whether to perform an application context transfer based on the received information. The Source EES 897 can decide to transfer the application context if the following conditions are met. If the conditions are not met, the Source EES 897 can not decide to transfer the application context.

[0177] If the Source EES 897 decides to move the Application Context, steps 816 and 817 can be performed.

[0178] If the Source EES 897 determines that PSA relocation is necessary, the Source EES 897 can transmit a positive response to the AppRelocationInfo message. If the Source EES 897 determines that PSA-UPF relocation is not necessary, the Source EES 897 can transmit a negative response to the SMF 130.

[0179] If the Source EES 897 determines affirmatively to respond to the execution of PSA Relocation, the EES 897 may respond with an AppRelocationInfo message including at least one of the following pieces of information:

[0180] -Positive Response to PSA Relocation -Instructor that AF will be changed - Public address for the Target AF to receive the public announcement - Terminal upper layer network context maintenance indicator

[0181] The SMF 130 may receive a response message to the Early announcement from the Source EES (AF) 897. If a positive result is received in the response message, the SMF 130 may select a new PSA-UPF1 to generate an N4 session.

[0182] The SMF 130 can transmit late notification to the Source EES (AF) 897.

[0183] The delay notification message sent by the Source EES897 to the AF may include at least one of the following information:

[0184] -Target DNAI -The IP address of the device -Whether to provide higher-level context maintenance information -Whether to notify the terminal of local DN information -Local DN binding information control information (e.g., whether to delete or maintain L4 context bound to local DN, or delete DNS cache information)

[0185] After receiving the delay notice, the Source EES 897 can transmit the Application Context as in steps 823 to 824. The Source EES 897 can transmit Context Relocation Response information to an Edge Enabler Client (EEC) of the terminal 10 in step 814-2.

[0186] Thereafter, in step 815-1, the Source EES 897 responds to the SMF 130 by including at least one of the following pieces of information in the AppRelocation Info:

[0187] -Whether AppRelocation can be successfully executed -Target DNAI -Device subscriber information (GPSI, etc.)

[0188] The SMF 130 may receive a response to the delay announcement.

[0189] In step 816, the SMF 130 performs an update procedure for the N4 session.

[0190] In step 817, the SMF 130 can transmit a PDU session update message to the terminal 10 via the AMF 120 as determined in step 805. The PDU session update message can include local DN information and upper layer network context control information and be transmitted to the terminal 10 as described in the first embodiment.

[0191] If it is IPv6 multihoming in step 818, the SMF 130 can allocate a new IPv6 prefix to be used in PSA2 894 and send it to the terminal 10.

[0192] If it is determined in step 819 that the connection is IPv6 multihoming, the SMF 130 can reconfigure the terminal's IPv6 settings for PSA0 892.

[0193] In step 820, the SMF 130 detects the local PSA-UPF1 already connected to the terminal 10. 893 N4 sessions for can be released.

[0194] <Fifth Example> The fifth embodiment defines how the local DN information and upper layer network context control information transmitted from the SMF 130 to the terminal 10 via the AMF 120 are used in the terminal.

[0195] 9a and 9b are exemplary diagrams illustrating a procedure for providing local DN information and upper layer network context control information to a terminal and an operation in the terminal according to one embodiment of the present invention.

[0196] 9a and 9b, the same reference numerals as in FIG. 8 will be used for elements similar to those in FIG.

[0197] In step 901, the terminal 10 may request the SMF 130 to create a new PDU session. The SMF 130 may select the PSA-UPF0 892, create a tunnel between the PSA-UPF0 892 and the RAN 20, and send a permission message to the terminal 10 for the PDU session creation request. As described in FIG. 5, since the terminal 10 has created a new PDU, a network interface corresponding to the new PDU session may be created and these may be mapped. That is, a network interface corresponding to the new PDU session may be created between the CP 1010 and the AP 1030 in the terminal 10, and the new network interface and the configured PDU session may be mapped. In addition, applications corresponding to these mappings may also be mapped together.

[0198] In step 902, the terminal 10 can create a TCP connection with a server at a Central DN connected to PSA-UPF0 802. A TCP context can be created in the upper layer of the terminal 10. This is indicated by reference character (A) in FIG.

[0199] In step 903, according to the various embodiments described above, the SMF 130 can determine the addition of a local PSA-UPF and a ULCL / BP, select a local PSA-UPF1 893, and transmit information including a 3-tuple (destination IP address, destination port number, and protocol number) for traffic toward the local PSA-UPF to the ULCL / BP 891. The SMF 130 can transmit information about the local DN to the terminal 10. The terminal 10 that receives this can store information about the local DN. Detailed local DN information has been described in the first embodiment described above, so description will be omitted here. Information included therein can include a local DN identifier, a subnet address, a local DNS address, an EAS address in the local DNS, a 3-tuple address transmitted by the SMF to the ULCL, and the like.

[0200] In step 904, the terminal 10 can perform a DNS Query procedure for the EAS#1 FQDN at the request of the application layer. The DNS Query procedure can query the local DNS server located in Local DN1, or the DNS server located in Central DN. This allows the terminal 10 to know the IP address for EAS#1, which is where local DN#1 is located.

[0201] In step 905, the terminal 10 can create a TCP connection by requesting a TCP connection to the destination IP address of the EAS#1 that the terminal 10 has learned through the DNS Query procedure. The TCP connection created in this way is indicated by reference character (B) in FIG.

[0202] In step 906, if the terminal 10 moves and the DNAI detects a change or receives a PCC rule including traffic steering enforcement control information by an AF request, the SMF 130 can determine local-PSA movement and perform a procedure to change the local PSA-UPF. In this process, the SMF 130 can transmit a local DN addition notice to the terminal 10 informing the terminal 10 that a second local DN has been added. In addition, the SMF 130 can notify the terminal 10 that the first local DN1 that previously provided a connection has been deleted. At this time, the SMF 130 can transmit higher-level context control information regarding the local DN1 together with the information that the first local DN1 has been deleted. The higher-level context control information can include a higher-level context refresh indicator for the local DN2. If the higher-level network context control information includes context information refresh information corresponding to the local DN2, the terminal 10 can remove the higher-level context information corresponding to the local DN2. For example, the TCP context connected to EAS1 of Local DN1 generated in the above-mentioned step 904 can be released. At the same time, DNS cache refresh information is also included in the upper layer control information. The DNS cache refresh request may also include the domain name of the FQDN provided in the Local DN or the IP subnet address of Local DN1. When the information included in this way is received by the upper layer, i.e., the AP 1030 in the terminal, it can erase the DNS cache information related to the subnet address included in the request. Or, it can erase the DNS cache information corresponding to the Target FQDN or domain name information.

[0203] In step 907, the application becomes aware that the TCP connection with EAS#1 has been disconnected and can attempt to reconnect to EAS#1. At this time, since the corresponding DNS cache information has been deleted, the application can newly request and receive address information related to the EAS#1 FQDN from the DNS server.

[0204] In step 908, if EAS#1 exists in Local DN2 at the request of the application, a TCP session can be created in Local DN2 via Local PSA-UPF2 894.

[0205] In step 909, the terminal 10 leaves the local DNAI-B, or the SMF 130 receives an AF request and performs removal for the local PSA-UPF2 894. The SMF 130 can transmit Local DN information for DNAI-B to the terminal 10 according to a policy decision that information on the local DN should be changed from the PCC rule or a decision of the SMF 130 itself. The information sent to the terminal 10 is information on the removal of the Local DN, and can transmit upper layer network context control information together with this when removing the Local DN. The upper layer network context control information can include an upper layer network context refresh and DNS cache deletion request for the Local DN2. The AP of the terminal that receives such a request removes the TCP context and deletes the DNS cache.

[0206] Meanwhile, the first to fifth embodiments described above can be performed independently, but two or more of the embodiments can also work together. For example, the first embodiment describes the addition of BP / ULCL and local PSA-UPF, the second embodiment describes the removal of local PSA by detecting DNAI change, the third embodiment describes a method of transmitting local DN public and upper layer network context control information to a terminal based on an operator policy, the fourth embodiment describes a procedure of transmitting local DN information and upper layer network context information to a terminal during a procedure of changing a local PSA based on an AF request, and the fifth embodiment describes how the local DN information and upper layer network context control information transmitted to the terminal are used in the terminal.

[0207] Therefore, the fifth embodiment can be used together with the first embodiment, and the fifth embodiment can be used together with the second embodiment. Also, since one local PSA-UPF is added by the first embodiment, the second embodiment can be used together if another local PSA is removed. Also, the fifth embodiment can be used together with the first and second embodiments.

[0208] In addition, the first and third embodiments may be performed sequentially, such as when the third embodiment is applied and then the first embodiment is applied, or when the first embodiment is applied and then the third embodiment is applied.

[0209] As another example, when the first embodiment is performed based on the fourth embodiment, the second embodiment can be performed together, and therefore the fifth embodiment can be performed.

[0210] In this manner, when different embodiments are used together, some overlapping operations may be omitted in a particular embodiment or may be performed in their entirety.

[0211] FIG. 10 is a block diagram of a network function (NF) device according to the present invention. 10, the NF device may include a transceiver 1101, a controller 1102, and a memory 1103. The NF device may be a specific AF belonging to the above-described RAN, AMF, UPF, SMF, UDM, PCF, AUSF, AF, and DN.

[0212] The transceiver 1101 may provide an interface for communicating with other network entities. For example, if the NF is the AMF 120, the transceiver 1101 may transmit and receive signals / messages / information with the RAN 20, the AUSF 160, the SMF 130, the PCF 140, and other AMFs. Also, if the NF is the SMF 130, the transceiver 1101 may transmit and receive signals / messages / information with the AMF 120, the UDM 170, the UPF 110, and the PCF 140.

[0213] The control unit 1102 can control the operation of each NF described above. For example, the control unit 1102 can control the operation of each NF described in Figures 6 to 9. The control unit 1102 can be embodied by one or more processors.

[0214] The memory 1103 can store data required by the corresponding NF and can store information contained in the various messages / signals described above.

[0215] Although the above description is given by way of specific examples to facilitate understanding of the present invention, the present invention is not limited thereto and may be modified in various ways based on the above disclosure. [Industrial Applicability]

[0216] This can be applied when adding / changing / deleting a PDU session of a terminal in a wireless communication system. [Explanation of symbols]

[0217] 10 User Device 20 (Radio) Access Network ((R)AN) 110 User Plane Function Device 120 Access and Mobility Management Functionality Device 130 Session Management Facility (SMF) 140 Policy Control Function Device 150 Application Function Device 160 Authentication server function device 170 Data management device 180 Data Network 190 NEF 210 First UPF 220 Second UPF 230 The Third UPF 240DN 241 Edge Application Server (EAS) 310 UPF 320DN 321 EA 401, 402, 601, 891 ULCL / BP 410 First Data Network 411 PSA-UPF#1 413 EAS# 420 Second Local Data Network 421 PSA-UPF#2 423 EAS#1 500 5G core network 501 PSA-UPF 504 UDR 510, 514, 515 Data Network 511, 512 Edge Application Server 513 Domain Name Server 521, 522, 523 PDU Sessions 541 Local DN 542 Central DN 551 Local DN 552 EAS#1 553 AS#1 602 PSA1 603 PSA2 791 PSA-UPF 792 PSA2 793 ULCL / BP UPF 892 PSA0 893 local PSA-UPF1 894 PSA2 895 PCF, NEF 897AF 1010 Modem 1011 NAS Control Plane 1020 TCP / IP stack 1021, 1022 Fourth hierarchical context 1023 DNS Client 1024 Context Managers 1025 Interface Manager 1030 Application Processor 1031, 1032, 1033 Network Interfaces 1034 Application 1 1035 Application 2 1041 Socket Interface 1101 Transmitter / receiver 1102 Control section 1103 Memory

Claims

1. A method for providing local data network information to a terminal in a session management function (SMF) device of a wireless communication system, comprising: determining addition of a PDU Session Anchor-User Plane Function (PSA-UPF) for a protocol data unit (PDU) session based on the first information according to mobility of the terminal; forming a PDU session with the PSA-UPF determined to be added; establishing a PDU path for a downlink and an uplink between the PSA-UPF and the terminal; sending a PDU Session Modification Command to the terminal to instruct the terminal to add a new PSA-UPF; The first information is A method for providing local data network information to a terminal in an SMF of a wireless communication system, comprising at least one of policy and charging control (PCC) information and local data network (DN) configuration information received from a policy control function (PCF) device.

2. The local DN configuration information is 2. The method of claim 1 for providing local data network information to a terminal in an SMF of a wireless communication system, comprising: a domain name on which a Domain Name Server (DNS) operates; and an internet protocol (IP) address range of the local DNS.

3. The first information is The method of claim 1 for providing local data network information to a terminal in an SMF of a wireless communication system, further comprising: local DN public control information; and upper layer context control information of the terminal.

4. The local DN configuration information is 2. The method of claim 1 for providing local data network information to a terminal in an SMF of a wireless communication system, the method being configured in the SMF itself.

5. The local DN configuration information is 2. The method of claim 1 for providing local data network information to a terminal in an SMF of a wireless communication system, comprising: 3-tuple information, a Domain Name Server (DNS) address, and a subnet address of a local DNS.

6. Further transmitting second information together with the PDU session modification command; The second information is The method of claim 1 for providing local data network information to a terminal in an SMF of a wireless communication system, comprising at least one of an added 3-tuple list, an added Subnet address, and an existing DNS Refresh indicator.

7. 1. A method for receiving local data network information from a session management function (SMF) device in a terminal of a wireless communication system, comprising: transmitting / receiving a protocol data unit (PDU) using a PDU session established in the terminal; receiving a PDU Session Modification Command indicating addition of a new PDU Session Anchor-User Plane Function (PSA-UPF) from a Session Management Function (SMF) device; receiving a Router Advertisement (RA) message sent by the SMF via the new PSA-UPF; re-configuring the new PSA-UPF; and and performing higher layer control based on the reconfiguration of the new PSA-UPF.

8. The upper layer control includes:

8. The method of claim 7 for receiving local data network information at a terminal of a wireless communication system, the method being one of: an upper layer context retrain or an upper layer refresh.

9. A session management function (SMF) device for providing local data network information to a terminal of a wireless communication system, comprising: a transceiver for communicating with other network entities; a memory configured to store configuration information; at least one processor; The processor, determining addition of a PDU Session Anchor-User Plane Function (PSA-UPF) for the PDU session based on the first information according to the mobility of the terminal; Controlling the formation of a PDU session with the PSA-UPF determined to be added using the transceiver unit; Controlling PDU path setting for downlink and uplink between the PSA-UPF and the terminal using the transceiver unit; Controlling the terminal to transmit a PDU Session Modification Command instructing the terminal to add a new PSA-UPF via the transceiver unit; The first information is The SMF device provides local data network information to a terminal of a wireless communication system, the local data network information including at least one of policy and charging control (PCC) information and local data network (DN) configuration information received from a policy control function (PCF) device.

10. The local DN configuration information is 10. The SMF device of claim 9, further comprising: a Domain Name Server (DNS) configured to provide local data network information to a terminal of a wireless communication system, the local data network information including domain names on which the DNS operates and internet protocol (IP) address ranges of local DNSs.

11. The first information is The SMF device according to claim 9, further comprising: local DN public control information; and upper layer context control information of the terminal, for providing local data network information to a terminal of a wireless communication system.

12. The local DN configuration information is The SMF device according to claim 9, further comprising: providing local data network information to a terminal of a wireless communication system, the local data network information being configured in the SMF itself.

13. The local DN configuration information is 10. The SMF device of claim 9, further comprising: providing local data network information to a terminal of a wireless communication system, the local data network information including 3-Tuple information, a Domain Name Server (DNS) address, and a subnet address of a local DNS.

14. Further transmitting second information together with the PDU session modification command; The second information is 10. The SMF device of claim 9, further comprising: providing local data network information to a terminal of a wireless communication system, the local data network information including at least one of an added 3-Tuple list, an added Subnet address, and an existing DNS Refresh indicator.

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