Apparatus and method for routing DNS traffic of home routing session dressing session in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a high data transmission rate. A method performed by a first SMF entity of a first network in a wireless communication system according to the present disclosure comprises: receiving, from an AMF entity, an SM context creation request message including an ID of a second SMF of a second network, HR-SBO permission information, and PDU session creation information; and selecting an EASDF entity or a plurality of candidate EASDF entities of the first network based on the SM context creation request message.

Description

Technical Field

[0001] The present disclosure generally relates to a wireless communication system, and more particularly, to subscriber information for a home routing session of a terminal roaming in a cellular wireless communication system, supporting a session breakout method by adding / changing / deleting a local user plane function (UPF) in a visited network, a session management (SM) method based on the subscriber information, and a method for sending and receiving Domain Name Service (DNS) services between the terminal and a Visited-Edge Application Server Discovery Function (V-EASDF) in a Visited Public Land Mobile Network (VPLMN). Background Art

[0002] Fifth-generation (5G) mobile communication technology defines a wide frequency band, making relatively higher transmission rates and new services possible, and can be implemented in "sub-6 GHz" frequency bands such as 3.5 gigahertz (GHz) and "above 6 GHz" frequency bands including 28 GHz and 39 GHz, which can be referred to as millimeter waves (mmWave). In addition, sixth-generation (6G) mobile communication technology (which can be referred to as a super-5G system) has been considered for implementation in terahertz (THz) frequency bands (e.g., 95 GHz to 3 THz bands) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth that of 5G mobile communication technology.

[0003] Since the initial development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), standardization has been ongoing on various technologies, including beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio wave path loss and increasing radio wave transmission range in millimeter waves, dynamic operation of supporting numerologies (e.g., operating multiple subcarrier spacings) and time slot formats for efficient utilization of millimeter wave resources, initial access technology for supporting multi-beam transmission and wideband, definition and operation of bandwidth parts (BWPs), new channel coding methods (such as low-density parity-check (LDPC) codes for large-scale data transmission and polar codes for highly reliable transmission of control information), layer 2 (L2) pre-processing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] In view of the services to be supported by the updated 5G mobile communication technology, discussions are also underway on improvements and performance enhancements to the initial 5G mobile communication technology, including on physical layer standardization of technologies such as Vehicle-to-Everything (V2X) for assisting driving determination of autonomous vehicles based on information about the vehicle's position and status transmitted by the vehicle and for enhancing user convenience, New Radio Unlicensed (NR-U) for system operation in compliance with various regulatory requirements in unlicensed bands, NR User Equipment (UE) power saving, Non-Terrestrial Network (NTN) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In terms of air interface architecture / protocol, standardization is also underway on various technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and dual-active protocol stack (DAPS) handover, and two-step random access (NR's 2-step RACH) for simplifying the random access procedure.

[0006] In terms of system architecture / services, standardization is also underway on various technologies: 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software-defined networking (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0007] With the commercialization of 5G mobile communication systems, the number of devices connected to the communication network is expected to grow exponentially, and therefore it is expected that enhanced functionality and performance of 5G mobile communication systems and the integrated operation of connected devices will become necessary. To this end, new research is planned related to the following technologies: extended reality (XR) for effectively supporting augmented reality (AR), virtual reality (VR), mixed reality (MR), etc.; 5G performance improvement and complexity reduction through the use of artificial intelligence (AI) and machine learning (ML); AI service support; metaverse service support; and drone communications.

[0008] Furthermore, such development of 5G mobile communication systems will serve as a foundation for the development of new waveforms for providing coverage in the THz band for 6G mobile communication technology, multi-antenna transmission technologies (such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas), metamaterial-based lenses and antennas for improving coverage of THz band signals, high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), as well as full-duplex technologies for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for achieving system optimization and internalizing end-to-end AI support functions by leveraging satellites and AI from the design stage, and next-generation distributed computing technologies for enabling services with a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources.

[0009] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above content is applicable as prior art with respect to the present disclosure. Summary of the Invention

[0010] Technical issues

[0011] One aspect of the present disclosure is to provide a technology that allows a roaming terminal to access an EAS provided in an edge computing environment of a VPLMN network using an Uplink Classifier (ULCL) / Branching Point (BP) technology (which is a 5G SM Function (SMF)) in the VPLMN by using a home routing session.

[0012] One aspect of the present disclosure provides a VPLMN network structure that provides Home Routing Session Breakout (HR-SBO) in one Protocol Data Unit (PDU) session, which allows connection to a data network (DN) provided by a home network while simultaneously connecting to a local DN provided by a visited network, a method for routing DNS traffic sent by a terminal to and received from a V-EASDF in a UPF of the VPLMN, and a technique for selecting a V-EASDF and routing DNS traffic to the V-EASDF.

[0013] Technical Solution

[0014] According to one aspect of the present disclosure, a method performed by a first SMF entity of a first network in a wireless communication system is provided. The method includes: receiving an SM context creation request message from an access and mobility management function (AMF) entity, the SM context creation request message including an identifier (ID) of a second SMF of a second network, HR-SBO permission information, and PDU session creation information; and selecting an EAS discovery function (EASDF) entity of the first network or multiple candidate EASDF entities based on the SM context creation request message.

[0015] According to another aspect of the present disclosure, a first SMF entity of a first network in a wireless communication system is provided. The first SMF entity includes a transceiver; and a processor connected to the transceiver. The processor is configured to receive an SM context creation request message from an AMF entity, the SM context creation request message including an ID of a second SMF of a second network, HR-SBO permission information, and PDU session creation information, and is configured to select an EASDF entity of the first network or multiple candidate EASDF entities based on the SM context creation request message.

[0016] Beneficial effects

[0017] According to the present disclosure, when roaming, a terminal can simultaneously receive services provided by a DN connected to a home network and edge computing services provided by a visited network in one PDU session.

[0018] According to the present disclosure, a terminal can access edge computing services through an EHE provided by a visited network when roaming without creating an additional PDU session.

[0019] According to the present disclosure, even in the case where a private Internet Protocol (IP) address is allocated to a terminal in a Home Public Land Mobile Network (HPLMN), a DNS service routing function with a V-EASDF can be provided in a VPLMN network. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 shows a 5G system (5GS) structure represented as a reference point according to an embodiment;

[0022] Figure 2 shows a service-based 5GS according to an embodiment;

[0023] Figure 3 A roaming structure of a service-based 5GS providing HR-SBO in a roaming situation according to an embodiment is shown;

[0024] Figure 4 Problems occurring when a private IP version 4 (IPv4) network is operated in an HPLMN DN in a wireless communication system according to an embodiment are illustrated;

[0025] Figure 5 A structure for constructing a separate local DN corresponding to a private IPv4 network of an HPLMN in a VPLMN and selecting the constructed local network in a wireless communication system according to an embodiment is shown;

[0026] Figure 6 illustrates operations for routing DNS traffic using an N6 tunnel between a V-EASDF and a VPLMN UPF in a wireless communication system according to an embodiment;

[0027] Figure 7A and 7B 1. A signal flow diagram illustrating a process for configuring a DNS service route while creating a home routing PDU session capable of session breakout in a wireless communication system according to an embodiment;

[0028] Figure 8 A UE according to an embodiment is shown;

[0029] Figure 9 shows a base station according to an embodiment; and

[0030] Figure 10 Network entities according to an embodiment are shown. DETAILED DESCRIPTION

[0031] Hereinafter, the present disclosure will be described in detail by explaining various embodiments of the present disclosure with reference to the attached drawings.

[0032] The following description, with reference to the accompanying drawings, is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in understanding, but these details are to be regarded as merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. Furthermore, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

[0033] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to provide a clear and consistent understanding of the present disclosure. Therefore, the following description of various embodiments of the present disclosure is provided for illustration purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0034] Herein, singular forms such as "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0035] In some applications such as smart grids, precise time synchronization between terminals is required. In this case, 5GS can provide time synchronization between terminals.

[0036] Figure 1 The network structure and interface of 5GS according to the embodiment are shown.

[0037] According to the system implementation method, including Figure 1 The network entities in the 5GS network structure may include network functions (NFs).

[0038] refer to Figure 1 The network structure of 5GS includes various network entities. For example, 5GS includes Authentication Server Function (AUSF) 108, (Core) AMF 103, SMF 105, Policy Control Function (PCF) 106, Application Function (AF) 107, Unified Data Management (UDM) 109, DN 110, Network Exposure Function (NEF) 113, Edge Application Domain Repository (EDR) 113, EAS 114, EASDF 112, UPF 104, (Radio) Access Network ((R)AN) 102 and Terminal, i.e., UE 101.

[0039] Each of the NFs of 5GS can support the following functions.

[0040] AUSF 108 may process and store data used for authentication of UE 101 .

[0041] The AMF 103 may provide functions for access and mobility management on a UE-by-UE basis, and by default, each UE may be connected to one AMF. Specifically, AMF 103 can support functions including signaling between core network (CN) nodes for mobility between 3rd Generation Partnership Project (3GPP) access networks, termination of radio access network (RAN) control plane (CP) interface (i.e., N2 interface), termination of non-access stratum (NAS) signaling (N1), NAS signaling security (NAS encryption and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE reachability (including control and execution of paging retransmission), mobility management control (subscription and policy), support for intra-system mobility and inter-system mobility, support for network slicing, SMF selection, lawful interception (LI) (for AMF events and interface to LI system), provision of delivery of SM messages between UE and SMF, transparent proxy for SM message routing, access authentication, access authorization including roaming permission check, provision of delivery of SMS messages between UE and SMF, security anchor function (SAF) and / or security context management (SCM), etc. Some or all of the functions of the AMF 103 may be supported within a single instance of an AMF.

[0042] For example, the DN 110 may refer to an operator service, Internet access, a third-party service, etc. The DN 110 may transmit a downlink (DL) PDU to the UPF 104 or receive a PDU transmitted from the UE 101 from the UPF 104 .

[0043] The PCF 106 may receive information about packet flows from application servers and provide functionality for determining policies, such as mobility management and SM. Specifically, the PCF 106 may support the following functions: for example, supporting a unified policy framework to control network behavior, providing policy rules so that control plane functions (e.g., AMF, SMF, etc.) can implement the policy rules, and implementing a front end for accessing policy-determined subscription-related information in a user data repository (UDR).

[0044] The SMF 105 can provide an SMF, and in the case where a UE has multiple sessions, each session can be managed by a different SMF. Specifically, the SMF 105 can support functions including SM (e.g., session establishment, modification, and release, including tunnel maintenance between the UPF 104 and the (R)AN 102 node, UE IP address allocation and management (optionally with authentication), selection and control of UP functions, traffic steering configuration for routing traffic to the appropriate destination in the UPF 104, termination of the interface towards the PCF, implementation of the policy and control portion of Quality of Service (QoS), LI (for SM events and interface to the LI system), termination of the SM portion of NAS messages, DL data notification, initiator of access network (AN)-specific SM information (transmitted to the (R)AN 102 via the AMF 103 over N2), determination of the session and the service continuity (SSC) mode for the session, roaming functions, etc. Some or all of the functions of the SMF 105 can be supported within a single instance of an SMF.

[0045] The UDM 109 may store user subscription data, policy data, etc. The UDM 109 may include two parts, namely, the application front end (FE) and the UDR.

[0046] The FE can include the UDM-FE, which is responsible for location management, subscription management, and credential processing, and the PCF, which is responsible for policy control. The UDR can store data required for the functions provided by the UDM-FE and policy profiles required by the PCF. The data stored in the UDR can include user subscription data and policy data. User subscription data includes subscription IDs, security credentials, access and mobility-related subscription data, and session-related subscription data. The UDM-FE can access the subscription information stored in the UDR and support functions such as authentication credential processing, user identity processing, access authentication, registration / mobility management, subscription management, and SMS management.

[0047] The UPF 104 may deliver DL PDUs received from the DN 110 to the UE 101 via the (R)AN 102, and may deliver UL PDUs received from the UE 101 to the DN 110 via the (R)AN 102. Specifically, the UPF 104 may support functions including an anchor point for intra-radio access technology (RAT) / inter-RAT mobility, an external PDU session point for interconnecting with a data network, packet routing and forwarding, the user plane portion of packet inspection and policy rule enforcement, LI, traffic usage reporting, a UL classifier for supporting traffic flow routing to the data network, a branch point for supporting multi-homed PDU sessions, QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement), UL traffic verification (SDF mapping between service data flows (SDFs) and QoS flows), transport-level packet marking in the UL and DL, DL packet buffering, DL data notification triggering, etc. Some or all of the functions of the UPF 104 may be supported within a single instance of a UPF.

[0048] The AF 107 may interwork with the 3GPP CN to provide services (eg, support functions such as application impact on traffic routing, access to network capability exposure, interworking with a policy framework for policy control).

[0049] The (R)AN 102 may be collectively referred to as a new radio access network that supports both Evolved-UTRA (E-UTRA), which is an evolved version of the 4G RAT, and New Radio (NR) access technologies (eg, gNB).

[0050] The gNB may support functions including those for radio resource management (i.e., radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs via UL / DL (i.e., scheduling), IP header compression, ciphering and integrity protection of user data flows, selection of an AMF when a UE attaches if the route to the AMF is not determined based on information provided to the UE, user plane data routing to the UPF, control plane information routing to the AMF, connection establishment and release, scheduling and transmission of paging messages (generated based on the AMF), scheduling and transmission of system broadcast information (generated based on the AMF or Operation and Maintenance (O&M)), measurements and measurement report configuration for mobility and scheduling, transport level packet marking in the UL, SM, support of network slicing, QoS flow management and mapping to data radio bearers, support for UEs in inactive mode, NAS message distribution function, NAS node selection function, radio access network sharing, dual connectivity, and tight interworking between NR and E-UTRA).

[0051] The UE 101 may be referred to as a terminal, a mobile equipment (ME), a mobile station (MS), etc. In addition, the UE 101 may be a portable device such as a laptop computer, a mobile phone, a personal digital assistant (PDA), a smart phone, or a multimedia device, or may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device.

[0052] NEF 111 provides a way to securely expose services and capabilities provided by 3GPP network functions to third parties, such as internal exposure / re-exposure, application functions, or edge computing. NEF 111 can receive information from other NFs (based on the exposed capabilities of other NFs). NEF 111 can store the received information as structured data using standardized interfaces to data storage network functions. The stored information can be re-exposed by NEF 111 to other NFs and AFs, as well as used for other purposes such as analysis.

[0053] The EASDF 112 may be an NF that can add an ECS option for each fully qualified domain name (FQDN), where the ECS option may be represented as the address of the DNS server to which the DNS request is to be forwarded from the UE and the IP subnet address that may be added when the UE forwards the DNS request. The EASDF 112 may receive DNS processing rules from the SMF 105 and process the DNS request message received from the UE based on the received information. In addition, the EASDF 112 may be an NF that performs the following functions: receives the UE IP address, location information of the UE 101 in 3GPP, DNS message processing rules, and DNS message reporting rules from the SMF 105; processes the DNS query message received from the UE 101 and the DNS response message received from the DNS server; and transmits information in the DNS message and statistical information obtained by processing the information to the SMF 105 based on the DNS message reporting rules.

[0054] To make it clear, Figure 1 The NF Repository Function (NRF) is not shown in the Figure 1 All NFs shown in FIG can perform interworking with NRF as needed.

[0055] NRF can support service discovery. NRF can receive NF discovery requests from NF instances and provide information about the found NF instances to NF instances. In addition, NRF can maintain available NF instances and the services supported by the NF instances.

[0056] For ease of explanation, Figure 1, a reference model is shown for a case where UE 101 accesses one DN 110 by using one PDU session, but the present disclosure is not limited thereto.

[0057] UE 101 can access two (i.e., local and central) data networks simultaneously by 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 CP function (CPF) within a PDU session.

[0058] Furthermore, UE 101 may simultaneously access two (ie, local and central) data networks provided within a single PDU session.

[0059] In the 3GPP system, the conceptual links between NFs in the 5GS are defined as reference points. For example, Figure 1 The reference points within the 5GS include:

[0060] -N1: Reference point between UE 101 and AMF 103

[0061] -N2: Reference point between (R)AN 102 and AMF 103

[0062] -N3: Reference point between (R)AN 102 and UPF 104

[0063] -N4: Reference point between SMF 105 and UPF 104

[0064] -N5: Reference point between PCF 106 and AF 107

[0065] -N6: Reference point between UPF 104 and DN 110

[0066] -N7: Reference point between SMF 105 and PCF 106

[0067] -N8: Reference point between UDM 109 and AMF 103

[0068] -N9: Reference point between two core UPF 104

[0069] -N10: Reference point between UDM 109 and SMF 105

[0070] -N11: Reference point between AMF 103 and SMF 105

[0071] -N12: Reference point between AMF 103 and AUSF 108

[0072] -N13: Reference point between UDM 109 and AUSF 108

[0073] -N14: Reference point between two AMF 103s

[0074] -N15: Reference point between PCF and AMF in non-roaming scenarios, and between PCF and AMF in the visited network in roaming scenarios

[0075] -Nx: Reference point between SMF 105 and EASDF 112

[0076] Figure 2 A service-based 5GS network structure according to an embodiment is shown.

[0077] refer to Figure 2 , 5GS 200 includes UE 201, (R)AN 202, AMF 203, UPF 204, SMF 205, PCF 206, AF 207, AUSF 208, UDM 209, DN 210, NEF 211, EASDF 212, EDR 213, Network Slice Selection Function (NSSF) 214 and NRF 215.

[0078] Figure 2 UE 201, (R)AN 202, AMF 203, UPF 204, SMF 205, PCF 206, AF 207, AUSF 208, UDM 209, DN 210, NEF 211, EASDF 212 and EDR 213 in the Figure 1 The UE 101, (R)AN 102, AMF 103, UPF 104, SMF 105, PCF 106, AF 107, AUSF 108, UDM 109, DN 110, NEF 111, EASDF 112 and EDR 113 in the network perform the same functions.

[0079] NSSF 214 can select a set of network slice instances to serve UE 201. Furthermore, NSSF 214 can determine authorized network slice selection assistance information (NSSAI) and, if necessary, perform mapping to subscribed single-NSSAI (S-NSSAI). Furthermore, NSSF 214 can determine the configured NSSAI and, if necessary, perform mapping to subscribed S-NSSAI. Furthermore, NSSF 214 can determine the set of AMFs to serve the UE or, depending on the configuration, determine a list of candidate AMFs by querying NRF 215.

[0080] NRF 215 can support service discovery functionality. NRF 215 can receive NF discovery requests from NF instances and provide information about the found NF instances to the NF instances. In addition, NRF 215 can maintain available NF instances and the services supported by the NF instances.

[0081] Figure 3 A network structure supporting ULCL / BP UPF for HR-SBO in a home routed roaming scenario according to an embodiment is shown.

[0082] and Figure 2 Compared with the reference Figure 3 The NF in the visited network and the NF in the home network that require further explanation are described.

[0083] refer to Figure 3 , the visited network 300 includes AMF 303, V-SMF 305, V-UPF 304, V-EASDF 312 and visited DNS server 310.

[0084] The AMF 303 may exist in the visited network 300. The AMF 303 may receive and store a Visited SBO Permit Indicator from the UDM during the registration process of the UE 301. If the AMF 303 recognizes a request for a DNN / S-NSSAI sent by the UE 301 during the PDU session creation process, the AMF 303 may send the Visited SBO Permit Indicator to the V-SMF 305. Since the request for the HR session is sent, the AMF 303 may send the address and / or ID of the Home SMF (H-SMF) 305.

[0085] The V-SMF 305 can perform tunnel management for the Home UPF (H-UPF) 404 through the Visited UPF 304. The V-SMF 305 can determine session breakout (ULCL / BP) in the Visited Network 300 and manage UP sessions for the Local PDU Session Anchor (L-PSA) UPF 304b, the ULCL / BP UPF 304a, and the V-UPF 304 through N4. The V-SMF 305 can deliver HR-SBO support-related information to the H-SMF 405 to facilitate the addition, change, and removal of Local UPFs. The V-SMF 305 is the NF that manages sessions for the UE 301 in the Visited Network 300. If the UE 301 requests the creation of a PDU session, the V-SMF 305 can receive a request message from the AMF 303 requesting the creation of a PDU session. The V-SMF 305 may receive a request message from the AMF 303 that includes the HR-SBO permission indicator and the ID / address of the H-SMF 405. The V-SMF 305 receives the HR-SBO permission indicator from the AMF 303 and, in the case of a home-routed session, if the V-SMF 305 receives the H-SMF ID / IP address from the AMF 303, may transmit a request message for HR session creation to the H-SMF 405. The V-SMF 305 may include an indicator requesting provision of HR-SBO (or an indicator indicating support for the HR-SBO function) in the request message for HR session creation and transmit the request message to the H-SMF 405. The V-SMF 305 may deliver the address of the V-EASDF 312 (visited DNS server address) to the H-SMF 405. The V-SMF 305 may send routing rules for the local domain name (LDN) to the H-SMF 405. The V-SMF 305 may determine whether to add / change / delete the ULCL / BP 304a and the local UPF 304b. If the V-SMF 305 adds the ULCL UPF 304b, the V-SMF 305 may report the network address of the LDN to be forwarded to the local UPF 304a to the H-SMF 405. The H-SMF 405 of the home PLMN 400 may be responsible for packet forwarding for the HR session.

[0086] The V-UPF 304 may be a NF for transmitting traffic occurring within the visited network 300 to the H-UPF 404. When the UE 301 is in an idle state, the V-UPF 304 may buffer DL data packets. The V-UPF 304 may perform packet forwarding functions with the H-UPF 404 via an N9 tunnel. The V-UPF 304 may support the ULCL / BP UPF 304a or the Local UPF 304b functions together, or may exist independently. The V-UPF 304 may be provided in a form separate from the ULCL / BP UPF 304a or the Local UPF 304b.

[0087] The L-PSA UPF 304b may be an NF that performs the local PSA UPF function. The L-PSA UPF 304b may be connected to the local portion of the DN 314 via N6. The L-PSA UPF 304b may perform the function of forwarding packets sent and received between the UE 301 and the EAS 314 of the visited network 300.

[0088] The ULCL / BP UPF 304a may be a UPF that branches PDUs. The ULCL / BP UPF 304a may receive packet forwarding rules corresponding to the ULCL from the V-SMF 305 and branch and forward packets received from the UE 301 to the UPF 304 using the destination address of the UE 301 or the IPv6 prefix of the UE 301.

[0089] V-EASDF 312 can perform EAS discovery functions in visited network 300. V-EASDF 312 located in visited network 300 can be connected to V-SMF 305. V-EASDF 312 can receive session-level and node-level DNS message handling rules from V-SMF 305. When a PDU session is created or changed, the address of V-EASDF 312 can be used as the DNS address transmitted to UE 301 as a protocol configuration option (PCO). The home DNS server address can be delivered to V-EASDF 312 via message handling rules for DNS queries from V-SMF 305. The DNS message handling rules can be used as the DNS server address for forwarding DNS queries from V-EASDF 312, allowing DNS queries to be sent to the DNS server of home network 400 for resolution of the IP address of the FQDN included in the DNS query sent from UE 301, which is not registered in the home network. Alternatively, the DNS message handling rules can be used as the default DNS server address. DNS message processing rules may exist in the LDN.In certain implementations, a structure in which the V-UPF 304 and the EASDF 312 may be collocated is also possible.

[0090] NFs providing functions for the HR-SBO session in the home network 400 may include a UDM 409 , an H-SMF 405 , an H-UPF 404 , a home PCF (H-PCF) 406 , and a home DNS server 410 .

[0091] The H-PCF 406 may determine a policy for home-routed sessions. The H-PCF 406 may store and manage a roaming offloading policy for each VPLMN for each HR-SBO session of the VPLMN, in accordance with a service level agreement between the operators of the HPLMN 400 and the VPLMN 300. The roaming offloading policy for each VPLMN may include information for routing traffic to the local portion of the DN 314 within the visited network 300, such as an IP address range and a domain address range of the local portion of the DN 314, as well as QoS and charging policy information (e.g., session aggregate maximum bit rate (AMBR) information for the local portion of the DN 314).

[0092] The UDM 409 may store subscriber policies for SM based on a previous roaming agreement between the HPLMN 400 and the VPLMN 300. The subscriber policies may include policies such as whether HR-SBO is allowed for each DNN / S-NSSAI of the UE 301 and roping off-route for each VPLMN. During registration of the UE 301 through the visited network 300, the UDM 409 may deliver to the AMF 303 whether HR-SBO is allowed. At the time of registration of the UE 301 through the visited network 300, the UDM 409 may deliver to the AMF 303 whether HR-SBO is allowed. Whether HR-SBO is allowed is separate from the LBO allowed indicator, and if LBO allowed is configured, HR-SBO may be configured to be not allowed.

[0093] The H-SMF 405 may receive the SM-related subscriber information stored in the UDM 409 and ultimately determine whether HR-SBO is supported. When the H-SMF 405 allows HR-SBO, the H-SMF 405 may send an HR-SBO usage permission indicator. Alternatively, the DNS server address of the PCO message transmitted to the UE 301 may be configured as the address of the V-EASDF provided by the V-SMF 305. The Home SMF 405 may deliver a billing collection request to the V-SMF 305 for billing collection. The V-SMF 305 may collect usage data from the UPF 404 through user plane reporting rules.

[0094] UE 301 may send and receive 5G control plane messages through AMF 303 and SMF 305. UE 301 may access EAS 314 through a PDU session via UPF 304 via a user plane. UE 301 may receive a DNS server address from SMF 305. UE 301 may send a DNS query to the DNS server address.

[0095] Figure 4 Problems occurring when a private IPv4 network is operated in an HPLMN DN in a wireless communication system according to an embodiment are illustrated.

[0096] refer to Figure 4 In the HPLMN 400, the DNs 410-1 and 410-2 may be constructed using a private IPv4 network.

[0097] A PDU session that applies HR-SBO to a PDU session provided with a home route configured in this manner can be created. The HR-SBO session is a method for providing a home route in the VPLMN 300 by configuring the ULCL / BP UPF 304a and the local UPF 304b in the VPLMN 300.

[0098] In order to use the HR-SBO function in the VPLMN 300 and add / change the local UPF 304b of the VPLMN 300, the V-EASDF 312 can be introduced in the VPLMN 300. When the V-EASDF 312 is introduced, the DNS address of the UE 301-1, 301-2, 301-3, and 301-4 for the PDU session supporting HR-SBO is configured to the V-EASDF 312, and the UE 301-1, 301-2, 301-3, and 301-4 uses the V-EASDF address as the address of the DNS server and sends a DNS query to the V-EASDF 312. For DNS queries sent by UEs 301-1, 301-2, 301-3, and 301-4, V-EASDF 312 can configure a DNS server address to forward the DNS query based on the IP addresses of UEs 301-1, 301-2, 301-3, and 301-4, the locations of UEs 301-1, 301-2, 301-3, and 301-4, and the DN access IDs (DNAIs). Furthermore, when HR-SBO is provided, if the DNS query does not correspond to an edge computing service provided by VPLMN 300, V-EASDF 312 should forward the DNS query to a DNS server provided by HPLMN 400.

[0099] In the network structure for providing such HR-SBO, when the HPLMN 400 operates an IPv4 private network, the following problems may occur.

[0100] When the DNS query (Message 2) sent by UEs 301-1, 301-2, 301-3, and 301-4 reaches V-EASDF 312, a problem may arise in that V-EASDF 312 cannot identify an appropriate DNSContext using only the IP addresses of UEs 301-1, 301-2, 301-3, and 301-4.

[0101] When the V-EASDF 312 transmits the DNS response message (Message 5) to the UEs 301-1, 301-2, 301-3, and 301-4, a problem may occur in that the local UPF 304b may not be able to identify the UEs 301-1, 301-2, 301-3, and 301-4 through the destination IP addresses.

[0102] Figure 5 A structure for constructing a separate local DN corresponding to a private IPv4 network of an HPLMN in a VPLMN and selecting the constructed local network in a wireless communication system according to an embodiment is shown.

[0103] More specifically, as a solution Figure 4 The method of the problem raised in Figure 5 The method for constructing a separate local DN corresponding to the private IPv4 network of the HPLMN 400 in the VPLMN 300 and selecting the constructed local network is shown. Figure 5 is a conceptual diagram showing a method for separately constituting a local part of a DN network in a VPLMN 300 corresponding to a private network of the HPLMN 400 .

[0104] refer to Figure 5 , a separate local part of DN 310-1 corresponding to the private IPv4 network A provided by HPLMN 400 is constructed, and V-EASDF 312-1 can be installed in this network. Similarly, the local part of DN 310-2 corresponding to the private IPv4 network B provided by HPLMN 400 is constructed from a separate network, and V-EASDF #2 312-2 can be installed there.

[0105] Since the DNS services transmitted and received from the UEs 301-1, 301-2, 301-3, and 301-4 can be independently connected to the independently installed V-EASDFs 312-1 and 312-2 by forming an independent network in the VPLMN 300, the problem of DNS traffic being transmitted and received due to network formation can be solved. Figure 4 The questions raised in .

[0106] In order to independently select local DNs 310-1 and 310-2, local UPFs 304b-1 and 304b-2, and V-EASDFs 312-1 and 312-2 for each DN 410-1 and 410-2 of the private IP domain and the HPLMN 400, the following method may be performed during the PDU session creation procedure so that local DNs 310-1 and 310-2, local UPFs (V-UPFs) 304b-1 and 304b-2, and V-EASDFs 312-1 and 312-2 may be selected.

[0107] 1) Method selected from V-SMF 305: Based on the pre-configured information / roaming agreement of each DNN, S-NSSAI and HPLMN, after receiving the PDU Session Creation Request message of the SM Context Creation Request for the PDU Session from the AMF 303 and before delivering the message to the H-SMF 405, the V-SMF 305 may select the Local UPF (V-UPF) 304b-1 and 304b-2 and the V-EASDF 312-1 and 312-2.

[0108] 2) Method of selection from H-SMF 405: V-SMF 305 may send a list of V-EASDF information and local DN information (e.g., IP address range, DNAI, DNN, and S-NSSAI information) available in the V-SMF 305 to the H-SMF 405, and select V-EASDFs 312-1 and 312-2 of the VPLMN 300 corresponding to the IP addresses of the UEs 301-1, 301-2, 301-3, and 301-4 allocated by the H-SMF 405 or local DNs 310-1 and 310-2 that may be provided by the VPLMN 300. An advantage of this method is that, when there is no prior agreement between the VPLMN 300 and the HPLMN 400, the network configuration of the VPLMN 300 changes dynamically, or the network configuration of the HPLMN 400 changes dynamically, the local UPFs 304b-1 and 304b-2 or the local DNs 310-1 and 310-2 or the V-EASDFs 312-1 and 312-2 of the VPLMN 300 can be dynamically selected based on information about the network provided by the HPLMN 400 based on a list of local DNs 310-1 and 310-2 of the V-EASDFs 312-1 and 312-2 obtainable from the V-SMF 305 and the IP addresses of the UEs 301-1, 301-2, 301-3 and 301-4. To provide this method, the V-SMF 305 may deliver information on the network configurations of the V-EASDFs 312-1 and 312-2 to the H-SMF 405, and the H-SMF 405 may select one of the network configurations for the plurality of V-EASDFs 312-1 and 312-2.

[0109] Figure 6 An operation of routing DNS traffic using an N6 tunnel between a V-EASDF and a VPLMN UPF in a wireless communication system according to an embodiment is illustrated.

[0110] refer to Figure 6 , as a solution to Figure 4 As a second method for solving the problem raised in FIG. 1 , a method for creating an N6 tunnel between the V-EASDF 312 and the UPF 304 in the VPLMN 300 and routing DNS traffic by distinguishing IP addresses allocated by the home private network 400 will be described.

[0111] For the transmission and reception of DNS services between the local DN 310 to which the V-EASDF 312 belongs and the UEs 301-1, 301-2, 301-3, and 301-4, the ULCL / BP UPF 304a and the local UPF 304b may be used. Figure 6In the embodiment, the V-UPF 304 may be constructed to include a ULCL / BP UPF 304a and a local UPF 304b.

[0112] In order to route DNS traffic between the UEs 301-1, 301-2, 301-3, and 301-4 and the V-EASDF 312 in the V-SMF 305, it is determined whether to use an N6 tunnel between the local UPF 304b and the V-EASDF 312. In the case where the N6 tunnel is created, N6 tunnel information may be exchanged to deliver the DNS traffic between the local UPF 304b and the V-EASDF 312. The N6 tunnel information may be identified for the N6 tunnel between the V-EASDF 312 and the local UPF 304b of each network, and may be identified for each of the UEs 301-1, 301-2, 301-3, and 301-4.

[0113] For DNS traffic routing, the V-SMF 305 may send the N4 rule for DNS traffic separation to the ULCL / BP 304a. The V-SMF 305 may send the N4 rule for receiving DNS traffic.

[0114] The PDU sessions requested by UEs 301-1, 301-2, 301-3, and 301-4 from H-SMF 405 are HR-SBO sessions, and when DNs 410-1 and 410-2 of HPLMN 400 utilize a private network and an N6 tunnel is used between the local UPF 304b and the V-EASDF 312, V-SMF 305 may determine to utilize a route using the N6 tunnel.

[0115] When the V-SMF 305 determines to use the N6 tunnel between the local UPF (V-UPF) 304b and the V-EASDF 312, the V-SMF 305 may deliver information about the N6 tunnel to the local UPF (V-UPF) 304b and the V-EASDF 312, respectively.

[0116] Figure 7A and 7B 1 is a signal flow diagram illustrating a process for configuring a DNS service route while creating a home routing PDU session capable of session breakout in a wireless communication system according to an embodiment.

[0117] More specifically, Figure 7A and 7B The process for configuring DNS service routing in the process of creating a home routing PDU session capable of session breakout is shown. In FIG. 7 , a method for configuring an independent network and a method for using an N6 tunnel (e.g., as Figure 5shown) can be used together or can be used separately as separate methods.

[0118] refer to Figure 7A In step 701, UE 301 sends a PDU Session Create Request message to AMF 303 requesting the creation of a PDU session. AMF 303 may receive the PDU Session Create Request message from UE 301 requesting the creation of a PDU session. UE 301 may create the PDU Session Create Request message based on UE Route Selection Policy (URSP) information received after the registration process, local configuration within UE 301, or a request from an application.

[0119] In step 702, the AMF 303 sends an SM context creation request message (CreateSMContext Request) to the V-SMF 305. The V-SMF 305 may receive the SM context creation request message from the AMF 303. Based on the PDU session creation request message received from the UE 301, the AMF 303 may identify the subscriber information of the UE 301, the DNN and S-NSSAI information requested by the UE 301, and whether HR-SBO and LBO are allowed. If LBO is allowed, the AMF 303 may determine LBO and select a V-SMF 305 that supports LBO. The AMF 303 selects a home routing session for the PDU session requested by the UE 301, and if it is a home routing session, the AMF 303 may identify whether HR-SBO is allowed. When the session requested by UE 301 is a home-routed session and HR-SBO is allowed, AMF 303 may select a V-SMF 305 that supports HR-SBO and may send information identifying H-SMF 405 for home routing (H-SMF ID or H-SMF address) and an indicator indicating whether HR-SBO is allowed to the V-SMF 305. AMF 303 may pre-store the ID or address of H-SMF 405 of UE 301's home operator network. AMF 303 may send an SM Context Creation Request (PDU Session Create SM Context Request message) to V-SMF 305 to create a PDU session for the home-routed session. If the Visited SBO Allowed indicator is present in the subscriber information of the home operator corresponding to the DNN and S-NSSAI included in the PDU Session Request message requested by UE 301, AMF 303 may determine that SBO is allowed for the HR session. If SBO is allowed, the AMF 303 may send a request message including the UE subscription ID, the address or ID of the H-SMF 405, the VSBO permission indicator, the DNN, and the S-NSSAI information in the SM context creation request message to the V-SMF 305. The V-SMF 305 may determine the creation of an HR session and the provision of session breakout of the HR session based on the HR-SBO permission indicator and the information related to the H-SMF 405 (i.e., the ID of the H-SMF 405 or the address of the H-SMF 405) included in the PDU session SM context creation request message received from the AMF 303.

[0120] In step 703, when the V-SMF 305 receives the HR-SBO allowed indicator, it may select one V-EASDF 312 or multiple candidate V-EASDFs (EASDF selection (or candidate EASDF)).

[0121] In step 703A, the V-SMF 305 may perform a process of creating an EASDF with the V-EASDF 312 (EASDF Creation with V-EASDF (Retrieve V-EASDF IP Address)). The V-SMF 305 may select a local UPF (V-UPF) 304 and the V-EASDF 312 based on information pre-configured for each DNN, S-NSSAI, and HPLMN or information configured according to a roaming agreement.

[0122] The V-SMF 305 may send configuration information about local DN candidates for connecting to the V-EASDF 312 (e.g., IP address range, DNAI, DNN, and S-NSSAI information) and a list of candidate V-EASDFs to the H-SMF 405 for the HR-SBO session provided by the VPLMN network 300.

[0123] When the V-SMF 305 selects the V-EASDF 312 corresponding to the address to be sent to the H-SMF 405, the V-EASDF 312 may send a request to the selected V-EASDF 312 to obtain the N6 IP address of the V-EASDF 312 accessible from the UE 301. The V-SMF 305 may send the N6 IP address of the V-EASDF 312 obtained from the selected V-EASDF 312 to the H-SMF 405.

[0124] In step 704, if the V-SMF 305 determines to provide an HR session, it may send a PDU session creation request message (PDUSession_Create Request) to the H-SMF 405 corresponding to the H-SMF ID or address received from the AMF 303. The PDU session creation request message may include an HR-SBO indicator. The VSBO indicator sent from the V-SMF 305 to the H-SMF 405 may instruct the V-SMF 305 to utilize the ULCL / BP 304a to provide a session breakout function for the currently requested home-routed PDU session.

[0125] The visited SMF 305 may interwork with the V-EASDF 312 and configure the address of the V-EASDF 312 interworking with the V-SMF 305 as the DNS server address of the PDU session currently being created by the UE 301, so as to provide a session breakout function corresponding to the EAS discovered through the DNS message of the UE 301. To this end, the V-SMF 305 may send the address of the V-EASDF 312 (i.e., the DNS server address to be sent to the UE 301 as the PCO and configured for the PDU session of the UE 301) to the H-SMF 405.

[0126] The V-SMF 305 may transmit information for selecting the V-EASDF 312 to the H-SMF 405 .

[0127] The V-SMF 305 may transmit information about the local DN for routing DNS services of the V-EASDF 312 to the H-SMF 405. The information about the local DN corresponding to the V-EASDF 312 transmitted from the V-SMF 305 to the H-SMF 405 may include the IP address of the V-EASDF, the DNAI corresponding to the local DN in the VPLMN 300, IP range information in the local DN, etc.

[0128] In step 705, H-SMF 405 receives the PDU session creation request from V-SMF 305 in step 703. H-SMF 405 may send a request message to the UDM to obtain subscriber information for the session. To receive information for each VPLMN in a roaming scenario, H-SMF 405 may include the ID of the currently serving VPLMN in a Subscriber Data Management (SDM) request message for obtaining subscriber information and send the SDM request message to the UDM. The UDM may identify the serving network information (VPLMN ID) of UE 301 and the subscription information and HR-SBO allowance information provisioned for each VPLMN via the HPLMN 400 and SLA. The UDM may include in the response message an indicator indicating whether HR-SBO is allowed for each VPLMN 300, either via the DNN and S-NSSAI or via the DNN. If HR-SBO is allowed, the UDM may also include offload subscriber policy information for the VPLMN. The subscriber offload policy information for each VPLMN may include traffic routing information of the local portion of the DN in the VPLMN 300, which allows routing of traffic of the UE 301 to the local portion of the DN in the VPLMN 300, for example, local traffic path configuration information such as an IP address range, an FQDN range, etc. In addition, information such as a session AMBR of subscriber information as the local portion of the DN may be additionally included.

[0129] The H-SMF 405 may select one of a plurality of V-EASDFs provided by the V-SMF 305. The H-SMF 405 may select the V-EASDF 312 of the VPLMN 300 corresponding to the allocated IP address of the UE 301 or the local DN that may be provided by the VPLMN 300. The H-SMF 405 may determine the IP address to be allocated to the UE by considering the V-EASDF information provided by the V-SMF 305 and the information on the local DN for V-EASDF interworking. An advantage of this method is that, in the event that there is no prior agreement between the VPLMN 300 and the HPLMN 400, the network configuration of the VPLMN 300 changes dynamically, or the network configuration of the HPLMN 400 changes dynamically, the local UPF 304 or local DN or V-EASDF 312 of the VPLMN 300 can be dynamically selected based on information about the network provided by the HPLMN 400 based on a list of V-EASDF local DNs obtainable from the V-SMF 305 and the IP address of the UE 301.

[0130] In step 706, the H-SMF 405 identifies whether the HR visited SBO is allowed based on the SM subscriber information received from the UDM or the roaming agreement agreed with the subscriber's serving network. When the use of the SBO provided by the visited network 300 is allowed and the VSBO is received from the visited SMF 305, the H-SMF 405 may allow the address of the V-EASDF 312 sent by the visited SMF 305 to be used as the DNS server address sent to the UE 312.

[0131] The H-SMF 405 may configure the address of the V-EASDF 312 as the DNS server address to be sent to the UE 301, and configure the address of the V-EASDF 312 as the DNS address in the PCO field together with the PDU Session Allow message to be sent to the UE 301. The H-SMF 405 may send a PDU Session Create Response message to the V-SMF 305. The H-SMF 405 may send the result of the HR-SBO request to the V-SMF 305.

[0132] When the V-SMF 305 allows VSBO to be performed and sends the address of the V-EASDF 312 provided by the V-SMF 305 to the PCO as the DNS server address of the UE 301, the H-SMF 405 may send the DNS server address of the home network 400, which has previously been intended to be used as the DNS server address of the UE 301, to the V-SMF 305.

[0133] The H-SMF 405 uses a private IP address, and in preparation for a situation where IP address overlap occurs by using multiple private IP addresses within one PLMN, the H-SMF 405 can send to the V-SMF 305 whether the private IP address of the HPLMN 400 is used or an IP private network domain ID that can distinguish different private IP networks.

[0134] When the V-SMF 305 receives DNAI information for distinguishing local DNs provided by multiple VPLMNs, the H-SMF 405 may determine the DNAI to be used in the VPLMN 300 based on pre-configured DNAI information, information configured for a roaming agreement (such as a roaming offload policy), offload configuration information received from the UDM, the offload policy for the VPLMN 300 received from the H-PCF 306, the IP address assigned to the UE 301, and whether the IP address assigned to the UE 301 is a private IP address.

[0135] The H-SMF 405 may send the determined DNAI information to the V-SMF 305.

[0136] refer to Figure 7B In step 707, the V-SMF 305 performs N4 configuration of the V-UPF 304 (N4 establishment (N6 routing information) with the V-UPF, ULCL / BP, and local UPF).

[0137] The V-SMF 305 may receive the PDU Session Create Response message and send the N4 rule to the V-UPF 304 to configure the N9 tunnel information related to the H-UPF 404. The V-SMF 305 may determine whether to provide HR-SBO based on whether the HR-SBO received from the AMF 303 is allowed for HR-SBO and whether permission is received from the H-SMF 405.

[0138] If HR-SBO is determined to be provided, the V-SMF 305 may configure the V-UPF 304 (ULCL / BP UPF 304 a and Local UPF 304 b ) and configure rules for routing DNS queries from the UE 301 to the V-EASDF 312 to the V-UPF 304 .

[0139] Here, V-UPF 304 may refer to UPF 304, which includes the functions of ULCL / BP UPF 304a, the functions of local UPF 304b, and the functions of UPF 404 connecting N9 tunnel and HPLMN 400, such as Figure 5 and Figure 6 Alternatively, the V-UPF 304 may exist independently by being divided into the ULCL / BP UPF 304a and the local UPF 304b, as shown in FIG. Figure 5 and Figure 6 shown.

[0140] The V-SMF 305 may determine to add the ULCL / BP 304a and the local UPF 304b to route the traffic to the V-EASDF 312.

[0141] In order to route the DNS service to the V-EASDF 312, the V-SMF 305 may select the local UPF 304b based on its own pre-configured information, information configured by the roaming agreement, the DNN, S-NSSAI and HPLMN ID as information included in the roaming offload policy received from the H-SMF 405, the IP address of the UE 301, whether the DN 410 of the HPLMN 400 is a private IP network, an IP private network domain ID that can distinguish private IP networks, and at least one of DNAI information.

[0142] When the ULCL / BP 304b and the local UPF 304b are added, in order to guide the traffic sent from the UE 301 to the V-EASDF 312 to the added ULCL / BP UPF 304a, the V-SMF 305 can send a packet detection rule (PDR) with the N6 IP address of the selected V-EASDF 312 as the destination address and a packet forwarding rule for the PDR to the ULCL / BP UPF 304a.

[0143] like Figure 6 As shown, the V-SMF 305 may transmit, to the local UPF 304b, routing information about the N6 tunnel used to transmit and receive DNS services to and from the V-EASDF 312. The routing information of the N6 tunnel may have different N6 tunnel information for each UE, or may have tunnel information for each network having different tunnel information for each network corresponding to the DN 410 of the HPLMN 400.

[0144] In step 708, the V-SMF 305 and the V-EASDF 312 create or update a DNS context (DNS context creation (or update) (N6 routing information, DN processing rules (for H-DNS, HPLMN ID)).

[0145] Before requesting PDU session creation, the V-SMF 305 may have already selected the V-EASDF 312 (step 703). Alternatively, the V-SMF 305 may send information for selecting the V-EASDF 312 to the H-SMF 405, and when the H-SMF 405 selects the V-EASDF 312, the V-SMF 305 may receive information related to the selected V-EASDF 312 from the H-SMF 405.

[0146] The V-SMF 305 may perform a process for configuring a DNS context for the selected V-EASDF 312 .

[0147] The V-SMF 305, which has received the DNS server address of the home network, may create a DNS message processing rule to be sent to the V-EASDF 312. The V-EASDF 312 may create a DNS message rule for each EAS domain based on the EAS deployment information.

[0148] When there is no FQDN rule corresponding to the edge application deployment information (EAS deployment information) of the VPLMN 300, the V-SMF 305 may send a DNS message processing rule to the V-EASDF 312, which configures the DNS server address of the home network as the default DNS server address to route the DNS query to the DNS server 410 of the HPLMN 400.

[0149] The V-SMF 305 may receive the IP address of the UE 301, the private network IP network ID, or information indicating whether a private network is used from the H-SMF 405.

[0150] The V-SMF 305 may determine to use the N6 tunnel between the V-EASDF 312 and the local UPF 304b to send and receive DNS traffic. The V-SMF 305 may send the N6 tunnel routing information to the V-EASDF 312.

[0151] Alternatively, if the V-SMF 305 has received the HR-VSBO permission indicator in step 706 from the AMF 303, the V-SMF 305 may determine to provide HR-SBO without the HR-SBO permission procedure from the H-SMF 405.

[0152] As another alternative, the V-SMF 305 may determine to add the ULCL / BP 304a and the local UPF 304b through its own configuration according to the roaming agreement between the HPLMN 400 and the operator.

[0153] In step 709, the V-SMF 305 sends a response message (CreateSMContext Response) to the SM context creation request to the AMF 303. The response message may include information indicating the PDU session creation result (acceptance or rejection). The V-SMF 305 may send a response message including a PCO value to the AMF 303, wherein the DNS server address included in the PCO value received from the H-SMF 405 is configured as the EASDF server address.

[0154] In step 710, AMF 303 may send the PDU session creation result received from V-SMF 305 to UE 301.

[0155] In step 711, UE 301 sends a DNS query message to V-EASDF 312 through UPF 304. V-EASDF 312 may receive the DNS query message from UE 301 through UPF 304.

[0156] In step 712, V-EASDF 312 sends the DNS query message to H-DNS 410. H-DNS 410 may receive the DNS query message from V-EASDF 312.

[0157] In step 713, H-DNS 410 sends a DNS response message to V-EASDF 312. V-EASDF 312 may receive the DNS response message from H-DNS 410.

[0158] In step 714, V-EASDF 312 sends a DNS response message to UE 301 through UPF 304. UE 301 may receive the DNS response message from V-EASDF 312 through UPF 304.

[0159] Figure 8 A UE according to an embodiment is shown.

[0160] refer to Figure 8 , the UE includes a transceiver 810, a memory 820, and a processor 830. The UE can communicate with Figure 1 UE 101 in Figure 2 UE 201 in Figures 4 to 6 UE#1 301-1, UE#2 301-2, UE#3 301-3 or UE#4 301-4, or Figure 7A and Figure 7B The UE 301 in is the same or similar.

[0161] The processor 830, transceiver 810 and memory 820 of the UE may operate according to the operating method of the UE. The components of the UE are not limited to Figure 8 For example, a UE may include Figure 8 Furthermore, the processor 830, the transceiver 810, and the memory 820 may be implemented as a single chip.

[0162] The transceiver 810 can be collectively referred to as the receiver and transmitter of the UE, and can transmit and receive signals to and from a base station or network entity. The signals transmitted to and received from the base station may include control information and data. To this end, the transceiver 810 may include a radio frequency (RF) transmitter for up-converting and amplifying transmitted signals, and an RF receiver for low-noise amplifying and down-converting received signals. However, this is merely an embodiment of the transceiver 810, and the components of the transceiver 810 are not limited to the RF transmitter and RF receiver.

[0163] In addition, the transceiver 810 may include a wired or wireless transceiver and may include various components for transmitting and receiving signals.

[0164] The transceiver 810 may receive a signal through a radio channel and output the signal to the processor 830 , and may transmit a signal output from the processor 830 through a radio channel.

[0165] The transceiver 810 may receive a communication signal and output it to the processor, and transmit a signal output from the processor 830 to a network entity through a wired or wireless network.

[0166] The memory 820 may store programs and data required for the operation of the UE. In addition, the memory 820 may store control information or data included in signals obtained by the UE. The memory 820 may include a storage medium or a combination of storage media, such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a compact disc ROM (CD-ROM), and a digital versatile disc (DVD).

[0167] The processor 830 may control a series of processes so that the UE can operate according to the above-described embodiments of the present disclosure. The processor 830 may include one or more processors. For example, the processor 830 may include a communication processor for performing communication control and an application processor (AP) for controlling upper layers such as application programs.

[0168] The UE according to the present disclosure may be at least one of various types of communication nodes. For example, the UE may be at least one of a terminal, a base station, or various network entities used in various communication systems.

[0169] Figure 9 A base station according to an embodiment is shown.

[0170] refer to Figure 9 , the base station can be Figure 1 (R)AN 102 or Figure 2 At least one of the (R)AN 202 in .

[0171] The base station includes a processor 930 that controls the overall operation of the base station 900, a transceiver 910 including a transmitter and a receiver, and a memory 920. The components of the base station are not limited to the above examples, and the base station may include more than Figure 9 More components or fewer components than shown in the figure.

[0172] The transceiver 910 may transmit and receive signals to and from at least one of a network entity or a UE. The signals transmitted and received by at least one of the network entity or the UE may include control information and data.

[0173] The processor 930 can control the base station to execute the above Figure 1 7. The processor 930, the memory 920, and the transceiver 910 do not necessarily need to be implemented as separate modules and may be implemented as one component in the form of a single chip. In addition, the processor 930 and the transceiver 910 may be electrically connected.

[0174] The memory 920 may store basic programs, application programs, and data such as configuration information for operating the base station. Specifically, the memory 920 provides stored data in response to a request from the processor 930. The memory 920 may include a storage medium or a combination of storage media, such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Furthermore, multiple memories 920 may be provided. The processor 930 may execute the above-described embodiments based on the program for executing the embodiments of the present disclosure stored in the memory 920.

[0175] Figure 10 Network entities according to an embodiment are shown.

[0176] refer to Figure 10 , the network entity may be at least one of the following: Figure 1 AMF 103, UPF 104, SMF 105, PCF 106, AF 107, AUSF 108, UDM 109, NEF 111, EASDF 112, DNS 113, or EAS 114, Figure 2 AMF 203, UPF 204, SMF 205, PCF 206, AF 207, AUSF 208, UDM 209, NEF 211, EASDF 212, NSSF 214, or NRF 215, Figure 3 To the AMF 303, UPF 304, ULCL / BP UPF 304a, local UPF 304b, V-SMF 305, PCF 306, AF 307, V-EASDF 312, EAS 314, NRF 315, V-EASDF#1 312-1, V-EASDF#2 312-2, H-UPF 404-1, H-UPF 404-2, H-SMF 405, H-SMF 405-1, H-SMF 405-2, H-DNS 410-1 or H-DNS 410-2 in Figure 7.

[0177] The network entity includes a processor 1030 that controls the overall operation of the network entity, a transceiver 1010 including a transmitter and a receiver, and a memory 1020. The components of the network entity are not limited to the above examples, and the network entity may include more than Figure 10The components shown may include more components or fewer components.

[0178] The transceiver 1010 may transmit and receive signals to and from at least one of other network entities, UEs, and base stations. The signals transmitted and received with at least one of other network entities, UEs, and base stations may include control information and data.

[0179] The processor 1030 can control the network entity to execute the above Figure 1 7. The processor 1030, the memory 1020, and the transceiver 1010 do not necessarily need to be implemented as separate modules and may be implemented as one component in the form of a single chip. In addition, the processor 1030 and the transceiver 1010 may be electrically connected.

[0180] The memory 1020 can store basic programs, application programs, and data such as configuration information for operating network entities. In particular, the memory 1020 provides stored data in response to a request from the processor 1030. The memory 1020 can include a storage medium or a combination of storage media, such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. In addition, multiple memories 1020 can be provided. The processor 1030 can execute the above-described embodiments based on the program for executing the embodiments of the present disclosure stored in the memory 1020.

[0181] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a first session management function (SMF) entity of a first network in a wireless communication system, the method comprising: receiving a session management (SM) context creation request message from an access and mobility management function (AMF) entity, the SM context creation request message including an identifier (ID) of a second SMF of the second network, home routing session breakout (HR-SBO) permission information, and protocol data unit (PDU) session creation information; and An edge application server (EAS) discovery function (EASDF) entity of the first network or a plurality of candidate EASDF entities is selected based on the SM context creation request message.

2. The method according to claim 1, further comprising: Sending a request message to the EASDF entity requesting the address information of the EASDF entity; and A response message including address information of the EASDF entity is received from the EASDF entity.

3. The method according to claim 2, further comprising: Sending a PDU session creation request message to the second SMF of the second network, wherein the PDU session creation request message includes the address information of the EASDF entity of the first network and the HR-SBO indicator, The address information of the EASDF entity of the first network is configured as a Domain Name System (DNS) server address of the PDU session, and The HR-SBO indicator indicates that the session breakout function is provided by the uplink classifier / branching point (ULCL / BP) user plane function (UPF).

4. The method according to claim 3, further comprising: A PDU session creation response message is received from the second SMF, the PDU session creation response message including information indicating whether HR-SBO is allowed for the first network, information about an Internet Protocol (IP) address allocated to the terminal, and offload subscriber policy information for the first network.

5. The method according to claim 4, further comprising: Based on the PDU session creation response message, create N6 routing information for configuring the ULCL / BP UPF entity, local UPF entity, and UPF entity; and Send N6 routing information to the UPF entity.

6. The method according to claim 5, further comprising: Send a DNS context creation request message including N6 routing information and DNS processing rules to the EASDF entity, The DNS processing rule includes an IP address assigned to the terminal and an ID of the second network.

7. The method according to claim 6, further comprising: Send an SM context creation response message to the AMF, where the SM context creation response message indicates whether to allow or reject the establishment of the PDU session. The SM context creation response message includes a value in which the IP address allocated to the terminal is configured as the address of the EASDF entity.

8. The method according to claim 1, further comprising: Sending a request message requesting address information of the plurality of candidate EASDF entities to each of the plurality of candidate EASDF entities; and A response message including address information of the plurality of candidate EASDF entities is received from each of the plurality of candidate EASDF entities.

9. The method according to claim 1, further comprising: Based on the PDU session creation information, a first user plane function (UPF) of the first network is selected.

10. The method according to claim 1, further comprising: Based on the PDU session creation information, a local UPF and an uplink classifier / branching point (ULCL / BP) user plane function (UPF) of the first network are selected.

11. A first session management function (SMF) entity of a first network in a wireless communication system, the first SMF entity comprising: transceiver; and processor, connected to the transceiver, The processor is configured as follows: receiving a session management (SM) context creation request message from an access and mobility management function (AMF) entity, the SM context creation request message including an identifier (ID) of a second SMF of the second network, home routing session breakout (HR-SBO) permission information, and protocol data unit (PDU) session creation information, and An edge application server (EAS) discovery function (EASDF) entity of the first network or a plurality of candidate EASDF entities is selected based on the SM context creation request message.

12. The first SMF entity according to claim 11, wherein: The processor is also configured to: Sending a request message to the EASDF entity requesting the address information of the EASDF entity, and A response message including address information of the EASDF entity is received from the EASDF entity.

13. The first SMF entity according to claim 12, wherein: The processor is further configured to: send a PDU session creation request message to the second SMF of the second network, wherein the PDU session creation request message includes address information of the EASDF entity of the first network and an HR-SBO indicator, The address information of the EASDF entity of the first network is configured as a Domain Name System (DNS) server address of the PDU session, and The HR-SBO indicator indicates that the session breakout function is provided by the uplink classifier / branching point (ULCL / BP) user plane function (UPF).

14. The first SMF entity according to claim 13, wherein: The processor is further configured to receive a PDU session creation response message from the second SMF, the PDU session creation response message including information indicating whether HR-SBO is allowed for the first network, information about an Internet Protocol (IP) address assigned to the terminal, and offload subscriber policy information for the first network.

15. The first SMF entity according to claim 14, wherein: The processor is also configured to: Create N6 routing information for configuring ULCL / BP UPF entity, local UPF entity and UPF entity based on PDU session creation response message, and Send N6 routing information to the UPF entity.

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