WO2022070140A1

WO2022070140A1 - N3iwf selection procedure when accessing snpn via plmn

Info

Publication number: WO2022070140A1
Application number: PCT/IB2021/059015
Authority: WO
Inventors: Peter Hedman; Jinyao CAO; George Foti
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2020-10-02
Filing date: 2021-09-30
Publication date: 2022-04-07

Abstract

Apparatuses and methods for N3IWF selection procedure when accessing SNPN via PLMN are disclosed. In one embodiment, a user equipment (UE) is configured to when attempting to access a standalone non-public network, SNPN, via a public land mobile network, PLMN, determine a first country in which the UE is located; in response to determining that a configured Non-3GPP Inter-working function, N3IWF is located in the first country, use an identifier of the N3IWF configured in the UE to access the SNPN; and in response to determining that the first country is different from a second country where the configured N3IWF is located, perform a domain name system, DNS, query based at least in part on an identifier of the SNPN and an identifier of the first country.

Description

N3IWF SELECTION PROCEDURE WHEN ACCESSING SNPN VIA PLMN

TECHNICAL FIELD

Wireless communication and in particular, methods and apparatuses for a N3IWF selection procedure when accessing stand-alone non-public network (SNPN) services via public land mobile network (PLMN).

BACKGROUND

The Third Generation Partnership Project (3 GPP) has defined how to access stand-alone non-public network (SNPN) services via public land mobile network (PLMN) in for example, 3GPP Technical Specification (TS) 23.501 clause 5.30.2.8. The user equipment (UE) establishes protocol data unit (PDU) session in the PLMN and uses the Internet Protocol (IP) connectivity provided in the PLMN to connect to a Non-3GPP Inter-working Function (N3IWF) deployed in the SNPN. The N3IWF fully qualified domain name (FQDN) is configured on the UE.

However, the SNPN may not reside in the same country in which the UE is located. In this case, if there is regulatory requirement in the country in which the UE is located regarding lawful inspection in non-public networks (NPNs), the current mechanism to select the N3IWF deployed in the SNPN may not be able to fulfill the regulatory requirement.

SUMMARY

Some embodiments advantageously provide methods and apparatuses for N3IWF selection procedure when accessing a SNPN via PLMN.

In one embodiment, a user equipment (UE) is configured to use geographic location information for the UE and at least one of stand-alone non-public network (SNPN) subscription information and at least one Non-3GPP Inter-working function (N3IWF) information to perform a domain name system (DNS) query; and based at least in part on a DNS response to the DNS query, perform at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PLMN). In one embodiment, a user equipment (UE) is configured to use a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a standalone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE is located in; and based at least in part on a DNS response to the DNS query, perform at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PEMN).

According to an aspect, a method implemented by a user equipment, UE, is provided. The method including when attempting to access a standalone non-public network, SNPN, via a public land mobile network, PLMN, determining a first country in which the UE is located. The method including in response to determining that a configured Non-3GPP Inter-working function, N3IWF is located in the first country, using an identifier of the N3IWF configured in the UE to access the SNPN. The method including in response to determining that the first country is different from a second country where the configured N3IWF is located, performing a domain name system, DNS, query based at least in part on an identifier of the SNPN and an identifier of the first country.

In some embodiments of this aspect, a country information identifying a country where the configured N3IWF is located is further configured in the UE. In some embodiments of this aspect, the identifier of the N3IWF comprises a N3IWF fully qualified domain name, FQDN, configured at the UE for the SNPN. In some embodiments of this aspect, the method further includes in response to determining that the first country is different from the second country where the configured N3IWF is located, performing at least one operation related to a N3IWF selection to access the SNPN via the PLMN, the at least one operation that is performed by the UE being based at least in part on a DNS outcome to the DNS query.

In some embodiments of this aspect, the DNS outcome is a DNS response containing no record; and in response to determining that the DNS response contains no record, determining that the first country where the UE is located does not mandate the N3IWF selection in the first country and using the identifier of the N3IWF configured in the UE to access the SNPN. In some embodiments of this aspect, the DNS outcome is no DNS response; and in response to determining that no DNS response is received by the UE, stopping the N3IWF selection. In some embodiments of this aspect, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating a local N3IWF in the first country, selecting the local N3IWF to access the SNPN.

In some embodiments of this aspect, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record, determining that the first country where the UE is located mandates the N3IWF selection in the first country. In some embodiments of this aspect, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating no local N3IWF in the first country, stopping the N3IWF selection.

According to another aspect, a user equipment, UE, comprises processing circuitry is provided. The processing circuitry is configured to cause the UE to implement any one or more of the methods and embodiments above.

According to yet another aspect, an apparatus is provided. The apparatus comprises computer program instructions stored in a non-transitory storage medium to cause the apparatus to implement any one or more of the methods and embodiments above.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 illustrates another example system architecture according to some embodiments of the present disclosure;

FIG. 2 illustrates yet another example system architecture and example hardware arrangements for devices in the system, according to some embodiments of the present disclosure; FIG. 3 is a flowchart of an example process in a UE according to some embodiments of the present disclosure;

FIG. 4 is a flowchart of an example process according to some embodiments of the present disclosure;

FIG. 5 is a flowchart of yet another example process according to some embodiments of the present disclosure;

FIG. 6 is a flowchart of an example process according to some embodiments of the present disclosure;

FIG. 7 is a flowchart of an example process according to some embodiments of the present disclosure; and

FIG. 8 is a flowchart of an example process according to some embodiments of the present disclosure.

DETAIEED DESCRIPTION

Some embodiments of the present disclosure describe a domain name system (DNS)-based procedure that enables a UE, located in a particular country, to determine one or more of:

-whether the desired SNPN is deployed in the same country that the UE is in; and/or

-whether there is a regulatory exemption for the desired SNPN in case the SNPN is not deployed in the same country.

In some embodiments the UE may, based on the DNS response, determine whether the access of the SNPN service via the PLMN is allowed or not.

In some embodiments, the UE may be configured to perform one or more of the following:

- a DNS procedure to determine in which country the SNPN is deployed based on the configured N3IWF FQDN for the SNPN;

- use one DNS record to indicate both if the SNPN has local deployment (e.g., in the country that the UE is in) and if the SNPN is exempted from the regulatory requirement.

Instead of using a SNPN ID to perform a DNS query or using a home/visit concept, some embodiments of the proposed solution uses the configured N3IWF FQDN on the UE to perform such DNS query, in order to obtain the information about the SNPN local deployment and whether the SNPN is associated with an exemption from a regulatory requirement (e.g., of the country that the UE is currently located in).

Some embodiments of the present disclosure provide arrangements for a new method to determine the relation between a UE's geographic location and the UE's SNPN subscription location, e.g., if they (i.e., UE’s geographical location and UE’s SNPN subscription location) are in the same country or not.

Some embodiments may provide new definition of a N3IWF identifier configured on the UE in case of SNPN.

Some embodiments may provide for at least two new DNS-based procedures in order to e.g., enable the country (e.g., a network node such as a DNS node associated with and/or located in the country; or information about the country) in which the UE is located (e.g., currently geographically located) to inform the UE as to one or more of: if the country has a regulatory requirement for SNPN; if the desired/target SNPN has one or more locally deployed facilities in the same country (e.g., that the UE is geographically located); and/or if there is a regulatory exemption for the desired/target SNPN in case the SNPN has no local deployed facilities in the same country.

In some embodiments, the UE may then, based on the DNS answer, determine if the access of the SNPN service via the PLMN is allowed or not.

Some embodiments provide arrangements for a method to distinguish if the UE's (e.g., current) geographic location (e.g., country) is the same as the UE's SNPN subscription location (e.g., country).

In some embodiments, when the two locations mentioned above are different, the solution provides a mechanism for (e.g., information about) the particular country in which the UE is geographically located to determine whether the UE can access the desired/target SNPN via the PLMN.

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to N3IWF selection procedure when accessing SNPN via PLMN. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of wireless device capable of communicating with a network node or another UE over radio signals. The UE herein can by any type of communication device capable of communicating with another UE, an application server, a network node, a server, a Network Function, via a wired connection and/or a wireless connection. The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low- cost and/or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device etc.

In some embodiments, the term “node” is used herein and can be any kind of node in a network, i.e., network node, such as, a Radio Access Network (RAN) node (e.g., base station, gNB, eNB, Wi-fi, 3GPP Access Network node, Non-3GPP Access Network node, etc.), a core network node, such as, a mobility management node (e.g., Mobility Management Entity (MME) and/or Access and Mobility Function (AMF)), a session management node (e.g., session management function (SMF) node), a user plane function (UPF) node or any network node. In some embodiments, the network node may be, for example, a core network node in a Public Land Mobile Network (PLMN) core network (CN). In some embodiments, the network node may include a core network node, such as an AMF node, SMF node, UPF node and a Non-3GPP Inter-Working Function (N3IWF) node in a Standalone Non-Public Network (SNPN) core network (CN). In some embodiments, the network node may be a domain name system (DNS) node.

In yet other embodiments, the network node may include any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), relay node, integrated access and backhaul (IAB), donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to denote any radio node, such as a UE or a radio network node.

A node may include physical components, such as processors, allocated processing elements, or other computing hardware, computer memory, communication interfaces, and other supporting computing hardware. The node may use dedicated physical components, or the node may be allocated use of the physical components of another device, such as a computing device or resources of a datacenter, in which case the node is said to be virtualized. A node may be associated with multiple physical components that may be located either in one location, or may be distributed across multiple locations.

Signaling may generally comprise one or more symbols and/or signals and/or messages. A signal may comprise or represent one or more bits and/or media packets. An indication may represent signaling, and/or be implemented as a signal, or as a plurality of signals. One or more signals may be included in and/or represented by a message. Signaling, in particular control signaling, may comprise a plurality of signals and/or messages, which may be transmitted on different carriers and/or be associated to different signaling processes, e.g. representing and/or pertaining to one or more such processes and/or corresponding information. An indication may comprise signaling, and/or a plurality of signals and/or messages and/or may be comprised therein. Signaling associated to an interface may be transmitted via the interface.

An indication generally may explicitly and/or implicitly indicate the information it represents and/or indicates. Implicit indication may for example be based on position and/or resource used for transmission. Explicit indication may for example be based on a parametrization with one or more parameters, and/or one or more index or indices corresponding to a table, and/or one or more bit patterns representing the information.

In some embodiments, the terms “country information” and/or “ identifier or a country” described herein may include a country code.

Configuring a Radio Node

Configuring a radio node, such as a terminal or user equipment or the WD, may refer to the radio node being adapted or caused or set and/or instructed to operate according to the configuration. Configuring may be done by one or more other devices, e.g., a network node (for example, a radio node of a network like a base station or gNodeB and/or a core node of a core network like a core network node) or configuring may be considered to be done more generally by the network, in which case it may be configured by any one or more of the network nodes described herein. Configuring may comprise transmitting configuration data to the radio node to be configured. Such configuration data may represent the configuration to be configured and/or comprise one or more instruction pertaining to a configuration. A radio node may configure itself, e.g., based on configuration data received from one or more network nodes, such as one or more base stations and/or one or more core network nodes. A network node may use, and/or be adapted to use, its circuitry/ies for configuring. Configuration data may comprise and/or be represented by configuration information, and/or one or more corresponding indications and/or message/s.

Alternatively, or additionally, configuration of a terminal, such as a UE/WD can be done by setting configuration data during manufacturing, before UE is taken into use by another UE or a separate system used for configuration of the UE. In some embodiments, such configuration may be considered “preconfiguration” of the UE. For example, a specification or standard may define the information, such as any one or more of the SNPN information and/or N3IWF information described herein, which information is then preconfigured into the UE.

In some embodiments, configuration of the UE can be done by setting configuring data after the UE has been taken into use by another UE or by communicating configuration data from a radio network node, or from a core network node via a radio network node or from a configuration node via a communication network e.g., a 5G network.

Configuring in General

Generally, configuring may include determining configuration data representing the configuration and providing, e.g. transmitting, it to one or more other nodes (parallel and/or sequentially), which may transmit it further to the radio node (or another node, which may be repeated until it reaches the UE). Alternatively, or additionally, configuring a radio node, e.g., by a network node or other device, may include receiving configuration data and/or data pertaining to configuration data, e.g., from one or more other nodes like one or more network nodes, which may include one or more higher-level nodes of the network, such as one or more core network nodes and/or transmitting received configuration data to the radio node. Accordingly, determining a configuration and transmitting the configuration data to the radio node may be performed by different network nodes or entities, which may be able to communicate via a suitable interface, e.g., an X2 interface in the case of LTE or a corresponding interface for NR.

Configuring a terminal (e.g., UE) may comprise, e.g., configuring the UE with one or more of: a N3IWF FQDN for an SNPN, N3IWF information which may include both a N3IWF identifier and associated country information and/or SNPN subscription information which may include both an SNPN identifier and associated country information.

Any two or more embodiments described in this disclosure may be combined with each other. Note also that some embodiments of the present disclosure may be supported by standard documents disclosed in Third Generation Partnership Project (3GPP) technical specifications. That is, some embodiments of the description can be supported by the above documents. In addition, all the terms disclosed in the present document may be described by the above standard documents.

Note that although terminology from one particular wireless system, such as, for example, 3^rd Generation Partnership Project (3GPP), Long Term Evolution (LTE), 5^th Generation (5G) and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a UE, or a network node described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Referring now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 1 a schematic diagram of the communication system 10, according to another embodiment, constructed in accordance with the principles of the present disclosure. The communication system 10 in FIG. 1 is a non-limiting example and other embodiments of the present disclosure may be implemented by one or more other systems and/or networks. Referring to FIG. 1, system 10 includes a user equipment (UE) 12, a PLMN 14, a SNPN 16, a DNS node 18 and a N3IWF 20. The system 10 may include and one or more radio access networks (RANs) 22. The RAN(s) 22 may include, e.g., 5G RAN also known as NR RAN, which may provide radio access to the UE 12.

In some embodiments, the PLMN 14 may include a core network (e.g., include AMF, UPF, SMF, etc.) associated with the RAN 22, and the SNPN 16 may include a core network corresponding to the NPN (e.g., include AMF, UPF, SMF, etc.).

The UE 12 may include a requestor 24 configured to cause the UE 12 to use a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a stand-alone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE 12 is located in; and based at least in part on a DNS response to the DNS query, perform at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PLMN).

FIG. 1 shows that the UE 12 is located in country A and the SNPN 16 that the UE 12 is attempting to access via the PLMN 14 is in country B. However it is noted that, while in some scenarios country A and B are different, in other scenarios, country A and B are the same. In some embodiments, based on the DNS response indicating which scenario, the UE 12 may be configured to perform certain operations, such as continuing to access the SNPN and/or selecting the N3IWF 20 or aborting the attempt to access the SNPN and/or stopping the N3IWF 20 selection procedure.

It should be understood that the system 10 may include numerous nodes of those shown in FIG. 1, as well as additional nodes not shown in FIG. 1. In addition, the system 10 may include many more connections/interfaces than those shown in FIG. 1.

Example implementations, in accordance with some embodiments, of UE 12 and a network node 26, which may include any of the network nodes discussed herein and will now be described with reference to FIG. 2.

The UE 12 includes a communication interface 28, processing circuitry 30, and memory 32. The communication interface 28 may be configured to communicate with any of the nodes in the system 10 according to some embodiments of the present disclosure. In some embodiments, the communication interface 28 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 28 may also include a wired interface.

The processing circuitry 30 may include one or more processors 34 and memory, such as, the memory 32. In particular, in addition to a traditional processor and memory, the processing circuitry 30 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 34 may be configured to access (e.g., write to and/or read from) the memory 32, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the UE 12 may further include software stored internally in, for example, memory 32, or stored in external memory (e.g., database) accessible by the UE 12 via an external connection. The software may be executable by the processing circuitry 30. The processing circuitry 30 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by the UE 12. The memory 32 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 32 that, when executed by the processor 34 and/or requestor 24 causes the processing circuitry 30 and/or configures the UE 12 to perform the processes described herein with respect to the UE 12 (e.g., processes described with reference to FIGS. 3-8 and/or any of the other figures).

The network node 26 (e.g., DNS node, RAN network node, N3IWF network 20, network node in PLMN 14, network node in SNPN 16, etc.) includes a communication interface 36, processing circuitry 38, and memory 40. The communication interface 36 may be configured to communicate with any of the nodes in the system 10 according to some embodiments of the present disclosure. In some embodiments, the communication interface 36 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 36 may also include a wired interface.

The processing circuitry 38 may include one or more processors 42 and memory, such as, the memory 40. In particular, in addition to a traditional processor and memory, the processing circuitry 38 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 42 may be configured to access (e.g., write to and/or read from) the memory 40, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the network node 26 may further include software stored internally in, for example, memory 40, or stored in external memory (e.g., database) accessible by the network node 26 via an external connection. The software may be executable by the processing circuitry 38. The processing circuitry 38 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed by any of the network nodes described. The memory 40 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 40 that, when executed by the processor 42, causes the processing circuitry 38 and/or configures the network node 26 to perform the processes described herein with respect to the network node 26, such as a DNS node receiving and responding to a DNS query according to some embodiments of the present disclosure.

In FIG. 2, the connection between the UE 12 and network node 26 is shown without explicit reference to any intermediary devices or connections. However, it should be understood that intermediary devices and/or connections may exist between these devices, although not explicitly shown.

Although FIG. 2 shows requestor 24 as being within a processor, it is contemplated that this element may be implemented such that a portion of the element is stored in a corresponding memory within the processing circuitry. In other words, the element may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 3 is a flowchart of an example process in a UE 12 according to some embodiments of the present disclosure. One or more Blocks and/or functions and/or methods performed by the UE 12 may be performed by one or more elements of UE 12 such as by requestor 24 in processing circuitry 30, memory 32, processor 34, communication interface 28, etc. according to the example process/method. The example process includes using (Block S100), such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, geographic location information for the UE and at least one of stand-alone non-public network (SNPN) subscription information and at least one Non-3GPP Inter-working function (N3IWF) information to perform a domain name system (DNS) query. The method includes based at least in part on a DNS response to the DNS query, performing (Block S102), such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PLMN).

In some embodiments, the “based at least in part on a DNS response” may also encompass lack of a DNS response, i.e., a situation in which a DNS query is sent but there is no DNS response (e.g., process in step S128 where there is no response and then the UE 12 proceeds to step S140).

In some embodiments, the geographic location information for the UE 12 includes at least one of a country code, global positioning system (GPS) location information, and any other information that indicates a geographic location and/or a country that the UE 12 is currently physically in (e.g., while attempting to access the SNPN according to some embodiments of the present disclosure, etc.).

In some embodiments, the SNPN subscription information comprises country information indicating a country that the SNPN is deployed and/or the at least one N3IWF identifier comprises country information indicating at least one country that the N3IWF is deployed; and/or the UE 12 is configured with the SNPN subscription information and/or the at least one N3IWF identifier. In some embodiments, the using comprises using, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a stand-alone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE 12 is located in.

In some embodiments, the at least one operation includes at least one of: selecting the N3IWF for the SNPN and accessing the SNPN via the PLMN; selecting a configured at least one N3IWF identifier to access the SNPN via the PLMN; selecting a locally deployed N3IWF to access the SNPN via the PLMN; and stopping the N3IWF selection procedure and aborting the attempt to access the SNPN via a public land mobile network (PLMN). In some embodiments, the N3IWF FQDN is configured at the UE 12. In some embodiments, the method further includes one or more of: determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, from a record in the DNS response whether a country that the SNPN is located in is a same as the country that the UE is located in; and determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, whether the SNPN is exempted from lawful interception (LI) in the country that the UE 12 is located in.

In some embodiments, the using includes using a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a stand-alone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE is located in.

In some embodiments, the at least one operation includes one of: selecting, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the N3IWF 20 for the SNPN 16 and accessing, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the SNPN 16 via the PLMN 14; and stopping, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the N3IWF 20 selection procedure and aborting, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the attempt to access the SNPN 16 via a public land mobile network (PLMN) 14.

In some embodiments, the N3IWF FQDN is configured at the UE 12. In some embodiments, the method includes one or more of: determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, from a record in the DNS response whether a country that the SNPN 16 is located in is a same as the country that the UE 12 is located in; and determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, whether the SNPN 16 is exempted from lawful interception (LI) in the country that the UE 12 is located in.

FIG. 4 is a flowchart of an example process in a UE 12 according to some embodiments of the present disclosure. One or more Blocks and/or functions and/or methods performed by the UE 12 may be performed by one or more elements of UE 12 such as by requestor 24 in processing circuitry 30, memory 32, processor 34, communication interface 28, etc. according to the example process/method. The method includes when attempting to access a standalone non-public network, SNPN, via a public land mobile network, PLMN, determining (Block S104), such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, a first country in which the UE is located. The method includes in response to determining that a configured Non-3GPP Inter-working function, N3IWF is located in the first country, using (Block S106), such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, an identifier of the N3IWF configured in the UE to access the SNPN. The method includes in response to determining that the first country is different from a second country where the configured N3IWF is located, performing (Block S108), such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, a domain name system, DNS, query based at least in part on an identifier of the SNPN and an identifier of the first country.

In some embodiments, country information identifying a country where the configured N3IWF is located is further configured in the UE. In some embodiments, the identifier of the N3IWF comprises a N3IWF fully qualified domain name, FQDN, configured at the UE for the SNPN. In some embodiments, the method further includes in response to determining that the first country is different from the second country where the configured N3IWF is located, performing, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, at least one operation related to a N3IWF selection to access the SNPN via the PLMN, the at least one operation that is performed by the UE being based at least in part on a DNS outcome to the DNS query.

In some embodiments, the DNS outcome is a DNS response containing no record; and in response to determining that the DNS response contains no record, determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, that the first country where the UE is located does not mandate the N3IWF selection in the first country and using the identifier of the N3IWF configured in the UE to access the SNPN. In some embodiments, the DNS outcome is no DNS response; and in response to determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, that no DNS response is received by the UE, stopping the N3IWF selection. In some embodiments, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating a local N3IWF in the first country, selecting, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the local N3IWF to access the SNPN. In some embodiments, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record, determining, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, that the first country where the UE is located mandates the N3IWF selection in the first country.

In some embodiments, the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating no local N3IWF in the first country, stopping, such as via requestor 24, processing circuitry 30, memory 32, processor 34 and/or communication interface 28, the N3IWF selection.

Having generally described arrangements for N3IWF selection procedure when accessing SNPN via PLMN, a more detailed description of some of the embodiments are provided as follows with reference to FIGS. 5-8, and which may be implemented by may be implemented by UE 12 and/or any one or more of the network nodes described herein (e.g., the network node 26).

As shown in FIG. 5, an example process for a N3IWF 20 selection procedure when accessing SNPN 16 via PLMN 14 includes one or more of the following:

Step SI 10: The UE 12 attempts to access an SNPN 16 via a PLMN 14. The SNPN 16 and the UE 12 may be located in a same country or in different countries. The UE 12 may perform different operations/actions based at least in part on whether the SNPN 16 and the UE 12 are in the same or different countries.

SI 12: The UE 12 performs a DNS query (e.g., sending DNS request to DNS node 18), based on the configured N3IWF’s 20 FQDN for the SNPN 16 and the country (e.g., country code) in which the UE 12 is located in. For example, the DNS query may include the FQDN for the N3IWF 20 associated with the SNPN 16 that the UE 12 is attempting to access, which N3IWF’s 20 FQDN may be configured at the UE 12. S 114: The UE 12 may determine whether there is a DNS response. When there is a DNS response (i.e., yes), the DNS response (e.g., sent by DNS node 18 and received by the UE 12) may include a record to indicate to the UE 12 if the desired SNPN 16 is deployed in the same country in which the UE 12 is located.

If, in step SI 16, the desired SNPN 16 is deployed in the same country in which the UE 12 is located, then in step S 118, the N3IWF FQDN used in step S 112 is selected to proceed with the access SNPN 16 via PLMN 14 procedure.

On the other hand, if the desired SNPN 16 is not deployed in the same country in which the UE 12 is located, then in step S120, the UE 12 determines whether the desired SNPN 16 is exempted from lawful interception (LI) in the country in which the UE 12 is located.

If the record in the DNS response indicates that the desired SNPN 16 is not deployed in the same country in which the UE 12 is located, but the SNPN 16 is exempted from a regulatory requirement (e.g., the lawful interception regulation), then the N3IWF FQDN used in step SI 12 is selected to proceed with the access SNPN 16 via PLMN 14 procedure as in step SI 18.

On the other hand, if the record in the DNS response indicates that the desired SNPN 16 is not deployed in the same country in which the UE 12 is located, and the SNPN 16 is not exempted from the lawful interception regulation, then the UE 12 proceeds to step S122, where the UE 12 stops the N3IWF 20 selection procedure and aborts the attempt to access SNPN 16 services via PLMN 14.

If there is no DNS response received by the UE 12, then the UE 12 proceeds to step S122, where the UE 12 stops the N3IWF 20 selection procedure and aborts the attempt to access SNPN 16 services via PLMN 14.

Referring now primarily to FIGS. 6-8, some embodiments may include one or more steps in the following sequence of events.

Some embodiments may include at least two new configurations:

1) The SNPN subscription configured at the UE 12 may include country related information regarding where (e.g., countries) the SNPN 16 is deployed in.

2) The SNPN UE 12 may be configured with N3IWF Identifiers (IDs), which includes the FQDN and/or IP address of the N3IWF 20 and also may include the corresponding country information regarding where the N3IWF 20 is deployed. There may be at least one N3IWF 20 identifier's country information in the same as the country information configured at the SNPN subscription level. There may be other N3IWF 20 identifiers configured with different country information than the one configured at the SNPN subscription level.

Some embodiments may provide arrangement for a N3IWF 20 selection procedure for accessing the SNPN 16, which may include one or more of at least the following two parts (which may be performed by UE 12 and/or network node 26):

1) Use UE's 12 configuration data to determine the relation between the UE's 12 geographic location and the UE's 12 subscription/N3IWF Identifier location.

2) Use DNS procedure to determine if the country in which the UE 12 is located allows the UE 12 to access the SNPN 16 via the N3IWF 20.

Referring to FIG. 6, an example process is shown, which may be considered part 1 of a multi-part process. The process may include one or more of the following steps:

1. In step S124 and S126, the UE 12 may determine to attempt to access a SNPN 16 via a PLMN 14 and, as a result, the UE 12 may determine its geographic location.

2. In step S128, the UE 12 compares its geographic location with its subscription location.

3. If they are in the same country, the process proceeds to step S130, where the UE 12 uses the configured N3IWF 20 identifier whose country information is the same as the SNPN subscription to access the SNPN 16.

4. If they are different countries, the process proceeds to step S132, where the UE 12 checks the N3IWF 20 identifier configuration information in order to determine if there is any N3IWF 20 identifier's country information that is the same as the UE's 12 current geographic location.

5. If there is any found, the process proceeds to step S130, where the UE 12 uses this configured N3IWF 20 identifier to access the SNPN 16.

6. If neither the subscription location, nor any N3IWF 20 identifier's location is the same as the UE's 12 geographic location, the UE 12 may perform procedures described in part 2 (see FIG. 7) or part 2 (alternative, see FIG. 8). Referring to FIG. 7, part 2, in some embodiments, the process may include one or more of the following steps:

1. In step S134, the UE 12 performs a DNS query, based on a unique identity of the SNPN 16 and the country code in which the UE 12 is geographically located in.

2. In step S136, the UE 12 determines if there is a DNS response.

3. In step S138, if there is a DNS response, the UE 12 determines whether the DNS response includes a record.

4. If the DNS response contains no record, the process may proceed to step S140, where the UE 12 determines the country does not mandate the N3IWF 20 selection in this country, then the UE 12 selects a configured N3IWF 20 Identifier to access the SNPN 16 via the PLMN 14.

5. In step S142, if the DNS response contains a record to indicate the desired SNPN 16 is exempted from the regulatory requirement in the country in which the UE 12 is located, then the UE 12 proceeds to step S140, where the UE 12 selects a configured N3IWF 20 identifier of the SNPN 16 to continue with the procedure of accessing SNPN 16 via PLMN 14.

6. In step S142, if the DNS response contains a record to indicate the desired SNPN 16 is not exempted from the regulatory requirement in the country in which the UE 12 is located but, in step S144, a local deployed N3IWF 20 exists, then the UE 12 proceeds to step S146, where the UE 12 selects the local deployed N3IWF 20 to continue with the procedure of accessing the SNPN 16 via the PLMN 14.

7. If the DNS response contains a record to indicate the desired SNPN 16 is not exempted from the regulatory requirement in the country in which the UE 12 is located and, in step S144, the UE 12 determines there is no local deployed N3IWF 20, then the UE 12 may proceed to step S148, where the UE 12 may stop the N3IWF 20 selection and aborts the attempt to access the SNPN 16 via the PLMN 14.

8. If there is no DNS response received by UE 12 in step S136, the UE 12 also proceeds to step S148 where the UE 12 stops the N3IWF 20 selection and aborts the attempt to access the SNPN 16 services via the PLMN 14. Referring to FIG. 8, part 2 (alternative), in some embodiments, the process may include one or more of the following steps:

1. In step S150, the UE 12 may perform a generic DNS query without specifying the desired SNPN 16, in order to determine if the country in which the UE 12 is located mandates the selection of N3IWF 20 in this country or if the desired SNPN 16 is exempted from the regulatory requirement in this country.

2. In step S152, the UE 12 determines whether there is a DNS response.

3. In step S154, the UE 12 determines whether there are records in the DNS response. If the DNS response contains no record, then the UE 12 proceeds to step S156, where the UE 12 determines that the country in which the UE 12 is located does not mandate the selection of N3IWF 20 in this country, and the configured N3IWF 20 identifier of the SNPN 16 is selected by the UE 12 to continue with the procedure of accessing the SNPN 16 via the PLMN 14.

4. If the DNS response contains one or more records, then the UE 12 determines that the country in which the UE 12 is geographically located mandates the selection of N3IWF 20 in this country and possibly with exemptions. Each record in the DNS response may include a unique identity of an SNPN 16. In step S158, the UE 12 may compare the subscription configuration of the desired SNPN 16 with the identity of the SNPN 16 in the DNS records:

1) If there is a match found, the process may proceed to e.g., step S160, where the UE 12 determines whether the DNS record indicates a locally deployed N3IWF 20. If the DNS record contains an indication of local deployed N3IWF 20 for the desired SNPN 16, the UE 12 may select the locally deployed N3IWF 20 to access the desired SNPN 16 in step S162.

2) If there is a match found in e.g., step S 158, but without the indication of local deployed N3IWF 20 for the desired SNPN 16 in e.g., step S160, then the UE 12 determines the desired SNPN 16 is exempted from the regulatory requirement and proceeds to step S156 where the UE 12 selects the configured N3IWF 20 identifier to access the desired SNPN 16.

3) If there is no match found (e.g., no DNS record for the SNPN 16 in e.g., step S154), the UE 12 may proceed to step S164, where the UE 12 may stop the N3IWF 20 selection and abort the attempt to access the SNPN 16 via the

PLMN 14.

4) If UE 12 does not receive a DNS response in step S152, the UE 12 may also proceed to step S164, where the UE 12 may stop the N3IWF 20 selection and abort the attempt to access SNPN 16 via PLMN 14.

Some embodiments may include one or more of the following:

Embodiment Al. A method implemented in a user equipment (UE) configured to communicate with a network node, the method comprising: using geographic location information for the UE and at least one of standalone non-public network (SNPN) subscription information and at least one Non- 3GPP Inter-working function (N3IWF) information to perform a domain name system (DNS) query; and based at least in part on a DNS response to the DNS query, performing at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PLMN).

Embodiment A2. The method of Embodiment Al, wherein one or more of: the SNPN subscription information comprises country information indicating a country that the SNPN is deployed and/or the at least one N3IWF identifier comprises country information indicating at least one country that the N3IWF is deployed in; and/or the UE is configured with the SNPN subscription information and/or the at least one N3IWF identifier.

Embodiment A3. The method of any one of Embodiments Al and A2, wherein: the using comprises using a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a stand-alone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE is located in.

Embodiment A4. The method of any one of Embodiments Al -A3, wherein the at least one operation includes at least one of: selecting the N3IWF for the SNPN and accessing the SNPN via the PLMN; selecting a configured at least one N3IWF identifier to access the SNPN via the PLMN; selecting a locally deployed N3IWF to access the SNPN via the PLMN; and stopping the N3IWF selection procedure and aborting the attempt to access the SNPN via a public land mobile network (PLMN).

Embodiment A5. The method of Embodiment A2, wherein the N3IWF FQDN is configured at the UE.

Embodiment A6. The method of any one of Embodiments A1-A5, further comprising one or more of: determining from a record in the DNS response whether a country that the SNPN is located in is a same as the country that the UE is located in; and determining whether the SNPN is exempted from lawful interception (LI) in the country that the UE is located in.

Embodiment BL A user equipment (UE) configured to communicate with a network node, the UE comprising processing circuitry and/or a communication interface, the processing circuitry and/or the communication interface configured to cause the UE to: use geographic location information for the UE and at least one of stand-alone non-public network (SNPN) subscription information and at least one Non-3GPP Inter- working function (N3IWF) information to perform a domain name system (DNS) query; and based at least in part on a DNS response to the DNS query, perform at least one operation related to at least one of a N3IWF selection procedure and an attempt to access the SNPN via a public land mobile network (PLMN).

Embodiment B2. The UE of Embodiment B l, wherein one or more of: the SNPN subscription information comprises country information indicating a country that the SNPN is deployed and/or the at least one N3IWF identifier comprises country information indicating at least one country that the N3IWF is deployed; and/or the UE is configured with the SNPN subscription information and/or the at least one N3IWF identifier. Embodiment B3. The UE of any one of Embodiments B 1 and B2, wherein the UE and/or the processing circuitry and/or the communication interface is configured to cause the UE to use by being configured to cause the UE: use a Non-3GPP Inter-working function (N3IWF) fully qualified domain name (FQDN) for a stand-alone non-public network (SNPN) or an identifier of the SNPN and a country code to perform a domain name system (DNS) query, the country code corresponding to a country that the UE is located in.

Embodiment B4. The UE of any one of Embodiments B1-B3, wherein the at least one operation includes at least one of: selecting the N3IWF for the SNPN and accessing the SNPN via the PLMN; selecting a configured at least one N3IWF identifier to access the SNPN via the PLMN; selecting a locally deployed N3IWF to access the SNPN via the PLMN; and stopping the N3IWF selection procedure and aborting the attempt to access the SNPN via a public land mobile network (PLMN).

Embodiment B5. The UE of Embodiment B2, wherein the N3IWF FQDN is configured at the UE.

Embodiment B6. The UE of any one of Embodiments B1-B5, wherein the UE and/or the processing circuitry and/or the communication interface is further configured to cause the UE to one or more of: determine from a record in the DNS response whether a country that the SNPN is located in is a same as the country that the UE is located in; and determine whether the SNPN is exempted from lawful interception (LI) in the country that the UE is located in.

Some embodiments may use one or more of the following abbreviations:

Abbreviation Description

5GC 5G Core

AMF Access and Mobility Management Function

CP Control Plane

DNS Domain Name System

FQDN Fully Qualified Domain Name PLMN Public Land Mobile Network

SNPN Standalone Non-Public Network

SUPI Subscription Permanent Identifier

UE User Equipment

UP User Plane

N3IWF Non-3GPP InterWorking Function

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, and/or computer program product. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, may be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and may support claims to any such combination or subcombination.

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

29 What is claimed is:

1. A method implemented by a user equipment, UE (12), the method comprising: when attempting to access a standalone non-public network, SNPN, via a public land mobile network, PLMN, determining (S104) a first country in which the UE (12) is located; in response to determining that a configured Non-3GPP Inter-working function, N3IWF is located in the first country, using (S106) an identifier of the N3IWF configured in the UE (12) to access the SNPN; and in response to determining that the first country is different from a second country where the configured N3IWF is located, performing (S108) a domain name system, DNS, query based at least in part on an identifier of the SNPN and an identifier of the first country.

2. The method of Claim 1, wherein a country information identifying a country where the configured N3IWF is located is further configured in the UE (12).

3. The method of Claim 1, wherein the identifier of the N3IWF comprises a N3IWF fully qualified domain name, FQDN, configured at the UE (12) for the SNPN.

4. The method of any one of Claims 1-3, further comprising: in response to determining that the first country is different from the second country where the configured N3IWF is located, performing at least one operation related to a N3IWF selection to access the SNPN via the PLMN, the at least one operation that is performed by the UE (12) being based at least in part on a DNS outcome to the DNS query.

5. The method of Claim 4, wherein the DNS outcome is a DNS response containing no record; and in response to determining that the DNS response contains no record, determining that the first country where the UE (12) is located does not mandate the 30

N3IWF selection in the first country and using the identifier of the N3IWF configured in the UE (12) to access the SNPN.

6. The method of Claim 4, wherein the DNS outcome is no DNS response; and in response to determining that no DNS response is received by the UE (12), stopping the N3IWF selection.

7. The method of Claim 4, wherein the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating a local N3IWF in the first country, selecting the local N3IWF to access the SNPN.

8. The method of Claim 4, wherein the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record, determining that the first country where the UE (12) is located mandates the N3IWF selection in the first country.

9. The method of Claim 4, wherein the DNS outcome is a DNS response containing at least one record; and in response to determining that the DNS response contains the at least one record indicating no local N3IWF in the first country, stopping the N3IWF selection.

10. A user equipment, UE (12), comprising processing circuitry 30), the processing circuitry (30) configured to cause the UE (12) to implement any one or more of the methods of Claims 1-9.

11. An apparatus comprising computer program instructions stored in a non-transitory storage medium (32) to cause the apparatus to implement any one or more of the methods of Claims 1-9.