PROVIDING COMMUNICATION SERVICES TO A USER EQUIPMENT USING A USER EQUIPMENT SUBSCRIPTION OF A FIRST NETWORK AND SUBSCRIPTION IDENTIFIER INFORMATION OF A SECOND NETWORK

In order to provide the communication services to a user equipment comprising or applying secure edge protection proxy authentication: in a first step, a network function of a visited telecommunications network receives a request related to the user equipment, triggering a message towards a third secure edge protection proxy entity or functionality; and in a second step, the third secure edge protection proxy entity or functionality accesses a first secure edge protection proxy entity or functionality in an authenticated manner such that a message related to a second network identifier information is able to be sent, by the visited telecommunications network, to a network function in a first telecommunications network and accepted by the first telecommunications network.

CROSS-REFERENCE TO PRIOR APPLICATIONS

Priority is claimed to European Patent Application No. EP 22161128.8, filed on Mar. 9, 2022, the entire disclosure of which is hereby incorporated by reference herein.

FIELD

The present invention relates a method for providing communication services to a user equipment involving first and second telecommunications networks (composed of network functions and being able to be accessed by or via a first and second secure edge protection proxy entity or functionality), wherein, in case that the user equipment uses or is connected to an access network of a visited telecommunications network, the visited telecommunications network composed of network functions likewise comprising a third secure edge protection proxy entity or functionality, the user equipment uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network while the respective subscription identifier information comprises the second network identifier information.

Furthermore, the present invention relates to a system for providing communication services to a user equipment involving first and second telecommunications networks (composed of network functions and being able to be accessed by or via a first and second secure edge protection proxy entity or functionality), wherein, in case that the user equipment uses or is connected to an access network of a visited telecommunications network, the visited telecommunications network composed of network functions likewise comprising a third secure edge protection proxy entity or functionality, the user equipment uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network while the respective subscription identifier information comprises the second network identifier information.

Furthermore, the present invention relates to a program and to a computer-readable medium for providing communication services to a user equipment according to a method according to the invention.

BACKGROUND

In conventional telecommunications networks, it is possible for network operators to provide users with connectivity, e.g. machine type communication or machine-to-machine communication (or M2M connectivity), certain customers, via relying on a solution whereby network subscriptions (e.g. subscriber identity module cards, or SIM cards) of a certain telecommunications network (e.g. a public land mobile network in, say, a country or region B) are used while the corresponding core network infrastructure (serving these customers) is placed in (or related to) another telecommunications network (e.g. a public land mobile network in a country or region A), whereas each network is identified by a network identity. It is thereby possible to offer best-coverage in the area of the other telecommunications network (i.e. in country or region A), especially in case that limitations apply regarding national roaming, or in case that no national roaming is allowed, as it is the case, e.g., in some European countries by using a network in a different country and thus a setup providing permanent or quasi-permanent roaming to users. An example of such an implementation includes, e.g., cars using a SIM containing a SIM from an American operator while for cars sold in Europe the core network (serving these customers) is placed in Europe (e.g. for latency, organizational or regulatory reasons).

However, with the mandatory use of security, authentication and/or concealment mechanisms or functionalities, such as the use of secure edge protection proxy entities or functionalities and/or the use of subscription concealed identifiers, it is more and more difficult, if not impossible, to realize such an implementation of users or subscribers of a telecommunications network being served by a specific core network (e.g. a public land mobile network in country or region A) while still using a subscriber identity comprising a network identity associated with another telecommunications network (e.g. a public land mobile network in country or region B), especially when in a roaming situation, i.e. connected to a visited network (e.g. in country or region C).

SUMMARY

In an exemplary embodiment, the present invention provides a method for providing communication services to a user equipment involving a first telecommunications network composed of network functions and a second telecommunications network composed of network functions. The first telecommunications network uses or is assigned to a first network identifier information and is able to be accessed by or via a first secure edge protection proxy entity or functionality, and the second telecommunications network uses or is assigned to a second network identifier information and is able to be accessed by or via a second secure edge protection proxy entity or functionality. In case that the user equipment uses or is connected to an access network of a visited telecommunications network, the visited telecommunications network composed of network functions likewise comprising a third secure edge protection proxy entity or functionality, the user equipment uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network while the respective subscription identifier information comprises the second network identifier information. Either subscriber permanent identifier information is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network, or subscription concealed identifier information containing information derived from the subscriber permanent identifier and/or a routing indicator information is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network. Messages between, on the one hand, the visited telecommunications network and, on the other hand, the first telecommunications network or the second telecommunications network or both of the first and second telecommunications networks are forwarded via a bidirectional channel between, on the one hand, the third secure edge protection proxy entity or functionality and, on the other hand, the first secure edge protection proxy entity or functionality or the second secure edge protection proxy entity or functionality or both of the first and second secure edge protection proxy entities or functionalities, and vice-versa. Deconcealment of subscription concealed identifier information into a subscriber permanent identifier information is performed by the first telecommunications network. In order to provide the communication services to the user equipment comprising or applying secure edge protection proxy authentication, the method comprises the following steps: in a first step, a network function of the visited telecommunications network receives a request related to the user equipment, triggering a message towards the third secure edge protection proxy entity or functionality; and in a second step, the third secure edge protection proxy entity or functionality accesses the first secure edge protection proxy entity or functionality in an authenticated manner such that a message related to the second network identifier information is able to be sent, by the visited telecommunications network, to a network function in the first telecommunications network and accepted by the first telecommunications network.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention provide technically simple, effective and cost effective solutions for providing communication services to a user equipment involving first and second telecommunications networks using or being assigned to, respectively, a first and second network identifier information, wherein, in case that the user equipment uses or is connected to an access network of a visited telecommunications network, the user equipment uses a user equipment subscription, especially including subscriber permanent identifier information, that is related or assigned to the first network while the respective subscription identifier information comprises the second network identifier information and despite of the telecommunications networks communicating via secure edge protection proxy entities or functionalities an authenticated communication is possible. Exemplary embodiments of the present invention further provide a corresponding system, and a corresponding program and computer-readable medium.

Exemplary embodiments of the present invention provide a method for providing communication services to a user equipment involving a first telecommunications network composed of network functions and a second telecommunications network composed of network functions, wherein the first telecommunications network uses or is assigned to a first network identifier information and is able to be accessed by or via a first secure edge protection proxy entity or functionality, and wherein the second telecommunications network uses or is assigned to a second network identifier information and is able to be accessed by or via a second secure edge protection proxy entity or functionality,

wherein, in case that the user equipment uses or is connected to an access network of a visited telecommunications network, the visited telecommunications network composed of network functions likewise comprising a third secure edge protection proxy entity or functionality, the user equipment uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network while the respective subscription identifier information comprises the second network identifier information,

wherein either subscriber permanent identifier information is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network, or subscription concealed identifier information containing information derived from the subscriber permanent identifier and/or a routing indicator information is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network,

wherein messages between, on the one hand, the visited telecommunications network and, on the other hand, the first or the second telecommunications network or both of the first and the second telecommunications network are forwarded via a bidirectional channel between, on the one hand, the third secure edge protection proxy entity or functionality and, on the other hand, the first or second secure edge protection proxy entity or functionality or both of the first and second secure edge protection proxy entity or functionality, and vice-versa,

wherein deconcealment of subscription concealed identifier information into a subscriber permanent identifier information is performed by the first telecommunications network, wherein, in order to provide the communication services to the user equipment comprising or applying secure edge protection proxy authentication, the method comprises the following steps:in a first step, a network function of the visited telecommunications network receives a request related to the user equipment, triggering a message towards the third secure edge protection proxy entity or functionality,in a second step, the third secure edge protection proxy entity or functionality accesses the first secure edge protection proxy entity or functionality in an authenticated manner, especially such that a message related to the second network identifier information is able to be sent, by the visited telecommunications network, to a network function in the first telecommunications network and accepted by the first telecommunications network.

It is thereby advantageously possible according to the present invention that a user equipment uses or is connected to an access network of a visited telecommunications network and the user equipment uses a user equipment subscription that is related or assigned to the first network while the respective subscription identifier information comprises the second network identifier information, and that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities and/or the use of concealed identifiers, an authenticated communication is possible.

In other words, it is possible to realize an implementation such that botha user equipment, while using a network identifier information of one telecommunications network, is able to be served by another telecommunications network, especially in case of M2M communication,and additionally such an implementation is in accordance with 5G mechanisms, especially maintaining 5G security, i.e. an exchange of (control plane) messages in an authenticated manner between the telecommunications networks (despite using a ‘wrong’ network identifier information).

According to the present invention, it is advantageously possible and preferred that the first secure edge protection proxy entity or functionality is reachable by the third secure edge protection proxy entity or functionality via a first domain and/or host name related to the first network identifier information;

wherein the second secure edge protection proxy entity or functionality is reachable, by the third secure edge protection proxy entity or functionality, via a second domain and/or host name related to the second network identifier information;

wherein a specific network function in the first telecommunications network is reachable, by a consumer network function in the visited telecommunications network, via a further first domain and/or host name related to the specific network function and the first network identifier information;

wherein a further specific network function in the second telecommunications network is reachable, by a consumer network function in the visited telecommunications network, via a further second domain and/or host name related to the further specific network function and the second network identifier information,

wherein especially in order to provide the communication services to the user equipment using service-based interfaces and/or a network repository function, a network function service is requested and/or provided, by the specific network function of the first telecommunications network, to the consumer network function of the visited telecommunications network.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

According to the present invention, it is furthermore advantageously possible and preferred that, in or during the first step, the request related to the user equipment is especially triggered by the user equipment accessing the visited telecommunications network to connect or to be connected thereto.

According to the present invention, it is furthermore advantageously possible and preferred that—especially according to a first solution or embodiment—, in order for the third secure edge protection proxy entity or functionality accessing the first secure edge protection proxy entity or functionality in an authenticated manner, prior to the first secure edge protection proxy entity or functionality being accessed by the third secure edge protection proxy entity or functionality, the third secure edge protection proxy entity or functionality accesses the second secure edge protection proxy entity or functionality related to the user equipment, especially via transmitting a network function discovery query message to the second secure edge protection proxy entity or functionality,

wherein the second secure edge protection proxy entity or functionality transmits an indication that the first secure edge protection proxy entity or functionality is to be accessed regarding the requested network function, wherein especially the second telecommunications network comprises a network repository function related to the second network identifier information, and the method comprises the following steps:in a step A, the visited telecommunications network receives, from the user equipment, a message containing subscription concealed identifier information and/or routing indicator information,in a step B, the visited telecommunications network queries the network repository function for a network function capable of deconcealing the received concealed identifier information and/or routing indicator information,in a step C, the network repository function returns information related to the specific network function and including the further first domain and/or host name related to the first network identifier information,in a step D, the visited telecommunications network is configured to forward, based on the first network identifier information contained within the further first domain and/or host name, a message containing the subscription concealed identifier information and/or the routing indicator information to the specific network function, especially while this message contains a subscription concealed identifier information and/or a routing indicator information related to the second network identifier information and especially thereby realizing the second step, e.g. by forwarding a message requesting the deconcealment of the subscription concealed identifier received from the user equipment in the first step.

Furthermore, it is advantageously possible and preferred according to the present invention, and likewise regarding or in view of the first solution or embodiment, that the third secure edge protection proxy entity or functionality accessing the first secure edge protection proxy entity or functionality in an authenticated manner, especially step D, requires the third secure edge protection proxy entity or functionality to have received or to be able to access secure edge protection proxy information, especially comprising an allow redirection-to-indication containing network identifier information and/or domain and/or host name information, and/or an allow-redirection-from-indication containing network identifier information and/or domain and/or host name information regarding the first and/or second secure edge protection proxy entity or functionality and/or regarding the first and/or second telecommunications network, wherein especially the secure edge protection proxy information is accessed from a secure edge protection proxy metadata repository, wherein especiallyonly if the allow-redirection-to-indication from the second secure edge protection proxy entity or functionality includes the first network identifier information and/or domain and/or host name information related to the first telecommunications network, oronly if the allow-redirection-from-indication from the first secure edge protection proxy entity or functionality includes the second network identifier information and/or domain and/or host name information related to the second telecommunications network , oronly if both the allow-redirection-to-indication from the second secure edge protection proxy entity or functionality includes the first network identifier information and/or domain and/or host name information related to the first telecommunications network and the allow-redirection-from-indication from the first secure edge protection proxy entity or functionality includes the second network identifier information, and/or domain and/or host name information related to the second telecommunications network.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

Furthermore, it is advantageously possible and preferred according to the present invention that—especially according to a second solution or embodiment—, in order for the third secure edge protection proxy entity or functionality accessing the first secure edge protection proxy entity or functionality in an authenticated manner, the third telecommunications network is configured to use a domain and/or host name resolver entity or functionality, and the method comprises the following steps:in a step E, the visited telecommunications network receives, from the user equipment, a message containing subscription concealed identifier information and/or routing indicator information,in a step F, the visited telecommunications network requests the domain and/or host name resolver entity or functionality to resolve the second domain and/or host name and includes the routing indicator information in the resolve request,in a step G, the domain and/or host name resolver entity or functionality returns an address related to the first secure edge protection proxy entity or functionality,in a step H, the visited telecommunications network forwards a message related to the message received in step E via the first secure edge protection proxy entity or functionality.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

According to a further preferred embodiment of the present invention—especially according to a first variant of a third solution or embodiment—, in order for the third secure edge protection proxy entity or functionality accessing the first secure edge protection proxy entity or functionality in an authenticated manner, the third secure edge protection proxy entity or functionality accesses the first secure edge protection proxy entity or functionality based on a specific routing indicator information, wherein the specific routing indicator information is part of the request, related to the user equipment, received by the network function of the visited telecommunications network in the first step, and triggering a message towards the third secure edge protection proxy entity or functionality,

wherein a routing-indicator-specific domain and/or host name information related to a secure edge protection proxy entity or functionality additionally comprises, as a part or field thereof, routing indicator information or information derived from the routing indicator, and

wherein the first secure edge protection proxy entity or functionality is reachable using a routing-indicator-specific domain and/or host name information having as a part or field thereof the specific routing indicator information or information derived from the routing indicator,

wherein the first secure edge protection proxy entity or functionality is reachable, by the third secure edge protection proxy entity or functionality, via a first routing-indicator-specific domain and/or host name, wherein the first routing-indicator-specific domain and/or host name is related to the second network identifier information, whereinin a step K, the visited telecommunications network receives, from the user equipment, a message containing subscription concealed identifier information and a routing indicator information corresponding to the specific routing indicator information,in a step L, the visited telecommunications network is configured to use the first routing-indicator-specific domain and/or host name in order to access the first secure edge protection proxy entity or functionality.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

According to a further preferred embodiment of the present invention—especially according to a second variant of the third solution or embodiment—, in order for the third secure edge protection proxy entity or functionality accessing the first secure edge protection proxy entity or functionality in an authenticated manner, the third secure edge protection proxy entity or functionality receives or is able to access secure edge protection proxy information, especially comprising addressing and/or domain name information containing a list of routing indicators and/or routing indicator ranges and corresponding to related domain and/or host names,

wherein the first secure edge protection proxy entity or functionality is reachable, by the third secure edge protection proxy entity or functionality, via a fourth domain and/or host name,

wherein the fourth domain and/or host name is related to the second network identifier information and one or more routing indicators and/or routing indicator ranges,in a step M, the visited telecommunications network receives from the user equipment a message containing subscription concealed identifier information and a routing indicator, wherein the secure edge protection proxy information corresponds to the fourth domain and/or host name and one or more routing indicators and/or routing indicator rangesin a step N, the visited telecommunications network is configured to use the fourth domain and/or host name in order to access the first secure edge protection proxy entity or functionality.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

Furthermore, it is advantageously possible and preferred according to the present invention that network identifier information comprises a mobile country code, mobile network code and/or network identifier.

According to a further preferred embodiment of the present invention,in a step O, the visited telecommunications network forwards towards the first telecommunications network a message containing subscription concealed identifier information and/or routing indicatorin a step P, the first telecommunications network returns deconcealed subscriber permanent identifier information comprising the second network identifier informationin a step Q, the third secure edge protection proxy entity or functionality maps the return deconcealed subscriber permanent identifier information to the first secure edge protection proxy entity or functionality, especially by storing a mapping between the deconcealed subscriber permanent identifier information and the first domain and/or host name, routing indicator, and/or its resolved addressin a step R, the visited telecommunications network receives a message containing the previously mapped subscriber permanent identifier information comprising the second network identifier informationin a step S, the third secure edge protection proxy entity or functionality sends the message via the first secure edge protection proxy entity or functionality as per the stored mapping.

It is thereby advantageously possible to realize and implement a method according to the invention in a comparatively simple and efficient manner.

Furthermore, the present invention relates to a system for providing communication services to a user equipment involving a first telecommunications network composed of network functions and a second telecommunications network composed of network functions, wherein the first telecommunications network uses or is assigned to a first network identifier information and is able to be accessed by or via a first secure edge protection proxy entity or functionality, and wherein the second telecommunications network uses or is assigned to a second network identifier information and is able to be accessed by or via a second secure edge protection proxy entity or functionality,

wherein, in case that the user equipment uses or is connected to an access network of a visited telecommunications network, the visited telecommunications network composed of network functions likewise comprising a third secure edge protection proxy entity or functionality, the user equipment uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network while the respective subscription identifier information comprises the second network identifier information,

wherein either subscriber permanent identifier is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network, or subscription concealed identifier information containing information derived from the subscriber permanent identifier and/or a routing indicator information is included by the user equipment for identification and/or routing purposes in messages towards the visited telecommunications network,

wherein messages between, on the one hand, the visited telecommunications network and, on the other hand, the first or the second telecommunications network or both of the first and the second telecommunications network are forwarded via a bidirectional channel between, on the one hand, the third secure edge protection proxy entity or functionality and, on the other hand, the first or second secure edge protection proxy entity or functionality or both of the first and second secure edge protection proxy entity or functionality, and vice-versa, wherein deconcealment of subscription concealed identifier information into a subscriber permanent identifier information is performed by the first telecommunications network, wherein, in order to provide the communication services to the user equipment comprising or applying secure edge protection proxy authentication, the system is configured such that:a network function of the visited telecommunications network receives a request related to the user equipment, triggering a message towards the third secure edge protection proxy entity or functionality,the third secure edge protection proxy entity or functionality accesses the first secure edge protection proxy entity or functionality in an authenticated manner, especially such that a message related to the second network identifier information is able to be sent, by the visited telecommunications network, to a network function in the first telecommunications network and accepted by the first telecommunications network.

Additionally, the present invention relates to a program comprising a computer readable program code which, when executed on a computer and/or on a user equipment and/or on a network node of a first, second and/or third telecommunications network, especially a first, second and/or third secure edge protection proxy entity or functionality, or in part on the user equipment and/or in part on the network node of the first, second and/or third telecommunications network, especially the first, second and/or third secure edge protection proxy entity or functionality, causes the computer and/or the user equipment and/or the network node of the first, second and/or third telecommunications network to perform a method according to the invention.

Furthermore, the present invention relates to a computer-readable medium comprising instructions, which, when executed on a computer and/or on a user equipment and/or on a network node of a first, second and/or third telecommunications network, especially a first, second and/or third secure edge protection proxy entity or functionality, or in part on the user equipment and/or in part on the network node of the first, second and/or third telecommunications network, especially the first, second and/or third secure edge protection proxy entity or functionality, causes the computer and/or the user equipment and/or the network node of the first, second and/or third telecommunications network to perform a method according to the invention.

InFIG.1, a user equipment20is schematically shown being connected to a visited telecommunications network300comprising an access network310and a core network320, and the visited telecommunications network300being connected to a first telecommunications network100and to a second telecommunications network200. The telecommunications networks100,200,300are shown to communicate via respective secure edge protection proxy entities or functionalities, i.e. the first telecommunications network100comprises a first secure edge protection proxy entity or functionality102, the second telecommunications network200comprises a second secure edge protection proxy entity or functionality202, and the visited telecommunications network300comprises a third secure edge protection proxy entity or functionality302. In the context of the present invention, the terms “visited telecommunications network300” and “third telecommunications network300” are used synonymously. The telecommunications networks100,200,300comprise the respective secure edge protection proxy entities or functionalities102,202,302, respectively, besides other network functions105,205,305, or, in other words, the telecommunications networks100,200,300are composed of network functions105,205,305(i.e. the first telecommunications network100comprises (first) network functions105, the second telecommunications network200comprises (second) network functions205, and the visited telecommunications network300comprises (third) network functions305), and the secure edge protection proxy entities or functionalities102,202,302, respectively, are part thereof. According to the present invention, the first telecommunications network100uses or is assigned to a first network identifier information101, typically being a (first) public land mobile network identifier information, and is able to be accessed by or via the first secure edge protection proxy entity or functionality102(especially by the third or visited telecommunications network300or its third secure edge protection proxy entity or functionality302). Likewise, the second telecommunications network200uses or is assigned to a second network identifier information101, typically being a (second) public land mobile network identifier information, and is able to be accessed by or via the second secure edge protection proxy entity or functionality202(especially by the third or visited telecommunications network300or its third secure edge protection proxy entity or functionality302).

As already said, the visited telecommunications network300comprises an access network310(or visited (or third) access network310) and a core network320(or visited (or third) core network320). Likewise, the first telecommunications network100comprises a (first) access network and a (first) core network120, and the second telecommunications network200comprises a (second) access network and a (second) core network220. Schematically,FIG.1shows the (third) access network310of the visited telecommunications network300comprising a plurality of radio cells11,12. In the exemplary situation or scenario shown inFIG.1, a first base station entity311generates or is associated with or spans the first radio cell11, and a second base station entity312generates or is associated with or spans the second radio cell12. The user equipment20. The user equipment20is typically, but not necessarily, mobile i.e. able to move with respect to the (typically, but not necessarily static) radio cells11,12or corresponding base station entities311,312of the considered access network310. In the exemplarily represented illustration ofFIG.1, the (third) core network320(of the visited telecommunications network300) is connected to the first telecommunications network100, especially the first core network120, and to the second telecommunications network200, especially the second core network220via, its (third) secure edge protection proxy entity or functionality302and via the first and second secure edge protection proxy entity or functionality102,202, respectively. Additionally,FIG.1shows the second telecommunications network200comprising (especially as part of its network functions205) a (second) network repository function250.

According to the present invention, different solutions are provided for the following situation of a roaming situation of a user equipment involving telecommunications networks communicating in an authenticated manner among each other (especially involving 5G networks or 5G systems or, typically, higher generation networks), especially the telecommunications networks being accessed via a SEPP (secure edge protection proxy entity or functionality):

For a given PLMN ID (or network identifier information, especially the second network identifier information), a (first) group of subscribers (hereinafter also designated via user equipment20′) with subscriptions containing this PLMN ID shall be served from (or by) a core network (as it is ordinarily the use case for telecommunications networks, i.e. in the exemplary situation this core network shall be the second core network220).

According to the present invention, however, another (second) group of subscribers (such as user equipment20)—also with subscriptions containing this PLMN ID (or network identifier information, especially the second network identifier information) or, at least, using this PLMN ID (or network identifier information according to the second network identifier information201—shall be served from (or by) another core network (i.e. by the core network of another telecommunications network, in the context of the present invention, especially the first core network120, i.e. a core network associated to another, namely the first network identifier information101).

The same is applicable for the cases where other network identifiers are used instead of a PLMN ID, e.g. for Standalone Non-Public Networks (SNPNs), whereby a combination of PLMN ID (sometimes a generic one such as99999) and Network Identifier (NID) is used instead of a PLMN ID. Furthermore, the same is also applicable when, e.g. in SNPNs when subscriber data is in NAI form (i.e. user@domain), a network domain identifies a network.

In case that the user equipment20is in a roaming situation, i.e. the visited telecommunications network300is present or involved, this means that the third secure edge protection proxy entity or functionality302needs to somehow access the correct network function within the first telecommunications network (especially within the first core network120) while still using the second network identifier information201of the second telecommunications network200(whose network identifier information is used by the subscription of the user equipment20).

This case is schematically shown inFIG.3, which represents the user equipment20accessing the third access network320of the visited telecommunications network300(i.e. the respective USIM comprises the subscriber permanent identifier information, the mobile country code (MCC), e.g. “241”, the mobile network code (MNC), e.g. “03”, the IMSI, and a routing indicator information, e.g. “RI=99”), and the respective secure edge protection proxy entities or functionalities302,202,102are communicating with each other. In case the user equipment uses the second network identifier information201(e.g. public land mobile network identifier information “241 03” for country two, i.e. for the second telecommunications network200), the third network repository function350exemplarily requests to discover the respective authorization functionality (AUSF) via forwarding (via the third and the second secure edge protection proxy entity or functionality302,202) this request (“Discover AUSF for ‘241 03’; forwarded to nrf.5gc.mnc03.mcc241.3gppnetwork.org via V-SEPP”) to the second network repository function250of the second telecommunications network200(i.e. assigned to the used network identifier information “241 03”).

In case the user equipment is a user equipment20′ (having the second telecommunications network200as its home network, i.e. especially having another routing indicator information (instead of “99”)), the second network repository function250provides as an answer (or forwards the request to) the respective authorization functionality (AUSF) of the second telecommunications network200, i.e. the respective authorization functionality responsible for an IMSI range in 241 03, and SIMs assigned to Ms (routing indicators), e.g., 01 to 98. In case the user equipment is a user equipment20(having the first telecommunications network100as its home network (or at least being served by the first core network120)—but nevertheless using the network identifier information of the second telecommunications network200), the answer is to be provided by (or the requests needs to be forwarded to) the respective authorization functionality (AUSF) of the first telecommunications network100, i.e. the respective authorization functionality responsible for an IMSI range in 241 03, and SIMS assigned to RI (routing indicator), e.g., 99.

This is in contrast to an implementation possible in conventionally known telecommunications networks (e.g. 4G networks), shown inFIG.2, where a communication among telecommunications networks is not necessarily and/or mandatorily conducted in an authenticated manner and/or via a SEPP (secure edge protection proxy entity or functionality):

In such conventionally known telecommunications networks, it is possible, e.g., to simply reserve different IMSI ranges for the different groups of user equipments (i.e. the (first) group of subscribers20′ and the (second) group of subscribers20) such that either the visited telecommunications network300or an IP exchange (IPX)390between the third telecommunications network300and the first and second telecommunications networks100,200is configured such that messages regarding a certain IMSI range (of the second group of user equipments20) are routed to the first telecommunications network100(e.g. a network having or using network identifier information “267 01” in country one), while messages regarding a (normal) IMSI range (of the first group of user equipments20′, or “normal SIMS of country two”) are routed in a normal manner, i.e. to the second telecommunications network200, e.g. in country two.

Hence, in conventionally known telecommunications networks, the issue is resolved in a transparent way (i.e. V-PLMNs300need not be aware of it) by having an IP Exchange (IPX)390re-route signaling messages based on the IMSI (or based on different IMSI ranges) within the (control plane) message(s). In such a scenario, the visited telecommunications networks (or V-PLMNs) use standardized fully qualified domain names (FQDNs), fully qualified domain names (GSMA, 3GPP), wherein in this case, target FQDNs for an EPC (enhanced packet core network, or 4G core network) are all within the well-known home network domain (HND) or home network realm of the second telecommunications network200, i.e. for example “epc.mnc03.mcc241.3gppnetwork.org”. Similar syntax is used for other network components, and IPX providers390can, based on the DNS queries used to resolve said FQDNs, source/destination IP addresses of the exchanged signaling packets and the content of the packets, evaluate whether a given signaling packet belongs to a given IMSI range. In this way, packets nominally belonging to the second telecommunications network200(having as public land mobile network identifier information “241 03”) but actually belonging to user equipments20being served by the first telecommunications network100are able to be re-routed towards targets in the first telecommunications network100(having public land mobile network identifier information “267 01”) without requiring specific configuration(s) in roaming partner's (V-PLMNs') networks, i.e. the IPX providers390provide network operators with inter-operator connectivity and are able to transparently re-route messages towards network “267 01” based on the determination of corresponding IMSI ranges, despite such messages comprising reference to network “241 03”.

According to the present invention and as already said, different solutions are provided for the situation of the user equipment20roaming in the visited telecommunications network300and using the network identifier information201(especially the PLMN ID) of the second telecommunications network200but being served by the first telecommunications network100(or its core network120): In this situation, the involved telecommunications networks exchange messages, especially control plane messages, in order to provide the requested communication services to the user equipment20but this message exchange is performed in an authenticated manner, using a secure edge protection proxy entity or functionality102,202,302as part of the involved telecommunications networks100,200,300. Especially, this means that a message related to the second network identifier information201is able to be sent, by the visited telecommunications network300, to a network function105in the first telecommunications network100and accepted by the first telecommunications network100.

Three main such solutions are provided according to the present invention, each comprising a number of variants:

According to the first solution provided according to the present invention, the (second) network repository function250returns (to a request received from the visited telecommunications network300) network function profiles containing FQDNs pointing to the first telecommunications network, i.e. PLMN-level NRF250for country two's operator is returning network function profiles containing FQDNs pointing to country one's operator PLMN.

According to the second solution provided according to the present invention, the routing indicator is added as a parameter to the DNS request resolving the FQDN of the respective secure edge protection proxy entity or functionality (and, hence, which telecommunications network) to be addressed.

According to the third solution provided according to the present invention, the routing indicator is added as part of the well-known FQDN of the secure edge protection proxy entity or functionality or mapping information is provided between one or more routing indicators and/or routing indicator ranges and a FQDN.

According to all solutions of the present invention and/or variants thereof, it is advantageously possible to realize an implementation such that botha user equipment, while using a network identifier information of one telecommunications network, is able to be served by another telecommunications network, especially in case of M2M communication,and additionally such an implementation is in accordance with 5G mechanisms, especially maintaining 5G security, i.e. an exchange of (control plane) messages in an authenticated manner between the telecommunications networks (despite using a ‘wrong’ network identifier information).

In conventionally known telecommunications networks, especially according to the 5G standard, it is known to use a roaming architecture involving secure edge protection proxy entities or functionalities.

These secure edge protection proxy entities or functionalities serve for communication purposes—especially implementing or realizing the so-called N32 reference point (or interface) on the control plane, especially according to 3GPP TS 23.501, clause 4.2.4—between a visited public land mobile network (or visited network) and a home public land mobile network (or home network) of the user equipment considered (a further reference point or interface between such two telecommunications networks being the so-called N9 reference point or interface for the user plane or for user plane data or traffic).

Typically, each of the telecommunications networks comprises a plurality of network functions associated to the control plane network functions, providing APIs (application programming interfaces) associated to each network function. The purpose of the secure edge protection proxy entities or functionalities is detailed in 3GPP TS 23.501, clause 6.2.17; the secure edge protection proxy (SEPP) entity or functionality is a non-transparent proxy and supports the functionalities of message filtering and policing on inter-PLMN control plane interfaces, as well as topology hiding, and especially both for service producer (network functions) and for service consumer (network functions), the result of the service relaying is equivalent to a direct service interaction; the secure edge protection proxy entities or functionalities communicate either directly (e.g. via TLS, transport layer security) or via one or more IPX providers390; it is not possible for an IPX390to divert messages towards a different secure edge protection proxy (such as a home-secure edge protection proxy) than the one initially intended as 5G has built-in functionality to prevent man-in-the-middle attacks; as such, a visited secure edge protection proxy entity or functionality (e.g.302) is ensured to be communicating with the intended (i.e. “correct”) home secure edge protection proxy entity or functionality (e.g.102).

Furthermore in conventionally known telecommunications networks, especially according to the 5G standard, subscriber data may be encrypted and/or concealed, especially in order to reduce the applicability of IMSI-catchers.

According to the 5G standard, besides a subscriber permanent identifier information (Subscriber Permanent Identifier, SUPI), a subscription concealed identifier information (Subscription Concealed Identifier, SUCI) is used. The subscription concealed identifier information can only be de-concealed by the home network (or home public land mobile network) and the network functions responsible are the authorization functionality (AUSF) and the unified data management (UDM).

The subscription concealed identifier, typically contains the network identifier information (or PLMN ID) of the subscription owner, the routing indicator (RI) information (especially for cases, e.g. in large networks, where more than one AUSFs exists), the concealed subscriber permanent identifier information (typically the IMSI in case the subscriber permanent identifier information is an and the Home Network Public Key Identifier (an identifier used to indicate which public/private key pair is used for subscriber permanent identifier protection and de-concealment of the subscription concealed identifier).

In conventionally known telecommunications networks (especially in accordance to 3GPP TS 23.502, clause 4.2.2.2.2), prior to the authentication/security step (involving the decryption or de-concealment of the subscription concealed identifier information) inter-network signaling only comprises the public land mobile network identifier information and the routing indicator information; after this step (and also for further procedures), the public land mobile network identifier information as well as the mobile subscription identification number, MSIN, is available.

Furthermore, service-based architecture (3GPP TS 23.501) and network function discovery (3GPP TS 23.502) are established concepts in conventionally known telecommunications networks.

Furthermore, in conventionally known telecommunications networks, it is possible that several network repository functions can be deployed via a hierarchical structure (3GPP TS 23.501). In such a hierarchical structure, NRFs are placed based on a PLMN and slice hierarchy, e.g. a PLMN-level NRF is responsible for NF profiles within the whole PLMN. Communication between PLMNs (e.g. in the case of roaming) can be managed by PLMN-level NRFs. As per 3GPP TS 23.501 and GSMA IR.67, the PLMN level NRF for a given PLMN is reachable via the well-known FQDN “nrf.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org”.

An AMF in a V-PLMN queries its NRF (the V-NRF) for AUSFs for the given H-PLMN ID and includes available information such as:

SUCI: includes PLMN ID, ROUTING INDICATORAccess Technology (5G NR, Wifi, etc.)The V-NRF contacts the H-NETWORK REPOSITORY FUNCTIONvia its well-known FQDN,which is reached by a matching SEPP based on the H-NRF's HND, that is5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org.

According to the present invention, a method for providing communication services to a user equipment20is provided, wherein in case that the user equipment20uses or is connected to the access network310of the visited telecommunications network300, the user equipment20uses a user equipment subscription including subscriber permanent identifier information that is related to or assigned to the first network100while the respective subscription identifier information comprises the second network identifier information201.

Typically, either subscriber permanent identifier information is included by the user equipment20for identification and/or routing purposes in messages towards the visited telecommunications network300, or subscription concealed identifier information containing information derived from the subscriber permanent identifier and/or a routing indicator information is included by the user equipment20for identification and/or routing purposes in messages towards the visited telecommunications network300.

In such a situation according to the present invention, messages between, on the one hand, the visited telecommunications network300and, on the other hand, the first or the second telecommunications network100,200or both of the first and the second telecommunications network100,200are forwarded via a bidirectional channel between, on the one hand, the third secure edge protection proxy entity or functionality302and, on the other hand, the first or second secure edge protection proxy entity or functionality102,202or both of the first and second secure edge protection proxy entity or functionality102,202, and vice-versa. Additionally, deconcealment of subscription concealed identifier information into a subscriber permanent identifier information is performed by the first telecommunications network100(or its core network120).

According to the present invention, in order to provide the communication services to the user equipment20comprising or applying secure edge protection proxy authentication, the method comprises the following steps:in a first step, a network function of the visited telecommunications network300receives a request related to the user equipment20(typically due to the user equipment20requesting a communication service, e.g. in order to be connected to the visited telecommunications network300), triggering a message towards the third secure edge protection proxy entity or functionality302,in a second step, the third secure edge protection proxy entity or functionality302accesses the first secure edge protection proxy entity or functionality102in an authenticated manner, especially such that a message related to the second network identifier information201is able to be sent, by the visited telecommunications network300, to a network function105in the first telecommunications network100and accepted by the first telecommunications network100.

It is thereby advantageously possible to realize an implementation such that not only it is possible that a user equipment, while using a network identifier information of one telecommunications network, is able to be served by another telecommunications network, especially in case of M2M communication, is able to communicate but also that such an implementation is in accordance with 5G mechanisms, especially maintaining 5G security, i.e. an exchange of (control plane) messages in an authenticated manner between the telecommunications networks (despite the user equipment20using network identifier information related to the second telecommunications network200while being served by the first telecommunications network100).

As explained in relation toFIG.3, according to the present invention, different solutions are provided for the situation of a roaming user equipment (roaming in the third telecommunications network300), and using the second network identifier information (or public land mobile network identifier information) of the second telecommunications network200is nevertheless served by the (or from) the first telecommunications network100or its core network120. This requires the involved telecommunications networks100,200,300to communicate with each other, and, according to the different solutions and variants of the present invention, this is possible in accordance with the security and authentication mechanisms introduced with the implementation of telecommunications networks according to the 5G standard, i.e. it is possible that the telecommunications networks communicate among each other in an authenticated manner (especially involving 5G networks or 5G systems or, typically, higher generation networks), especially the telecommunications networks being accessed via a SEPP (secure edge protection proxy entity or functionality): In the roaming situation, the visited telecommunications network300(via its third secure edge protection proxy entity or functionality302) needs to access the correct network function within the first telecommunications network100(especially within the first core network120) while still using the second network identifier information201of the second telecommunications network200(whose network identifier information is used by (or as part of) the subscription of the user equipment20).

According to the present invention, it is especially preferred that in or during the first step, the request related to the user equipment20is especially triggered by the user equipment20accessing the visited telecommunications network300to connect or to be connected thereto.

Furthermore, it is provided according to the present invention to be able to use a predefined (or well-known) FQDN in order to be able to access the secure edge protection proxy entity or functionality of a specific telecommunications network.

In conventionally known telecommunications network, it is only defined and expected that in a given telecommunications network, especially for a given network identifier information or PLMN identifier information, one secure edge protection proxy entity or functionality (or secure edge protection proxy instance) exists.

According to the present invention, it is provided to be able to use a predefined (or well-known) FQDN in order to access a respective secure edge protection proxy entity or functionality of a telecommunications network; for example, the well-known FQDN “sepp.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org” might be used for allowing the visited telecommunications network300to construct a FQDN addressing the respective secure edge protection proxy entity or functionality of the identified telecommunications network. In this respect, it is important that the FQDN via which a secure edge protection proxy entity or functionality is reachable is the FQDN used in the certificates that are used for mutual authentication between secure edge protection proxy entities or functionalities.

Thus, even if two IP addresses resolve to the same FQDN (e.g., for load balancing purposes), a valid certificate matching the FQDN must be provided, otherwise the third secure edge protection proxy entity or functionality302(V-SEPP or visited SEPP) might deem the first secure edge protection proxy entity or functionality102(H-SEPP or home-SEPP) as an impersonator and authentication fails.

Hence, using the predefined FQDN, it is advantageously possible, according to the present invention, that communication towards a given PLMN ID (or towards a given telecommunications network) is done via its matching secure edge protection proxy entity or functionality, and, hence, for any given secure edge protection proxy entity or functionality, it is ensured that the SEPP counterpart is authenticated.

Hence, according to the present invention, it is preferred that the first secure edge protection proxy entity or functionality102is reachable by the third secure edge protection proxy entity or functionality302via a first domain and/or host name102′ (especially a FQDN such as “sepp.5gc.mnc<MNC of 100>.mcc<MCC of 100>.3gppnetwork.org”) related to the first network identifier information101; this is schematically hinted at via reference sign102′ inFIG.3;

wherein the second secure edge protection proxy entity or functionality202is reachable, by the third secure edge protection proxy entity or functionality302, via a second domain and/or host name202′ (especially a FQDN such as “sepp.5gc.mnc<MNC of 200>.mcc<MCC of 200>.3gppnetwork.org”) related to the second network identifier information201;

wherein a specific network function105in the first telecommunications network100is reachable, by a consumer network function305in the visited telecommunications network300, via a further first domain and/or host name105′ related to the specific network function105and the first network identifier information101;

wherein a further specific network function205in the second telecommunications network200is reachable, by a consumer network function305in the visited telecommunications network300, via a domain and/or host name205′ related to the further specific network function205and the second network identifier information201,

wherein especially in order to provide the communication services to the user equipment20using service-based interfaces and/or a network repository function, a network function service is requested and/or provided, by the specific network function105of the first telecommunications network100, to the consumer network function305of the visited telecommunications network300.

InFIGS.4,5and6a first solution according to the present invention is schematically shown for providing communication services to a user equipment in the situation as described—i.e. involving first and second telecommunications networks100,200using or being assigned to, respectively, a first and second network identifier information101,201, wherein, in case that the user equipment20uses or is connected to an access network320of a visited telecommunications network300, the user equipment20uses a user equipment subscription, especially including subscriber permanent identifier information, that is related or assigned to the first telecommunications network100while the respective subscription identifier information comprises the second network identifier information—such that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities, an authenticated communication is possible.

According to the first solution or embodiment according to the present invention—in order for the third secure edge protection proxy entity or functionality302accessing the first secure edge protection proxy entity or functionality102in an authenticated manner—, prior to the first secure edge protection proxy entity or functionality102being accessed by the third secure edge protection proxy entity or functionality302, the third secure edge protection proxy entity or functionality302accesses the second secure edge protection proxy entity or functionality202related to the user equipment20, especially via transmitting a network function discovery query message to the second secure edge protection proxy entity or functionality202,

wherein the second secure edge protection proxy entity or functionality202transmits an indication that the first secure edge protection proxy entity or functionality102is to be accessed regarding the requested network function, wherein especially the second telecommunications network200comprises a network repository function250related to the second network identifier information201, and the method comprises the following steps:in a step A, the visited telecommunications network300receives, from the user equipment20, a message containing subscription concealed identifier information and/or routing indicator information,in a step B, the visited telecommunications network300queries the network repository function250for a network function capable of deconcealing the received concealed identifier information and/or routing indicator information,in a step C, the network repository function250returns information related to the specific network function105and including the further first domain and/or host name105′ related to the first network identifier information101,in a step D, the visited telecommunications network300is configured to forward, based on the first network identifier information101contained within the further first domain and/or host name105′, a message containing the subscription concealed identifier information and/or the routing indicator information to the specific network function105, especially while this message contains a subscription concealed identifier information and/or a routing indicator information related to the second network identifier information201and especially thereby realizing the second step.

This is exemplarily shown inFIG.6which shows an embodiment of the network repository function of the second telecommunications network200returning network function profiles containing FQDNs pointing to the first telecommunications network100, illustrated via a communication diagram between a consuming network function (e.g. an (or the) access and mobility management function as an example of such a network function305) of the visited telecommunications network300, the network repository function350of the visited telecommunications network300, the third secure edge protection proxy entity or functionality302, the second secure edge protection proxy entity or functionality202, the network repository function250of the second telecommunications network200, the first secure edge protection proxy entity or functionality102, and the serving network function105of the first telecommunications network100.

In a first processing step611, the access and mobility management function (or network function)305transmits a network function discovery query regarding a network function “X” (e.g. a unified data management network function, or also called the specific network function105), especially comprising control parameters; this processing step is typically triggered by step A mentioned above. In a second processing step612, the network repository function350of the visited telecommunications network300directs the network function discovery query to the third secure edge protection proxy entity or functionality302, indicating the network repository function250of the second telecommunications network200as destination, e.g. via an FQDN “nrf.5gc.mnc03.mcc241.3gppnetwork.org”. In a third processing step613, the secure edge protection proxy entity or functionality302of the visited telecommunications network300forwards the network function discovery query to the secure edge protection proxy entity or functionality202of the second telecommunications network200, especially using the well-known FQDN “sepp.5gc.mnc03.mcc241.3gppnetwork.org”. In a fourth processing step614, the secure edge protection proxy entity or functionality202of the second telecommunications network200forwards the network function discovery query to the network repository function250of the second telecommunications network200, i.e. to the public land mobile network-level network repository function (of the second telecommunications network200). The second, third and fourth processing steps612,613,614correspond to step B mentioned above. In a fifth processing step615, the network repository function250of the second telecommunications network200comprises or contains information that the queried (or requested) network function (i.e. network function “X”) is placed (or located) in another telecommunications network, namely the first telecommunications network100(e.g. having as public land mobile network identifier information “267 01”). In a sixth, seventh, eighth and ninth processing step616,617,618,619, the (requested) network function profile information, especially including the home network realm or domain or the corresponding information for network “267 01” (i.e. for the first telecommunications network100, e.g. “nf-x.5gc.mnc01.mcc267.3gppnetwork.org” as the further first domain and/or host name105′ related to the first network identifier information101“267 01”) is transmitted, by the network repository function250of the second telecommunications network200, back to the requesting access and mobility management function (or network function)305(via the secure edge protection proxy entity or functionality202of the second telecommunications network200, the secure edge protection proxy entity or functionality of the visited telecommunications network300, the network repository function350of the visited telecommunications network300). The sixth, seventh, eighth and ninth processing steps616,617,618,619correspond to step C mentioned above.

In a tenth processing step620, the access and mobility management function (or network function)305generates and transmits a request (especially comprising an FQDN information and/or parameters) towards the received information regarding the discovery query (of processing steps611to619), i.e. for example to “nf-x.5gc.mnc01.mcc267.3gppnetwork.org”, via the secure edge protection proxy entity or functionality302of the visited telecommunications network300as it targets another network (identifier information), especially another public land mobile network, namely the (network identifier information of the) first telecommunications network100. In an eleventh processing step621, the secure edge protection proxy entity or functionality302of the visited telecommunications network300evaluates if the requested redirection from the second telecommunications network200(“241 03”) towards the first telecommunications network100(“267 01”) is allowed. In a twelfth processing step622, the secure edge protection proxy entity or functionality302of the visited telecommunications network300directs the request towards the secure edge protection proxy102of the first telecommunications network100(“267 01”) as per the FQDN's home network realm or domain (i.e. not as per the subscriber permanent identifier's or subscription concealed identifier's public land mobile identifier information or network identifier information). In a thirteenth processing step623, the secure edge protection proxy entity or functionality102of the first telecommunications network100evaluates if the requested redirection from the second telecommunications network200(“241 03”) towards the first telecommunications network100(“267 01”) is allowed. In a fourteenth processing step624the request is forwarded to the targeted serving network function105of the first telecommunications network100.

Especially in order for the evaluations in the eleventh processing step621and in the thirteenth processing step623being conducted or processed correctly and securely, it is preferred according the present invention that the third secure edge protection proxy entity or functionality302accessing the first secure edge protection proxy entity or functionality102in an authenticated manner, especially step D, requires the third secure edge protection proxy entity or functionality302to have received or to be able to access secure edge protection proxy information, especially comprising an allow redirection-to-indication containing network identifier information and/or domain and/or host name information, and/or an allow-redirection-from-indication containing network identifier information and/or domain and/or host name information regarding the first and/or second secure edge protection proxy entity or functionality102,202and/or regarding the first and/or second telecommunications network100,200, wherein especially the secure edge protection proxy information is accessed from a secure edge protection proxy metadata repository502, wherein especiallyonly if the allow-redirection-to-indication from the second secure edge protection proxy entity or functionality202includes the first network identifier information101, and/or domain and/or host name information related to the first network, oronly if the allow-redirection-from-indication from the first secure edge protection proxy entity or functionality102includes the second network identifier information201and/or domain and/or host name information related to the second network, oronly if both the allow-redirection-to-indication from the second secure edge protection proxy entity or functionality202includes the first network identifier information101and/or domain and/or host name information related to the first network and the allow-redirection-from-indication from the first secure edge protection proxy entity or functionality102includes the second network identifier information201, and/or domain and/or host name information related to the second network.

This is exemplarily shown inFIG.4illustrating an embodiment of the visited telecommunications network300(or, rather, the secure edge protection proxy entity or functionality302) being provided with secure edge protection proxy information directly from the first telecommunications network100and/or the second telecommunications network200—illustrated via a communication diagram between the visited telecommunications network300, the second telecommunications network200, and the first telecommunications network100.

In a first processing step601, the second telecommunications network200(especially the second secure edge protection proxy entity or functionality202) transmits, to the visited telecommunications network300(especially to the third secure edge protection proxy entity or functionality302) an information or a message comprising secure edge protection proxy information indicating “allow redirect to”, i.e. the allow-redirection-to-indication (from the second secure edge protection proxy entity or functionality202) includes the first network identifier information101. In a second processing step602, the first telecommunications network100(especially the first secure edge protection proxy entity or functionality102) transmits, to the visited telecommunications network300(especially to the third secure edge protection proxy entity or functionality302) an information or a message comprising secure edge protection proxy information indicating “allow redirect from”, i.e. the allow-redirection-from-indication (from the first secure edge protection proxy entity or functionality102) includes the second network identifier information201. In a third processing step603, the visited telecommunications network300, especially the third secure edge protection proxy entity or functionality302, comprises the secure edge protection proxy information for network (or public land mobile networks) “241 03” and “267 01” (i.e. the second and first telecommunications network200,100).

As an alternative embodiment,FIG.5shows an embodiment of the visited telecommunications network300(or, rather, the secure edge protection proxy entity or functionality302) being able to access secure edge protection proxy information indirectly from the first telecommunications network100and/or the second telecommunications network200—illustrated via a communication diagram between the visited telecommunications network300, a secure edge protection proxy metadata repository502, the second telecommunications network200, and the first telecommunications network100.

In a first processing step604, the second telecommunications network200(especially the second secure edge protection proxy entity or functionality202) transmits, to the secure edge protection proxy metadata repository502an information or a message comprising secure edge protection proxy information indicating “allow redirect to”, i.e. the allow-redirection-to-indication (from the second secure edge protection proxy entity or functionality202) includes the first network identifier information101. In a second processing step605, the first telecommunications network100(especially the first secure edge protection proxy entity or functionality102) transmits, to the secure edge protection proxy metadata repository an information or a message comprising secure edge protection proxy information indicating “allow redirect from”, i.e. the allow-redirection-from-indication (from the first secure edge protection proxy entity or functionality102) includes the second network identifier information201. In a third processing step606, the visited telecommunications network300, especially the third secure edge protection proxy entity or functionality302, queries the secure edge protection proxy information from the secure edge protection proxy metadata repository502, and in a fourth processing step607, the secure edge protection proxy metadata repository502transmits the secure edge protection proxy information including the “allow redirect to” and “allow redirect from” indications to the requesting third secure edge protection proxy entity or functionality302(or the visited telecommunications network300). In a fifth processing step608the visited telecommunications network300, especially the third secure edge protection proxy entity or functionality302, comprises the secure edge protection proxy information for network (or public land mobile networks) “241 03” and “267 01” (i.e. the second and first telecommunications network200,100).

Hence, according to the first solution according to the present invention, the public land mobile network-level network repository function250of the second telecommunications network200(“country two's network repository function250”) returns network function profiles containing FQDNs pointing to the first telecommunications network100(“German public land mobile network”), and the visited telecommunications network300obtains secure edge protection proxy information (either directly—especially as part of the roaming agreement with the mobile network operator of the first and/or second telecommunications networks100,200—or via the secure edge protection proxy metadata repository502, especially accessed via a well-known FQDN and especially managed by a central entity. Regardless of which option, or variant, is used, information related to relevant secure edge protection proxy entities or functionalities (e.g. of the first and second telecommunications network100,200) is available at the visited telecommunications network300. The secure edge protection proxy information especially comprises the following two secure edge protection proxy parameters:

“Allow redirect to”-indication: This relates to the indication that messages from the given PLMN are able to contain targets (e.g., URLs located in any of the PLMNs in the list); this solves the issue of the third secure edge protection proxy302(V-SEPP) blocking outgoing messages where the target home network realm or domain in the FQDN does not match the information contained in the subscriber permanent identifier or subscription concealed identifier, e.g., HND mnc01.mcc267.3gppnetwork.org and SUPI/SUCI containing PLMN ID 263 03.

“Allow redirect from”-indication: Analogous to the prior parameter but indicating that the target H-SEPP (i.e. the first secure edge protection proxy entity or functionality102) allows incoming messages from the given PLMNs, i.e. “indication that this PLMN can also process messages from said PLMNs”.

InFIG.7, a second solution according to the present invention is schematically shown for providing communication services to a user equipment in the situation as described—i.e. involving first and second telecommunications networks100,200using or being assigned to, respectively, a first and second network identifier information101,201, wherein, in case that the user equipment20uses or is connected to an access network320of a visited telecommunications network300, the user equipment20uses a user equipment subscription, especially including subscriber permanent identifier information, that is related or assigned to the first telecommunications network100while the respective subscription identifier information comprises the second network identifier information—such that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities, an authenticated communication is possible.

According to the second solution or embodiment according to the present invention, in order for the third secure edge protection proxy entity or functionality302accessing the first secure edge protection proxy entity or functionality102in an authenticated manner, the third telecommunications network300is configured to use a domain and/or host name resolver entity or functionality501, and the method comprises the following steps:in a step E, the visited telecommunications network300receives, from the user equipment20, a message containing subscription concealed identifier information and/or routing indicator information,in a step F, the visited telecommunications network300requests the domain and/or host name resolver entity or functionality501to resolve the second domain and/or host name202′ and includes the routing indicator information in the resolve request,in a step G, the domain and/or host name resolver entity or functionality501returns an address related to the first secure edge protection proxy entity or functionality102,in a step H, the visited telecommunications network300forwards a message related to the message received in step E via the first secure edge protection proxy entity or functionality102.

This is exemplarily shown inFIG.7which schematically illustrates a second solution according to the present invention for providing communication services to a user equipment in an exemplary situation such that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities, an authenticated communication is possible. According to this solution, the visited telecommunications network is configured to use a domain and/or host name resolver entity or functionality, and the additional use of the routing indicator as parameter to the DNS request resolving the FQDN of a secure edge protection proxy entity or functionality. In this case, the IPX's DNS server (domain and/or host name resolver entity or functionality501) is used by the visited telecommunications network300(V-PLMN) to resolve the address of the first secure edge protection proxy entity or functionality102(H-SEPP), i.e. “nrf.5gc.mnc03.mcc241.3gppnetwork.org”. The DNS request especially contains the FQDN to resolve, i.e., “nrf.5gc.mnc03.mcc241.3gppnetwork.org”, as well as the routing indicator information of the subscription concealed identifier. Based on the routing indicator information (i.e. the RI's value/range), the IPX's DNS (domain and/or host name resolver entity or functionality 501) returns a DNS record pointing towards the “normal 241 03 SEPP” or another SEPP instance to serve the given routing indicator range.

This is illustrated via a communication diagram between a consuming network function (e.g. an (or the) access and mobility management function as an example of such a network function305) of the visited telecommunications network300, the third secure edge protection proxy entity or functionality302, the domain and/or host name resolver entity or functionality501, the second secure edge protection proxy entity or functionality202, the first secure edge protection proxy entity or functionality102, the authorization functionality AUSF of the first telecommunications network100, and the serving network function105of the first telecommunications network100.

In a first processing step631, the network function305receives a request related to a subscription concealed identifier information (related to the user equipment20) which should be processed in region “X”. In a second processing step632, the network function305transmits a signaling message comprising the subscription concealed identifier information as well as an indication of the serving network function, e.g. “ausf.5gc.mnc03.mcc241.3gppnetwork.org”. In a third processing step633, the third secure edge protection proxy entity or functionality302determines the DNS resolution for FQDN of the second secure edge protection proxy entity or functionality202(i.e. for public land mobile network identifier information “241 03”). In a fourth processing step634a DNS request including the routing indicator information of the subscription concealed identifier information and FQDN “sepp.5gc.mnc03.mcc241.3gppnetwork.org” is transmitted, by the third secure edge protection proxy entity or functionality302, to the domain and/or host name resolver entity or functionality501. In a fifth processing step635, in case that the indicated routing indicator information is configured for redirection towards the first telecommunications network100(i.e. the “267 01” network), the domain and/or host name resolver entity or functionality501returns the IP address pointing to the first secure edge protection proxy entity or functionality102, i.e. in “region X”. In a sixth processing step636, the domain and/or host name resolver entity or functionality501returns the corresponding IP address, pointing to the first secure edge protection proxy entity or functionality, i.e. “in region X” (or in “country X”). In a seventh processing step637, the third secure edge protection proxy entity or functionality302provides for a DNS record caching, taking into account the returned FQDN and the corresponding routing indicator information. In this processing step, DNS records may be cached at the V-SEPP. In order to ensure that a request containing a SUCI is not mapped to a wrong SEPP, DNS cache records must be stored indexed by not only FQDN but also the routing indicator information.

In an eighth processing step638, the third secure edge protection proxy entity or functionality302forwards the request towards the first secure edge protection proxy entity or functionality102“in region X”. In a ninth processing step639, this message is forwarded to the authorization functionality AUSF of the first telecommunications network100. In a tenth processing step640the subscription concealed identifier information is decrypted by the authorization functionality AUSF of the first telecommunications network100. In an eleventh processing step641, the message response including the subscriber permanent identifier information (i.e. the deconcealed subscription concealed identifier information, or at least part thereof) is transmitted to the first secure edge protection proxy entity or functionality102, and in a twelfth processing step642towards the third secure edge protection proxy entity or functionality302. In a thirteenth processing step643, the received subscriber permanent identifier information is mapped, by the third secure edge protection proxy entity or functionality302, to the routing indicator information in the message of the second processing step632. The V-SEPP must recognize messaging responses containing SUCI decryption. The V-SEPP must map the received SUCI to its RI value. The reason being that subsequent messages will not contain a SUCI and/or RI but rather a SUPI. Especially, this mapping is necessary so that the correct DNS record is used.

In case that after these preparatory steps and in a fourteenth processing step644, there is a signaling message being transmitted from the consuming network function305to the third secure edge protection proxy entity or functionality302, the signaling message comprising the subscriber permanent identifier information and an indication to request a service from a network function “X” (e.g. via the indication “nf-x.5gc.mnc03.mcc241.3gppnetwork.org”) then the third secure edge protection proxy entity or functionality302is able, in a fifteenth processing step645, to use the DNS cache for the mapped FQDN and routing indicator information or re-request the DNS resolution for the FQDN and the mapped routing indicator information. In a sixteenth processing step646, the request is forwarded to the first secure edge protection proxy entity or functionality102with an endpoint in “region X”, i.e. in a seventeenth processing step647, transmitted to the producing network function105of the first telecommunications network100.

It should be considered that both H-SEPPs (i.e. the first secure edge protection proxy entity or functionality102and the second secure edge protection proxy entity or functionality202) may need to use the same certificate. From the point of view of the V-SEPP (or third secure edge protection proxy entity or functionality302), both IP endpoints belong to the same SEPP instance (same FQDN).

InFIG.8, a third solution according to the present invention is schematically shown for providing communication services to a user equipment in the situation as described—i.e., involving first and second telecommunications networks100,200using or being assigned to, respectively, a first and second network identifier information101,201, wherein, in case that the user equipment20uses or is connected to an access network320of a visited telecommunications network300, the user equipment20uses a user equipment subscription, especially including subscriber permanent identifier information, that is related or assigned to the first telecommunications network100while the respective subscription identifier information comprises the second network identifier information—such that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities, an authenticated communication is possible.

According to a first variant of the third solution or embodiment according to the present invention, in order for the third secure edge protection proxy entity or functionality302accessing the first secure edge protection proxy entity or functionality102in an authenticated manner, the third secure edge protection proxy entity or functionality302accesses the first secure edge protection proxy entity or functionality102based on a specific routing indicator information, wherein the specific routing indicator information is part of the request, related to the user equipment20, received by the network function of the visited telecommunications network300in the first step, and triggering a message towards the third secure edge protection proxy entity or functionality302,

wherein a routing-indicator-specific domain and/or host name information related to a secure edge protection proxy entity or functionality additionally comprises , as a part or field thereof, routing indicator information or information derived from the routing indicator, and wherein the first secure edge protection proxy entity or functionality102is reachable using a routing-indicator-specific domain and/or host name information having as a part or field thereof the specific routing indicator information or information derived from the routing indicator,

wherein the first secure edge protection proxy entity or functionality102is reachable, by the third secure edge protection proxy entity or functionality302, via a first routing-indicator-specific domain and/or host name102″, wherein the first routing-indicator-specific domain and/or host name102″ is related to the second network identifier information201, whereinin a step K, the visited telecommunications network300receives, from the user equipment20, a message containing subscription concealed identifier information and a routing indicator information corresponding to the specific routing indicator information,in a step L, the visited telecommunications network300is configured to use the first routing-indicator-specific domain and/or host name102″ in order to access the first secure edge protection proxy entity or functionality102.

This first variant of the third solution or embodiment according to the present invention is exemplarily shown inFIG.8which schematically illustrates a second solution according to the present invention for providing communication services to a user equipment in an exemplary situation such that despite the telecommunications networks communicating via secure edge protection proxy entities or functionalities, an authenticated communication is possible. According to this solution, explicit support is added for RI-specific FQDNs of secure edge protection proxy entities or functionalities, i.e. basically, the V-PLMN has additional information to construct RI-dependent FQDN. According to the first variant of the third solution or embodiment, a SEPP FQDN is generated that includes the routing indicator information of the SUCI in the request, e.g., a FQDN such as, e.g., “sepp.5gc.ri99.mnc03.mcc241.3gppnetwork.org”, potentially requiring to have DNS registers for each RI (100 or 1000 records per SEPP, depending on whether a two- or three-digit RI is used). Hence, the routing indicator-dependent FQDN corresponds to the routing-indicator-specific domain and/or host name information102″ (especially related to a secure edge protection proxy entity or functionality such as the first secure edge protection proxy entity or functionality102; this is schematically hinted at via reference sign102″ inFIG.3) and—in addition to, e.g., the content or parts of the first domain and/or host name102′—comprises the “.ri99.”-part as routing indicator information that is a part or field of the routing-indicator-specific domain and/or host name information (or of the routing indicator-dependent FQDN). Alternatively (or cumulatively) to the routing indicator information “.ri99.”, the routing-indicator-specific domain and/or host name information comprises an information derived from the routing indicator, e.g. the “.iot.” part in “sepp.5gc.iot.mnc03.mcc241.3gppnetwork.org”.

This is illustrated via a communication diagram between a consuming network function (e.g. an (or the) access and mobility management function as an example of such a network function305) of the visited telecommunications network300, the third secure edge protection proxy entity or functionality302, the second secure edge protection proxy entity or functionality202, the first secure edge protection proxy entity or functionality102, the authorization functionality AUSF of the first telecommunications network100, and the serving network function105of the first telecommunications network100.

In a first processing step651, the network function305receives a request related to a subscription concealed identifier information (related to the user equipment20) with a routing indicator information, e.g. “RI=99”. In a second processing step652, the network function305transmits a signaling message comprising the subscription concealed identifier information as well as an indication of the serving network function, e.g. “ausf.5gc.mnc03.mcc241.3gppnetwork.org”. In a third processing step653, the third secure edge protection proxy entity or functionality302constructs the FQDN based on the network identifier information (or public land mobile network identifier information) and the routing indicator information if supported. In a fourth processing step654the third secure edge protection proxy entity or functionality302transmits or forwards the request towards the first secure edge protection proxy entity or functionality102, and in a fifth processing step655towards the authorization functionality AUSF of the first telecommunications network100. In a sixth processing step656, the subscription concealed identifier information is decrypted by the authorization functionality AUSF of the first telecommunications network100. In a seventh processing step657, the message response including the subscriber permanent identifier information (i.e. the deconcealed subscription concealed identifier information, or at least part thereof) is transmitted to the first secure edge protection proxy entity or functionality102, and in an eighth processing step658towards the third secure edge protection proxy entity or functionality302. In a ninth processing step659, the received subscriber permanent identifier information is mapped, by the third secure edge protection proxy entity or functionality302, to the routing indicator information in the message of the second processing step652. The V-SEPP must recognize messaging responses containing SUCI decryption. The V-SEPP must map the received SUCI to its RI value. The reason being that subsequent messages will not contain a SUCI and/or RI but rather a SUPI. Especially, this mapping is necessary so that the correct FQDN and as such, the correct DNS record is used.

In case that after these preparatory steps and in a tenth processing step660, there is a signaling message being transmitted from the consuming network function305to the third secure edge protection proxy entity or functionality302, the signaling message comprising the subscriber permanent identifier information and an indication to request a service from a network function “X” (e.g. via the indication “nf-x.5gc.mnc03.mcc241.3gppnetwork.org”) then the third secure edge protection proxy entity or functionality302is able, in an eleventh processing step661, to use the mapping between, on the one hand, the subscriber permanent identifier information, and, on the other hand, the routing indicator information, and forward to secure edge protection proxy FQDN based on the network identifier information (or public land mobile network identifier information) and routing indicator information. In a twelfth processing step662, the request is forwarded to the first secure edge protection proxy entity or functionality102, and in a thirteenth processing step663, transmitted to the producing network function105of the first telecommunications network100.

The SUPI being initially sent in the registration procedure encrypted (SUCI) towards the V-PLMN, wherein the following information is visible in the SUCI:PLMN ID (PLMN ID-A)Routing Indicator (RI) with value X (RI-X)

The first secure edge protection proxy entity or functionality102is reachable via a FQDN containing the respective routing indicator information “RI-X” (first variant of the third solution or embodiment) or via a specific FQDN in a list of RI ranges and matching FQDN; in this case, the generated FQDN may not contain the RI but rather a given FQDN (second variant of the third solution or embodiment). Especially, the third secure edge protection proxy entity or functionality302is able to construct a SEPP FQDN based on the network identifier information of the second telecommunications network200and the respective routing indicator information “RI-X” in the received requests.

According to a second variant of the third solution or embodiment according to the present invention, in order for the third secure edge protection proxy entity or functionality302accessing the first secure edge protection proxy entity or functionality102in an authenticated manner, the third secure edge protection proxy entity or functionality302receives or is able to access secure edge protection proxy information, especially comprising addressing and/or domain name information containing a list of routing indicators and/or routing indicator ranges and corresponding to related domain and/or host names,

wherein the first secure edge protection proxy entity or functionality102is reachable, by the third secure edge protection proxy entity or functionality302, via a fourth domain and/or host name102″′, wherein the fourth domain and/or host name102′ is related to the second network identifier information201and one or more routing indicators and/or routing indicator ranges,

in a step M, the visited telecommunications network300receives from the user equipment20a message containing subscription concealed identifier information and a routing indicator, wherein the secure edge protection proxy information corresponds to the fourth domain and/or host name102″′ and one or more routing indicators and/or routing indicator rangesin a step N, the visited telecommunications network300is configured to use the fourth domain and/or host name102″′ (this is schematically hinted at via reference sign102″′ inFIG.3) in order to access the first secure edge protection proxy entity or functionality102. Hence, according to the second variant of the third solution or embodiment of the present invention, secure edge protection proxy information (especially comprising addressing and/or domain name information containing a list of routing indicators and/or routing indicator ranges and corresponding to related domain and/or host names) is used that needs to be distributed or disseminated.

Especially the same dissemination forms as of the first solution or embodiment (cf.FIGS.4and5) is used, such that the following SEPP metadata (or secure edge protection proxy information) for a given PLMN (or network) is able to be provided to (or accessed by) the respective V-PLMN (i.e. the visited telecommunications network300):Addition of a support indication of RI-specific SEPP FQDNs in the SEPP metadata (same dissemination forms as in Solution 1). If the RI-specific FQDN cannot be resolved (e.g. by the DNS), the V-PLMN can construct a H-SEPP FQDN based on the well-known FQDN without the addition of RI information (e.g. “sepp.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org”)List of RI and/or RI ranges and matching FQDN. For a RI mapping not contained in the SEPP metadata, the V-PLMN can construct a H-SEPP FQDN based on the well-known FQDN without the addition of RI information (e.g. “sepp.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org”).

Basically, the V-PLMN has additional information to construct RI-dependent FQDN, especially via explicitly listing in the SEPP metadata Ms and/or RI ranges and a matching SEPP FQDN, e.g. including in the SEPP metadata that Ms 00-98 should use “sepp.5gc.mnc03.mcc241.3gppnetwork.org” (the “generic SEPP”) and RI 99 should use “sepp.5gc.iot.mnc03.mcc241.3gppnetwork.org” (a specific FQDN that may or may not contain a RI) or “sepp.5gc.mnc01.mcc267.3gppnetwork.org” (a specific FQDN that may not even share the same HND).