Patent Description:
Furthermore, the present invention relates to a user equipment for being operated with at least one telecommunications network, wherein the user equipment is connected to the telecommunications network using an access network of the telecommunications network and the telecommunications network further comprising a core network to which the user equipment is connected, wherein the user equipment is used with the telecommunications network by means of transmitting and/or receiving user plane data and control plane data, wherein, regarding user plane data exchanged between the user equipment and the telecommunications network, at least either a first user plane mode of operation or a second user plane mode of operation is able to be used for a given access technology.

Additionally, the present invention relates to a system or telecommunications network for using a user equipment with the telecommunications network, wherein the user equipment is connected to the telecommunications network using an access network of the telecommunications network and the telecommunications network further comprising a core network to which the user equipment is connected, wherein the user equipment is used with the telecommunications network by means of transmitting and/or receiving user plane data and control plane data, wherein, regarding user plane data exchanged between the user equipment and the telecommunications network, at least either a first user plane mode of operation or a second user plane mode of operation is able to be used for a given access technology.

Furthermore, the present invention relates to a program and to a computer-readable medium for using a user equipment with the telecommunications network according to the inventive method.

In conventionally known telecommunications networks, it is known to use segment routing (SR) as a variant of source routing. In a segment-routed network, an ingress node may prepend a header to data packets that contain a list of segments, which are instructions that are executed on subsequent nodes in the network. These instructions may be forwarding instructions, such as an instruction to forward a packet to a specific destination or interface.

In the case of SRv6, segment routing is combined with the IPv6 (internet protocol version <NUM>) protocol, where it is possible for a data packet (typically comprising some payload data) to comprise a plurality of different IPv6 headers (such as IPv6 header <NUM>, IPv6 header <NUM>,. , IPv6 header N), wherein by means of each IPv6 header a corresponding action is indicated, e.g. an action <NUM> for IPv6 header <NUM>, e.g. "apply quality-of-service", an action <NUM> for IPv6 header <NUM>, e.g. "route via router A",. , an action N for IPv6 header N, e.g. "route via router B", and the like. Thereby, network elements are able to add and/or to remove (push and/or pop) SRv6 headers based on network-defined logic, thereby especially reducing statefulness of network elements during network transit of data packets. In this context <CIT> describes methods for SRv6 service delivery in end-to-end fashion with collaboration across different control planes of a fifth-generation environment. It has already been proposed to use segment routing to replace the GTP-U encapsulation protocol used in the N3 interface between the (radio) access network (AN, RAN) and the core network (CN) of a telecommunications network or of a mobile communication network, which GTP-U encapsulation protocol transports user plane traffic on its way to and/or from a data network (DN). The N3 interface is located between the access network (e.g. radio access network) and the core network user plane processing function, which in the case of a <NUM> network is the user plane function, UPF.

Between the UE and the AN (and in case of a <NUM> system - new radio, NR), the user plane stack, e.g., comprises, above the physical layer, the MAC layer, the RLC layer, the PDCP layer, and the service data adaptation protocol, SDAP, layer according to TS <NUM>. Between the UE and the AN (and in case of a <NUM> system - untrusted non-3GPP Access), the user plane stack, e.g., comprises, above the physical layer, the MAC layer, the internet protocol, IP, layer, internet protocol security, IPsec, layer, generic routing encapsulation, GRE, layer according to TS <NUM>.

On the reverse side (AN-UE), the reverse process is performed.

However, providing connectivity is a more complex issue and it often involves a plurality of operators and devices, often having different or divergent capabilities, e.g., - besides the telecommunications network to which the user equipment is directly connected - a further telecommunications network acting as the home network to the user equipment (roaming scenario of the user equipment). In the general context of exposing service capabilities to external entities <CIT> describes a method for providing a mechanism for a communication network to expose its quality of service capabilities to entities outside of the communication network Furthermore, user needs may be location-dependent (e.g. a campus network or a network slice within a specific location may provide different capabilities than the nationwide network outside thereof).

An object of the present invention is to provide a technically simple, effective and cost effective solution for using a user equipment with at least one telecommunications network, wherein user plane data are able to be exchanged between the user equipment and the telecommunications network by means of using at least either a first user plane mode of operation or a second user plane mode of operation for a given access technology. A further object of the present invention is to provide a corresponding user equipment, system or telecommunications network, and a corresponding program and computer-readable medium.

The object of the present invention is achieved by a method according to claim <NUM>.

According to the present invention, it is advantageously possible that different user plane modes of operation are possible or able to be applied regarding user plane data being exchanged between the user equipment and the telecommunications network, and this in response to or in dependance on capability information being sent by the user equipment (and received by the telecommunications network) relating to the capability of the user equipment to apply or to use the first user plane mode of operation and/or the second user plane mode of operation. An analogous exchange (or transmission) of capability information is, according to the present invention, also envisaged regarding different telecommunications networks (e.g. between a visited network and a home network of the user equipment). Hence, according to the present invention, the operation on one or multiple networks of a combination of user plane modes of operation and the exchange of corresponding or related capability information is advantageously possible. It is thereby advantageously possible that a user plane mode of operation is associated with a user plane protocol stack, combination of user plane and control plane protocol stacks, configuration of user plane protocol stack, or configuration of control and user plane protocol stacks such that transmission and/or reception of user plane data is realized via a specific and/or specifically configured protocol stack(s). It is thereby advantageously possible that the simultaneous use of legacy user plane modes of operation (especially GTP-U-based) and also of more efficient SR-based user plane modes of operation, especially SRv6, is enabled without service degradation for legacy users.

Hence, according to the present invention, it is advantageously possible to provide for a signaling of a segment routing capability for (or regarding) the user equipment and/or the (visited) access network (i.e. of the visited network of the user equipment, V-PLMN AN) and/or the (visited) core network (i.e. of the visited network of the user equipment, V-PLMN CN) and/or the (home) core network (i.e. of the home network of the user equipment, H-PLMN CN) so that the user equipment is especially able to be aware whether (or not) SRv6 is usable and/or whether (or not) two core networks (e.g. the ones of the visited and the home network of the user equipment) can know whether SRv6 is usable.

Furthermore, it is advantageously possible according to the present invention that a conditional header manipulation of uplink/downlink data packets is able to be applied on the user equipment (or by the user equipment), whereas the conditions are especially based on location parameters, time parameters and/or network parameters. It is furthermore advantageously possible that given a partially overlapping support of user plane modes of operation, a common user plane mode of operation can be chosen end-to-end, E2E, e.g. between user equipment, visited network and home network such that the need for user plane translation and/or encapsulation/decapsulation can be minimized or even removed. It is furthermore advantageously possible that given a partially overlapping support of user plane modes of operation among different access technologies supported by a user equipment, a common user plane mode of operation is chosen for all access technologies supported by the user equipment, such that mobility and/or handover of user plane between different access technologies can be seamlessly realized.

In a conventional telecommunications network, a common use case in roaming is that of network slice mapping, whereas different network slice identifiers are used in the visited public land mobile network, V-PLMN, of the user equipment and in the home public land mobile network, H-PLMN, of the user equipment for a given service. In such a case, the user equipment (subscribed to the H-PLMN) receives a network slice mapping information informing it of the mapping between a H-PLMN network slice and a V-PLMN network slice. Furthermore, regarding the communication between the visited and home public land mobile networks, the <NUM> architecture defines - regarding control plane communication or data exchange - a secure element enabling secure and authenticated exchange of control plane information between the networks: the secure edge protection proxy (SEPP), cf. especially TS <NUM>, clause <NUM>. Regarding user plane communication or data exchange, <NUM> defines an inter PLMN user plane security (IPUPS) functionality, which can be deployed at the border of the respective networks to protect the respective networks from invalid inter-PLMN N9 traffic. The IPUPS functionality forwards GTP-U packets (received via the N9 interface) only if they belong to an active PDU Session and are not malformed, as described in TS <NUM>.

According to the present invention, it is advantageously possible that a user equipment is used with at least one telecommunications network (but typically, especially in a roaming situation, with two or more telecommunications networks). The user equipment is connected to the (visited or home) telecommunications network using an access network thereof (i.e. an access network, or radio access network, of the telecommunications network or assigned to or associated with the telecommunications network), and, of course, the telecommunications network furthermore also comprises a core network to which the user equipment is connected.

The user equipment is used with the telecommunications network (or with the (radio) access network (thereof)) by means of transmitting and/or receiving user plane data and control plane data, wherein, regarding user plane data exchanged between the user equipment and the telecommunications network (or the (radio) access network (thereof)), at least either a first (or legacy) user plane mode of operation or a second (or non-legacy, i.e. segment routing-related) user plane mode of operation is able to be used for a given access technology.

In such a situation, according to the present invention, the user equipment transmits a capability information to the telecommunications network (or, rather or more specifically, to its (radio) access network), the capability information being related to the capability of the user equipment to apply or to use the first user plane mode of operation and/or the second user plane mode of operation. As a result thereof (i.e. of the transmission of the capability information transmitted by the user equipment, and irrespective of the form of such transmission or the kind of message transporting such capability information), either the first user plane mode of operation or the second user plane mode of operation is applied (especially between the user equipment and the access network) in accordance with the capability information.

Especially according to the present invention, it is to be understood that the use of at least either a first (or legacy) user plane mode of operation or a second (or non-legacy, i.e. segment routing-related) user plane mode of operation (regarding user plane data exchanged between the user equipment and the telecommunications network (or the (radio) access network (thereof))) is able to be used not only in dependency of a given access technology but also in dependency of a specific packet data unit session, i.e. in two different packet data unit sessions it might be possible (for one and the same user equipment) to apply different user plane modes of operation (e.g. the first user plane mode of operation in a first packet data unit session and the second user plane mode of operation in a second packet data unit session) - i.e. in such an implementation of the present invention:.

According to the present invention, it is furthermore advantageously possible and preferred that the user equipment is either capable of applying or using:.

Furthermore, it is advantageously possible and preferred according to the present invention to support that only part of the access network, especially specific tracking areas, TAs, and/or locations, support a given user plane mode, such that the conditional application of the given user plane mode is restricted to that part of the access network. It is similarly advantageously possible and preferred according to the present invention to support that only a given slice or set of slices supports a given user plane mode such that the conditional application of the given user plane mode is restricted to elements serving the given slice or set of slices.

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

According to the present invention, it is furthermore advantageously possible and preferred that the first user plane mode of operation corresponds to, or relies on, radio link control, RLC, packet data convergence protocol, PDCP, or using the service data adaptation protocol, SDAP, or a variant thereof. According to the invention, the second user plane mode of operation corresponds to, or relies on, a segment routing protocol, especially the segment routing version <NUM> protocol, SRv6.

Furthermore, it is advantageously possible and preferred according to the present invention that the user plane protocol between the access network, especially a gNB, and the core network, especially a user plane function, UPF, is chosen based on the applied user plane mode of operation used between the user equipment and the access network, especially when the first user plane mode of operation is associated to the GPRS tunneling protocol, GTP.

It is thereby advantageously possible to efficiently realize and implement the inventive method in a comparatively simple and flexible manner.

Furthermore, it is advantageously possible and preferred according to the present invention that, besides the user equipment, a further user equipment is connected to the telecommunications network and wherein the further user equipment transmits a further capability information to the telecommunications network, the further capability information being related to a further capability of the further user equipment to apply or to use the first user plane mode of operation and/or the second user plane mode of operation, wherein, especially in case that the capability information and the further capability information differ, the first user plane mode of operation is applied in accordance with the capability information, and the second user plane mode of operation is applied in accordance with the further capability information, or vice versa, between the user equipments and the telecommunications network.

It is thereby advantageously possible to realize and implement the inventive method in a comparatively simple and efficient manner, where - regarding different user equipments - different user plane modes of operation are possible to be used or applied.

Furthermore, it is advantageously possible and preferred according to the present invention that the capability information is transmitted, by the user equipment to the telecommunications network, by means of, or upon, at least one out of the following:.

Furthermore, it is advantageously possible and preferred according to the present invention that a further telecommunications network, connected to the telecommunications network is serving the user equipment, especially as a home network, wherein, regarding user plane data exchanged between the telecommunications network and the further telecommunications network, at least either the first user plane mode of operation or the second user plane mode of operation is able to be used for a given access technology,
wherein either.

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

Furthermore, it is advantageously possible and preferred according to the present invention that a further telecommunications network, connected to the telecommunications network is serving the user equipment, especially as a home network, wherein, regarding user plane data exchanged between the user equipment and the further telecommunications network, at least either the first user plane mode of operation or the second user plane mode of operation is able to be used for a given access technology,
wherein the user equipment transmits the capability information also to the further telecommunications network, the capability information being related to the capability of the user equipment to apply or to use the first user plane mode of operation and/or the second user plane mode of operation, this resulting in either the first user plane mode of operation or the second user plane mode of operation being applied in accordance with the capability information between the user equipment and the further telecommunications network.

Furthermore, according to the present invention that in case that the second user plane mode of operation is used, at least one out of the following applies:.

Furthermore, the present invention relates to a user equipment according ot claim <NUM>.

Furthermore, the present invention relates to a system or telecommunications network according to claim <NUM>.

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 telecommunications network, especially a control plane and/or user plane function, or in part on the user equipment and/or in part on the network node of a telecommunications network, especially the control plane function and/or user plane function, causes the computer and/or the user equipment and/or the network node of the telecommunications network to perform the inventive method.

Additionally, 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 telecommunications network, especially a control plane function and/or user plane function, or in part on the user equipment and/or in part on the network node of a telecommunications network, especially the control plane function and/or user plane function, causes the computer and/or the user equipment and/or the network node of the telecommunications network to perform the inventive method.

The present invention will be described with respect to particular embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are nonlimiting.

In <FIG>, a telecommunications network <NUM> comprising an access network <NUM>, and a core network <NUM> as well as connected to a user equipment <NUM> is schematically shown, wherein - regarding user plane data exchanged between the user equipment and the telecommunications network, and especially regarding a specific packet data unit session - at least either a first user plane mode of operation or a second user plane mode of operation is able to be used for a given access technology, and wherein regarding such a use of user plane modes of operation capability information <NUM> is transmitted, by the user equipment, to the telecommunications network <NUM>. The telecommunications network <NUM> is especially realized as a mobile (cellular) communication network <NUM> (and is, hereinafter and at least partly, also called like this). The telecommunications network <NUM>, especially the core network <NUM>, typically comprises a number of network functions or services, wherein of these, <FIG> exemplarily shows an access and mobility management function <NUM> of the telecommunications network <NUM>, a session management function <NUM>, and a user plane function <NUM>.

The access network <NUM> comprises a plurality of radio cells <NUM>, <NUM>. In the exemplary situation or scenario shown in <FIG>, a first base station entity <NUM> generates or is associated with or spans the first radio cell <NUM>, and a second base station entity <NUM> generates or is associated with or spans the second radio cell <NUM>. In the exemplary situation shown in <FIG>, the user equipment <NUM> is connected to the telecommunications network <NUM> via a radio interface to the first base station entity <NUM> (and the user plane data being exchanged between the user equipment <NUM> and the telecommunications network <NUM> schematically being indicated by means of two opposed arrows between the user equipment <NUM> and the first base station entity <NUM>).

The user equipment <NUM> is typically, but not necessarily, mobile - i.e. able to move - with respect to the - typically, but not necessarily, static - radio cells <NUM>, <NUM> or corresponding base station entities <NUM>, <NUM> of the access network <NUM>. Especially, the user equipment <NUM> might comprise an application (not specifically depicted in <FIG>) as part of the user equipment <NUM>; the application typically runs on the user equipment <NUM>, i.e. the user equipment <NUM> typically runs or executes an operating system (such as a mobile (devices) operating system, e.g., android, iOS, iPadOS, etc.), and the application is running on the operating system; alternatively, the application might also be a lower level application not running on or as part of the operating system but as part of, e.g., the subscriber identity module of the user equipment <NUM>.

Exemplarily, <FIG> also represents a further telecommunications network <NUM> connected to the telecommunications network <NUM>, and the further telecommunications network <NUM> also comprising an access and core network, hereinafter called further access network <NUM> (designated by means of reference sign <NUM>) and further core network <NUM> (designated by means of reference sign <NUM>).

In conventionally known telecommunications networks, the use of GTP-U encapsulation used in the N3 interface (between the (radio) access network and the core network of a telecommunications network, especially for the transport of user plane traffic on its way to and/or from a data network DN) is established, and it has already been proposed to use segment routing to replace the GTP-U encapsulation protocol. In a segment-routed network, an ingress node may prepend a header to data packets that contain a list of segments, which are instructions that are executed on subsequent nodes in the network. These instructions may be forwarding instructions, such as an instruction to forward a packet to a specific destination or interface. In the case of SRv6, segment routing is combined with the IPv6 (internet protocol version <NUM>) protocol.

However, providing connectivity to the user equipment <NUM> often involves a plurality of operators and devices (such as, e.g., the further telecommunications network <NUM>, e.g. acting, in a roaming scenario of the user equipment <NUM>, as home network to the user equipment <NUM>).

The present invention therefore proposes to apply - regarding user plane data being exchanged between the user equipment <NUM> and the telecommunications network <NUM> - different user plane modes of operation in response to or in dependance on capability information being sent by the user equipment <NUM> (and received by the telecommunications network <NUM>) relating to the capability of the user equipment <NUM> to apply or to use these user plane modes of operation. Basically according to the present invention, a first user plane mode of operation and/or at least a second user plane mode of operation are possible to be applied (for a given access technology and especially in a specific packet data unit session), wherein, of course, for a specifically considered packet data unit session (or logical data channel or user plane data stream) only either the first or the second user plane mode of operation is able to be applied, and not both for the same packet data unit session and/or the same logical data channel or data stream. In this respect, "user plane mode of operation" should not be mixed up with "packet data unit session type": While a packet data unit session may transmit traffic of type IP, ethernet or others, said user plane is transmitted in the same way, that is, via GTP-U encapsulation. The user plane mode of operation relates to how the user plane is transmitted, not the payload type being transported.

An analogous exchange (or transmission) of capability information is, according to the present invention, also envisaged regarding different telecommunications networks (e.g. between a visited network and a home network of the user equipment, e.g. the telecommunications network <NUM> and the further telecommunications network <NUM>). Hence, according to the present invention, the operation on one or multiple networks of a combination of user plane modes of operation and the exchange of corresponding or related capability information is advantageously possible.

The different possibilities where capability information is susceptible to be transmitted according to the present invention are schematically illustrated in <FIG>, which schematically illustrates different interfaces or reference points - between different parts of a plurality of telecommunications networks <NUM>, <NUM> - for such an exchange, or a transmission, of capability information. Specifically, <FIG> shows the user equipment <NUM>, the access network <NUM> (especially of the telecommunications network <NUM> acting as visited network), the core network <NUM> (especially of the telecommunications network <NUM> acting as visited network), and the further core network <NUM> (especially of the further telecommunications network <NUM> acting as home network of the user equipment <NUM>). Reference sign A designates the transmission of capability information <NUM> between the user equipment <NUM> and the access network <NUM>, especially the transmission of (user equipment-related) capability information <NUM> towards the access network <NUM>. Reference sign B designates the transmission of capability information <NUM> between the user equipment <NUM> and the core network <NUM>, especially the transmission of (user equipment-related) capability information <NUM> towards the core network <NUM>. Reference sign C designates the transmission of capability information <NUM> between the user equipment <NUM> and the further core network <NUM>, especially the transmission of (user equipment-related) capability information <NUM> towards the further core network <NUM>. Reference sign D designates the transmission of capability information between the core network <NUM> (of the telecommunications network <NUM>) and the further core network <NUM> (of the further telecommunications network <NUM>).

By means of transmitting such capability information, especially user equipment-related capability information <NUM>, it is advantageously possible, according to the present invention, to enable the user equipment <NUM> in the telecommunications network <NUM> to realize multiple user plane modes, including, e.g., a SRv6 user plane mode, in multi-network setups.

Thus, the segment routing capabilities, if present, are able to be signaled. The Introduction of a segment routing-based user plane mode (second user plane mode of operation) as a new user plane requires architectural changes in how user equipments and network elements are designed and how data packets are processed. On the other hand, flexibly usable means to provide for backward-compatibility are required; a network or user equipment supporting both segment routing-based and legacy-based (GTP-U/SDAP) user plane modes of operation can thus be considered as having more than one user plane mode of operation.

Hence especially, according to the present invention, a solution is provided how to enable the user equipment <NUM> to use multiple user plane modes of operation, especially to enable the user equipment <NUM> to be part of the SRv6 logic in a backwards-compatible manner, especially in multi-network setups such as roaming, which advantageously has the potential to allow the user equipment <NUM> to offload user plane processing from the network, especially the access network (no GTP-U encapsulation needed, reduced packet processing load) and the user plane function <NUM> (reduced packet processing load). Furthermore, the present invention allows for current (legacy) user equipments to still make use of such networks (being able to apply, e.g., SRv6 logic), i.e. according to the present invention, there is no service degradation to current users.

Hence, <FIG> shows how to flexibly apply this functionality of capability indication, or capability signaling, especially from the user equipment <NUM> towards the network (telecommunications network <NUM> or further telecommunications network <NUM>), i.e. whether segment routing header functionality is supported (or not), and as well between communicating the networks <NUM>, <NUM>.

According to the present invention, multiple user plane modes of operation - i.e. to exchange user plane traffic between the user equipment <NUM> and the telecommunications network <NUM> - are supported, especially comprising network-based steering, via the control plane, so that the most optimum user plane mode of operation is able to be used based on network and/or user equipment capabilities and such that backwards-compatibility is able to be ensured. Especially - regarding uplink traffic and regarding each individual traffic stream or logical data channel - it is decided, within the user equipment <NUM>, which one of a plurality of different user plane modes of operation is to be used or applied for such uplink traffic towards the access network <NUM> and/or the core network <NUM>.

The capability information <NUM> that the user equipment <NUM> transmits, according to the present invention, to the access network <NUM> and/or the core network <NUM> of the telecommunications network <NUM> preferably indicates that the user equipment <NUM> is either capable of applying or using:.

Preferably, the capability information <NUM> additionally indicates (especially in case that both user plane modes of operation are possible) a preferred user plane mode of operation out of the first and second user plane modes of operation.

It is furthermore preferred that, cumulatively or alternatively, the capability information <NUM> indicates conditional application and/or preference of a given user plane mode of operation, especially the applicability to (or, the dependency of a conditional application and/or a preference of a given user plane mode of operation from) a given time and/or location and/or a given application or service (especially the applicability to local, home and/or roaming service), and/or a given type of traffic (especially internet protocol and ethernet traffic).

According to the present invention, it is advantageously possible to provide inter-operability between different kinds of user equipments and between different kinds of networks, especially including:.

Hence for the case of a roaming-like situation of the user equipment <NUM>, having a H-PLMN registration (towards the further telecommunications network <NUM>) and being connected to the telecommunications network <NUM> obtaining connectivity towards a data network (DN) in a roaming-like situation:.

This results in - dependent on the user plane capabilities of the transmission nodes (or networks) involved - the following typical or basic setups regarding the most efficient data plane with regards of usage of segment routing-based functionality:.

In the following, it is described in detail, exemplarily how the first user plane mode of operation, or, alternatively, the second user plane mode of operation is used as a result of capability information being transmitted, by the user equipment <NUM>, to the telecommunications network <NUM>.

In order for the access network <NUM> and/or the core network <NUM> to be able to know whether the user equipment <NUM> supports more than one user plane mode of operation, the user equipment <NUM> signals this capability (e.g. when the user equipment <NUM> registers at the network <NUM> as part of connection capabilities). This could trigger the network <NUM> to implicitly assume that all PDU session establishment requests imply the signaled capabilities. Alternatively or cumulatively, the user equipment <NUM> can indicate the requested/preferred user plane mode of operation in the packet data unit session establishment request (e.g. one or more), which the network <NUM>, based on its own capabilities and deployment (e.g. the requested slice may support only legacy user plane) can then accordingly reply to. <FIG> shows the case when a user equipment <NUM> requests a given user plane mode of operation and it is granted, resulting in an end-to-end segment routing-based user plane. <FIG> shows the case when the user equipment <NUM> is not granted its preferred/requested user plane mode of operation, but rather an alternative one, also supported by the user equipment <NUM> (fallback to legacy mode).

In <FIG>, a communication diagram between the user equipment <NUM> and network nodes or elements of the telecommunications network <NUM> is schematically and exemplarily shown, representing an example according to the present invention how the second user plane mode of operation is susceptible to be used between the user equipment <NUM> and the telecommunications network <NUM>. <FIG> explicitly shows the access and mobility management function <NUM>, the session management function <NUM>, and the user plane function <NUM> of the telecommunications network <NUM>. In a first processing step <NUM>, the user equipment <NUM> indicates (e.g. as part of a registration procedure) to the access and mobility management function <NUM> of the telecommunications network <NUM> that it supports both the first and second user plane mode of operation (i.e. especially both a segment routing-based and a GTP-U based user plane mode of operation). In a second processing step <NUM>, a packet data unit session establishment request is sent, by the user equipment <NUM>, to the session management function <NUM> of the telecommunications network <NUM>, the packet data unit session establishment request comprising the request, that the second user plane mode of operation (e.g. SRv6) be used (regarding the specific packet data unit session considered or requested). In a third processing step <NUM>, the session management function evaluates segment routing support, especially based on, e.g., the capabilities of the requested (or to be used) S-NSSAI and/or data network name, DNN, as well as the capabilities of the user plane function <NUM>. In case that this evaluation results in these capabilities being present and ready, in a fourth processing step <NUM>, the session management function <NUM> configures the user plane function <NUM> for the second user plane mode of operation (i.e. especially for a segment routing-based packet data unit session), and, in a fifth processing step <NUM>, the session management function <NUM> configures the access network <NUM> (especially via the access and mobility management function <NUM>) for the second user plane mode of operation (i.e. for a segment routing-based packet data unit session). In a sixth processing step <NUM>, the session management function <NUM> transmits a packet data unit session establishment accept message to the user equipment <NUM>, comprising an indication that the user plane mode of operation to be used corresponds to the second user plane mode of operation, i.e. especially the SRv6. Furthermore, the session management function <NUM> transmits to the user equipment <NUM> - especially as part of the packet data unit session establishment accept message - the relevant segment routing header information required to implement the segment routing-based user plane mode of operation. In a seventh processing step <NUM>, the user plane communication is able to be conducted between the user equipment <NUM> and the user plane function <NUM>, based on using the second user plane mode of operation using, or realizing, a segment routing-based N3 interface (or reference point).

In contrast, in <FIG>, a communication diagram (between, again, the user equipment <NUM> and network nodes or elements of the telecommunications network <NUM>) is schematically and exemplarily shown, representing an example according to the present invention how the first user plane mode of operation is susceptible to be used between the user equipment <NUM> and the telecommunications network <NUM>. Again, <FIG> explicitly shows the access and mobility management function <NUM>, the session management function <NUM>, and the user plane function <NUM> of the telecommunications network <NUM>.

In a first processing step <NUM>, the user equipment <NUM> indicates (e.g. as part of a registration procedure) to the access and mobility management function <NUM> of the telecommunications network <NUM> that it supports both the first and second user plane mode of operation (i.e. especially both a segment routing-based and a GTP-U based user plane mode of operation). In a second processing step <NUM>, a packet data unit session establishment request is sent, by the user equipment <NUM>, to the session management function <NUM> of the telecommunications network <NUM>, the packet data unit session establishment request comprising the request, that either one of the second user plane mode of operation (e.g. SRv6) or the first user plane mode of operation (GTP-U based) be used (regarding the specific packet data unit session considered or requested). In a third processing step <NUM>, the session management function evaluates segment routing support, especially based on, e.g., the capabilities of the requested (or to be used) S-NSSAI and/or data network name, DNN, as well as the capabilities of the user plane function <NUM>. In case that this evaluation results in these capabilities (regarding using the second user plane mode of operation) are lacking (i.e. not being present and ready), in a fourth processing step <NUM>, the session management function <NUM> configures the user plane function <NUM> for the first user plane mode of operation (i.e. especially for a GTP-U based packet data unit session), and, in a fifth processing step <NUM>, the session management function <NUM> configures the access network <NUM> (especially via the access and mobility management function <NUM>) for the first user plane mode of operation (i.e. especially for a GTP-U based packet data unit session). In a sixth processing step <NUM>, the session management function <NUM> transmits a packet data unit session establishment accept message to the user equipment <NUM>, comprising an indication that the user plane mode of operation to be used corresponds to the first user plane mode of operation, i.e. especially GTP-U with legacy parameters. In a seventh processing step <NUM>, the user plane communication is able to be conducted between the user equipment <NUM> and the user plane function <NUM>, based on using the first user plane mode of operation, especially using, or realizing, a legacy N3 interface (or reference point), i.e. using SDAP/GTP-U.

In case that, the user equipment <NUM> had, in either the first processing step <NUM> or the second processing step <NUM>, indicated that it supports only (or is only capable of) the first user plane mode of operation (i.e. especially a GTP-U based user plane mode of operation) or that it requests (as part of the packet data unit session establishment request of the second processing step <NUM>) that the first user plane mode of operation (GTP-U based) be used (regarding the specific packet data unit session considered or requested), the evaluation, in the third processing step <NUM>, would have needed to be conducted to verify that legacy support (especially GTP-U support) is available regarding the requested (or to be used) S-NSSAI and/or data network name, DNN, as well as regarding the user plane function <NUM>; if this would have been verified, the fourth, fifth, sixth and seventh processing steps <NUM>, <NUM>, <NUM>, <NUM> would have been conducted as described above.

It is possible, according to the present invention, that one and the same user equipment <NUM> requests different user plane modes of operation for different packet data unit sessions: E. for a first packet data unit session (of that user equipment <NUM>, e.g. relating to a first application thereof), the packet data unit session establishment request (of the second processing step <NUM>/<NUM> as described above) comprises the indication that the first user plane mode of operation (GTP-U based) be used, and for a second packet data unit session (of that same user equipment <NUM>, e.g. relating to a second application thereof), the packet data unit session establishment request (of the second processing step <NUM>/<NUM> as described above) comprises the indication that the second user plane mode of operation (segment routing-based) be used. It is then up to the telecommunications network <NUM> to decide (or to evaluate in the third processing step <NUM>/<NUM>) which user plane mode of operation is to be used.

It is furthermore possible, according to the present invention, that - besides the user equipment <NUM> - a further user equipment (not shown) is connected to the telecommunications network <NUM> and transmits a further capability information to the telecommunications network <NUM> (analogously to the first and second processing steps <NUM>/<NUM>, <NUM>/<NUM> - wherein, of course, the further capability information is related to a further capability of the further user equipment to apply or to use the first user plane mode of operation and/or the second user plane mode of operation) and that, in case that the capability information <NUM> and the further capability information differ, different user plane modes of operation are applied for the user equipment <NUM> and for the further user equipment.

In the following, it is described in detail, exemplarily how the first user plane mode of operation, or, alternatively, the second user plane mode of operation is used as a result of network capability information being transmitted between different telecommunications networks, especially taking into consideration the case of a roaming situation (of the user equipment <NUM>), i.e. where the further telecommunications network <NUM> is connected to the telecommunications network <NUM> (and is serving the user equipment <NUM>, especially as a home network): Regarding user plane data exchanged between the telecommunications networks <NUM>, <NUM>, at least either the first user plane mode of operation or the second user plane mode of operation is able to be used for a given access technology (and, especially, regarding a given packet data unit session or logical data channel or user plane data stream.

Hence, in case of inter-network connectivity, the typical case is that of roaming. In this case, session management functions (SMFs) from each network are responsible for setting up a user plane path between two user plane functions (UPFs). The session management function exchange typically occurs via secure edge protection proxies (SEPPs or inter-PLMN secure gateways), while the user plane may be directly routed or routed with IPUPS functionality for additional security. <FIG> shows method analogous to the above-mentioned user equipment-network case when both ends (i.e. both networks <NUM>, <NUM>) support a given user plane mode of operation, resulting, e.g., in an end-to-end segment routing-based user plane. However, also in case of inter-network connectivity, there is a need to support the case when one network, especially the interconnection between the two networks, does not support a given type of user plane; for this case <FIG> shows a network <NUM> using a given user plane mode of operation (e.g. SRv6) that needs to bridge (or translate) between SRv6 and GTP-U.

In <FIG>, a communication diagram between the access network <NUM> and network nodes or elements of the telecommunications network <NUM> as well as of the further telecommunications network <NUM> is schematically and exemplarily shown, representing an example according to the present invention how the second user plane mode of operation is susceptible to be used between the telecommunications network <NUM> and the further telecommunications network <NUM>. <FIG> explicitly shows the session management function <NUM>, the user plane function <NUM>, and the secure edge protection proxy (function) <NUM> of the telecommunications network <NUM> (i.e. the visited session management function <NUM>, the visited user plane function <NUM> and the visited secure edge protection proxy (function) <NUM>, the visited user plane function <NUM> especially also comprising or referring to the (visited) inter PLMN user plane security (IPUPS) functionality of the telecommunications network <NUM>). Furthermore, <FIG> explicitly shows the further session management function <NUM> of the further telecommunications network <NUM>, the further user plane function <NUM> of the further telecommunications network <NUM>, and the further secure edge protection proxy (function) <NUM> of the further telecommunications network <NUM> (i.e. the home session management function <NUM>, the home user plane function <NUM> and the home secure edge protection proxy (function) <NUM>, the home user plane function <NUM> especially also comprising or referring to the (visited) inter PLMN user plane security (IPUPS) functionality of the further telecommunications network <NUM>).

In a first processing step <NUM>, the visited session management function <NUM> requests to the home session management function <NUM> (via the secure edge protection proxies <NUM>, <NUM>, thereby realizing, in a second processing step <NUM>, an N32-based control plane exchange) to set up N9 connectivity (i.e. connectivity of or according to the N9 interface or reference point), the indication to use (or the indication that there is a capability to use) the second user plane mode of operation (i.e. segment routing-based) for user plane traffic as well as the corresponding segment routing header information (to be used by the home network <NUM>, especially by the home user plane function <NUM>), i.e. the indication that it supports the second user plane mode of operation (or even that it supports both the first and second user plane mode of operation, i.e. especially both a segment routing-based and a GTP-U based user plane mode of operation). In a third processing step <NUM>, the home session management function <NUM> transmits, to the visited session management function <NUM> (again via the secure edge protection proxies <NUM>, <NUM>, thereby realizing, again, an N32-based control plane exchange) an accept message, especially comprising the indication of accepting the use of the second user plane mode of operation (i.e. segment routing-based) for user plane traffic as well as the corresponding segment routing header information (to be used by the visited network <NUM>, especially by the visited user plane function <NUM>). In a fourth processing step <NUM>, the visited session management function <NUM> sets up segment routing-based user plane functionality (by means of setting up - in the visited user plane function/IPUPS <NUM> - the processing of the segment routing header information received from the home session management function <NUM>), and in a fifth processing step <NUM>, the home session management function <NUM> sets up segment routing-based user plane functionality (by means of setting up - in the home user plane function/IPUPS <NUM> - the processing of the segment routing header information received from the visited session management function <NUM>). As a result thereof, in a sixth and seventh processing step <NUM>, <NUM>, the segment routing-based user plane communication (i.e. the second user plane mode of operation) is established, on the one hand between the access network <NUM> of the telecommunications network <NUM> towards the visited user plane function/IPUPS <NUM> (sixth processing step <NUM>) as a segment routing-based N3 interface (or reference point), and on the other hand between the visited user plane function/IPUPS <NUM> and the home user plane function/IPUPS <NUM> (seventh processing step <NUM>) as a segment routing-based N9 interface.

In contrast, in <FIG>, a communication diagram between, again, the access network <NUM> and network nodes or elements of the telecommunications network <NUM> as well as of the further telecommunications network <NUM> is schematically and exemplarily shown, representing an example according to the present invention how the first user plane mode of operation is susceptible to be used between the telecommunications network <NUM> and the further telecommunications network <NUM>. Again, <FIG> explicitly shows the session management function <NUM>, the user plane function <NUM>, and the secure edge protection proxy (function) <NUM> of both the telecommunications network <NUM> and the further telecommunications network <NUM>, the respective user plane functions <NUM>, <NUM> again especially also comprising or referring to the (visited/home) inter PLMN user plane security (IPUPS) functionality of the respective telecommunications networks <NUM>, <NUM>.

In a first processing step <NUM>, the visited session management function <NUM> requests to the home session management function <NUM> (via the secure edge protection proxies <NUM>, <NUM>, thereby realizing, in a second processing step <NUM>, an N32-based control plane exchange) to set up N9 connectivity, the indication to use (or the indication that there is a capability to use) the second user plane mode of operation (i.e. segment routing-based) for user plane traffic as well as the corresponding segment routing header information (to be used by the home network <NUM>, especially by the home user plane function <NUM>), i.e. the indication that it supports the second user plane mode of operation (or even that it supports both the first and second user plane mode of operation, i.e. especially both a segment routing-based and a GTP-U based user plane mode of operation). In a third processing step <NUM>, the home session management function <NUM> transmits, to the visited session management function <NUM> (again via the secure edge protection proxies <NUM>, <NUM>, thereby realizing, again, an N32-based control plane exchange) a message indicating that segment routing-based user plane communication (second user plane mode of operation) is not supported and that a legacy user plane communication (first user plane mode of operation) shall be used. This results, in a fourth processing step <NUM>, the visited session management function <NUM> setting up processing to convert or translate segment routing-based user plane processing or functionality to GTP-U-based user plane processing or functionality in the visited user plane function/IPUPS <NUM>, and in a fifth processing step <NUM>, the home session management function <NUM> sets up legacy user plane processing in the home user plane function/IPUPS <NUM>. As a result thereof, in a sixth and seventh processing step <NUM>, <NUM>, the segment routing-based user plane communication (i.e. the second user plane mode of operation) is established between the access network <NUM> of the telecommunications network <NUM> towards the visited user plane function/IPUPS <NUM> (sixth processing step <NUM>) as a segment routing-based N3 interface (or reference point), and the legacy GTP-U-based user plane processing is established between the visited user plane function/IPUPS <NUM> and the home user plane function/IPUPS <NUM> (seventh processing step <NUM>) as a GTP-U-based N9 interface.

In case that, the visited session management function <NUM> had, in the first processing step <NUM>, indicated that it supports only (or is only capable of) the first user plane mode of operation (i.e. especially a GTP-U based user plane mode of operation) or that it requests the first user plane mode of operation to be used (regarding the specific packet data unit session considered or requested), the response, in the third processing step <NUM>, from home session management function <NUM> would have been either identical (or perhaps with the indication that segment routing-based user plane processing would be possible), and the fourth, fifth, sixth and seventh processing steps <NUM>, <NUM>, <NUM>, <NUM> would have been conducted as described above.

Again, it is possible, according to the present invention, that regarding different packet data unit sessions different user plane modes of operation are used between the telecommunications network <NUM> and the further telecommunications network <NUM>.

As has been mentioned, the present invention comprises - besides transmitting capability information, e.g. the capability information <NUM> of the user equipment <NUM> or the further capability information or the network capability information - also transmitting segment routing header information (in case that segment routing-based user plane functionality is to be used). In this sense, the method relates to the telecommunications network <NUM> (or the further telecommunications network <NUM>) (either the access network <NUM> or the core network <NUM>, <NUM>) to signal the user equipment <NUM> segment routing-related functionality so that the user equipment <NUM> is able to:.

The transmission of (or the possibilities to transmit) segment routing-related information - especially segment routing header information - is schematically shown in <FIG> which schematically (and in a simplified manner) illustrates different interfaces or reference points, between different parts of a plurality of telecommunications networks, where segment routing header information (and/or corresponding conditions or condition information) is susceptible to be transmitted according to the present invention in order to define how the second user plane mode of operation is to be implemented. Specifically, <FIG> shows the user equipment <NUM>, the access network <NUM> (especially of the telecommunications network <NUM> acting as visited network), the core network <NUM> (especially of the telecommunications network <NUM> acting as visited network), and the further core network <NUM> (especially of the further telecommunications network <NUM> acting as home network of the user equipment <NUM>). Reference sign A designates the transmission of segment routing header information (and/or corresponding conditions or condition information) from the access network <NUM> to the user equipment <NUM>. Reference sign B designates the transmission of segment routing header information (and/or corresponding conditions or condition information) from the core network <NUM> to the user equipment <NUM>. Reference sign C designates the transmission of segment routing header information (and/or corresponding conditions or condition information) from the further core network <NUM> to the user equipment <NUM>. The user equipment <NUM> evaluates the conditions and applies the segment routing header (information) based on the communicated conditions, i.e. for the uplink direction, the network <NUM>, <NUM> instructs the user equipment <NUM> to add specific segment routing header(s) (segment routing header information) and to apply packet processing logic, to specific traffic and when given conditions such as time, location and/or network conditions are met.

This is schematically shown in <FIG>, schematically illustrating a communication diagram between the user equipment <NUM>, the telecommunications network <NUM>, and (exemplarily) a data network <NUM>, showing how the second user plane mode of operation (i.e. segment routing) is susceptible to be implemented regarding uplink traffic from the user equipment <NUM> towards the telecommunications network <NUM>: In a first processing step <NUM>, information is transmitted, by the telecommunications network <NUM>, to the user equipment <NUM>, indicating the segment routing header information to add to uplink (user plane) traffic (i.e. user plane traffic to be sent, by the user equipment <NUM>, towards the network <NUM>, i.e. in uplink direction). The term segment routing header information is used to indicate the segment routing header information per se (or: as such) as well as, if applicable, mapping information and, as well if applicable, information related to conditions to respect. In a second processing step <NUM>, matching traffic is generated by the user equipment <NUM>, e.g. by an application running on the user equipment <NUM> hardware/operating system. In a third processing step <NUM>, and in case that the conditions - indicated as part of the segment routing header information received by the user equipment <NUM> - are met, segment routing header information (i.e. one or a plurality of segment routing header(s)) is added to (user plane) data packets or (user plane) payload so that the data packets can be further transmitted and/or processed accordingly. In a fourth processing step <NUM>, the data packets - i.e. including the segment routing header(s) - are sent (by the user equipment <NUM>) towards the telecommunications network <NUM> (i.e. to the respective access network or core network node or element), and, in a fifth processing step <NUM>, the traffic is processed (by the telecommunications network <NUM>) as per the segment routing header(s), and, eventually, in a sixth processing step <NUM>, sent (in the exemplary situation shown in <FIG>) to the data network <NUM>.

Regarding the opposite direction, i.e. (user plane) traffic towards the user equipment <NUM>, <FIG> schematically illustrates a communication diagram between the user equipment <NUM>, the telecommunications network <NUM>, and (exemplarily) a data network <NUM>, showing how the second user plane mode of operation (i.e. segment routing) is susceptible to be implemented regarding downlink traffic from the telecommunications network <NUM> towards the user equipment <NUM>:
In a first processing step <NUM>, information is transmitted, by the telecommunications network <NUM>, to the user equipment <NUM>, indicating the segment routing header information to remove from downlink (user plane) traffic (i.e. user plane traffic to be sent, by the telecommunications network <NUM>, towards the user equipment <NUM>, i.e. in downlink direction). The term segment routing header information, again, is used to indicate the segment routing header information per se (or: as such) as well as, if applicable, mapping information and, as well if applicable, information related to conditions to respect. In a second processing step <NUM>, the telecommunications network <NUM> receives data packets or traffic, in downlink direction from (exemplarily) the data network <NUM>, the telecommunications network <NUM> furthermore adds, in a third processing step <NUM>, segment routing header information to (user plane) the data packets/traffic or payload, and, in a fourth processing step <NUM>, sends the data packets or traffic - i.e. including the segment routing header(s) - to the user equipment <NUM>. In case that the conditions (being explicitly or implicitly) indicated are met, the user equipment <NUM> removes the segment routing header(s) from the respective data packets, and applies the respective data processing. Finally, in a sixth processing step <NUM>, the data packets (or the payload) is forwarded to the respective application of the user equipment <NUM>. Hence, in summary, the user equipment <NUM> receives the user plane traffic containing the segment routing header(s) or segment routing header information, and the telecommunications network <NUM> instructs the user equipment <NUM> to remove specific segment routing header(s) (segment routing header information) and to apply packet processing logic, to specific traffic and when given conditions such as time, location and/or network conditions are met.

In terms of mapping, i.e. the establishment of a relationship between two elements, such as where to apply segment routing headers and/or what actions given segment routing headers trigger, which occurs for both uplink and downlink directions, the following mappings are considered to be signaled from the telecommunications network <NUM> to the user equipment <NUM>:.

By signaling appropriate segment routing header and mapping information to the user equipment <NUM>, the following use cases can be realized:.

With regard to the question how to deliver the mapping information to the user equipment <NUM>, several methods are considered. In terms of network functionality, and based on current protocol layers available for telecom networks, it is advantageous if current architectures are compatible with the use of segment routing header. The following delivery methods are possible and preferred according to the present invention:.

The core network can use non-access stratum (NAS) protocol, especially in the form of protocol containers within the non-access stratum protocol, especially the session management container (between the user equipment <NUM> and session management function <NUM>), as exemplary shown in <FIG>, which schematically illustrates different possibilities how the segment routing header information - or mapping information - is susceptible to be transmitted between different network elements or components, and especially towards the user equipment <NUM>. On the left hand side, <FIG> shows one alternative for transmitting such segment routing header information - or mapping information - towards the user equipment <NUM>, namely using the session management function <NUM> (and via the packet data unit establishment procedure), wherein, in a first processing step <NUM>, the packet data unit session establishment is requested (by means of a corresponding requesting message, sent by the user equipment <NUM> to the session management function <NUM>), and, in the second processing step <NUM>, the packet data unit session establishment accept message is sent, by the session management function <NUM> to the user equipment <NUM>, the packet data unit session establishment accept message comprising the segment routing parameters and/or mapping information (i.e. the segment routing header information).

As an alternative delivery method albeit only applicable to uplink traffic, <FIG> shows, on its right hand side, a communication diagram between the user equipment <NUM> and a policy and charging function <NUM> of the telecommunications network <NUM>, wherein the transmission of the corresponding information involves the policy and charging function <NUM> and is part of a user equipment route selection policy (URSP) rule transmission, i.e. via the policy container part in non-access stratum signaling, i.e. in the signaling between user equipment <NUM> and the policy and charging function <NUM>, in a first processing step <NUM>, the user equipment <NUM> policy association between the user equipment <NUM> and the policy and charging function <NUM> occurs or takes place, and, in a second processing step <NUM>, the segment routing parameters (or the segment routing header information) is included in user equipment route selection policy rules sent to the user equipment <NUM>.

Furthermore according to the present invention, multi-network routing is preferably enabled: In order to better support the indication of the target for some considered data packets in transit through the visited telecommunications network (i.e. telecommunications network <NUM> or V-PLMN), it is preferred that the H-PLMN (or further telecommunications network <NUM>) signals the user equipment <NUM> to include segment routing header information indicating the target network identifier (e.g. containing the PLMN ID of the home network <NUM>) so that the V-PLMN (or telecommunications network <NUM>) can easily route said data packets towards the home network <NUM>.

Claim 1:
Method for using a user equipment (<NUM>) with at least one telecommunications network (<NUM>), wherein the user equipment (<NUM>) is connected to the telecommunications network (<NUM>) using an access network (<NUM>) of or assigned to or associated with the telecommunications network (<NUM>) and the telecommunications network (<NUM>) further comprising a core network (<NUM>) to which the user equipment (<NUM>) is connected,
wherein the user equipment (<NUM>) is used with the telecommunications network (<NUM>) by means of transmitting and/or receiving user plane data and control plane data, wherein, regarding user plane data exchanged between the user equipment (<NUM>) and the telecommunications network (<NUM>), at least either a first user plane mode of operation or a second user plane mode of operation is able to be used for a given access technology, wherein the second user plane mode of operation is a segment-routing-related second user plane mode of operation,
wherein the method comprises the following steps:
-- in a first step, the user equipment (<NUM>) transmits a capability information (<NUM>) to the telecommunications network (<NUM>), the capability information (<NUM>) being related to a capability of the user equipment (<NUM>) to apply or to use the first user plane mode of operation and/or the second user plane mode of operation,
-- in a second step, the first user plane mode of operation or the second user plane mode of operation is applied in accordance with the capability information (<NUM>),
wherein in case that the second user plane mode of operation is used, at least one out of the following applies:
-- the telecommunications network (<NUM>) signals to the user equipment (<NUM>) a segment routing-related functionality,
-- the user equipment (<NUM>) adds segment routing header information to uplink traffic,
-- the user equipment (<NUM>) removes segment routing header information from downlink traffic,
-- the user equipment (<NUM>) applies, to either uplink or downlink traffic, packet processing logic to matching traffic,
-- the user equipment (<NUM>) applies a mapping between packet data unit sessions, quality-of-service flows or quality-of-service subflows and/or application traffic and one or more pieces of segment routing header information.