Reallocation of subscriptions in 5gc

Abstract

A first instance of a Network Function (NF) producer supports reallocation of subscriptions of a plurality of User Equipments (UEs) from the first instance to a second instance of the NF producer The first instance of the NF producer may determine that the subscriptions of the plurality of UEs are to be reallocated to the second instance. After the determination, the first instance of the NF producer may send to an NF consumer a restoration notification including a reallocation indication and information identifying the plurality of UEs.

Description

[0001]REALLOCATION OF SUBSCRIPTIONS IN 5GC TECHNICAL FIELD The present disclosure generally relates to reallocating subscriptions of User Equipments (UEs) from one instance of a network function (NF) producer to another instance of the NF producer in 5G Core (5GC). In particular, the present disclosure leverages a restoration procedure that restores NF profiles to complete subscription reallocation. BACKGROUND The 3rd generation partnership project (3GPP) allows deployment of different instances of NF producers to manage different sets of subscriptions of UEs within a public land mobile network (PLMN). Example NF producers may include authentication server function (AUSF), unified data management (UDM), and unified data repository (UDR). NF profiles for different instances of NF producers are stored in a network repository function (NRF). Once an NF producer restarts or detects data corruption, data loss or data inconsistency, NF profiles across different NF producers may need to be resynchronized to minimize adverse impacts on a network operator’s services. FIG. 1 illustrates a sequence diagram showing interactions among different network entities to resynchronize NF profiles. This process is also known as a restoration procedure. Subscriptions of UEs sometimes need to be reallocated from an original instance of an NF producer to a target instance of an NF producer. Subscription reallocation is also known in some cases as “user data migration.” Although static data can be easily provisioned from the original instance to the target instance, dynamic data such as user registration information is not. Presently, there is no user-based routing performed by any NF. For example, the service communication proxy (SCP) in 5GC does not perform user-based routing. Therefore, it is up to the NF consumer to route the dynamic data to the target instance. Currently, it is not possible to use the restoration procedure for NF profiles to reallocate subscriptions from one instance of the NF producer to another instance in 5GC due to the following issues. First, the restoration notification sent by an NF producer, e.g., the UDM, to its consumer includes a time window during which the UDR has been down. In the case that the registration of the user in the UDM consumer is not impacted by the UDR down time, the UDM consumer is prevented from performing restoration / reallocation towards UDM / UDR. Second, even if the UDM consumer triggers the restoration / reallocation towards the UDM / UDR, the UDM consumer may still address the original UDM / UDR instance / segment where the subscription was defined, instead of the target UDM / UDR where the UDM consumer registration is expected to take place. During the original registration, the UDM consumers stores the UDM Group ID, and AUSF Group ID in the case of access and mobility management function (AMF). As a result, during restoration, the UDM consumer will select a UDM instance belonging to the original Group ID stored in the UDM consumer, rather than the target UDM / UDR in the new instance / segment. Third, when a UDR restoration is received in the AMF and there was a previously received NF profile notification change for UDMs also received in the AMF, it is not known to AMF that they are somehow related and that they are required to be taken into account for existing UE contexts. Fourth, because resynchronization takes place gradually, this may lead to inconsistent UE dynamic data as part of the dynamic data may be restored / resynced at some point in time, while other data is not yet restored / resynched. As an example, if AMF data is restored, and short message service function (SMSF) data is not restored yet, the user would be located and served by an AMF, but short message service (SMS) over 5G non-access stratum (NAS) would not be working until the SMSF restores its data in UDM / UDR. There is a need to address the above issues, and configure the restoration procedure to support subscription reallocation. SUMMARY The present disclosure extends the restoration procedure for NF profiles to support reallocation of subscriptions without service interruption. In particular, the present disclosure enables using the restoration procedure for NF Profiles to reallocate subscriptions from an original instance of an NF producer to a target instance in 5GC. The present disclosure enables resynchronization to be performed at the same time across all relevant network functions, e.g., AMF, session management function (SMF), so that the complete dynamic data is available when the original instance of the NF producer (e.g., AMF) triggers the resynchronization. In one aspect, the present disclosure implements an additional new reallocation indication within the restoration notification sent by the original instance to its NF consumers and implements corresponding reallocation logic in the NF consumers. The reallocation indication, which is an indication that the plurality of UEs are being allocated, may be complemented with additional information regarding identification of the target instance to be used during the reallocation procedure. According to one aspect of the disclosure, a method may be performed by a first instance of an NF producer to support reallocation of subscriptions of a plurality of UEs from the first instance to a second instance of the NF producer. The first instance may determine that the subscriptions of the plurality of UEs are to be reallocated to the second instance. In response to the determining, the first instance may send to an NF consumer a restoration notification including a reallocation indication and information identifying the plurality of UEs. In some embodiments, the NF producer may include one or more of the following: one or more UDMs and one or more AUSFs. In some embodiments, the NF consumer may be registered with the first instance. In some embodiments, the first instance may send the restoration notification via an operation and maintenance (O&M) command that requires reallocation of the plurality of UEs. In some embodiments, the information identifying the plurality of UEs may include a subscription permanent identifier (SUPI) range. In some embodiments, the method may include receiving a signal from a network operator to reallocate the plurality of UEs. In some embodiments, the restoration notification may include one or more of the following: a generic public subscription identifier (GPSI) range associated with the plurality of UEs, a reset identifier of temporary data associated with the plurality of UEs, and at least one routing indicator (RID) associated with the plurality of UEs. In some embodiments, the restoration notification may include an identifier associated with the second instance. In some embodiments, the identifier may be a group identifier associated with the second instance. In some embodiments, the identifier may indicate a need for authentication of the plurality of UEs for reallocating them to the second instance. In some embodiments, the restoration notification may include an authentication indication indicating a need for authenticating the plurality of UEs for reallocating them to the second instance. In some embodiments, the reallocation indication may indicate a need for authenticating the UEs for reallocating them to the second instance. In some embodiments, the NF consumer may include one or more of the following: AMF, session management function (SMF), SMSF, network data analytics function (NWADF) and network data analytics function (NEF). According to another aspect of the disclosure, a method may be performed by a first instance of an NF producer to support reallocation of subscriptions of a plurality of UEs from the first instance to a second instance of the NF producer. The method may comprise determining that the subscriptions of the plurality of UEs are to be reallocated to the second instance. In response to said determining, the first instance may send to an NF consumer, a restoration notification including information identifying the plurality of UEs and a reregistration indication. In some embodiments, the reregistration indication may request the NF consumer to deregister and reregister at least one UE of the plurality of UEs. In some embodiments, the reregistration indication may prompt the NF consumer to inform at least one other NF to deregister and reregister the at least one UE. In some embodiments, the first instance may receive a signal from a network operator to reallocate the plurality of UEs. According to yet another aspect of the disclosure, a method may be performed by an NF consumer to support reallocation of subscriptions of a plurality of UEs from a first instance of an NF producer to a second instance of the NF producer. The NF consumer may receive, from the first instance, a restoration notification including a reallocation indication and information identifying the plurality of UEs. The NF consumer may select, from the plurality of UEs, at least one UE registered with the NF consumer. The NF consumer may receive information associated with the second instance of the NF producer. The NF consumer may update UE context information stored by the NF consumer for the at least one selected UE based on the received information of the second instance. The NF consumer may send a registration request to the second instance to register the NF consumer for the at least one selected UE. In some embodiments, to receive the information associated with the second instance, the NF consumer may send to an NRF a discovery request associated with the at least one selected UE. In some embodiments, the information associated with the second instance may be received via a notification from an NRF regarding an update of NF profiles of the first instance and the second instance. In some embodiments, the information associated with the second instance may include an identifier associated with the second instance. In some embodiments, the NF producer may include one or more of the following: one or more UDMs, one or more AUSFs, and one or more UDRs. In some embodiments, the NF consumer may be registered with the first instance. In some embodiments, the information identifying the plurality of UEs may include a SUPI range. In some embodiments, the NF consumer may delay the updating and the sending based on a subsequent activity of the at least one selected UE in the NF consumer. The NF consumer may indicate during the delay that the at least one selected UE has pending restoration with reallocation. In some embodiments, the restoration notification may include one or more of the following: a GPSI range associated with the plurality of UEs, a reset identifier of temporary data associated with the plurality of UEs, and at least one RID associated with the plurality of UEs. In some embodiments, to receive the information associated with the second instance, the NF consumer may send to an NFR a discovery request associated with the at least one selected UE based on the at least one reset identifier and / or the at least one RID. In some embodiments, the restoration notification may include an identifier associated with the second instance. In some embodiments, the identifier may be a group identifier. In some embodiments, to receive the information associated with the second instance, the NF consumer may send to an NFR a discovery request for the at least one selected UE based on the identifier associated with the second instance. In some embodiments, the identifier may indicate a need for authenticating the plurality of UEs for reallocating them to the second instance. In some embodiments, the restoration notification may include an authentication indication indicating a need for authenticating the plurality of UEs for reallocating them to the second instance. In some embodiments, the reallocation indication may indicate a need for authenticating the plurality of UEs for reallocating them to the second instance. In some embodiments, the NF consumer may request authentication of the at least one selected UE. In some embodiments, subsequent to sending the registration request, the NF consumer may receive from the second instance a reauthentication error. In some embodiments, responsive to receiving the reauthentication error, the NF consumer may send to an NRF a discovery request for the at least one selected UE regarding authentication. The NF consumer may request authentication of the at least one selected UE. After successful authentication of the at least one selected UE, the NF consumer may send a second registration request to the second instance to register the NF consumer for the at least one selected UE. In some embodiments, the NF consumer may include one or more of the following: AMF, SMF, SMSF, NWADF and NEF. In some embodiments, the NF consumer may trigger at least one other NF consumer to perform restoration and reallocation with respect to the at least one selected UE. In some embodiments, the NF consumer may be an AMF. The at least one other NF consumer may include an SMF and / or an SMSF managing a packet data unit (PDU) session or an SMS for the at least one selected UE. In some embodiments, the triggering may include one or more of the following: sending a first request to the SMF via an Nsmsf service operation; and sending a second request to the SMSF via an Nsmsf service operation. In some embodiments, the triggering may include providing an identifier associated with the second instance to the at least one other NF consumer. According to another aspect of the disclosure, a method may be performed by an NF consumer to support reallocation of subscriptions of a plurality of UEs from a first instance of an NF producer to a second instance of the NF producer. The NF consumer may receive a restoration notification including a reregistration indication and information identifying the plurality of UEs. The NF consumer may select, from the plurality of UEs, at least one UE registered with the NF consumer. The NF consumer may deregister the at least one selected UE from the NF consumer. Subsequent to the deregistration, the NF consumer may receive a registration request from the at least one selected UE. Responsive to receiving the registration request, the NF consumer may send a discovery request to an NRF for the at least one selected UE to receive information associated with the second instance. The NF consumer may send a registration request to the second instance to register the NF consumer for the at least one selected UE. In some embodiments, the NF consumer may inform at least one other NF consumer to reregister the at least one selected UE. In some embodiments, the informing may include requesting, by the NF consumer, at least one SMF to release an ongoing PDU session and deregister from SMSF. According to yet another aspect of the disclosure, a method may be performed by an NRF to support reallocation of subscriptions of a plurality of UEs from a first instance of an NF producer to second instance of the NF producer. The NRF may receive a first update request, from the first instance, to update its NF profile to be dissociated with the plurality of UEs. The NRF may receive a second update request, from the second instance, to update its NF profile to be associated with the plurality of UEs. The second update request may include a reset identifier of temporary data associated with the plurality of UEs. The NRF may receive a discovery request, from an NF consumer, for at least one UE from the plurality of UEs. The discovery request may include one or more of the following: the reset identifier and an identifier associated with the second instance. Responsive to receiving the discovery request, the NRF may send information associated with the second instance to the NF consumer. In some embodiments, the second update request may include an RID identifying the plurality of UEs, and wherein the discovery request includes the RID. Of course, the present invention is not limited to the above features and advantages. Indeed, those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages will be more apparent from the following description of embodiments with reference to the accompanied drawings. FIG. 1 is a sequence diagram illustrating interactions among different network entities to resynchronize NF profiles according to one aspect of the technology. FIGS. 2-14 are block diagrams showing interactions among different network entities to reallocate subscriptions of UEs according to different aspects of the technology. FIG. 15 is a flow diagram illustrating a method implemented by a first instance of an NF producer according to one aspect of the technology. FIG.16 is a flow diagram illustrating another method implemented by the first instance of the NF producer according to one aspect of the technology. FIG.17 is a flow diagram illustrating a method implemented by an NF consumer according to one aspect of the technology. FIG. 18 is a flow diagram illustrating another method implemented by the NF consumer according to one aspect of the technology. FIG. 19 is a flow diagram illustrating a method implemented by an NRF according to one aspect of the technology. FIG. 20A is a block diagram illustrating components of the NF consumer according to one aspect of the technology. FIG. 20B is a block diagram illustrating components of an NF producer instance according to one aspect of the technology. FIG.20C is a block diagram illustrating components of the NRF according to one aspect of the technology. FIG.20D is a block diagram illustrating components of the UE according to one aspect of the technology. FIG.21 is a block diagram illustrating components of a virtualized environment. DETAILED DESCRIPTION Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is / are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 1. Network Entities Overview FIG. 2 shows a high-level block diagram illustrating interactions within a PLMN 200 to reallocate subscriptions of UEs 201 from a first instance 202 of an NF producer to a second instance 204 of the NF producer. Each network entity illustrated in FIG.2 is described in detail below. 1.1 NF Producer The NF producer may have a plurality of instances for managing different sets of subscriptions of UEs 201 within the PLMN 200. The first instance 202 of the NF producer may be referred to as the original instance or the first segment. The second instance 204 of the NF producer may be referred to as the target instance or the second segment. The term “instance” and the term “segment” may be used interchangeably throughout this disclosure. The NF producer may include one or more of the following: one or more UDMs, one or more AUSFs, and one or more UDRs. As shown in FIG.2, the first instance 202 of the NF producer may include UDMs 202a, AUSFs 202b and UDRs 202c. The second instance 204 of the NF producer may include UDMs 204a, AUSFs 204b and UDRs 204c. 1.1.1 Determine Reallocation The first instance 202 may determine that the subscriptions of the UEs 201 are to be reallocated to the second instance 204. For example, the first instance 202 may receive a signal from a network operator 205205 to reallocate the UEs 201. 1.1.2 Send Restoration Notification After determining that the subscriptions of the UEs 201 are to be reallocated, the first instance 202 may send to an NF consumer 206 a restoration notification 208 that requires reallocation of the UEs 201. The restoration notification 208 may be sent via an O&M command. The restoration notification 208 may include information identifying the UEs 201 to be reallocated. Such information may include one or more of the following: at least one SUPI range, at least one GPSI range associated with the UEs, at least one reset identifier of temporary data associated with the UEs, and at least one RID associated with the UEs. The reset identifier may identify a hardware resource and may contain a reset counter. The first instance 202 may assign the GPSI range(s) and the reset identifier(s) in an implementation specific way. In one example, the restoration notification 208 may include a reallocation indication. The reallocation indication may indicate a need to reallocate UEs. In another example, instead of the reallocation indication, the restoration notification 208 may include a reregistration indication. The reregistration indication may request the NF consumer 206 to deregister and reregister the UEs as shown in FIG.3. In one example, the reregistration indication may prompt the NF consumer 206 to inform at least one other NF consumer to deregister and reregister the UEs. The at least one other NF consumer may not be registered in the first instance of the NF producer. For instance, an AMF may inform an NEF, not registered in a first UDM instance, to deregister and reregister the UEs. In one embodiment, the realloca^on procedure may not be fully completed un^l all NF consumers move their registra^on / data to the second instance 204 of the NF producer. In one example, the restoration notification 208 may include an identifier associated with the second instance 204 of the NF producer. The identifier may be a group identifier associated with the second instance 204. In one example, the identifier associated with the second instance 204 may indicate a need for authenticating the UEs. In another example, the reallocation indication may indicate a need for authenticating the UEs. In yet another example, the restoration notification 208 may include an authentication indication that is configured to indicate a need for authenticating the UEs 201. 1.2 NF Consumer The NF consumer 206 may be initially registered with the first instance 202 of the NF producer. In one example, the NF consumer 206 may be a UDR consumer and / or a UDM consumer. The UDR consumer may be UDM. Example UDM consumers may include, but not limited to, AMF, SMF, SMSF, NWADF and NEF. 1.2.1 Receive Restoration Notification The NF consumer 206 may receive, from the first instance 202, the restoration notification identifying the UEs to be reallocated. The NF consumer 206 may select, from the identified UEs, at least one UE registered with the NF consumer 206. 1.2.2 Receive Information of the Second Instance The NF consumer 206 may receive information associated with the second instance 204 of the NF producer. The information associated with the second instance may include an identifier associated with the second instance 204. In one example, to receive the information associated with the second instance 204, the NF consumer 206 may send, to the NRF 210, a discovery request 212. The discovery request 212 may, for instance, include one or more of the following: at least one reset identifier, at least one RID, and an identifier associated with the second instance 204. By doing so, the NF consumer 206 may discover via the NRF 210 and identify the second instance 204 that supports the reset identifier and / or the RID, or identify the second instance 204 by its associated identifier. In another example, referring to FIG. 4, the NF consumer 206 may subscribe to the NRF 210 to receive notifications 213 from the NRF 210 of any newly updated NF profile of an NF (e.g., NF service instances taken in or out of service), or newly registered de-registered NF instances. When the subscriptions of the UEs are reallocated from the first instance 202 to the second instance 204, the NF consumer 206 may receive a notification 213 indicating an update of the NP profile of the first instance 202 or an update of the NP profile of the second instance 204. The notification 213 may indicate that the first instance 202 no longer supports a given set of UEs, or indicating that the second instance 204 starts to support the given set of UEs. The NF consumer 206 may receive the information associated with the second instance 204 via the notification 213 from the NRF 210. 1.2.3 Update UE Context Information After receiving the information associated with the second instance 204, the NF consumer 206 may update UE context information stored by the NF consumer 206 for the selected UE(s) based on the received information of the second instance 204. The NF consumer 206 may send a registration request 214 to the second instance 204 to register the NF consumer 206 for the selected UE(s). In one example, the NF consumer 206 may delay updating the UE context information, and may also delay sending the registration request to the second instance 204. The delay may be based on a subsequent activity of the selected UE(s) in the NF consumer 206. The NF consumer 206 may indicate during the delay that the selected UE(s) has pending restoration with reallocation. 1.2.4 Authenticate UE In one example, the NF consumer 206 may request authentication of the selected UE(s). Referring to FIG. 5, the NF consumer 206 may send a registration and authentication request 216 to the second instance 204. In another example, referring to FIG.6, after sending the registration request 214 to the second instance 204, the NF consumer 206 may receive from the second instance 204 a reauthentication error 218. The reauthentication error 218 may indicate that the selected UE(s) is not authenticated. After receiving the reauthentication error 218, the NF consumer 206 may send to the NRF 210 a discovery request 212 for the selected UE(s) regarding authentication. Then, the NF consumer 206 may request authentication of the selected UE(s) by sending an authentication request 220 to the second instance 204. After successful authentication of the selected UE(s), the NF consumer 206 may send another registration request to the second instance 204 to register the NF consumer 206 for the selected UE(s). 1.2.5 Reregister UE Referring to FIG.3, the NF consumer 206 may receive a restoration notification 208 including a reregistration indication and information identifying the UEs to be reallocated. The NF consumer 206 may select, from the UEs, at least one UE registered with the NF consumer 206. The NF consumer 206 may deregister the selected UE(s) from the NF consumer 206 by sending a deregister request 222. Subsequent to the deregistration, the NF consumer 206 may receive a registration request 224 from the selected UE(s). After receiving the registration request 224, the NF consumer 206 may send a discovery request 212 to the NRF 210 for the selected UE(s) to receive information associated with the second instance 204. The NF consumer 206 may send a registration request 214 to the second instance 204 to register the NF consumer 206 for the selected UE(s). In one example, the NF consumer 206 may inform one or more other NF consumers to reregister the selected UE(s). The other NF consumers 206 may include one or more of the following: an SMF, an SMSF configured to manage a PDU session, and an SMS. For instance, the NF consumer 206 may request an SMF to release an ongoing PDU session, and deregister from the SMSF. 1.2.6 Trigger Other NF Consumer Referring to FIG.7, to speed up resynchronization across different NFs, the NF consumer 206 may trigger one or more other NF consumers 230 to perform restoration and reallocation with respect to the selected UE(s). The NF consumer 206 may send a reallocation request 232 to the other NF consumer(s) 230. The NF consumer 206 may provide an identifier associated with the second instance 204 to the other NF consumer(s). In turn, the other NF consumer(s) may send a registration request 214 to the second instance 204. By way of example, the NF consumer 206 may send a first reallocation request to the SMF via an Nsmf service operation, and send a second reallocation request to the SMSF via an Nsmsf service operation. 1.3 NRF The NRF 210 may maintain NF profiles for different instances of the NF producer. NF profiles registered in the NRF 210 include one or more of the following segmentation parameters: an NF group ID, one or more routing indicators, one or more SUPI / GPSI Ranges, among other possibilities. The NF group ID may identify the instance of the NF producer. In one example, NF profiles for AUSF, UDM and UDR may indicate that they support multiple SUPI / GPSI Ranges. NF profiles for AUSF / UDM may indicate that they support multiple routing indicators. To support reallocation of the subscriptions of the UEs, the NRF 210 may update the respective instances of the NF producer to be associated or disassociated with the UEs. The update may be performed via an Nnrf_NFManagement_NFRegister service operation. In one example, the NRF 210 may receive a first update request, from the first instance 202, to update its NF profile to be dissociated with the UEs. The NRF 210 may receive a second update request, from the second instance 204, to update its NF profile to be associated with the UEs. The second update request may include a reset identifier of temporary data (e.g., a resource) associated with the UEs. In one example, the second update request may include an RID identifying the UEs. The NRF 210 may receive a discovery request 212, from the NF consumer 206, for a selected UE(s). The discovery request 212 may include one or more of the following: the reset identifier and an identifier associated with the second instance 204. In one example, the discovery request may include the RID. In response to the discovery request, the NRF 210 may send information associated with the second instance 204 to the NF consumer 206. 1.4 Network Operator To initiate reallocation of the subscriptions of the UEs, the network operator 205 may provision the second instance 204 of the NF producer to serve the subscriptions of the UEs as identified in the first instance 202 of the NF producer. The provision may be done via provisioning mechanisms not defined in 3GPP. As a result of the provision, the NF profiles of both the first instance 202 and the second instance 204 may be updated in the NRF 210. 1.5 UE The UE 201 may refer to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE may include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE. 2. Use Case Examples FIGS.8-14 illustrate various use case examples of the present technology. 2.1 Restoration Notification with Reallocation FIG.8 illustrates an example of using a restoration notification with a reallocation indication. As shown in FIG.8, a first UDM instance 202a may trigger a restoration notification 208 to an NF consumer 206, such as a UDM consumer or AMF, registered in the first UDM / UDR instance 202a / 202c. The restora^on notification 208 may include one or more SUPI ranges identifying impacted UEs. The NF consumer 206 may be configured to manage one or more of the impacted UEs. The restoration notification 208 may include a new reallocation indication. Since this is not related to a UDR incident, the first UDM instance 202a may decide to send the restoration notification 208 via an O&M command that requires reallocation for the impacted UEs. Upon receiving the restoration notification 208 with the new reallocation indication from the first UDM 202a, the NF consumer 206 may identify UEs impacted by the reallocation request. If there is at least one impacted UE registered in the NF consumer 206, the NF consumer 206 may ignore the UDM Group ID value stored in the UE context, if any. The UDM Group ID may identify the UDM instance. For example, the UDM Group ID value may initially identify the first UDM instance 202a. The NF consumer 206 may perform a new UDM selection / discovery request for the impacted UEs due to the reallocation request. The new UDM selection request may be performed via an Nnrf_NFManagement_NFDiscovery service operation. Alternatively, if the NF consumer 206 has subscribed to NF profile updates in the NRF 210, the NF consumer 206 may have already received notification from the NRF 210 of the update of the NF profiles of the first UDM / UDR instance 202a / 202c and the second UDM / UDR instance 204a / 204c. Based on the result of the UDM selection, the NF consumer 206 may send a registration request, e.g., Nudm_UECM_Reg, to the second UDM / UDR instance 204a / 204c. By doing so, the NF consumer 206 may register in the second UDM / UDR instance 204a / 204c and store the NF consumer registration data in the second UDM / UDR instance 204a / 204c. The result of the UDM discovery / selection may provide the NF consumer 206 with the information of the new UDM Group ID value. The new UDM Group ID value may be indicative of the second UDM instance 204a. The NF consumer 206 may decide to throttle the execution of the restoration, e.g., with reallocation, of its registration for the affected UEs in the second UDM instance 204a. For example, the NF consumer 206 may decide to throttle the execution based on a subsequent UE activity in the NF consumer 206. In this case, the affected UEs may be marked as pending restoration, e.g., with reallocation. As a result, selection of the new UDM Group ID and transmission of the actual registration may take place at a later stage. 2.2 Restoration Notification with Other UE Identifiers Referring to FIG. 9, aside from the SUPI range(s) as shown in FIG. 8, other UE identifiers such as GPSI range(s), reset identifier(s) and / or RID(s) may be used to identify the set of subscriptions that are moved from the first UDM / UDR instance 202a / 202c to another instance within the PLMN. These other UE identifiers may enable the NF consumer 206 to optimize the UDM discovery / selection. The NRF may store one or more SUPI range(s), GPSI range(s), reset identifier(s) and RID(s) supported by each UDM instance 202a / 204a in their respective NF profiles. In one example, the first UDM instance 202a may send the GPSI range(s) associated with the SUPI range(s) to the NF consumer 206 via Nudm_SDM service. The first UDR instance 202c may assign the reset identifier(s) of temporary data associated with the SUPI range(s) or the GPSI range(s) in an implementation specific way. For example, the reset identifier(s) may be provided to the NF consumer 206, e.g., UDR consumer and UDM consumer, in the response of a request that has created temporary data in the first UDR instance 202. The response may be a Nudm_UECM_Registration Response. The restoration notification 208 may include one or more of the following: the SUPI / GPSI range(s), the reset identifier(s), the RID(s), and the reallocation indication. The NF consumer 206 may update the UE context to include the RID(s) and reset identifier(s). The NF consumer 206 may send a discovery request to the NRF 210. The discovery request may include the RID(s) and / or the reset identifier(s). 2.3 Restoration Notification Identifying Second NF Producer Instance Referring to FIG. 10, to facilitate the selection of the second UDM / UDR instance 204a / 204c where the impacted UEs shall be reallocated, the first UDM instance 202 may include in the restoration notification 208 an identifier that identifies the second UDM / UDR instance 204a / 204c. The identifier may for example be a UDM Group ID identifying the target instance, e.g., Target UDM Group ID. The NF consumer 206 may optimize the UDM discovery / selection based on the provided UDM Group ID. 2.4 Restoration Notification with Reauthentication Indication During primary authentication, the first AUSF instance 202b may generate an authentication key Kausf for the UE. The first AUSF instance 202b may store the authentication key Kausf locally. The first AUSF instance 202b may inform the first UDM instance 202a about the result of the authentication so that the first UDM instance also knows the identifier of the first AUSF instance 202b that has the authentication key Kausf for the UE. Referring to FIG. 11, the first UDM instance 202a may include an authentication indication within the restoration no^fica^on 208 sent to the NF consumer 206. In one example, the authentication indication may be implicitly provided by providing the identifier of the second AUSF instance 204b, e.g., Target AUSF Group ID, to be used for the reauthentication. Alternatively, the authentication indication may be implicitly provided by providing the reallocation indication. As a result of receiving the explicit or implicit authentication indication, before registering with the second UDM instance 204a, the NF consumer may request the second AUSF instance 204b to authenticate the UE and generate an authentication key Kausf for the UE. Alternatively, as shown in FIG.12, if the NF consumer does not request authentication prior to registration with the second UDM instance 204a, the second UDM instance 204a may reject the registration request from the NF consumer with a reauthentication error indication. Since the registration request was sent due to a reallocation request, the NF consumer 206 may ignore the identifier of the AUSF instance, e.g., AUSF Group ID value, stored in the UE context. The NF consumer 206 may perform a new AUSF selection request for the UE. After successful authentication, the NF consumer 206 may send the registration request again to the second UDM instance 204a. 2.5 Restoration Notification with Reregistration Indication Referring to FIG.13, to ensure that all NF consumers complete their reallocation all at once or at about the same time, the first UDM instance 202a may only send the restoration notification to one NF consumer, e.g., AMF. Instead of including a reallocation indication in the restoration notification, the first UDM instance 202a may include a reregistration indication. The NF consumer may then initiate a deregistration procedure towards the impacted UEs. In addition, the NF consumer may inform other NFs, all of which shall remove the UE context related to the impacted UEs. For example, the NF consumer may request the SMFs to release ongoing PDU sessions and deregister from SMSF. When each UE registers again, the NF consumers may discover and select the second AUSF / UDM instance 204b / 204a thus completing the reallocation all at once. The approach may achieve the consistent reallocation of the registration of multiple NF consumers for a given UE. 2.6 Restoration Notification without Reregistration Indication The fifth example described above may have the drawback of requiring the UEs to register again with the obvious UE service experience and network load. FIG. 14 illustrates an example to avoid the deregistration of the UEs. As illustrated in FIG. 14, the first UDM instance 202a may send the following to the NF consumer(e.g., AMF): the restoration notification, reallocation indication and optionally an identifier identifying the second UDM / AUSF instance. When the NF consumer completes the restoration with reallocation procedure for a given UE in the second UDM instance, the NF consumer may request any SMF and / or SMSF which are managing PDU sessions or SMS service for that UE to also execute restoration with reallocation procedure for that UE with immediate action. For example, the NF consumer may request the SMF via an appropriate Nsmf service operation. The NF consumer may request the SMSF via an appropriate Nsmsf service operation. The request sent by the NF consumer to the SMF or the SMSF may include an identifier identifying the second UDM instance. When SMF and SMSF receive the request from the NF consumer, SMF / SMSF may execute the restoration with the reallocation procedure towards the second UDM instance for the UE as requested. 3. Example Flow Charts FIG. 15 is a flow chart illustrating a method performed by the first instance 202 of the NF producer to support reallocation of subscriptions of UEs from the first instance 202 to the second instance 204 of the NF producer. At 1502, the first instance 202 may determine that the subscriptions of the plurality of UEs are to be reallocated to the second instance 204. At 1504, in response to said determining, the first instance 202 may send to an NF consumer 206 a restoration notification 208 including a reallocation indication and information identifying the plurality of UEs. FIG. 16 is a flow chart illustrating another method performed by the first instance 202 of the NF producer to support reallocation of subscriptions of UEs from the first instance 202 to the second instance 204 of the NF producer. At 1602, the first instance 202 may determine that the subscriptions of the plurality of UEs are to be reallocated to the second instance 204. At 1604, in response to said determining, the first instance 202 may send to an NF consumer 206, a restoration notification 208 including information identifying the plurality of UEs and a reregistration indication. FIG. 17 is a flow chart illustrating a method performed by an NF consumer 206 to support reallocation of subscriptions of a plurality of UEs from the first instance 202 of the NF producer to the second instance 204 of the NF producer. At 1702, the NF consumer 206 may receive, from the first instance, a restoration notification including a reallocation indication and information identifying the plurality of UEs. At 1704, the NF consumer 206 may select, from the plurality of UEs, at least one UE registered with the NF consumer. At 1706, the NF consumer 206 may receive information associated with the second instance of the NF producer. At 1708, the NF consumer 206 may update UE context information stored by the NF consumer for the at least one selected UE based on the received information of the second instance. At 1710, the NF consumer 206 may send a registration request to the second instance to register the NF consumer for the at least one selected UE. FIG. 18 is a flow chart illustrating a method performed by the NF consumer 206 to support reallocation of subscriptions of a plurality of UEs from the first instance 202 of the NF producer to the second instance 204 of the NF producer. At 1802, the NF consumer 206 may receive a restoration notification including a reregistration indication and information identifying the plurality of UEs. At 1804, the NF consumer 206 may select, from the plurality of UEs, at least one UE registered with the NF consumer. At 1806, the NF consumer 206 may deregister the at least one selected UE from the NF consumer. At 1808, subsequent to the deregistration, the NF consumer 206 may receive a registration request from the at least one selected UE. At 1810, responsive to receiving the registration request, the NF consumer 206 may send a discovery request to the NRF for the at least one selected UE to receive information associated with the second instance. At 1812, the NF consumer 206 may send a registration request to the second instance to register the NF consumer for the at least one selected UE. FIG.19 is a flow chart illustrating a method performed by the NRF 210 to support reallocation of subscriptions of the UEs from the first instance 202 of the NF producer to the second instance 204 of the NF producer. At 1902, the NRF 210 may receive a first update request, from the first instance, to update its NF profile to be dissociated with the plurality of UEs. At 1904, the NRF 210 may receive a second update request, from the second instance, to update its NF profile to be associated with the plurality of UEs. The second update request may include a reset identifier of temporary data associated with the plurality of UEs. At 1906, the NRF 210 may receive a discovery request, from the NF consumer, for at least one UE from the plurality of UEs. The discovery request may include one or more of the following: the reset identifier and an identifier associated with the second instance. At 1908, responsive to receiving the discovery request, the NRF 210 may send information associated with the second instance to the NF consumer. 4. Example Components of Entities FIGS.20A-20D illustrate example components of the NF consumer 206, the first instance 202 or the second instance 204 of the NF Producer, the NRF 210 and the UE 201, respectively. Each may include processing circuitry 2002a, 2002b, 2002c and 2002d communicatively coupled with memory 2004a, 2004b, 2004c and 2004d, respectively. The memory 2004a, 2004b, 2004c and 2004d may store instructions executable by the processing circuitry 2002a, 2002b, 2002c and 2002d to perform methods described in this disclosure. The processing circuitry 2002a, 2002b, 2002c and 2002d may be configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 2004a, 2004b, 2004c and 2004d. The processing circuitry may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 2002a, 2002b, 2002c and 2002d may include multiple central processing units (CPUs). The memory 2004a, 2004b, 2004c and 2004d may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 2004a, 2004b, 2004c and 2004d includes one or more application programs, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data. The memory 2004a, 2004b, 2004c and 2004d may store any of a variety of various operating systems or combinations of operating systems. In general, the various exemplary embodiments may be implemented in hardware or special purpose chips, circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure. Figure 21 is a block diagram illustrating a virtualization environment 2100 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 2100 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 2100 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface. Applications 2102 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein. Hardware 2104 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 2106 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 2108a and 2108b (one or more of which may be generally referred to as VMs 2108), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 2106 may present a virtual operating platform that appears like networking hardware to the VMs 2108. The VMs 2108 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 2106. Different embodiments of the instance of a virtual appliance 2102 may be implemented on one or more of VMs 2108, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment. In the context of NFV, a VM 2108 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 2108, and that part of hardware 2104 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 2108 on top of the hardware 2104 and corresponds to the application 2102. Hardware 2104 may be implemented in a standalone network node with generic or specific components. Hardware 2104 may implement some functions via virtualization. Alternatively, hardware 2104 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 2110, which, among others, oversees lifecycle management of applications 2102. In some embodiments, hardware 2104 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 2112 which may alternatively be used for communication between hardware nodes and radio units.

Claims

CLAIMS:

1. A method performed by a first instance of a network function, NF, producer to support reallocation of subscriptions of a plurality of user equipments, UEs, from the first instance to a second instance of the NF producer, the method comprising: determining that the subscriptions of the plurality of UEs are to be reallocated to the second instance; in response to said determining, sending to an NF consumer a restoration notification including a reallocation indication and information identifying the plurality of UEs.

2. The method of claim 1, wherein the NF producer includes one or more of the following: one or more unified data managements, UDMs, and one or more authentication server functions, AUSFs.

3. The method of any one of the preceding claims, wherein the NF consumer is registered with the first instance.

4. The method of any one of the preceding claims, wherein the first instance sends the restoration notification via an operation and maintenance command that requires reallocation of the plurality of UEs.

5. The method of any one of the preceding claims, wherein the information identifying the plurality of UEs includes a subscription permanent identifier, SUPI, range.

6. The method of any one of the preceding claims, further comprising receiving a signal from a network operator to reallocate the plurality of UEs.

7. The method of any one of the preceding claims, wherein the reallocation indication is an indication that the plurality of UEs are being reallocated.

8. The method of any one of the preceding claims, wherein the restoration notification further includes one or more of the following: a generic public subscription identifier, GPSI, range associated with the plurality of UEs,a reset identifier of temporary data associated with the plurality of UEs, and at least one routing indicator, RID, associated with the plurality of UEs.

9. The method of any one of the preceding examples wherein the reallocation indication is for triggering the NF consumer to discover or associate the plurality of UEs to the second instance.

10. The method of any one of the preceding claims, wherein the restoration notification includes an authentication indication indicating a need for authenticating the plurality of UEs for reallocating them to the second instance.

11. The method of any one of the preceding claims, wherein the NF consumer includes one or more of the following: access and mobility management function, AMF, session management function, SMF, short message service function, SMSF, network data analytics function, NWADF, and network data analytics function, NEF.

12. A method performed by a first instance of a network function, NF, producer to support reallocation of subscriptions of a plurality of user equipments, UEs, from the first instance to a second instance of the NF producer, the method comprising: determining that the subscriptions of the plurality of UEs are to be reallocated to the second instance; in response to said determining, sending to an NF consumer, a restoration notification including information identifying the plurality of UEs and a reregistration indication.

13. The method of claim 12, wherein the reregistration indication requests the NF consumer to deregister and reregister at least one UE of the plurality of UEs.

14. The method of any one of claims 12 or 13, wherein the reregistration indication is to inform at least one UE to deregister and reregister again.

15. The method of any one of claims 12-14, further comprising receiving a signal from a network operator to reallocate the plurality of UEs.

16. A method performed by a network function, NF, consumer to support reallocation of subscriptions of a plurality of user equipments, UEs, from a first instance of a network function,NF, producer to a second instance of the NF producer, the method performed by the NF consumer comprising: receiving, from the first instance, a restoration notification including a reallocation indication and information identifying the plurality of UEs; selecting, from the plurality of UEs, at least one UE registered with the NF consumer; updating UE context information stored by the NF consumer for the at least one selected UE based on the received information of the second instance; and sending a registration request to the second instance to register the NF consumer for the at least one selected UE.

17. The method of claim 16, wherein the reallocation indication is an indication that the plurality of UEs are being reallocated.

18. The method of claim 16 or 17, wherein the method further comprises: receiving information associated with the second instance of the NF producer.

19. The method of claim 18, wherein the receiving the information associated with the second instance is responsive to: sending, by the NF consumer, to a network repository function, NRF, a discovery request associated with the at least one selected UE.

20. The method of claim 18, wherein the information associated with the second instance is received via a notification from an NRF regarding an update of NF profiles of the first instance and the second instance.

21. The method of any one of claims 18-20, wherein the information associated with the second instance includes an identifier associated with the second instance.

22. The method of any one of claims 16-21, wherein the NF producer includes one or more of the following: one or more unified data managements, UDMs, and one or more authentication server functions, AUSFs.

23. The method of any one of claims 16-22, wherein the NF consumer is registered with the first instance.

24. The method of any one of claims 16-23, wherein the information identifying the plurality of UEs includes a subscription permanent identifier, SUPI, range.

25. The method of any one of claims 16-24, further comprising: delaying, by the NF consumer, the updating and the sending based on a subsequent activity of the at least one selected UE in the NF consumer; and indicating, by the NF consumer, during the delay, that the at least one selected UE has pending restoration with reallocation.

26. The method of any one of claims 16-25, wherein the restoration notification includes one or more of the following: a generic public subscription identifier, GPSI, range associated with the plurality of UEs, a reset identifier of temporary data associated with the plurality of UEs, and at least one routing indicator, RID, associated with the plurality of UEs.

27. The method of claim 26, wherein the receiving the information associated with the second instance is responsive to: sending, by the NF consumer, to an NRF, a discovery request associated with the at least one selected UE based on the at least one reset identifier and / or the at least one RID.

28. The method of any one of claims 16-27, wherein the restoration notification includes an identifier associated with the second instance.

29. The method of claim 28, wherein the identifier is a group identifier.

30. The method of any one of claims 28-29, wherein the receiving is responsive to: sending, by the NF consumer, to an NFR, a discovery request for the at least one selected UE based on the identifier associated with the second instance.

31. The method of any one of claims 28-30, wherein the identifier indicates a need for authenticating the plurality of UEs for reallocating them to the second instance.

32. The method of any one of claims 16-31, wherein the restoration notification includes an authentication indication indicating a need for authenticating the plurality of UEs for reallocating them to the second instance.

33. The method of any one of claims 16-31, wherein the reallocation indication indicates a need for authenticating the plurality of UEs for reallocating them to the second instance.

34. The method of any one of claims 31-33, further comprising: requesting, by the NF consumer, authentication of the at least one selected UE.

35. The method of any one of claims 16-30, further comprising: subsequent to sending the registration request, receiving by the NF consumer from the second instance, a reauthentication error.

36. The method of claim 35, further comprising: responsive to receiving the reauthentication error and being aware of the reallocation of subscriptions, sending by the NF consumer, to an NRF, a discovery request for the at least one selected UE regarding authentication; requesting, by the NF consumer, authentication of the at least one selected UE; after successful authentication of the at least one selected UE, sending a second registration request, by the NF consumer, to the second instance to register the NF consumer for the at least one selected UE.

37. The method of any one of claims 18-36, wherein the NF consumer includes one or more of the following: access and mobility management function, AMF, session management function, SMF, short message service function, SMSF, network data analytics function, NWADF, and network data analytics function, NEF.

38. The method of any one of claims 18-37, further comprising: triggering, by the NF consumer, at least one other NF consumer to perform restoration and reallocation with respect to the at least one selected UE.

39. The method of claim 38, wherein the NF consumer is an AMF, and wherein the at least one other NF consumer includes an SMF and / or an SMSF managing a packet data unit, PDU, session or a short message service, SMS, for the at least one selected UE.

40. The method of claim 39, wherein the triggering includes one or more of the following: sending a first request to the SMF including reallocation indication Nsmf service operation; and sending a second request to the SMSF via an Nsmsf service operation.

41. The method of any one of claims 38-40, wherein the triggering includes providing the reallocation indication and an identifier associated with the second instance to the at least one other NF consumer.

42. A method performed by a network function, NF, consumer to support reallocation of subscriptions of a plurality of user equipments, UEs, from a first instance of a network function, NF, producer to a second instance of the NF producer, the method performed by the NF consumer comprising: receiving a restoration notification including a reregistration indication and information identifying the plurality of UEs; selecting, from the plurality of UEs, at least one UE registered with the NF consumer; deregistering the at least one selected UE from the NF consumer; subsequent to the deregistration, receiving a registration request from the at least one selected UE; responsive to receiving the registration request, sending a discovery request to a network repository function, NRF, for the at least one selected UE to receive information associated with the second instance; and sending a registration request to the second instance to register the NF consumer for the at least one selected UE.

43. The method of claim 42, further comprising: informing, by the NF consumer, at least one other NF consumer to reregister the at least one selected UE.

44. The method of claim 43, wherein the informing includes:requesting, by the NF consumer, at least one session management function, SMF, to release an ongoing packet data unit, PDU, session and deregister from short message service function, SMSF.

45. A method performed by a network repository function, NRF, to support reallocation of subscriptions of a plurality of user equipments, UEs, from a first instance of a network function, NF, producer to a second instance of the NF producer, comprising: receiving a first update request, from the first instance, to update its NF profile to be dissociated with the plurality of UEs; receiving a second update request, from the second instance, to update its NF profile to be associated with the plurality of UEs, the second update request including a reset identifier of temporary data associated with the plurality of UEs; receiving a discovery request, from an NF consumer, for at least one UE from the plurality of UEs, the discovery request including one or more of the following: the reset identifier and an identifier associated with the second instance; and responsive to receiving the discovery request, sending information associated with the second instance to the NF consumer.

46. The method of claim 45, wherein the second update request includes a routing indicator, RID, identifying the plurality of UEs, and wherein the discovery request includes the RID.

47. Apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 1 to claim 11, from claim 12 to claim 15, from claim 16 to claim 41, from claim 42 to claim 44, or from claim 45 to claim 46.

48. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to any of claims from claim 1 to claim 11, from claim 12 to claim 15, from claim 16 to claim 41, from claim 42 to claim 44, or from claim 45 to claim 46.

49. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by a processor, causing the processor to performthe method according to any of claims from claim 1 to claim 11, from claim 12 to claim 15, from claim 16 to claim 41, from claim 42 to claim 44, or from claim 45 to claim 46.

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