Method and system for managing subscription at network function

Abstract

The disclosure provides a system (108) and a method (400) for managing subscription at a Network Repository Function (NRF) (304). The method (400) includes storing, by the NRF (304), subscription data associated with the subscription of a NF consumer (301) for a validity time. Upon an expiration of the validity time, the method (400) includes implementing, by the NRF (304), a hold timer to retain stored subscription data. Upon an expiration of the hold timer, the method (400) further includes sending, by the NRF (304), a validity challenge request to the NF consumer to verify stored subscription data. Further, the method (400) includes receiving, by the NRF (304), a validity challenge response from the NF consumer (301) corresponding to a status of the validity challenge request. The method (400) further includes updating, by the NRF (304), the stored subscription data at the NRF (304) based on the validity challenge response.

Description

METHOD AND SYSTEM FOR MANAGING SUBSCRIPTION AT NETWORK FUNCTION RESERVATION OF RIGHTS

[0001] A portion of the disclosure of this patent document contains material, which is subject to intellectual property rights such as, but are not limited to, copyright, design, trademark, Integrated Circuit (IC) layout design, and / or trade dress protection, belonging to Jio Platforms Limited ( JPL) or its affiliates (hereinafter referred as owner). The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all rights whatsoever. All rights to such intellectual property are fully reserved by the owner.TECHNICAL FIELD

[0002] The present disclosure relates to a field of telecommunications network. In particular, the present disclosure relates to a method and a system for managing subscription at network function (NF).DEFINITION

[0003] As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used to indicate otherwise.

[0004] The term ‘Service-Based Architecture (SB A)’ used herein in the specification refers to a programmable framework that connects Fifth Generation (5G) Network Functions (NFs). The SBA fundamentally shifts how network functions (NFs) interact, moving away from traditional point-to-point communication models toward a more flexible and scalable service -oriented approach.

[0005] The term ‘Network Functions (NFs)’ used herein in the specification refers to modular and virtualized entities that perform specific roles within the network architecture, typically as microservices. The NFs are essential components of the 5G network and are defined in Service-Based Architecture (SBA). The NFscommunicate with each other through standardized Application Programming Interfaces (APIs).

[0006] The term ‘Network Repository Function (NRF)’ used herein in the specification refers to a component that manages and coordinates the discovery and communication between the NFs within a network. Acting as a central registry, the NRF allows NFs to register their profiles, services, and capabilities, making them discoverable by other NFs. The NRF also supports subscription and notification mechanisms, enabling NFs to be updated on relevant changes within the network. By handling requests for NF status updates, profile management, and service discovery, the NRF helps optimize network efficiency, reduce latency, and support scalable, dynamic interactions across a 5G network, enhancing overall service reliability and responsiveness.

[0007] The term ‘NF consumer’ used herein in the specification refers to a network function that subscribes to receive notifications from the Network Repository Function (NRF) in a telecommunications network.

[0008] The term ‘Service Communication Proxy (SCP)’ used herein in the specification refers to 5G core proxy that sits inside a PLMN to broker SBI traffic between Network Functions (NFs) handling routing, load-balancing, retries, and resiliency.

[0009] The term ‘validity period’ used herein in the specification refers to a designated time span during which a subscription remains active and valid in the NRF. When an NF subscribes to receive notifications or other services from the NRF, a validity timer is set. Once the timer expires, the subscription is deemed invalid unless it is actively renewed by the NF consumer. During the period, the NRF maintains the subscription details and continues to send notifications to the subscribing NF consumer.

[0010] The term ‘Subscription Validity Challenge Request’ used herein in the specification refers to a request to verify the subscription status with the NFconsumer before removing its subscription data. The request is sent when the validity period of a subscription is nearing expiration and the NRF has not received an update request from the NF consumer. By sending the challenge request, the NRF queries the NF consumer to confirm whether the subscription is still needed and provides an option to extend its validity.

[0011] The term ‘Subscription Validity Challenge Response’ used herein in the specification refers to a response indicating whether the subscription can be extended or should be terminated corresponding to the Subscription Validity Challenge Request. The Subscription Validity Challenge response ensures that both the NRF and the NF consumer maintain synchronized subscription information, preventing data inconsistencies and enhancing overall network reliability.

[0012] These definitions are in addition to those expressed in the art.BACKGROUND

[0013] The following description of related art is intended to provide background information pertaining to the field of the disclosure. This section may include certain aspects of the art that may be related to various features of the present disclosure. However, it should be appreciated that this section be used only to enhance the understanding of the reader with respect to the present disclosure, and not as admissions of prior art.

[0014] In the context of Fifth Generation (5G) networks, a Network Repository Function (NRF) manages and coordinates communication between network functions (NFs). The NRF facilitates the registration, deregistration, and updating of NF profiles, allowing efficient service discovery and status notifications for NF consumers. To maintain current information, the NRF includes a subscription mechanism that notifies NF consumers about NF instance status updates.

[0015] A significant challenge arises when the subscription validity period approaches expiration. The NF consumers must renew subscriptions by sending anupdate request to the NRF, extending the subscription’s validity. However, due to network fluctuations, transmission delays, or system errors, the NRF may not receive this update request, or the NRF may encounter errors in processing it. If the update fails (for example, if update message is not delivered to the NRF or an error code is received from the peer node (SCP)), the NRF will automatically remove the subscription data from its database once the validity timer expires. The removal of outdated subscriptions, while necessary for maintaining database integrity, risks causing a mismatch between the subscription data stored by the NRF and that held by NF consumers. Such discrepancies may prevent notifications from reaching the NF consumers, potentially impacting network performance and reliability.

[0016] Thus, the conventional methods are limited to retry mechanisms, where NF consumers may re-attempt to update subscriptions following a failure. However, in cases where multiple retries are unsuccessful, the NF consumer and NRF may still end up with misaligned subscription data, leading to degraded network Key Performance Indicators (KPIs), reduced efficiency, and impaired communication reliability.

[0017] There is, therefore, a need in the art to provide a method and a system that can mitigate the disadvantages of the prior art.SUMMARY OF THE DISCLOSURE

[0018] In an exemplary embodiment, a method for managing subscription at a Network Repository Function (NRF) is described. The method includes storing, by the NRF, subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the method includes implementing, by the NRF, a hold timer to retain the stored subscription data. Upon an expiration of the hold timer, the method further includes sending, by the NRF, a validity challenge request to the NF consumer to verify the stored subscription data. Further, the method includes receiving, by the NRF, a validity challenge response from the NF consumer corresponding to a status of the validity challenge request.The method further includes updating, by the NRF, the stored subscription data at the NRF based on the validity challenge response.

[0019] In an embodiment, the validity challenge request including at least one of a subscription validity challenge request and a notification request.

[0020] In another embodiment, the subscription validity challenge request including at least one of a subscription identifier and the validity time.

[0021] In another embodiment, the notification request including at least one of an event type, the validity time, and a network function instance Uri.

[0022] In another embodiment, the validity challenge response including at least one of a subscription validity challenge response corresponding to the subscription validity challenge request and a notification response corresponding to the notification request.

[0023] In another embodiment, if capability to receive the subscription validity challenge request as a service operation is absent at the NF consumer, the method includes sending, by the NRF, the notification request towards the NF consumer. The notification request includes an event type identifying a subscription validity challenge event, the validity time for the subscription, and a network function instance Uri identifying the NF consumer. Further, the method includes receiving, by the NRF, the notification response corresponding to the notification request from the NF consumer indicating whether the subscription remains valid. The method includes updating, by the NRF, the stored subscription data based on the notification response.

[0024] In another embodiment, updating the stored subscription data including at least one of continue storing the subscription data, and deleting the stored subscription data from the NRF.

[0025] In another embodiment, the method includes receiving, by the NRF, a subscription request from the NF consumer. The subscription request including atleast one of the subscription data and the validity time. Further, the method includes sending, by the NF consumer, an update subscription request to the NRF. The update subscription request corresponds to updating the validity time.

[0026] In another embodiment, the validity challenge request is transmitted by the NRF in a home Public Land Mobile Network (PLMN) to the NF consumer associated with either the home PLMN or a serving PLMN, and when at least one of a Security Edge Protection Proxy (SEPP) and a Service Communication Proxy (SCP) is designated as the notification endpoint and the network function instance Uri corresponds to the SEPP or the SCP, the NRF transmits the subscription validity challenge request to the SEPP or the SCP for delivery to the NF consumer.

[0027] In another exemplary embodiment, a system for managing subscription at a Network Repository Function (NRF) is described. The system includes a memory, and a processing engine coupled to the memory to execute a set of instructions stored in the memory. The processing engine is configured to store subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the processing engine is configured to implement a hold time to retain the stored subscription data. Upon an expiration of the hold timer, a transceiver unit is configured to send a validity challenge request to the NF consumer to verify the subscription data. Further, the transceiver unit is configured to receive a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The processing engine is configured to update the stored subscription data at the NRF based on the validity challenge response.

[0028] In yet another embodiment, a computer program product including a non-transitory computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute a method for managing subscription at a Network Repository Function (NRF) is disclosed. The method includes storing, by the NRF, subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validitytime, the method includes implementing, by the NRF, a hold timer to retain the stored subscription data. Upon an expiration of the hold timer, the method further includes sending, by the NRF, a validity challenge request to the NF consumer to verify the stored subscription data. Further, the method includes receiving, by the NRF, a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The method further includes updating, by the NRF, the stored subscription data at the NRF based on the validity challenge response.OBJECTIVES OF THE PRESENT DISCLOSURE

[0029] Some of the objectives of the present disclosure, which at least one embodiment herein satisfies, are as follows:

[0030] An objective of the present disclosure is to provide a method and a system to maintain aligned subscription information between the NRF and NF consumers, preventing discrepancies when updates fail or are delayed.

[0031] Another objective of the present disclosure is to provide a method and a system to enhance key network performance indicators (KPIs), including the reliability and accuracy of notifications sent to NF consumers by ensuring consistent subscription data.

[0032] Another objective of the present disclosure is to provide a method and a system to introduce a “Subscription Validity Challenge” that verifies the subscription status on the NF consumer’s side before removing or updating subscription data in the NRF.

[0033] Another objective of the present disclosure is to provide a method and a system to allow a grace period such as hold time after the subscription validity timer expires, enabling additional attempts to update the subscription before it is removed.

[0034] Another objective of the present disclosure is to provide a method and a system to provide responses based on whether the challenge request is successful, fails, or times out, improving error management and response actions within the network.

[0035] Another objective of the present disclosure is to enable direct communication for validity challenges without involving intermediate NRFs in other Public Land Mobile Network (PLMNs), simplifying the update process and reducing communication overhead.

[0036] Another objective of the present disclosure is to manage the NRF database more effectively by only retaining active, verified subscriptions, which leads to efficient resource use and database optimization.

[0037] Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated herein, and constitute a part of this disclosure, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that disclosure of such drawings includes the disclosure of electrical components, electronic components or circuitry commonly used to implement such components.

[0039] FIG. 1 illustrates an exemplary network architecture of a system for managing subscription at a Network Repository Function (NRF), in accordance with an embodiment of the present disclosure.

[0040] FIG. 2 illustrates an exemplary block diagram of the system configured for managing subscription at the NRF, in accordance with an embodiment of the present disclosure.

[0041] FIG. 3 illustrates an exemplary process flow for managing subscription at the NRF, in accordance with an embodiment of the present disclosure.

[0042] FIG. 4 illustrates an exemplary process flow of a method for managing subscription at the NRF, in accordance with an embodiment of the present disclosure.

[0043] FIG. 5 illustrates an exemplary computer system in which or with which the embodiments of the present disclosure may be implemented.

[0044] The foregoing shall be more apparent from the following more detailed description of the disclosure.LIST OF REFERENCE NUMERALS100 - Network architecture102 - User(s)104 -User Equipments (UEs)106 - Network108 - System200 - Block diagram202 - Processor(s)04 - Memory06 -Interface(s)08 - Processing engine10 - Database00 - Flow Diagram301 - Network Function (NF) consumer302 - Service Communication Proxy (SCP)304 - Network Repository Function (NRF)400 - Method500 - Computer system510 - External Storage Device520 - Bus530 - Main Memory540 - Read Only Memory550 - Mass Storage Device560 - Communication Port570 - ProcessorDETAILED DESCRIPTION

[0045] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding ofembodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Example embodiments of the present disclosure are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.

[0046] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the disclosure as set forth.

[0047] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

[0048] Also, it is noted that individual embodiments may be described as a process that is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel orconcurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure . A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.

[0049] The word “exemplary” and / or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and / or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive like the term “comprising” as an open transition word without precluding any additional or other elements.

[0050] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0051] The terminology used herein is to describe particular embodiments only and is not intended to be limiting the disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms “comprises” and / or“comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any combinations of one or more of the associated listed items. It should be noted that the terms “mobile device”, “user equipment”, “user device”, “communication device”, “device” and similar terms are used interchangeably for the purpose of describing the invention. These terms are not intended to limit the scope of the invention or imply any specific functionality or limitations on the described embodiments. The use of these terms is solely for convenience and clarity of description. The invention is not limited to any particular type of device or equipment, and it should be understood that other equivalent terms or variations thereof may be used interchangeably without departing from the scope of the invention as defined herein.

[0052] As used herein, an “electronic device”, or “portable electronic device”, or “user device” or “communication device” or “user equipment” or “device” refers to any electrical, electronic, electromechanical, and computing device. The user device is capable of receiving and / or transmitting one or parameters, performing function / s, communicating with other user devices, and transmitting data to the other user devices. The user equipment may have a processor, a display, a memory, a battery, and an input-means such as a hard keypad and / or a soft keypad. The user equipment may be capable of operating on any radio access technology including but not limited to IP-enabled communication, Zig Bee, Bluetooth, Bluetooth Low Energy, Near Field Communication, Z-Wave, Wi-Fi, Wi-Fi direct, etc. For instance, the user equipment may include, but not limited to, a mobile phone, smartphone, virtual reality (VR) devices, augmented reality (AR) devices, laptop, a general-purpose computer, desktop, personal digital assistant, tablet computer, mainframe computer, or any other device as may be obvious to a person skilled in the art for implementation of the features of the present disclosure.

[0053] Further, the user device may also comprise a “processor” or “processing unit” includes processing unit, wherein processor refers to any logic circuitry for processing instructions. The processor may be a general-purpose processor, a special purpose processor, a conventional processor, a digital signal processor, a plurality of microprocessors, one or more microprocessors in association with a Digital Signalling Processing (DSP) core, a controller, a microcontroller, Application Specific Integrated Circuits, Field Programmable Gate Array circuits, any other type of integrated circuits, etc. The processor may perform signal coding data processing, input / output processing, and / or any other functionality that enables the working of the system according to the present disclosure. More specifically, the processor is a hardware processor.

[0054] While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment, as well as other embodiments of the disclosure, will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

[0055] Wireless communication technology has rapidly evolved over the past few decades. The first generation of wireless communication technology was analog, offering only voice services. Further, text messaging and data services became possible when the second-generation (2G) technology was introduced. The third generation (3G) technology marked the introduction of high-speed internet access, mobile video calling, and location-based services. The fourth generation (4G) technology revolutionized the wireless communication with faster data speeds, improved network coverage, and security. Currently, fifth generation (5G) technology is being deployed, offering significantly faster data speeds, lower latency, and the ability to connect many devices simultaneously. These advancements represent a significant leap forward from previous generations,enabling enhanced mobile broadband, improved Internet of Things (loT) connectivity, and more efficient use of network resources. The sixth generation (6G) technology promises to build upon these advancements, pushing the boundaries of wireless communication even further. While the 5G technology is still being rolled out globally, research and development into the 6G are rapidly progressing, with the aim of revolutionizing the way to connect and interact with technology.

[0056] A Fifth Generation (5G) network includes a plurality of Network Functions (NFs), such as Policy Control Function (PCF), Binding Support Function (BSF), Charging Function (CHF), Network Repository Function (NRF), etc. The NFs are critical in managing control plane responsible for managing network access, subscription data, availability, and policies and a user plane that handles data transfer. The continuous availability and performance of these NF applications is crucial for maintaining the overall efficiency and reliability of the network.

[0057] In the 5G network, the NRF manage the registration, discovery, and lifecycle of NFs. Through a Nnrf_NFManagement service, the NRF allows NFs to register, deregister, and update their profiles, enabling efficient network orchestration. Additionally, the NFStatusSubscribe service allows NF consumers to subscribe to notifications regarding NF lifecycle events, ensuring that NF instances are consistently updated on registration status changes, profile modifications, or deregistration’s within the NRF. To maintain active subscriptions, the NRF uses a validity period, set when an NF consumer initiates or updates a subscription. The validity period specifies the time during which the subscription is valid, after which it automatically expires unless renewed. However, discrepancies between the NRF and NF consumers regarding subscription status may arise due to network failures, impacting the synchronization of subscription information and resulting in performance.

[0058] The NRF enable the NFs to subscribe to status notifications through a specified validity period. The validity period, set by the NF consumer, requiresperiodic renewal to prevent subscription expiration. In cases where network connectivity issues or communication failures occur, such as delayed or unsuccessful delivery of subscription updates, the NRF may silently delete the expired subscription information. As a result, the NF consumer may continue to operate under the assumption that the subscription is active, while the NRF has already invalidated the subscription. The misalignment between the NRF and NF consumer’s subscription status may disrupt critical notification services and negatively impact network Key Performance Indicators (KPIs) by hindering timely NF lifecycle updates. Given the high dependency on synchronized subscription data. The conventional method does not account for such communication inconsistencies, leading to potential performance degradation and operational challenges.

[0059] To address the above-mentioned issue, the present disclosure provides a method and a system to manage subscription at the NF. The method includes a custom service operation within the NRF, enabling proactive verification of subscription status with the NF consumer before deleting expired subscriptions. When the validity period nears expiration, the NRF initiates a “Subscription Validity Challenge Request” to the NF consumer, including the current subscription ID and an updated validity time. The request allows the NF consumer to confirm or extend the subscription, maintaining synchronization with the NRF’ s records. If the NF consumer accepts the request, the NF consumer responds with an acknowledgment, allowing the NRF to reset the subscription’s validity period. If the NF consumer fails to respond or the subscription ID is unrecognized, the NRF may safely remove the subscription data.

[0060] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. The various embodiments throughout the disclosure will be explained in more detail with reference to FIG. 1 -FIG. 5.

[0061] FIG. 1 illustrates an exemplary network architecture 100 of a system 108 for managing subscription at a Network Repository Function (NRF), in accordance with an embodiment of the present disclosure. As illustrated in FIG. 1, the network architecture 100 may include one or more User Equipments (UEs) 104-1, 104-2...104-N associated with one or more users 102-1, 102-2... 102 -N in an environment. A person of ordinary skill in the art will understand that one or more users 102-1, 102-2... 102-N may be collectively referred to as the users 102. Similarly, a person of ordinary skill in the art will understand that one or more UEs 104-1, 104-2... 104-N may be collectively referred to as the UE 104, the UEs 104. Although only three UE 104 are depicted in FIG. 1, however, any number of the UE 104 may be included without departing from the scope of the ongoing description.

[0062] In an embodiment, the UE 104 may include smart devices operating in a smart environment, for example, an Internet of Things (loT) system. In such an embodiment, the UE 104 may include, but are not limited to, smartphones, smart watches, smart sensors (e.g., a mechanical, a thermal, an electrical, a magnetic, etc.), networked appliances, networked peripheral devices, networked lighting system, communication devices, networked vehicle accessories, networked vehicular devices, smart accessories, tablets, a smart television (TV), computers, a smart security system, a smart home system, other devices for monitoring or interacting with or for the users 102 and / or entities, or any combination thereof. A person of ordinary skill in the art will appreciate that the UE 104 may include, but not limited to, intelligent, multi-sensing, network-connected devices, that may integrate seamlessly with each other and / or with a central server or a cloudcomputing system or any other device that is network-connected.

[0063] Additionally, in some embodiments, the UE 104 may include, but not limited to, a handheld wireless communication device (e.g., a mobile phone, a smartphone, a phablet device, and so on), awearable computer device (e.g., aheadmounted display computer device, a head-mounted camera device, a wristwatch computer device, and so on), a Global Positioning System (GPS) device, a laptopcomputer, a tablet computer, or another type of portable computer, a media playing device, a portable gaming system, and / or any other type of computer device with wireless communication capabilities, and the like. In an embodiment, the UE 104 may include, but are not limited to, virtual reality (VR) devices, augmented reality (AR) devices, a laptop, a general-purpose computer, a desktop, a personal digital assistant, a tablet computer, a mainframe computer, or any other computing device. Further, the UE 104 may include one or more in-built or externally coupled accessories including, but not limited to, a visual aid device such as a camera, an audio aid, a microphone, a keyboard, and input devices for receiving input from the user 102 or an entity such as a touchpad, a touch-enabled screen, an electronic pen, and the like. A person of ordinary skill in the art will appreciate that the UE 104 may not be restricted to the mentioned devices and various other devices may be used.

[0064] In FIG. 1, the UE 104 may communicate with the system 108 through a network 106 for sending or receiving various types of data. In an embodiment, the network 106 may include at least one of a 5G network, a Sixth Generation (6G) network, or the like. The network 106 may enable the UE 104 to communicate with other devices in the network architecture 100 and / or with the system 108. The network 106 may include a wireless card or some other transceiver connection to facilitate this communication. In another embodiment, the network 106 may be implemented as, or include any of a variety of different communication technologies such as a wide area network (WAN), a local area network (LAN), a wireless network, a mobile network, a Virtual Private Network (VPN), the Internet, the Public Switched Telephone Network (PSTN), or the like.

[0065] In an embodiment, the network 106 may include, by way of example but not limitation, at least a portion of one or more networks having one or more nodes that transmit, receive, forward, generate, buffer, store, route, switch, process, or a combination thereof, etc. one or more messages, packets, signals, waves, voltage or current levels, some combination thereof, or so forth. The network 106 may also include, by way of example but not limitation, one or more of the RAN, a wirelessnetwork, a wired network, an internet, an intranet, a public network, a private network, a packet-switched network, a circuit-switched network, an ad hoc network, an infrastructure network, a Public-Switched Telephone Network (PSTN), a cable network, a cellular network, a satellite network, a fiber optic network, or some combination thereof.

[0066] In an embodiment, the UE 104 is communicatively coupled with the network 106. The network 106 may receive a connection request from the UE 104. The network 106 may send an acknowledgment of the connection request to the UE 104. The UE 104 may transmit a plurality of signals in response to the connection request.

[0067] In an embodiment, the system 108 may be configured to store, by the NRF, subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the system 108 may implement, by the NRF, a hold time to retain the subscription data. Upon an expiration of the hold timer, the system 108 may send, by the NRF, a validity challenge request to the NF consumer to verify the subscription data. Further, the system 108 may receive, by the NRF, a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The system 108 may update, by the NRF, the stored subscription data at the NRF based on the validity challenge response.

[0068] Although FIG. 1 shows exemplary components of the network architecture 100, in other embodiments, the network architecture 100 may include fewer components, different components, differently arranged components, or additional functional components than depicted in FIG. 1. Additionally, or alternatively, one or more components of the network architecture 100 may perform functions described as being performed by one or more other components of the network architecture 100.

[0069] FIG. 2 illustrates an exemplary block diagram 200 of the system 108 configured for managing subscription at the NRF, in accordance with an embodiment of the disclosure.

[0070] In an embodiment, the system 108 may include one or more processor(s) 202. The one or more processor(s) 202 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and / or any devices that process data based on operational instructions. Among other capabilities, the one or more processor(s) 202 may be configured to fetch and execute computer-readable instructions stored in a memory 204 of the system 108. The memory 204 may be configured to store one or more computer-readable instructions or routines in a non-transitory computer readable storage medium, which may be fetched and executed to create or share data packets over a network service. The memory 204 may include any non-transitory storage device including, for example, volatile memory such as a Random-Access Memory (RAM), or a non-volatile memory such as an Erasable Programmable Read Only Memory (EPROM), a flash memory, and the like.

[0071] In an embodiment, the system 108 may include an interface(s) 206. The interface(s) 206 may include a variety of interfaces, for example, interfaces for data input and output devices (RO), storage devices, and the like. The interface(s) 206 may facilitate communication through the system 108. The interface(s) 206 may also provide a communication pathway for one or more components of the system 108. Examples of such components include, but are not limited to, a processing engine 208 and a database 210.

[0072] In an embodiment, the system 108 may include a processing engine 208 and a transceiver unit 212 that may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processing engine 208 and the transceiver unit 212. In examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the processing engine 208 and the transceiver unit 212 may be processor-executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the processing engine 208 and the transceiver unit 212 may comprise a processing resource (for example, one or more processors), to execute suchinstructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the processing engine 208 and the transceiver unit 212. In such examples, the system 108 may comprise the machine-readable storage medium storing the instructions and the processing resource to execute the instructions, or the machine-readable storage medium may be separate but accessible to the system 108 and the processing resource. In other examples, the processing engine 208 and the transceiver unit 212 may be implemented by electronic circuitry. In an aspect, the processing engine 208 and the transceiver unit 212 may be implemented within the Network Repository Function (NRF).

[0073] In an embodiment, the processing engine 208 is configured to store subscription data associated with the subscription of a NF consumer for a validity time. The validity time is an expiration time for the subscription. The validity time is a predefined time limit during which the NRF maintains subscription data for the NF consumer. The validity time is established when the NF consumer subscribes to notifications related to NF lifecycle events, such as registration, deregistration, or profile updates. The validity time serves as an expiration timer for the subscription, after which the NRF automatically considers the subscription invalid if no renewal is received.

[0074] Upon an expiration of the validity time, the processing engine 208 is configured to implement a hold timer to retain the stored subscription data. In an exemplary embodiment, the processing engine 208 implements a configurable hold timer to retain the subscription data temporarily. The hold timer acts as a buffer period, allowing for potential communication delays or retries in receiving an updated subscription request from the NF consumer. During the hold timer, the subscription data is retained in the database 210 even after the validity period has expired. The retention period ensures that the NF consumer has additional time to send an update subscription request and extend the subscription’s validity.

[0075] Upon an expiration of the hold timer, the transceiver unit 212 is configured to send a validity challenge request to the NF consumer to verify the subscription data. The validity challenge request includes at least one of a subscription validity challenge request and a notification request. In an embodiment, the validity challenge request may be a subscription validity challenge request configured to verify the subscription data. The subscription identifier allows the NF consumer to recognize which subscription is being referenced by the NRF and the new validity period proposes an extended timeframe for the subscription to remain active. In an exemplary embodiment, the subscription validity challenge request is sent directly to the NF consumer to proactively confirm or update the subscription status. By sending the validity challenge request, the processing engine 208 ensures that both the NRF and the NF consumer synchronize on the subscription’s status. Further, the subscription validity challenge request includes at least one of a subscription identifier and the validity time. The notification request includes at least one of an event type, the validity time, and a network function instance Uri. The validity challenge request is transmitted by the NRF in a home Public Land Mobile Network (PLMN) to the NF consumer associated with either the home PLMN or a serving PLMN, and when at least one of a Security Edge Protection Proxy (SEPP) and a Service Communication Proxy (SCP) is designated as the notification endpoint and the network instance Uri corresponds to the SEPP or the SCP, the NRF transmits the subscription validity challenge request to the SEPP or the SCP for delivery to the NF consumer.

[0076] In an embodiment, the processing engine 208 is configured to receive a subscription request from the NF consumer. The subscription request includes at least one of the subscription data and the validity time. Further, the processing engine 208 is configured to send an update subscription request to the NRF. The update subscription request corresponds to updating the validity time.

[0077] In some embodiments, if capability to receive the subscription validity challenge request as a service operation is absent at the NF consumer, the transceiver unit 212 is configured to send the notification request towards the NFconsumer. The notification request include an event type identifying a subscription validity challenge event, the validity time for the subscription, and a network function Instance Uri identifying the NF consumer. Further, the transceiver unit 212 is configured to receive the notification response corresponding to the notification request from the NF consumer indicating whether the subscription remains valid. The processing engine 208 is configured to update the stored subscription data based on the notification response.

[0078] Further, the transceiver unit 212 is configured to receive a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The validity challenge response includes at least one of a subscription validity challenge response corresponding to the subscription validity challenge request and a notification response corresponding to the notification request. The validity challenge response may be a subscription validity challenge response. In an exemplary embodiment, the subscription validity challenge response may be a successful response indicating that the NF consumer acknowledges the subscription and agrees to extend its validity. Further, the subscription validity challenge response may be a failure response or no response indicating removal of the subscription data at the NRF.

[0079] Further, the processing engine 208 is configured to update the stored subscription data at the NRF based on the validity challenge response. In some embodiments, updating the stored subscription data includes at least one of continue storing the subscription data and deleting the stored subscription data from the NRF. In an exemplary embodiment, if the validity challenge response is a successful response, the processing engine 208 updates the subscription validity period at the NRF to the new validity period specified in the validity challenge request, ensuring continued notifications and data consistency between the NRF and NF consumer. Further, if the validity challenge response is a failure response or no response, the processing engine 208 deletes or deactivates the subscription data at the NRF. The removal operation prevents redundant data storage and ensures that the NRF maintains active and required subscriptions.

[0080] FIG. 3 illustrates an exemplary process flow 300 for managing subscription at a Network Function (NF) 304, in accordance with an embodiment of the present disclosure. FIG. 3 depicts call flow execution between the NF consumer 301, a Service Communication Proxy (SCP) 302, and the NF (such as NRF) 304. FIG. 3 is explained in conjunction with FIGS. 1 and 2.

[0081] At step 306, a subscription request with subscription data is sent to the NRF 304 by the NF consumer 301 via the Service Communication Proxy (SCP) 302. The SCP 302 acts as an intermediary and proxy for routing and managing requests between the NF consumer 301 and the NRF 304. For example, when the NF consumer 301 tries to extend the subscription validity by sending an update request, the SCP 302 routes the request to the NRF 304. The subscription data includes information of a subscription necessary for the NF consumer 301 to receive notifications related to other NFs registered in the NRF 304. In some embodiments, the SCP 302 may affect subscription data consistency such as if the NRF 304 does not receive update due to SCP 302 related issues, the NRF 304 may assume the subscription is invalid, potentially leading to misalignment between the NF consumer 301 and NRF 304 subscription data.

[0082] At step 308, a subscription response with subscription data is received by the NF consumer 301 from the NRF 304 via the SCP 302. The NRF 304 sends a confirmation message containing the subscription data along with the validity time, specifying how long the subscription will remain active unless updated.

[0083] At step 310, the validity time is validated by the NF consumer 301 and the NRF 304. The NF consumer 301 is expected to send an update subscription request to restore the subscription at the NRF 304. In an exemplary embodiment, if the validity time is set as 4 hours. The NRF 304 may remove the subscription data after the 4 hours are passed, if the NRF 304 does not receive the updated subscription request from the NF consumer 301.

[0084] At step 312, an update subscription request for extension of validity time may be sent by the NF consumer 301 towards the NRF 304 via the SCP 302 beforethe expiration of the validity time. However, due to anomalies in the network the update subscription request may not be received by the NRF 304, causing unintentional removal of the subscription data at the NRF 304.

[0085] At step 314, to avoid the unintentional removal of the subscription data at the NRF 304, the NRF 304 configures a hold time, specifying additional time after expiration of the validity time. The NRF 304 may configure the hold time even before the expiration of the validity time. The hold time is a grace period that temporarily prevents the NRF 304 from immediately deleting the subscription after the validity time expires. This delay allows additional time for potential recovery or retry of the update process. In an exemplary embodiment, the NRF 304 may configure a hold time (for example, 1 hour) just before the validity time (4 Hours) is passed without receiving the update subscription request.

[0086] At step 316, at least one of a subscription validity challenge request and a notification request operation is sent by the NRF 304 directly to the NF consumer 301, without involving the SCP 302, avoiding inconsistencies in subscription data caused by SCP 302 related issues. The subscription validity challenge request includes the subscription ID and a new proposed validity time. The subscription validity challenge request is configured to verify the subscription data at the NF consumer 301. The purpose of the challenge request is to verify whether the NF consumer 301 still requires the subscription, ensuring that both parties have consistent subscription information. Further, the NRF 304 may send the notification request operation, if the subscription validity challenge request is not supported by the NF consumer 301. In an embodiment, the notification request operation may include an event type ‘NF_SUB_CHLG’ to verify the subscription data at the NF consumer 301. The ‘NF_SUB_CHLG’ is a custom -defined event created to address subscription validity issues between the NRF 304 and the NF consumer 301. In an exemplary embodiment, the NRF 304 may send a new notification message with the event type = ‘NF_SUB_CHLG’, validity time, and nflnstanceUri = ‘NF consumer instance URT as part of the subscription data check at the NF consumer 301.

[0087] At step 318, at least one of a subscription validity challenge response and a notification response is received by the NRF 304 directly from the NF consumer 301. The subscription validity challenge response may include status codes corresponding to the subscription validity challenge request, and the notification response may include status codes corresponding to the notification request operation. The subscription validity challenge response and the notification response may be 204 code indicating successful confirmation of the subscription, allowing the NRF 304 to extend the validity as per the new validity time. The subscription validity challenge response may be 404 code and the notification response may be 4xx code, indicating that the NF consumer 301 no longer recognizes the subscription or cannot confirm the subscription. Further, the subscription validity challenge response may be a 3xx code and the notification response may be a 3xx or 5xx code indicating that the NF consumer 301 request is redirected, potentially requiring further action or clarification.

[0088] At step 320, the subscription data may be updated at the NRF 304 based on the subscription validity challenge response and the notification response. In an embodiment, the NRF 304 may perform at least one operation based on the response received from the NF consumer 301. Based on the response from the NF consumer 301, the NRF 304 updates the subscription data or removes it from the NRF 304, ensuring that the NRF 304 maintains accurate and consistent subscription records aligned with the actual status of the NF consumer 301. In an exemplary embodiment, if the response received is 204 code, the NRF 304 may update the subscription data and the new validity time at its end. If the response received is 404 code or 4xx code, the NRF 304 may delete the subscription data at its end. Further, if the response received is 3xx code or 5xx code, the NRF 304 may redirect the request to other Network function of the network. If the NRF 304 does not receive a response, the NRF 304 may consider that the subscription is no longer valid and remove the subscription data from its end.

[0089] In an exemplary embodiment, the NRF supports the Nnrf_NFManagement service operation, enabling the NFs to register, deregister, and update the profileswithin the NRF. The NF consumers utilize the NFStatusSubscribe service operation to receive notifications based on subscription information request. This allows NF consumers to be notified when NF instances or sets are registered or deregistered or when their profiles are updated in the NRF. The request body includes the data indicating the type of notifications that the NF Consumer wants to receive. The request also contains a validity time representing the time period during which the subscription is desired to be kept active.

[0090] Further, the response includes the data related to the created subscription, including the validity time determined by the NRF, after which the subscription becomes invalid. The subscription becomes invalid once the validity time expires, and the NRF silently removes the subscription data. Further, the NRF may no longer notify the NF consumer. Upon the expiration of the subscription, the NF Service Consumer receives status notifications by the following methods: the NF consumer creates a new subscription in the NRF, or when the validity time for notifications on the NF consumer is about to expire, the subscription is updated to extend the validity time. The NF Service Consumer requests a new validity time from the NRF through an update subscription message. If the operation is successful, the NRF responds with the newly assigned validity time.

[0091] In scenarios where the operation is unsuccessful, the NRF may not receive the patch request (such as update subscription messages) from the NF consumer due to network fluctuations or hardware / software issues in a production network. The NF consumer may retry sending the subscription update message after encountering an error code or timeout from the NRF. If the retry limit is exceeded without receiving a successful response with the new validity time from the NRF, the NF consumer and NRF end up with differing subscription details. To counter the problem, the NRF retains the subscription data for a configurable period (such as Hold Time) after the validity timer expires, allowing for updates to the subscription data if the retry subscription mechanism is successful at the NF consumer.

[0092] Before removing the subscription data, the NRF sends new custom service operations as “Subscription Validity Challenge Request” messages to the NF consumer, including the subscription ID and a new validity timer. In such a scenario, the NRF uses the “NF_SUB_CHLG” event type in the NFStatus service operation. The NF SUB CHLG mechanism provides a way for the NRF to proactively verify the subscription status with the NF consumer before removing or updating the subscription data. The request may be a Http2 Subscription Validity Challenge Request. The request may include an Application Programming Interface Uniform Resource locator (API URI) {apiRoot}} / nnrf-nfm / vl / subscriptions-validity-challenge .Table 1

[0093] Further, if the NF consumer accepts the extension of the time period of the subscription and the requested value for the "validityTime" attribute, a response with the status code “204 No Content” is returned. If a successful response is received from the NF consumer, the NRF resumes the subscription data. It should be noted that the POST request is sent directly from the NRF in the home Public Land Mobile Network (PLMN) to the NF consumer (either at Home PLMN or Serving PLMN) without involving the intermediate NRF / SCP 302 in Serving PLMN. Further, If the NF consumer does not have the “subscriptionld”, the NF Consumer return “404 Not Found” status code with the ProblemDetails IE providing details of the error.

[0094] If a failure response is received from the NF consumer, the NRF removes the subscription information from its database based on the error code in the response message. A configuration flag is provided in case of a subscription challenge message timeout. If the flag is set to TRUE, the notification message is retried with configurable intervals and retry counts. If the flag is set to FALSE, the NRF deletes the subscription information. Further, in the case of redirection, the NF service consumer returns a 3xx status code, which contains a Location header with a URI pointing to the endpoint of another NF consumer.

[0095] FIG. 4 illustrates an exemplary process flow of a method 400 for managing subscription at the NRF, in accordance with an embodiment of the present disclosure. FIG. 4 is explained in conjunction with FIGS. 1, 2 and 3.

[0096] At step 402, subscription data associated with the subscription of a NF consumer is stored for a validity time. In an exemplary embodiment, a Policy Control Function (PCF) instance (NF consumer) calls NFStatusSubscribe with desired validity “10 min.” The NRF creates subscriptionId=SUB-1234, sets validityTime for 10 minutes, and stores the tuple {SUB-1234, reqNfInstanceId=PCF-Al, filters, notificationUri, validityTime}.

[0097] Upon an expiration of the validity time, at step 404, a hold timer is implemented to retain the subscription data. In an exemplary embodiment, at 12:00:00 Z the validity expires. The NRF arms holdTimer=5 min (configurable). During this window, if the PCF retries an Update-Subscription that had previously failed over the network, the NRF may still reconcile and avoid a false deletion.

[0098] Upon an expiration of the hold timer, at step 406, a validity challenge request is sent to the NF consumer to verify the subscription data. The validity challenge request includes at least one of a subscription validity challenge request and a notification request. Further, the subscription validity challenge request includes at least one of a subscription identifier and the validity time. The subscription validity challenge request includes at least one of a subscription identifier and the validity time. The validity challenge request is transmitted by theNRF in a home Public Land Mobile Network (PLMN) to the NF consumer associated with either the home PLMN or a serving PLMN, and when at least one of a Security Edge Protection Proxy (SEPP) and a Service Communication Proxy (SCP) is designated as the notification endpoint and the network function instance Uri corresponds to the SEPP or the SCP, the NRF transmits the subscription validity challenge request to the SEPP or the SCP for delivery to the NF consumer. In an exemplary embodiment, if the NF is in the serving PLMN behind a SEPP, the NRF addresses the request to the SEPP endpoint designated as the notification endpoint. The SEPP forwards it to the NF consumer. If the NF consumer doesn’t support the challenge API, the NRF sends a notification with eventType=NF_SUB_CHLG, includes validityTime and nflnstanceUri of the consumer, and awaits a notification response.

[0099] In an embodiment, if capability to receive the subscription validity challenge request as a service operation is absent at the NF consumer, the notification request is sent towards the NF consumer. The notification request includes an event type identifying a subscription validity challenge event, the validity time for the subscription, and a network function instance Uri identifying the NF consumer. Further, the notification response corresponding to the notification request is received from the NF consumer indicating whether the subscription remains valid. Finally, the stored subscription data is updated based on the notification response.

[0100] At step 408, a validity challenge response is received from the NF consumer corresponding to a status of the validity challenge request. The validity challenge response includes at least one of a subscription validity challenge response corresponding to the subscription validity challenge request and a notification response corresponding to the notification request. In an exemplary embodiment, the PCF responds “204 No Content”. Alternatively, if the NF lost state, it responds 404 Not Found with ProblemDetails. The NRF then removes the stale subscription. If a 302 Found is received, the NRF resubmits to the provided location.

[0101] At step 410, the stored subscription data is updated at the NRF based on the validity challenge response. Further, updating the stored subscription data includes at least one of continue storing the subscription data and deleting the stored subscription data from the NRF. In an exemplary embodiment, upon 204 success, the NRF sets validityTime=12: 15:00 Z (or the value negotiated), preserving SUB-1234. Upon 404 Not Found, it removes SUB-1234 and ceases notifications to that NF.

[0102] In an embodiment, a subscription request is received from the NF consumer. The subscription request includes at least one of the subscription data and the validity time . Further, an update subscription request is sent to the NRF. The update subscription request corresponds to updating the validity time. In an exemplary embodiment, the PCF, after recovering from an outage, sends a fresh create with subscriptionId=SUB-5678 (same filters and same reqNflnstanceld). The NRF overwrites SUB- 1234 with SUB-5678 so both sides converge. In normal operation, the PCF simply PATCHes validity ahead of expiry.

[0103] FIG. 5 illustrates an exemplary computer system 500 in which or with which embodiments of the present disclosure may be implemented. As shown in FIG. 5, the computer system 500 may include an external storage device 510, a bus 520, a main memory 530, a read-only memory 540, a mass storage device 550, communication port(s) 560, and a processor 570. A person skilled in the art will appreciate that the computer system 500 may include more than one processor and communication ports. The processor 570 may include various modules associated with embodiments of the present disclosure. The communication port(s) 560 may be any of an RS-232 port for use with a modem-based dialup connection, a 10 / 100 Ethernet port, a Gigabit or 10 Gigabit port using copper or fiber, a serial port, a parallel port, or other existing or future ports. The communication port(s) 560 may be chosen depending on a network, such a Eocal Area Network (EAN), Wide Area Network (WAN), or any network to which the computer system 500 connects.

[0104] The main memory 530 may be a Random Access Memory (RAM), or any other dynamic storage device commonly known in the art. The read-only memory 540 may be any static storage device(s) e.g., but not limited to, a Programmable Read Only Memory (PROM) chips for storing static information e.g., start-up or Basic Input / Output System (BIOS) instructions for the processor 570. The mass storage device 550 may be any current or future mass storage solution, which can be used to store information and / or instructions. Exemplary mass storage device 550 includes, but is not limited to, Parallel Advanced Technology Attachment (PATA) or Serial Advanced Technology Attachment (SATA) hard disk drives or solid-state drives (internal or external, e.g., having Universal Serial Bus (USB) and / or Firewire interfaces), one or more optical discs, Redundant Array of Independent Disks (RAID) storage, e.g. an array of disks.

[0105] The bus 520 communicatively couples the processor 570 with the other memory, storage, and communication blocks. The bus 520 may be, e.g. a Peripheral Component Interconnect (PCI) / PCI Extended (PCI-X) bus, Small Computer System Interface (SCSI), Universal Serial Bus (USB), or the like, for connecting expansion cards, drives, and other subsystems as well as other buses, such a front side bus (FSB), which connects the processor 570 to the computer system 500.

[0106] Optionally, operator and administrative interfaces, e.g. a display, keyboard, joystick, and a cursor control device, may also be coupled to the bus 520 to support direct operator interaction with the computer system. Other operator and administrative interfaces can be provided through network connections connected through the communication port(s) 560. Components described above are meant only to exemplify various possibilities. In no way should the aforementioned exemplary computer system 500 limit the scope of the present disclosure.

[0107] In an embodiment, the disclosure provides a method for managing subscription at a Network Repository Function (NRF). The method includes storing, by the NRF, subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the methodincludes implementing, by the NRF, a hold timer to retain the stored subscription data. Upon an expiration of the hold timer, the method further includes sending, by the NRF, a validity challenge request to the NF consumer to verify the stored subscription data. Further, the method includes receiving, by the NRF, a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The method further includes updating, by the NRF, the stored subscription data at the NRF based on the validity challenge response.

[0108] In another exemplary embodiment, the disclosure provides a system for managing subscription at a Network Repository Function (NRF). The system includes a memory, a processing engine and a transceiver unit coupled to the memory to execute a set of instructions stored in the memory. The processing engine is configured to store subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the processing engine is configured to implement a hold time to retain the stored subscription data. Upon an expiration of the hold timer, the transceiver unit is configured to send a validity challenge request to the NF consumer to verify the subscription data. Further, the transceiver unit is configured to receive a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. Further, the processing engine is configured to update the stored subscription data at the NRF based on the validity challenge response.

[0109] In yet another embodiment, the disclosure provides a computer program product including a non-transitory computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to execute a method for managing subscription at a Network Repository Function (NRF). The method includes storing, by the NRF, subscription data associated with the subscription of a NF consumer for a validity time. Upon an expiration of the validity time, the method includes implementing, by the NRF, a hold timer to retain the stored subscription data. Upon an expiration of the hold timer, the method further includes sending, by the NRF, a validity challenge request to the NF consumer to verify the stored subscription data. Further, the methodincludes receiving, by the NRF, a validity challenge response from the NF consumer corresponding to a status of the validity challenge request. The method further includes updating, by the NRF, the stored subscription data at the NRF based on the validity challenge response.

[0110] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.[oni] The method and system of the present disclosure may be implemented in a number of ways. For example, the methods and systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless specifically stated otherwise. Further, in some embodiments, the present disclosure may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0112] In some embodiments, the present disclosure ensures that the subscription validity challenge messages are appropriately authenticated and authorized to prevent unauthorized access. The present disclosure provides clear and informative error messages to assist the NRF in understanding and acting accordingly. Further, the present disclosure may provide a method that implements the Transactions Per Second (TPS) rate limit separately for subscription validity challenge requests from the NRF to the NF consumers. The present disclosure provides a method in whichthe subscription validity challenge service operation supports separate Fault, Configuration, Accounting, and Performance (FCAPs) and Logs for ease of operation in both the NRF and the NF consumers.

[0113] According to the present disclosure, if the subscription validity period expires at the NRF and no updated subscription request is received from the NF consumer, the NRF will have a configurable hold time before taking action on the stored subscription data. If the NF consumer sends a new subscription ID in a create a subscription request with the same reqNflnstanceld and subscription data, the NRF will overwrite the previously stored data with the new one. After the subscription holding time expires, the NRF will send a subscription validity challenge request directly to the NF consumer to verify the subscription and include the new validity time. A new event type, ‘NF_SUB_CHLG,’ is introduced for the subscription validity challenge request. Based on the response to the challenge request, the NRF can decide whether to maintain or remove the current subscription details from its storage. In the case of a new service operation where the NF consumer does not support the subscription validity challenge request, the NRF can send a new notification message with the event type = ‘NF_SUB_CHLG’, validity time, and nflnstanceUri = ‘NF consumer instance URL as part of the subscription details checks at the NF consumer end. Based on the response to this notification event from the NF consumer, the NRF may act on the subscription details.

[0114] The POST ‘Subscription Validity Challenge’ request will be sent directly from the NRF in the Home PLMN to the NF Consumer in the Serving / Home PLMN, bypassing (or without involving) the NRF / SCP in the Serving PLMN. If Security Edge Protection Proxy (SEPP)ZSCP is involved and the notification URI belongs to SEPP / SCP, the NRF can send the subscription validity challenge message to SEPP / SCP.

[0115] This allows the NRF to check the subscription status on the NF consumer side. Based on the response received (success, failure, or timeout), the NRF can decide whether to continue maintaining the subscription details or remove themfrom its storage. This approach ensures that subscription data consistency is maintained on both the NF and NRF sides. According to one aspect, a check is added before removing the NF subscription information from the NRF’s database. If the challenge request is successful, the NRF and NF consumer can extend the subscription validity timer, ensuring both have the same subscription details even in failure scenarios. The NRF can then send notification messages to the subscribed NF, improving overall network performance.

[0116] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be implemented merely as illustrative of the disclosure and not as a limitation.

[0117] The present disclosure provides significant technical advancements in maintaining accurate and resilient subscription state at the Network Repository Function (NRF) for NF consumer notifications across home and serving PLMNs. Conventional approaches rely on passive expiry and ad-hoc retries, which frequently leave stale or orphaned subscriptions, cause false deletions when transient failures delay updates, and create state divergence between the NRF and NF consumers. Such inconsistencies trigger unnecessary notifications, inflate signalling load, degrade observability, and complicate inter-PLMN roaming where SEPP / SCP traversal is involved. To overcome these limitations, the present disclosure introduces a validity-aware lifecycle including storage with explicit validity time, a post-expiry hold timer to absorb transient faults, and an active Subscription Validity Challenge. The NRF, operating in the home PLMN, transmits a subscription validity challenge request directly to the NF consumer (in home or serving PLMN) or, when the notification endpoint is a SEPP / SCP URI, via the SEPP / SCP for secure delivery. When an NF consumer lacks the challenge serviceoperation, a notification-based fallback conveys an event type identifying a subscription validity challenge together with validity time and NF instance URI, thereby preserving backward compatibility.

[0118] By actively verifying post-expiry state and offering a standards-aligned proxy path, the present disclosure realizes multiple technical benefits. First, it maximizes subscription state fidelity by preventing silent divergence, valid subscriptions are extended promptly while defunct ones are safely removed. Second, it reduces signalling overhead and resource wastage by eliminating redundant notifications from stale records and avoiding repeated subscription recreations after transient outages. Third, it improves recovery latency and service continuity through the hold-then-challenge sequence, enabling fast reconvergence without interrupting ongoing network functions (e.g., PCF / BSF / AMF consumers). Fourth, it enhances inter-PLMN robustness and security by supporting SEPP / SCP-mediated delivery when the endpoint resides at the security boundary, maintaining integrity while minimizing integration changes. Fifth, it scales reliably under dense deployments, configurable timers, retries, and TPS controls bound the challenge traffic, while overwrite semantics for duplicate create requests prevent subscription proliferation. Collectively, these capabilities stabilize notifications, improve KPI accuracy, and lower operational toil, delivering a faster, leaner, and more reliable subscription management plane in 5G service-based architectures.TECHNICAL ADVANCEMENTS

[0119] Subscription consistency maintenance: By implementing a subscription validity challenge before removing Network Function (NF) subscription data, the present disclosure ensures consistent subscription information between the Network Repository Function (NRF) and the NF consumer, preventing discrepancies caused by missed or failed update requests.

[0120] Improved network performance: With consistent subscription details, the NRF can reliably send notification messages to the subscribed NF, enhancingoverall network Key Performance Indicators (KPIs) such as reliability and data integrity.

[0121] Configurable hold time: The NRF uses a configurable hold time before deleting subscription data. The flexibility allows the NF consumer more time to retry sending an update if network errors or other issues occur, providing robustness in maintaining active subscriptions.

[0122] Error handling and resilience: When the NF consumer does not respond or fails the validity challenge, the NRF may adjust its response based on error codes or timeouts. The NRF either retries or, if unsuccessful, removes the subscription, ensuring efficient error management.

[0123] Direct communication without intermediate NRFs: The challenge request may be sent directly from the NRF in the Home PLMN to the NF consumer, bypassing intermediate NRFs in the Serving PLMN, simplifying communication and reducing latency.

[0124] Enhanced security and rate limiting: The present disclosure introduces measures for authentication, authorization, and rate limiting on HTTP / 2 requests for the Subscription Validity Challenge, preventing unauthorized access and controlling request rates for operational efficiency.

[0125] Better resource allocation: The present disclosure helps the NRF manage its database more efficiently by retaining confirmed subscriptions and optimizing resource allocation for valid subscriptions.

Claims

Claims1. A method (400) for managing subscription at a Network Repository Function (NRF) (304), the method (400) comprising:storing (402), by the NRF (304), subscription data associated with the subscription of a NF consumer (301) for a validity time;upon an expiration of the validity time, implementing (404), by the NRF (304), a hold timer to retain the stored subscription data;upon an expiration of the hold timer, sending (406), by the NRF (304), a validity challenge request to the NF consumer (301) to verify the stored subscription data;receiving (408), by the NRF (304), a validity challenge response from the NF consumer (301) corresponding to a status of the validity challenge request; and updating (410), by the NRF (304), the stored subscription data at the NRF (304) based on the validity challenge response.

2. The method (400) as claimed in claim 1, wherein the validity challenge request comprising at least one of a subscription validity challenge request and a notification request.

3. The method (400) as claimed in claim 2, wherein the subscription validity challenge request comprising at least one of a subscription identifier and the validity time.

4. The method (400) as claimed in claim 2, wherein the notification request comprising at least one of an event type, the validity time, and a network function instance Uri.

5. The method (400) as claimed in claim 1, wherein the validity challenge response comprising at least one of a subscription validity challenge response corresponding to the subscription validity challenge request and a notification response corresponding to the notification request.

6. The method (400) as claimed in claim 1, wherein if capability to receive the subscription validity challenge request as a service operation is absent at the NF consumer (301), further comprising:sending, by the NRF (304), the notification request towards the NF consumer (301), wherein the notification request comprises an event type identifying a subscription validity challenge event, the validity time for the subscription, and a network function instance Uri identifying the NF consumer (301);receiving, by the NRF (304), the notification response corresponding to the notification request from the NF consumer (301) indicating whether the subscription remains valid; andupdating, by the NRF (304), the stored subscription data based on the notification response.

7. The method (400) as claimed in claim 1, wherein updating the stored subscription data comprising at least one of:continue storing the subscription data; anddeleting the stored subscription data from the NRF (304).

8. The method (400) as claimed in claim 1, comprising:receiving, by the NRF (304), a subscription request from the NF consumer (301), wherein the subscription request comprising at least one of the subscription data and the validity time; andsending, by the NF consumer (301), an update subscription request to the NRF (304), wherein the update subscription request corresponds to updating the validity time.

9. The method (400) as claimed in claim 1, wherein the validity challenge request is transmitted by the NRF (304) in a home Public Land Mobile Network (PLMN) to the NF consumer (301) associated with either the home PLMN or a serving PLMN, and wherein when at least one of a Security Edge Protection Proxy (SEPP) and a Service Communication Proxy (SCP) (302) is designated as the notification endpoint and the network function instance Uri corresponds to the SEPP or the SCP (302), the NRF (304) transmits the subscription validity challenge request to the SEPP or the SCP (302) for delivery to the NF consumer (301).

10. A system (108) for managing subscription at a Network Repository Function (NRF) (304), the system (108) comprising:a memory (204); anda processing engine (208) coupled to the memory (204) to execute a set of instructions stored in the memory (204), wherein the processing engine (208) is configured to:store subscription data associated with the subscription of a NF consumer (301) for a validity time;upon an expiration of the validity time, implement a hold time to retain the stored subscription data;a transceiver unit (212) configured to:send a validity challenge request to the NF consumer (301) to verify the stored subscription data, upon an expiration of the hold timer; andreceive a validity challenge response from the NF consumer (301) corresponding to a status of the validity challenge request; andthe processing engine 208 is configured to update the stored subscription data at the NRF (304) based on the validity challenge response.

11. The system (108) as claimed in claim 10, wherein the validity challenge request comprising at least one of a subscription validity challenge request and a notification request.

12. The system (108) as claimed in claim 11, wherein the subscription validity challenge request comprising at least one of a subscription identifier and the validity time.

13. The system (108) as claimed in claim 11, wherein the notification request comprising at least one of an event type, the validity time, and a network function instance Uri.

14. The system (108) as claimed in claim 10, wherein the validity challenge response comprising at least one of a subscription validity challenge response corresponding to the subscription validity challenge request and a notification response corresponding to the notification request.

15. The system (108) as claimed in claim 10, wherein if capability to receive the subscription validity challenge request as a service operation is absent at the NF consumer (301), the transceiver unit (212) is configured to:Send the notification request toward the NF consumer (301), wherein the notification request comprises an event type identifying a subscription validity challenge event, the validity time for the subscription, a network function instance Uri identifying the NF consumer (301); andreceive the notification response corresponding to the notification request from the NF consumer (301) indicating whether the subscription remains valid; andthe processing engine (208) is configured to update the stored subscription data based on the notification response.

16. The system (108) as claimed in claim 10, wherein to update the stored subscription data, the processing engine (208) is configured to at least one of: continue store the subscription data; anddeleting the stored subscription data from the NRF (304).

17. The system (108) as claimed in claim 10, wherein the processing engine (208) is configured to:receive, by the NRF (304), a subscription request from the NF consumer (301), wherein the subscription request comprising at least one of the subscription data and the validity time; andsend, by the NF consumer (301), an update subscription request to the NRF (304), wherein the update subscription request corresponds to updating the validity time.

18. The system (108) as claimed in claim 10, wherein the validity challenge request is transmitted by the NRF (304) in a home Public Land Mobile Network (PLMN) to the NF consumer (301) associated with either the home PLMN or a serving PLMN, and wherein when at least one of a Security Edge Protection Proxy(SEPP) and a Service Communication Proxy (SCP) (302) is designated as the notification endpoint and the network function instance Uri corresponds to the SEPP or the SCP (302), the NRF (304) transmits the subscription validity challenge request to the SEPP or the SCP (302) for delivery to the NF consumer (301).

19. A computer program product comprising a non-transitory computer-readable medium comprising instructions that, when executed by one or more processors (202), cause the one or more processors (202) to execute a method (400) for managing subscription at a Network Repository Function (NRF) (304), the method (400) comprising:storing (402), by the NRF (304), subscription data associated with the subscription of a NF consumer (301) for a validity time;upon an expiration of the validity time, implementing (404), by the NRF (304), a hold timer to retain the subscription data;upon an expiration of the hold timer, sending (406), by the NRF (304), a validity challenge request to the NF consumer (301 ) to verify the subscription data;receiving (408), by the NRF (304), a validity challenge response from the NF consumer (301) corresponding to a status of the validity challenge request; and updating (410), by the NRF (304), the stored subscription data at the NRF (304) based on the validity challenge response.

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