System and method for discovering a network function (NF) in a communication network

Abstract

The present disclosure relates to a system (108) and a method (400) for discovering a network function (NF) in a communication network (106). The system (108) includes a requesting Network Repository Function (NRF) (204) to receive a discovery request comprising one or more discovery parameters associated with a target NF. The requesting NRF (204) then searches a local NRF database for an NF profile corresponding to the discovery parameters. If the NF profile is not found, the requesting NRF (204) applies a first routing policy comprising a first routing logic to determine a first routing path and forwards the request to a primary NRF (206). The primary NRF (206) searches a primary NRF database and, if unsuccessful, applies a second routing policy comprising a second routing logic to determine a second routing path. The primary NRF (206) then forwards request to a secondary NRF (208) to discover the target NF.

Description

SYSTEM AND METHOD FOR DISCOVERING A NETWORK FUNCTION (NF) IN A COMMUNICATION NETWORKRESERVATION 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.FIELD OF DISCLOSURE

[0002] The embodiments of the present disclosure generally relate to communication networks. In particular, the present disclosure relates to a system and a method for discovering a network function (NF) in the communication network.DEFINITIONS

[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 expression “Network Function (NF)” as used hereinafter in the specification refers to a component within a telecommunication network that performs specific network operations related to managing data plans, charging services, session handling, and policy enforcement. Examples of the NF includes a Policy Control Function (PCF), a Session Management Function (SMF), and aCharging Function (CHF), among others.

[0005] The expression “Consumer Network Function (NF)” used hereinafter in the specification refers to the NF that initiates a request for discovery and interaction with other NFs via a Network Repository Function (NRF). The consumer NF acts as a requesting entity seeking to identify and connect with appropriate NFs within the network.

[0006] The expression “Network Repository Function (NRF)” used hereinafter in the specification refers to a function responsible for storing and managing information about Network Functions (NFs), including their location, capabilities, and availability.

[0007] The expression “Requesting Network Repository Function (NRF)” used hereinafter in the specification refers to a function responsible for initiating the NF discovery process. The requesting NRF is an originating point of the request to locate a target network function. The requesting NRF may be a local NRF within a network domain or a higher-level NRF responsible for coordinating discovery across multiple domains.

[0008] The expression “Primary Network Repository Function (NRF)” used hereinafter in the specification refers to a network function that acts as the next-hop NRF, selected by the requesting NRF based on a first routing policy, for handling a discovery request when the target network function (NF) is not found locally at the requesting NRF.

[0009] The expression “Secondary Network Repository Function (NRF)” used hereinafter in the specification refers to a backup or auxiliary NRF that is selected by the primary NRF based on a second routing policy when the target NF is not found within a primary NRF database.

[0010] The expression “Routing Policy” used hereinafter in the specification refers to a set of rules that determine the order and priority of NetworkRepository Functions (NRFs) to be consulted during the NF discovery process.

[0011] The expression “Data Network Name (DNN)” used hereinafter in the specification refers to a Data Network, a logical network within a cellular network used to carry specific types of data traffic.

[0012] The expression “Slice Identifiers” used hereinafter in the specification refers to unique identifiers associated with network slices, which are segments of the network tailored for specific services or customers.

[0013] The expression “error response” used hereinafter in the specification refers to a response generated by an NRF when a target NF cannot be found.

[0014] The expression “success response” used hereinafter in the specification refers to the response generated by an NRF when the target NF is found.

[0015] These definitions are in addition to those expressed in the art.BACKGROUND OF DISCLOSURE

[0016] 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.

[0017] Wireless communication technology has rapidly evolved over the past few decades. The first generation of wireless communication technology was analog technology that offered only voice services. Further, when the second- generation (2G) technology was introduced, text messaging and data services became possible. The 3Gtechnology marked the introduction of high-speed internet access, mobile video calling, and location-based services. The fourth-generation (4G) technology revolutionized wireless communication with faster data speeds,improved network coverage, and security. Currently, the fifth-generation (5G) technology is being deployed, with even faster data speeds, low latency, and the ability to connect multiple devices simultaneously. The sixth generation (6G) technology promises to build upon these advancements, pushing the boundaries of wireless communication even further.

[0018] In telecommunication networks, particularly in 5G networks, the Network Repository Function (NRF) maintains and manages the repository of available Network Functions (NFs). The NFs are essential components of the network infrastructure, providing various services such as session management, policy control, and user authentication. The NRF is responsible for registering, discovering, and providing information about the NFs, enabling seamless communication and service delivery across the network.

[0019] However, as networks have evolved, so too have the challenges associated with managing the NFs, particularly in scenarios where multiple NRFs are deployed across different regions or domains. One significant issue arises when different NRFs manage two NFs, and a second NF among the two NFs is designated as a backup for a first NF. In such cases, if the first NF fails or becomes unreachable, it is crucial for the network to quickly discover and utilize the second NF to maintain service continuity. The existing systems for NF discovery are often limited by the scope of the NRF handling the discovery request.

[0020] Further, in a network scenario involving two Network Functions (NFs), where NF 1 is managed by NRF 1 and its backup, NF2, is managed by NRF2, a significant problem arises. Each NRF is responsible for different regions or domains and lacks visibility into the NFs managed by the other NRF. When a discovery request for the NF1 is sent to the NRF1, the NRF1 checks its local repository and returns information on the NF 1. However, if the NF 1 fails, the NRF 1 cannot discover and return the NF2 as a backup because the NF2 is registered with the NRF2, not the NRF 1. This lack of cross-NRF awareness leads to critical issues such as the inability to fall back on backup NFs, inefficient resource utilization,increased complexity in managing cross-domain operations, and potential network downtime due to failure in automated discovery and error handling.

[0021] Existing systems for NF discovery primarily focus on local NF instances within a single NRF. While the existing systems work well in isolated scenarios where all NFs are managed by a single NRF, they fall short in more complex environments involving multiple NRFs. In particular, the existing systems lack the capability to perform NF discovery across multiple NRFs.

[0022] There is, therefore, a need in the art to provide a method and a system that can overcome the shortcomings of the existing prior arts.OBJECTIVES OF THE PRESENT DISCLOSURE

[0023] Some of the objectives of the present disclosure, which at least one embodiment herein satisfies, are as listed herein below.

[0024] An object of the present disclosure is to provide a system and a method for discovering network functions (NFs) in a communication network using a hierarchical, multi-layered routing approach involving multiple Network Repository Functions (NRFs).

[0025] Another object of the present disclosure is to provide a system and a method for discovering the NFs across the multiple NRFs by applying routing policies at different levels, requesting primary and secondary NRFs, based on network-specific parameters.

[0026] Another object of the present disclosure is to provide a system and a method for improving error handling by enabling specific error responses when primary NFs are unavailable, facilitating faster troubleshooting and recovery by identifying backup NFs across different NRFs.

[0027] Other objectives 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.SUMMARY

[0028] In an exemplary embodiment, a method for discovering a network function (NF) in a communication network is disclosed. The method includes receiving, by a requesting Network Repository Function (NRF), a discovery request to discover a target NF. The discovery request includes one or more discovery parameters associated with the target NF. The method further includes searching, by the requesting NRF, a local NRF database for an NF profile that corresponds to one or more discovery parameters. The method further includes applying, by the requesting NRF, a first routing policy provisioned at the requesting NRF upon failure to locate the NF profile in the local NRF database. The first routing policy includes a first routing logic to determine a first routing path. The method further includes forwarding, by the requesting NRF, the discovery request along the first routing path to a primary NRF. The method further includes searching, by the primary NRF, a primary NRF database for the NF profile based on the one or more discovery parameters. The method further includes, upon failure to locate the NF profile in the primary NRF database, applying, by the primary NRF a second routing policy provisioned at the primary NRF. The primary NRF includes a second routing logic to determine a second routing path. The method further includes forwarding, by the primary NRF, the discovery request along the second routing path to a secondary NRF to discover the target NF.

[0029] In some embodiments, the method includes searching, by the secondary NRF, a secondary NRF database for the NF profile based on the one or more discovery parameters. The method further includes sending, by the secondary NRF, a success response to the primary NRF or the requesting NRF upon locating the NF profile in the secondary database. The method further includes sending, by the secondary NRF, an error response to the primary NRF or the requesting NRF if the NF profile is not located in the secondary NRF database.

[0030] In some embodiments, the method includes applying, by the secondary NR, a third routing policy provisioned at the secondary NRF in responseto determining that the NF profile is not available in the secondary NRF database, the third routing policy comprises a third routing logic to determine a third routing path.

[0031] In some embodiments, the method includes forwarding, by the primary NRF, the success response to the requesting NRF in response to receiving the success response from the secondary NRF.

[0032] In some embodiments, the NF profile is associated with the target NF.

[0033] In some embodiments, the method includes mapping, by the requesting NRF, the one or more discovery parameters against a first routing table configured at the requesting NRF using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path. The method further includes mapping, by the primary NRF, the one or more discovery parameters against a second routing table configured at the primary NRF using the second routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the second routing table to determine the second routing path. The method further includes mapping, by the secondary NRF, the one or more discovery parameters against a third routing table configured at the secondary NRF using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path.

[0034] In some embodiments, the method includes receiving, by the requesting NRF, the discovery request from a consumer NF.

[0035] In some embodiments, the method includes returning, by the requesting NRF, the error response to the consumer NF when the NF profile is notdiscovered after applying the first routing path, the second routing path, and the third routing path.

[0036] In some embodiments, the method includes sending, by the requesting NRF, a response to the consumer NF upon determining that the NF profile is not available in the requesting NRF database, wherein the response comprises of a routing information provided in the first routing policy provisioned at the requesting NRF. The method further includes redirecting, by the consumer NF, the discovery request to the primary NRF based on the routing information sent by the requesting NRF.

[0037] In some embodiments, the method includes sending, by the primary NRF, a response to the consumer NF upon determining that the NF profile is not available in the primary NRF database, wherein the response comprises of a routing information provided in the second routing policy provisioned at the primary NRF. The method further includes redirecting, by the consumer NF, the discovery request to the secondary NRF based on the routing information sent by the primary NRF.

[0038] In some embodiments, the method includes forwarding, by the requesting NRF, the discovery request to the primary NRF using the first routing policy provisioned at the requesting NRF. The method further includes forwarding, by the primary NRF, the discovery request to the secondary NRF using the second routing policy provisioned at the primary NRF upon determining that the NF profile is not located in the primary NRF database.

[0039] In some embodiments, the method includes selecting, by the requesting NRF, the primary NRF to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF. The method further includes selecting, by the requesting NRF, the secondary NRF, to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF after receiving the error response from the primary NRF.

[0040] In some embodiments, the one or more discovery parameters comprise at least one of a Network Function Type (NFT), a Slice / Service Type Identifier (S-NSSAI), a Data Network Name (DNN), a Public Land Mobile Network (PLMN) identifier, a geographical region, or a load-balancing metric.

[0041] In an exemplary embodiment, a system for discovering a network function (NF) in a communication network is disclosed. The system includes a requesting Network Repository Function (NRF). The requesting NRF is configured to receive a discovery request to discover a target NF. The discovery request includes one or more discovery parameters associated with the target NF. The requesting NRF is configured to search a local NRF database for an NF profile that corresponds to the one or more discovery parameters. Upon failure to locate the NF profile in the local NRF database, the requesting NRF is configured to apply, a first routing policy provisioned at the requesting NRF, the first routing policy comprising a first routing logic to determine a first routing path. The requesting NRF is configured to forward the discovery request along the first routing path to a primary NRF. The primary NRF is configured to search a primary NRF database for the NF profile based on the one or more discovery parameters, upon failure to locate the NF profile in the primary NRF database, the requesting NRF is configured to apply a second routing policy provisioned at the primary NRF, the primary NRF comprising a second routing logic to determine a second routing path and the requesting NRF is configured to forward the discovery request along the second routing path to a secondary NRF to discover the target NF.

[0042] In an exemplary embodiment, a computer program product comprising a non-transitory computer-readable medium is disclosed. The medium includes instructions that, when executed by one or more processors, cause the one or more processors to execute a method for discovering a network function (NF) in a communication network. The method includes receiving, by a requesting Network Repository Function (NRF), a discovery request to discover a target NF. The discovery request includes one or more discovery parameters associated with the target NF. The method further includes searching, by the requesting NRF, a localNRF database for an NF profile that corresponds to one or more discovery parameters. The method further includes applying, by the requesting NRF, a first routing policy provisioned at the requesting NRF upon failure to locate the NF profile in the local NRF database. The first routing policy includes a first routing logic to determine a first routing path. The method further includes forwarding, by the requesting NRF, the discovery request along the first routing path to a primary NRF. The method further includes searching, by the primary NRF, a primary NRF database for the NF profile based on the one or more discovery parameters. The method further includes, upon failure to locate the NF profile in the primary NRF database, applying, by the primary NRF a second routing policy provisioned at the primary NRF. The primary NRF includes a second routing logic to determine a second routing path. The method further includes forwarding, by the primary NRF, the discovery request along the second routing path to a secondary NRF to discover the target NF.

[0043] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF DRAWINGS

[0044] 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.

[0045] FIG. 1 illustrates an exemplary network architecture for discovering a network function (NF) in a communication network, in accordance with embodiments of the present disclosure.

[0046] FIG. 2A illustrates an exemplary architecture of a system for discovering the NF in the communication network, in accordance with embodiments of the present disclosure.

[0047] FIG. 2B illustrates a block diagram of the system for discovering the NF in the communication network, in accordance with embodiments of the present disclosure.

[0048] FIG. 3 illustrates an exemplary flow diagram of performing a method for discovering the NF in the communication network, wherein a consumer NF redirects a discovery request to a primary Network Repository Function (NRF) and subsequently to a secondary NRF based on routing information received from the NRFs in accordance with embodiments of the present disclosure.

[0049] FIG. 4 illustrates another exemplary flow diagram of performing a method for discovering the NF in the communication network, wherein the discovery request is forwarded through a chain of NRFs, and the response is sent back along the same chain from the secondary NRF to the primary NRF and finally to the requesting NRF in accordance with embodiments of the present disclosure.

[0050] FIG. 5 illustrates another exemplary flow diagram of performing a method for discovering the NF in the communication network, wherein the requesting NRF is provisioned with routing details of both the primary NRF and the secondary NRF and independently forwards the discovery request based on a first routing policy in accordance with embodiments of the present disclosure.

[0051] FIG. 6 illustrates an exemplary flow diagram of a method for discovering the NF in the communication network, in accordance with embodiments of the present disclosure.

[0052] FIG. 7 illustrates an exemplary computer system in which or with which the system may be implemented in accordance with an embodiment of the present disclosure.

[0053] The foregoing shall be more apparent from the following more detailed description of the disclosure.LIST OF REFERENCE NUMERALS100 - Network Architecture102-1, 102-2. . . 102-N - A plurality of users104-1, 104-2. . . 104-N - User Equipments (UEs)106 - Network108 - System200A - System architecture202 - Consumer network function (NF)204 - Requesting network repository function (NRF)206 - Primary network repository function (NRF)208 - Secondary network repository function (NRF)200B - Block diagram212 - Processor(s)214 - Memory216 - Interface(s)218 - Processing unit220 - Database300 - Flow diagram400 - Flow diagram500 - Flow diagram600 - Flow diagram700 - A computer system710 - External storage device720 - Bus730 - Main memory740 - Read only memory750 - Mass storage device760 - Communication port(s)770 - ProcessorDETAILED DESCRIPTION OF DISCLOSURE

[0054] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments 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 all 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.

[0055] 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.

[0056] 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.

[0057] Also, it is noted that individual embodiments may be described as a process which 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 or concurrently. 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.

[0058] 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 notnecessarily 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 in a manner similar to the term “comprising” as an open transition word without precluding any additional or other elements.

[0059] 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.

[0060] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” 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 and all combinations of one or more of the associated listed items.

[0061] In a communication network, the discovery of Network Functions (NFs) is a critical process that enables various network services and orchestration tasks. Conventional NF discovery systems often rely on a flat or two-layered approach, where a discovery request is forwarded from a visited NetworkRepository Function (NRF) to a home NRF primarily based on a Public Land Mobile Network (PLMN) mismatch. The limitations in the conventional NF discovery systems are that such systems lack the flexibility required to support dynamic, multi-domain, and high-availability scenarios, especially in networks with multiple overlapping or associated NRFs. The limitation results in delayed service discovery, increased signalling overhead, and limited fault tolerance in distributed network deployments.

[0062] In an aspect, the present disclosure provides a system and a method for discovering the NF in a communication network using a multi-layered routing architecture across a requesting NRF, a primary NRF, and a secondary NRF. Each NRF in the hierarchy applies its own routing policy based on one or more discovery parameters. The routing logic evaluates one or more discovery parameters against preconfigured routing tables to determine the most appropriate path for forwarding discovery requests and to perform better load distribution across NRFs. The present disclosure also allows flexible handling of responses through intermediate NRFs, further contributing to transparent and resilient NF service resolution.

[0063] The various embodiments throughout the disclosure will be explained in more detail with reference to FIG. 1- FIG. 7.

[0064] FIG. 1 illustrates an exemplary network architecture for discovering a Network Function (NF) in a communication network (106), in accordance with embodiments of the present disclosure.

[0065] Referring to FIG. 1, the network architecture (100) may include one or more computing devices or 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 individually referred to as the user (102) and collectively referred to as the users (102). Similarly, a person of ordinary skill in the art will understand that one or more user equipments (104-1, 104-2. .. 104-N) may be individually referred to as the user equipment (104) and collectively referred to asthe user equipment (104). A person of ordinary skill in the art will appreciate that the terms “computing device(s)” and “user equipment” may be used interchangeably throughout the disclosure. Although three user equipments (104) are depicted in FIG. 1, however, any number of the user equipments (104) may be included without departing from the scope of the ongoing description. In an embodiment, each of the user equipment (104) may have a first unique identifier attribute associated therewith. In an embodiment, the first unique identifier attribute may be indicative of Mobile Station International Subscriber Directory Number (MSISDN), International Mobile Equipment Identity (IMEI) number, International Mobile Subscriber Identity (IMSI), Subscriber Permanent Identifier (SUPI) and the like.

[0066] 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 user equipment (104) may include but is not limited to, smartphones, smart watches, smart sensors (e.g., mechanical, thermal, electrical, magnetic, etc.), networked appliances, networked peripheral devices, networked lighting system, communication devices, networked vehicle accessories, networked vehicular devices, smart accessories, tablets, smart television (TV), computers, smart security system, 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 user equipment (104) may include, but is not limited to, intelligent, multi -sensing, network-connected devices that can integrate seamlessly with each other and / or with a central server or a cloud-computing system or any other device that is network-connected.

[0067] In an embodiment, the UE (104) may include, but is not limited to, a handheld wireless communication device (e.g., a mobile phone, a smartphone, a phablet device, and so on), a wearable computer device (e.g., a head-mounted display computer device, a head-mounted camera device, a wristwatch computer device, and so on), a Global Positioning System (GPS) device, a laptop computer, a tablet computer, or another type of portable computer, a media playing device, aportable gaming system, and / or any other type of computer device with wireless communication capabilities, and the like. In an embodiment, the user equipment (104) may include but is not limited to, any electrical, electronic, electromechanical, or an equipment, or a combination of one or more of the above devices such as virtual reality (VR) devices, augmented reality (AR) devices, laptop, a general-purpose computer, desktop, personal digital assistant, tablet computer, mainframe computer, or any other computing device, the user equipment (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 the entity such as touchpad, touch-enabled screen, electronic pen, and the like. A person of ordinary skill in the art will appreciate that the user equipment (104) may not be restricted to the mentioned devices and various other devices may be used.

[0068] Referring to FIG. 1, the UE (104) may communicate with a system (108) via the network (106). The UE (104) may be communicatively coupled with the network (106). The communicative coupling comprises receiving, from the UE (104), a connection request by the network (106), sending an acknowledgment of the connection request to the UE (104), and transmitting a plurality of signals in response to the connection request. In an embodiment, the network (106) may include at least one of a Fourth Generation (4G) network, a Fifth Generation (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.

[0069] As depicted in FIG. 1, the UE (104) connects to the system (108) through the communication network (106), which may include 4G, 5G, 6G, or other network technologies. This connection facilitates the initiation of service procedures, such as NF discovery, handled by a requesting Network Repository Function (NRF) within the system (108), thereby enabling efficient interaction between user equipment (104) and a target NF provisioned in the network architecture (100).

[0070] 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).

[0071] FIG. 2A illustrates an exemplary architecture (200A) of the system (108) for discovering the network function (NF) in the communication network (106) in accordance with an embodiment of the present disclosure.

[0072] In an embodiment, the system architecture (200A) comprises a consumer NF (202), the requesting Network Repository Function (NRF) (204), a primary NRF (206) and a secondary NRF (208).

[0073] In an embodiment, the consumer NF (202) is the entity within the network (106) that initiates requests to discover or interact with other network functions. For instance, the consumer NF (202) may be an Access and Mobility Management Function (AMF) or a Session Management Function (SMF) seeking to locate other services. When the consumer NF (202) requires the services of another network function, the consumer NF (202) sends a request to the requesting NRF (204). The request can be a discovery request.

[0074] In an embodiment, the discovery request is sent to the system (108) for discovering the target NF by the consumer NF (202). The discovery request firstreaches the requesting NRF (204) via the consumer NF (202). The discovery request may include one or more parameters like DNN and network slice, which help in identifying the target NF.

[0075] In an embodiment, the requesting NRF (204) may be connected to the consumer NF (202) through a signalling interface within the network (106). The requesting NRF (204) maintains a repository of available NFs. In an embodiment, the requesting NRF (204) is configured to store and manage an ordinary Network Function (NF). In an embodiment, the ordinary NF refers to the target NF that is registered with the requesting NRF (204) using the one or more discovery parameters. The one or more discovery parameters may include only standard identifiers such as a Network Function Type (NFT), Public Land Mobile Network (PLMN) ID, or a generic region value. When a consumer NF (202) issues the discovery request to discover the target NF, and the target NF corresponds to the ordinary NF, the requesting NRF (204) is capable of locating the NF profile directly within the local NRF database based on the received one or more discovery parameters. In such a case, the target NF is located without escalation to external NRFs, and a success response is returned immediately . Further, when the discovery request is received, the requesting NRF (204) discovers or finds out the target NF that can fulfill the discovery request. In particular, the requesting NRF (204) searches for the target NF in the local NRF database comprising the NFs and checks a first routing policy that may point to external or backup NFs.

[0076] In an embodiment, the first routing policy is provisioned at the requesting NRF (204) and is invoked when the requesting NRF fails to discover a network function (NF) profile in the local NRF database. The first routing policy includes a first routing logic and a first routing table. The first routing logic is configured to evaluate one or more discovery parameters contained in the discovery request. The one or more discovery parameters may include Network Function Type (NFT), Slice / Service Type Identifier (S-NSSAI), Data Network Name (DNN), Public Land Mobile Network (PLMN) identifier, geographical region, and load-balancing metric. The first routing table stores predefined combinations of theone or more discovery parameters along with corresponding routing destinations. The first routing logic performs mapping of the one or more discovery parameters to the entries in the first routing table and selects a first routing path. Based on the mapping, the discovery request is forwarded to the primary NRF (206).

[0077] The requesting NRF (204) may then send the request to the primary NRF (206) if the target NF is not present in the local NRF database of the requesting NRF (204).

[0078] In an embodiment, the primary NRF (206) is the first point of contact for discovering the target NF. The primary NRF (206) is configured to manage a special Network Function (NF). In an embodiment, the special NF refers to the target NF that is registered with the primary NRF (206) and associated with specific one or more discovery parameters, such as a Slice / Service Type Identifier (S- NSSAI), Data Network Name (DNN), load-balancing metric, or a fine-grained geographical region. The requesting NRF (204), upon receiving the discovery request from the consumer NF (202), applies the first routing policy and determines that the NF profile matching the target NF is not available locally but is likely registered at the primary NRF (206). The target NF is thus considered as the special NF because it cannot be discovered through standard local search but requires routing logic for discovery. This mechanism supports use cases where enterprise services or network slices require dedicated NF instances that are only accessible through hierarchical routing. Further, the primary NRF (206) checks the primary NRF database to see if the target NF is available. If the target NF is found in the primary NRF database, the primary NRF (206) sends a response back to the requesting NRF (204). If the target NF is not found in the primary NRF database, the primary NRF (206) will follow a second routing policy to check if the target NF can be found through other means, such as the secondary NRF (208).

[0079] In an embodiment, the primary NRF (206) checks the primary NRF database to see if the target NF is available. If the target NF is found locally, therequesting NRF (204) immediately responds to the consumer NF (202), indicating that the target NF has been successfully discovered.

[0080] In an embodiment, if the target NF is not found in the primary NRF database, the primary NRF (206) then checks the second routing policy, which might point to other locations or repositories where the target NF could be registered. The primary NRF (206) may consult with the secondary NRF (208), as dictated by the second routing policy.

[0081] In an embodiment, the second routing policy is provisioned at the primary NRF (206), and the second routing policy is triggered when the primary NRF is unable to find the target NF profile in the primary NRF database. The second routing policy includes a second routing logic and a second routing table. Similar to the first routing policy, the second routing logic is configured to evaluate the same discovery parameters against the second routing table. The routing table defines associations between combinations of the one or more discovery parameters and next-hop destinations, typically pointing to the secondary NRF (208). The second routing logic performs mapping of the one or more discovery parameters to determine the second routing path. Once the mapping is complete, the discovery request is forwarded to the secondary NRF along the second routing path.

[0082] In an embodiment, the secondary NRF (208) is a backup repository for NFs not found by the primary NRF (206). In an embodiment, the secondary NRF (208) is configured to store a backup of a special NF. In an embodiment, the backup of the special NF refers to an auxiliary or failover NF instance registered with the secondary NRF (208), serving as the backup for the special NF hosted at the primary NRF (206). When the requesting NRF (204) or the primary NRF (206) fails to discover the NF profile associated with the special target NF, the routing logic, based on the second routing policy, determines that the discovery request should be forwarded to the secondary NRF (208). The secondary NRF (208) then attempts to discover the target NF using the secondary NRF database or the third routing policy.

[0083] The secondary NRF (208) then repeats the process, checking both the secondary NRF database and the third routing policy. If the secondary NRF (208) finds the target NF, the secondary NRF (208) sends a response back to the primary NRF (206), which then forwards the successful discovery response to the requesting NRF (204). If the target NF is not found even after checking by the secondary NRF (208), an error response is generated and sent back to the consumer NF (202) or the requesting NRF (204) or the primary NRF (206), indicating that the target NF is unavailable.

[0084] In an embodiment, the third routing policy is configured at the secondary NRF (208) and is activated when the secondary NRF fails to locate the requested NF profile in the secondary NRF database. The third routing policy includes a third routing logic and a third routing table. The third routing logic evaluates the one or more discovery parameters against the third routing table, which contains predefined parameter combinations and corresponding fallback actions. The fallback actions may include forwarding the request to another backup NRF or returning an error response if no valid path is found. Based on the mapping outcome, the secondary NRF either initiates an additional discovery action or terminates the process by generating a final error response.

[0085] In an embodiment, the response may also be sent directly to the requesting NRF (204) as per the third routing policy.

[0086] Although FIG. 2A shows exemplary components of the system (108), in other embodiments, the system (108) may include fewer components, different components, differently arranged components, or additional functional components than depicted in FIG. 2A. Additionally, or alternatively, one or more components of the system (108) may perform functions described as being performed by one or more other components of the system (108).

[0087] FIG. 2B illustrates an exemplary block diagram (200A) of the system (108) for discovering the network function (NF) in the communication network (106), in accordance with an embodiment of the present disclosure.

[0088] Referring to FIG. 2B, the system (108) may include an interface(s) (216) that may include a variety of interfaces, for example, interfaces for data input and output devices, referred to as VO devices, storage devices, and the like. The interface(s) (216) may facilitate communication to / from the system (108). The interface(s) (216) 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 unit (218) and a database (220).

[0089] In an embodiment, the processing unit (218) may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processing unit (218). In the examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the processing unit (218) may be processor-executable instructions stored on a non- transitory machine-readable storage medium, and the hardware for the processing unit (218) may include a processing resource (for example, one or more processors) to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the processing unit (218). In such examples, the system (108) may include 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 unit (218) may be implemented by electronic circuitry.

[0090] Among other capabilities, the processing unit (218) may be configured to fetch and execute computer-readable instructions stored in a memory (214) of the system (108). The memory (214) 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 (214) may include any non- transitory storage device, including, for example, volatile memory such as RandomAccess Memory (RAM), or non-volatile memory such as Erasable Programmable Read-Only Memory (EPROM), flash memory, and the like.

[0091] In an embodiment, the database (220) may include data that may be either stored or generated as a result of functionalities implemented by the processing unit (218). In an embodiment, the database (220) may be separate from the system (108). In an embodiment, the database (220) may be indicative of including, but not limited to, a relational database, a distributed database, a cloudbased database, or the like.

[0092] In an embodiment, the processing unit (218) is configured to execute functionalities of multiple network entities, such as the requesting Network Repository Function (NRF) (204), the primary NRF (206), and the secondary NRF (208). The processing unit (218) enables the system (108) to perform the necessary operations associated with receiving the discovery request, applying routing policies, determining routing paths, and forwarding the discovery request to appropriate NRFs for locating the target NF.

[0093] In an embodiment, the requesting NRF (204) is configured to perform multiple functions involved in network function (NF) discovery process. The requesting NRF (204) is responsible for initiating the NF discovery process upon receiving a discovery request from the consumer network function (202).

[0094] In an embodiment, the requesting NRF (204) receives an initial discovery request from the consumer NF (202), which is a network function or application seeking to communicate with or utilize the target NF.

[0095] In an embodiment, the discovery request comprises one or more discovery parameters associated with a target network function (NF). The one or more discovery parameters may include, but are not limited to, a Network Function Type (NFT), Slice / Service Type Identifier (S-NSSAI), Data Network Name (DNN), Public Land Mobile Network (PLMN) identifier, geographical region, or a load-balancing metric. The requesting NRF (204) may use a receiving unit to capture this request and extract the one or more discovery parameters.

[0096] In an embodiment, the requesting NRF (204) then attempts to search the local NRF database for the NF profile that corresponds to the one or more discovery parameters. The NF profile is stored in the local NRF database and the NF profile is uniquely associated with an NF instance and includes the one or more discovery parameters. When the discovery request is received, the requesting NRF evaluates the one or more discovery parameters against the NF profile stored in the local NRF database to determine whether a matching profile exists for the target NF.

[0097] In an embodiment, upon failure to locate the NF profile in the local NRF database, the requesting NRF (204) applies the first routing policy that is provisioned at the requesting NRF (204). The first routing policy comprises a first routing logic stored in the memory (214). The first routing logic is responsible for determining the first routing path by evaluating the received one or more discovery parameters and mapping the one or more discovery parameters to a plurality of entries present in the first routing table. The first routing table is configured at the requesting NRF (204) and maps predefined combinations of the one or more discovery parameters to routing destinations like the primary NRF (206).

[0098] In an embodiment, the requesting NRF (204) is configured to perform mapping of the one or more discovery parameters against the first routing table configured at the requesting NRF (204) using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path.

[0099] In an embodiment, the first routing path determines a next-hop NRF, designated as the primary NRF (206). The requesting NRF (204) then forwards the discovery request along the first routing path to the primary NRF (206), using a secure interface, e.g., Transport Layer Security (TLS) or Secure Sockets Layer (SSL).

[0100] In an embodiment, the primary NRF (206), upon receiving the forwarded discovery request, searches the primary NRF database for the NF profile based on the same discovery parameters.

[0101] In an embodiment, upon failure to locate the NF profile in the primary NRF database, the primary NRF (206) applies the second routing policy, provisioned at the primary NRF (206). The second routing policy includes a second routing logic, which determines the second routing path by mapping the one or more discovery parameters against the second routing table. The second routing table is configured at the primary NRF (206) and maps predefined combinations of the one or more discovery parameters to routing destinations like the secondary NRF (208) when the target NF is not found locally.

[0102] In an embodiment, the primary NRF (206) is configured to perform mapping of the one or more discovery parameters against the second routing table configured at the primary NRF (206) using the second routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the second routing table to determine the second routing path.

[0103] In an embodiment, based on the second routing logic evaluation, the primary NRF (206) then forwards the discovery request along the second routing path to the secondary NRF (208). The secondary NRF (208) may reside in a different region, PLMN, or load group, and is expected to perform a final NF profile lookup or apply the third routing policy.

[0104] In an embodiment, the secondary NRF (208) includes a secondary NRF database similar in functioning to that of the local NRF database and the primary NRF database. The secondary NRF database is configured to perform mapping of the received one or more discovery parameters against the stored NF profiles. Upon locating a match, the secondary NRF (208) generates and transmits the success response to either the primary NRF (206) or directly to the requesting NRF (204), depending on the second routing logic.

[0105] In an embodiment, the secondary NRF (208) is configured to perform mapping of the one or more discovery parameters against the third routing table configured at the secondary NRF (208) using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path. The third routing table is configured at the secondary NRF (208) and maps the one or more discovery parameters to fallback actions, such as forwarding the discovery request to another backup NRF or returning an error response to the primary NRF or the requesting NRF if no match is found via mapping the third routing table.

[0106] In an embodiment, if the NF profile is not found in the secondary NRF database, the secondary NRF (208) generates the error response and sends the error response to either the primary NRF (206) or the requesting NRF (204), based on the original routing path. The original routing path refers to the sequence of NRFs through which the discovery request was forwarded from the requesting NRF (204) to the secondary NRF (208). In an example, the requesting NRF (204) sends the discovery request to the primary NRF (206) based on the first routing policy. The primary NRF (206) then forwards the discovery request to the secondary NRF (208) based on the second routing policy. If the NF is not found, the secondary NRF (208) sends the error response to the primary NRF (206) (the previous hop), which then forwards it to the requesting NRF (204). In another example, the requesting NRF (204) may directly send the discovery request to both the primary NRF (206) and then the secondary NRF (208). If the NF is not found, the secondary NRF (208) sends the error response directly back to the requesting NRF (204), skipping the primary NRF (206).

[0107] In an embodiment, the secondary NRF (208) is provisioned with the third routing policy that includes the third routing logic. If the NF profile is not found in the secondary NRF database, the third routing logic evaluates the same or additional discovery parameters to determine whether further routing is necessary.The routing logic may point to an additional NRF (not shown in the Figure), depending on hierarchical configuration or fallback options.

[0108] In an embodiment, the primary NRF (206) acts as an intermediary and, upon receiving the success response from the secondary NRF (208), the primary NRF (206) forwards the same to the requesting NRF (204).

[0109] In an embodiment, the requesting NRF (204) is configured to perform mapping of the one or more discovery parameters against the first routing table configured at the requesting NRF (204) using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path.

[0110] In an embodiment, the primary NRF (206) is configured to perform mapping of the one or more discovery parameters against the second routing table configured at the primary NRF (206) using the second routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the second routing table to determine the second routing path.

[0111] In an embodiment, the secondary NRF (208) is configured to perform mapping of the one or more discovery parameters against the third routing table configured at the secondary NRF (208) using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path.

[0112] In an embodiment, the requesting NRF (204) acts as the initial entry point for receiving the discovery request from the consumer NF (202). The one or more discovery parameters are matched against entries in the first routing table that is provisioned at the requesting NRF (204). The first routing logic, also implemented at the requesting NRF (204), reads the values of the one or more discovery parameters and compares them with predefined entries in the first routingtable. The outcome of the comparison determines the first routing path to the primary NRF (206).

[0113] For example, the requesting NRF (204) may be provisioned with a Table 1 structured as follows:When a request includes parameters such as SMF, 01-001, PLMN 40401, and region “North,” the first routing logic maps the request to “Primary NRF A” based on the above table. The discovery request is then forwarded along the first routing path to the identified “Primary NRF A”.

[0114] In an embodiment, the primary NRF (206) receives the forwarded discovery request. The primary NRF (206) maintains the second routing table that is structured similarly to the first routing table but may contain more contextspecific or region-specific routing data. The second routing logic, implemented at the primary NRF (206), is responsible for evaluating same of one or more discovery parameters against the entries in the second routing table. The comparison process enables the primary NRF (206) to select the second routing path to the secondary NRF (208) if the target NF is not found in the primary NRF database.

[0115] The second routing table at the primary NRF (206) may appear as Table 2 below:If the current load on the SMF exceeds 75%, and the other parameters match, the second routing logic at the primary NRF (206) determines that the discovery request should be forwarded to the secondary NRF (208).

[0116] In an embodiment, the secondary NRF (208) receives the request forwarded along the second routing path. If the target NF is still not found in the secondary NRF database, the third routing logic provisioned at the secondary NRF evaluates the same discovery parameters against the third routing table. The mapping determines the third routing path, which may either lead to another backup NRF or conclude with an error response.

[0117] An example of the third routing table at the secondary NRF (208) is shown in Table 3 below:In this example, if the discovery request includes the DNN “internet” and the region “North,” the routing logic evaluates the table and identifies “Error response” as the mapped action. Similarly, for the discovery request with the DNN “video” and theregion “South-East,” the action remains “Error response,” indicating that no further forwarding occurs beyond the secondary NRF (208).

[0118] In an embodiment, if the requesting NRF (204) receives error responses or fails to resolve the discovery request through the primary NRF (206) and the secondary NRF (208), the primary NRF (206) returns a final error response to the consumer NF (202), indicating failure to locate the desired NF.

[0119] In an embodiment, the requesting NRF (204) is configured to send a response to the consumer NF (202) upon determining that the NF profile is not available in the local NRF database. The response comprises routing information provided in the first routing policy provisioned at the requesting NRF (204), and the consumer NF (202) is configured to redirect the discovery request to the primary NRF (206) based on the routing information sent by the requesting NRF (204). The requesting NRF (204) is configured to act as the first point of contact for the discovery request received from the consumer NF (202). In particular, when the requesting NRF (204) receives the request, it attempts to locate the corresponding NF profile in the local NRF database. If the target NF profile is not found, the requesting NRF (204) refers to the first routing policy, which includes routing information such as endpoint addresses or URIs of one or more NRFs, including the primary NRF (206). The requesting NRF (204) generates a message that includes the routing information and sends it to the consumer NF (202) via its communication interface. Upon receiving this message, the consumer NF (202) is configured to redirect the same discovery request to the primary (NRF 206) using the routing information provided.

[0120] In an embodiment, the primary NRF (206) is configured to send a response to the consumer NF (202) upon determining that the NF profile is not available in the primary NRF database. The response comprises routing information provided in the second routing policy provisioned at the primary NRF (206), and the consumer NF (202) is configured to redirect the discovery request to the secondary NRF (208) based on the routing information sent by the primary NRF(206). The primary NRF (206) receives the redirected discovery request from the consumer NF (202). The primary NRF (206) searches the primary NRF database to match the target NF profile based on the one or more discovery parameters. If the profile is not found, the primary NRF (206) refers to the second routing policy, provisioned and stored locally, which provides routing information for the next NRF, such as the secondary NRF (208). The primary NRF (206) then sends the routing information in a response message back to the consumer NF (202) using the interface. Once received, the consumer NF (202) uses the provided routing details to redirect the request to the secondary NRF (208).

[0121] In an embodiment, the requesting NRF (204) is configured to forward the discovery request to the primary NRF (206) using the first routing policy provisioned at the requesting NRF (204), and the primary NRF (206) is configured to forward the discovery request to the secondary NRF (208) using the second routing policy provisioned at the primary NRF (206) upon determining that the NF profile is not located in the primary NRF database. In this case, the requesting NRF (204) does not rely on the consumer NF (202) to manage redirection. Upon failing to locate the NF profile in the local NRF database, the requesting NRF (204) directly forwards the discovery request to the primary NRF (206) using routing data from the first routing policy. The first routing policy is provisioned within the memory of the requesting NRF (204) and interpreted by the processing unit (218). The primary NRF (206), upon receiving and processing the forwarded discovery request, similarly searches the primary NRF database for the required NF profile. If unsuccessful, the primary NRF (206) refers to the second routing policy and determines the secondary NRF (208) to forward the discovery request.

[0122] In an embodiment, the requesting NRF (204) is configured to determine the primary NRF (206) to which the discovery request is to be forwarded, based on the evaluation of a first routing policy provisioned at the requesting NRF (204). If the primary NRF (206) returns an error response indicating that the target NF profile is not available, the requesting NRF (204) further evaluates the firstrouting policy to determine and select the secondary NRF (208) as an alternative destination for forwarding the discovery request. The requesting NRF (204) not only selects the primary NRF (206) for the initial forward operation (based on the first routing policy) but also manages fallback selection in case of a failure. If the requesting NRF (204) receives an error response from the primary NRF (206) (e.g., NF profile not found or service unavailable), the requesting NRF (204) re-evaluates the first routing policy to determine the next NRF, which is the secondary NRF (208). This selection process is executed entirely by the requesting NRF (204), and the selection process does not depend on routing instructions from the primary NRF (206) or feedback from the consumer NF (202).

[0123] The system (108) enables each NRF in the routing chain to make independent routing decisions based on predefined logic and configurations. The routing logic and associated tables are maintained individually at the requesting NRF (204), the primary NRF (206), and the secondary NRF (208), without relying on resolution success at any other NRF level.

[0124] FIG. 3 illustrates an exemplary flow diagram of performing a method for discovering the NF in the communication network, wherein a consumer NF redirects a discovery request to the primary Network Repository Function (NRF) and subsequently to a secondary NRF based on routing information received from the NRFs in accordance with embodiments of the present disclosure. Each step of the method (300) may be performed by various units (e.g., the consumer NF (202), the requesting NRF (204), the primary NRF (206) and the secondary NRF (208) of the system (108).

[0125] At step 302, the consumer NF (202) initiates the discovery request to locate the target NF and transmits the discovery request to the requesting NRF (204).

[0126] At step 304, upon receiving the discovery request, the requesting NRF (204) checks the local NRF database and concurrently evaluates the first routing policy or performs these checks sequentially in either order. The processinvolves applying the first routing logic to assess whether the one or more discovery parameters in the discovery request match any locally stored NF profiles or any routing criteria specified in the first routing table. If a match is found locally, the requesting NRF (204) generates and sends the success response at step 306 back to the consumer NF (202), concluding the process successfully.

[0127] If the NF profile is not found locally, but the first routing policy yields routing information for an alternate NRF (e.g., primary NRF (206)), the requesting NRF (204) generates a redirect response at step 308. The redirect response includes routing details / information related to the primary NRF (206), such as a Uniform Resource Identifier (URI) or an endpoint.

[0128] Upon receiving the redirect response, the consumer NF (202) initiates redirect request (2) by sending the discovery request to the primary NRF (206), based on the routing details received from the requesting NRF (204).

[0129] At step 310, the primary NRF (206) again checks both the primary NRF database and the second routing policy provisioned at the primary NRF (206). The checks may be performed in any sequence. If the primary NRF (206) successfully finds the matching NF profile in the primary NRF database, the primary NRF (206) sends the success response at step 312 back to the consumer NF (202).

[0130] At step 320, if no local match is found, the primary NRF (206) evaluates the second routing policy to determine routing details for the secondary NRF (208). Upon determining the routing path, the primary NRF (206) sends a redirect response back to the consumer NF (202), which includes routing details of the secondary NRF (208).

[0131] Upon receiving the routing information from the primary NRF (206), the consumer NF (202) initiates a redirect request (3) to forward the discovery request to the secondary NRF (208).

[0132] At step 314, the secondary NRF (208) applies local search in the secondary NRF database and the third routing policy to locate the target NF profile. If the secondary NRF (208) finds a match in the secondary NRF database, the secondary NRF (208) sends the success response to the consumer NF (202) at step 306.

[0133] In the event that the secondary NRF (208) cannot locate the target NF profile locally and does not have any further routing options defined in the third routing policy, the secondary NRF (208) sends the error response at step 316 back to the consumer NF (202), indicating the failure to resolve the discovery request.

[0134] In a scenario where neither local data nor routing information is available at the requesting NRF (204), the flow proceeds from step 304 directly to step 318, where the requesting NRF (204) sends the error response to the consumer NF (202), signalling that the discovery request cannot be fulfilled.

[0135] FIG. 4 illustrates another exemplary flow diagram of performing a method for discovering the Network Function (NF) in the communication network, wherein the discovery request is forwarded through a chain of Network Repository Functions (NRFs), and the response is sent back along the same chain from the secondary NRF to the primary NRF and finally to the requesting NRF in accordance with embodiments of the present disclosure. Each step of the method (400) may be performed by various units (e.g., the consumer NF (202), the requesting Network Repository Function (NRF) (204), the primary NRF (206) and the secondary NRF (208) of the system (108).

[0136] At step 402, the discovery request is received by the requesting NRF (204) from the consumer NF (202). The discovery request includes the one or more discovery parameters, such as the Network Function Type (NFT), the Data Network Name (DNN), the Slice / Service Type Identifier (S-NSSAI), the geographical region, or the load-balancing metric, that may be used to identify the target NF.

[0137] At step 404, the requesting NRF (204) performs a search on the local NRF database to find the matching NF profile. Simultaneously or sequentially, therequesting NRF (204) applies the first routing policy provisioned at the requesting NRF (204), comprising the first routing logic that evaluates the one or more discovery parameters against the first routing table. If, as indicated by the “Found” path leading to step 406, the target NF profile is found in the local NRF database of the requesting NRF (204), then at step 406, the requesting NRF (204) sends the success response directly back to the consumer NF (202).

[0138] If the target NF profile is not found locally, the requesting NRF (204) evaluates the first routing policy and determines the first routing path to the primary NRF (206). The discovery request is then forwarded internally from the requesting NRF (204) to the primary NRF (206) at step 408.

[0139] At step 408, the primary NRF (206) repeats the same dual-check process, searching the primary NRF database and evaluating the second routing policy provisioned at the primary NRF (206) using the second routing logic and the second routing table. If the target NF profile is located at this level, the success response is returned to the requesting NRF (204) through path 416, which is then relayed to the consumer NF (202) at step 406. If the NF profile is not found in the primary NRF (206), the primary NRF (206) applies the second routing policy to identify the secondary NRF (208). The discovery request is forwarded from the primary NRF (206) to the secondary NRF (206) at step 410.

[0140] At step 410, the secondary NRF (208) performs the similar check, searching the secondary NRF database and applying the third routing policy. The third routing policy comprises the third routing logic that evaluates the one or more discovery parameters against the third routing table. The purpose is to determine whether the target NF exists or whether additional forwarding is needed.

[0141] If the target NF is found at the secondary NRF (208), the secondaryNRF (208) generates the success response and returns it to the primary NRF (206) through path 418. The primary NRF (206) then relays the success response back to the requesting NRF (204), as shown at step 412. The requesting NRF (204), upon receiving the success response, forwards it to the consumer NF (202) at step 406.

[0142] If no match is found at the secondary NRF (208), and the third routing policy does not provide further forwarding instructions, the error response is sent from the secondary NRF (208) to the primary NRF (206) through path 418. The primary NRF (206) then forwards the error response back to the requesting NRF (204), and the requesting NRF (204) finally delivers the error response to the consumer NF (202), as illustrated in step 414.

[0143] FIG. 5 illustrates another exemplary flow diagram of performing a method for discovering the Network Function (NF) in the communication network, wherein the requesting Network Repository Function (NRF) is provisioned with routing details of both the primary NRF and the secondary NRF and independently forwards the discovery request based on a first routing policy in accordance with embodiments of the present disclosure. Each step of the method (500) may be performed by various units (e.g., the consumer NF (202), the requesting NRF (204), the primary NRF (206) and the secondary NRF (208) present within of the system (108).

[0144] At step 502, the discovery request is received by the requesting NRF (204) from the consumer NF (202). The request comprises the one or more discovery parameters.

[0145] At step 504, the requesting NRF (204) performs a search in the local NRF database for the NF profile that corresponds to the one or more discovery parameters. In addition to the local search, the first routing logic provisioned in the requesting NRF (204) applies the first routing policy to evaluate the same discovery parameters and generate a list of routing destinations, including both primary and secondary NRFs (206, 208).

[0146] If the NF profile is found locally at the requesting NRF (204), the success response is returned at step 506 to the consumer NF (202), concluding the method (500).

[0147] If the NF profile is not found locally at the requesting NRF (204), a first forwarding operation is triggered to the primary NRF (206) based on the first routing policy.

[0148] At step 508, the primary NRF (206) checks the primary NRF database for the NF profile matching the one or more discovery parameters. The result of this search, whether successful or not, is sent back to the requesting NRF (204).

[0149] At step 510, the requesting NRF (204) evaluates whether a match was found in the primary NRF (206). If the NF profile is successfully located, the requesting NRF (204) issues the success response to the consumer NF (202), as shown in step 506.

[0150] If no matching NF profile is returned by the primary NRF (206), the requesting NRF (204) refers again to the first routing policy, which already includes a provisioned route according to the first routing policy to the secondary NRF (208).

[0151] At step 512, the secondary NRF (208) is queried by the requesting NRF (204). The secondary NRF (208) performs a search for the target NF in the secondary NRF database based on the one or more discovery parameters.

[0152] The secondary NRF (208) returns the result, either a successful match or a failure, back to the requesting NRF (204). If the match is found, the requesting NRF (204) issues the success response at step 506. If no NF profile is found at any level, including the secondary NRF (208), the error response is sent by the requesting NRF (204) to the consumer NF (202), as shown at step 514.

[0153] If the data is not found at the primary NRF (206) and subsequently not found at the secondary NRF (208), as indicated by the “Not found (at primary NRF 206 and the secondary NRF 208)” path from step 504, then at step 514, the requesting NRF (204) sends the error response back to the originating NF or the consumer NF (202), indicating that the target NF could not be discovered. The path from step 510 also leads to the “Not found (at primary NRF 206 and the secondaryNRF 208)” path and step 514 in the scenario where neither the primary NRF (206) nor the secondary NRF (208) could locate the target NF.

[0154] FIG. 6 illustrates an exemplary flow diagram of a method (600) for discovering the network function (NF) in the communication network (106), in accordance with an embodiment of the present disclosure.

[0155] At step 602, the method (600) begins with the requesting NRF (204) receiving the discovery request. The discovery request originates from the consumer NF (202) and contains one or more discovery parameters. The one or more discovery parameters may include, at least one of the Network Function Type (NFT), the Slice / Service Type Identifier (S-NSSAI), the Data Network Name (DNN), the Public Land Mobile Network (PLMN) identifier, the geographical region, or the load-balancing metric. The requesting NRF (204) accepts the discovery request.

[0156] At step 604, the requesting NRF (204) searches the local NRF database for the NF profile that corresponds to the one or more discovery parameters. The requesting NRF (204) queries the local NRF database to locate the NF profile that matches the one or more discovery parameters provided in the discovery request. If the match is found, the requesting NRF (204) generates the success response and terminates the method (600) at this point.

[0157] In an aspect, the NF profile is associated with the target NF. The NF profile includes capabilities, service area, load status, and identifiers such as NFT, DNN, or PLMN.

[0158] At step 606, upon failure to locate the NF profile in the local NRF database, the requesting NRF (204) applies the first routing policy provisioned at the requesting NRF (204). The first routing policy comprises the first routing logic to determine the first routing path. In particular, the first routing policy includes the first routing logic that analyzes the one or more discovery parameters and maps the one or more discovery parameters against entries in the first routing table. For instance, if the discovery request includes parameters like NFT = SMF and DNN =“video”, and the routing table maps this combination to a designated primary NRF (206), the first routing logic selects this routing path.

[0159] At step 608, the requesting NRF (204) forwards the discovery request along the first routing path to the primary NRF (206). This is accomplished via the communication interface, which handles inter-NRF communication.

[0160] At step 610, the primary NRF (206) searches the primary NRF database for the NF profile based on the one or more discovery parameters. The primary NRF (206) attempts to find the NF profile that matches the one or more discovery parameters in the primary NRF database. If the target NF is found, the primary NRF (206) sends the success response to the requesting NRF (204), and the method (600) concludes successfully.

[0161] At step 612, upon failure to locate the NF profile in the primary NRF database, the primary NRF (206) applies the second routing policy provisioned at the primary NRF (206). The primary NRF (206) comprises the second routing logic to determine the second routing path. The second routing policy is also provisioned in its memory and contains the second routing logic that evaluates the one or more discovery parameters and compares them against the second routing table. For example, if the primary NRF (206) receives the discovery request with NFT = PCF and Region = "South", the second routing logic may determine that the discovery request should be forwarded to the secondary NRF (208) based on the second routing policy.

[0162] At step 614, the primary NRF (206) forwards the discovery request along the second routing path to the secondary NRF (208) to discover the target NF.

[0163] In an embodiment, the method (600) further comprises searching, by the secondary NRF, the secondary NRF database upon receiving the discovery request for the NF profile that corresponds to the one or more discovery parameters from the original request. If the secondary NRF (208) successfully locates the NF profile, the secondary NRF (208) sends the success response. If the secondary NRF(208) does not find the matching NF profile based on the one or more discovery parameters, the secondary NRF (208) sends the error response.

[0164] In an embodiment, the secondary NRF (208) applies the third routing policy provisioned at the secondary NRF (208) in response to determining that the NF profile is not available in the secondary NRF database. The third routing policy comprises the third routing logic to determine the third routing path. If the NF profile is not found in the secondary NRF database, the secondary NRF (208) may still apply the third routing policy rather than returning the error immediately. The third routing policy includes the third routing logic and the third routing table. The discovery parameters are evaluated against the third routing table to determine if there is another possible path (e.g., to another backup NRF). For instance, if the parameters are NFT = “AMF”, Region = “West”, and the table suggests routing to an additional NRF for disaster recovery, the discovery request may be further redirected.

[0165] In an embodiment, the primary NRF (206) forwards the success response to the requesting NRF (204) in response to receiving the success response from the secondary NRF (208). If the secondary NRF (208) sends the success response upon locating the target NF, the primary NRF (206) acts as an intermediary and forwards that success response to the requesting NRF (204).

[0166] In an embodiment, the requesting NRF (204) is configured to perform mapping of the one or more discovery parameters against the first routing table configured at the requesting NRF (204) using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path.

[0167] In an embodiment, the primary NRF (206) is configured to perform mapping of the one or more discovery parameters against the second routing table configured at the primary NRF (206) using the second routing logic, wherein the one or more discovery parameters from the discovery request are mapped againstthe one or more predefined parameters provided in the second routing table to determine the second routing path.

[0168] In an embodiment, the secondary NRF (208) is configured to perform mapping of the one or more discovery parameters against the third routing table configured at the secondary NRF (208) using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path.

[0169] For example, the requesting NRF (204) may map NFT = “SMF”, DNN = “internet”, Region = “North” to the primary NRF (206) in an ‘X’ region. If not found, the primary NRF (206) may map those parameters to the secondary NRF (208) in ‘Y’ . Each NRF performs the mapping independently using local routing logic and policy configurations, enabling flexible, policy-driven routing of discovery requests.

[0170] In an embodiment, if the NF profile is not discovered across all three levels (requesting NRF —> primary NRF —> secondary NRF), the requesting NRF (204) generates and returns the error response to the consumer NF (202). This informs the consumer that no suitable NF is available in the system under the current configuration.

[0171] In an embodiment, the requesting NRF (204) sends the response to the consumer NF (202) upon determining that the NF profile is not available in the local NRF database. The response comprises routing information provided in the first routing policy provisioned at the requesting NRF (204), and the consumer NF (202) redirects the discovery request to the primary NRF (206) based on the routing information sent by the requesting NRF (204). The requesting NRF (204) is configured to act as the first point of contact for the discovery request received from the consumer NF (202). When the requesting NRF (204) receives the request, the requesting NRF (204) attempts to locate the corresponding network function (NF) profile in the local NRF database stored in memory (214). If the target NF profileis not found, the requesting NRF (204) refers to the predefined first routing policy, which includes routing information such as endpoint addresses or URIs of one or more candidate NRF s, including the primary NRF (206). The requesting NRF (204) generates a message that includes the routing information and sends it to the consumer NF (202) via its communication interface. Upon receiving this message, the consumer NF (202) is configured to redirect the same discovery request to the primary (NRF 206) using the routing information provided.

[0172] In an embodiment, the primary NRF (206) sends the response to the consumer NF (202) upon determining that the NF profile is not available in the primary NRF database. The response comprises the routing information provided in the second routing policy provisioned at the primary NRF (206) and the consumer NF (202) redirects the discovery request to the secondary NRF (208) based on the routing information sent by the primary NRF (206). The primary NRF (206) receives the redirected discovery request from the consumer NF (202). The primary NRF (206) searches the primary NRF database to match the target NF profile based on the discovery parameters. If the NF profile is not found, the primary NRF (206) refers to the second routing policy, which provides routing information for the next NRF, such as the secondary NRF (208). The primary NRF (206) then sends the routing information in the response message back to the consumer NF (202) using its interface module (216). Once received, the consumer NF (202) uses the provided routing details to redirect the request to the secondary NRF (208).

[0173] In an embodiment, the requesting NRF (204) forwards the discovery request to the primary NRF (206) using the first routing policy provisioned at the requesting NRF (204), and the primary NRF (206) forwards the discovery request to the secondary NRF (208) using the second routing policy provisioned at the primary NRF (206) upon determining that the NF profile is not located in the primary NRF database. The requesting NRF (204) does not rely on the consumer NF (202) to manage redirection. Upon failing to locate the NF profile in the local NRF database, the requesting NRF (204) directly forwards the discovery request to the primary NRF (206) using routing data from the first routing policy. The primaryNRF (206), upon receiving and processing the forwarded discovery request, similarly searches the primary NRF database for the required NF profile. If unsuccessful, the primary NRF (206) refers to the second routing policy and determines the secondary NRF (208) to forward the discovery request.

[0174] In an embodiment, the requesting NRF (204) selects the primary NRF (206) to forward the discovery request. The selection is based on the first routing policy provisioned at the requesting NRF (204) and selects the secondary NRF (208) to forward the discovery request. The selection is based on the first routing policy provisioned at the requesting NRF (204) after receiving the error response from the primary NRF (206). The requesting NRF (204) not only selects the primary NRF (206) for the initial forward operation (based on the first routing policy) but also manages fallback selection in case of a failure. If the requesting NRF (204) receives the error response from the primary NRF (206) (e.g., NF profile not found or service unavailable), the requesting NRF (204) re-evaluates the first routing policy stored in the memory to determine the next NRF, which is the secondary NRF (208). The selection process is executed entirely by the requesting NRF (204) using its processing unit (218), and the selection process does not depend on routing instructions from the primary NRF (206) or feedback from the consumer NF (202).

[0175] FIG. 7 illustrates an exemplary computer system (700) in which or with which embodiments of the present disclosure may be implemented.

[0176] As shown in FIG. 7, the system (108) may include an external storage device (710), a bus (720), a main memory (730), a read-only memory (740), a mass storage device (750), a communication port (760), and a processor (770). A person skilled in the art will appreciate that the system (108) may include more than one processor (770) and communication ports (760). Processor (770) may include various modules associated with embodiments of the present disclosure.

[0177] In an embodiment, the communication port (760) is any of an RS- 232 port for use with a modem-based dialup connection, a 10 / 100 Ethernet port, aGigabit or 10 Gigabit port using copper or fiber, a serial port, a parallel port, or other existing or future ports. The communication port (760) is chosen depending on a network, such a Local Area Network (LAN), Wide Area Network (WAN), or any network to which the system (108) connects.

[0178] In an embodiment, the memory (730) is Random Access Memory (RAM), or any other dynamic storage device commonly known in the art. Readonly memory (740) is 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 (770).

[0179] In an embodiment, the mass storage (750) is any current or future mass storage solution, which is used to store information and / or instructions. Exemplary mass storage solutions include, but are 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 (e.g., SATA arrays).

[0180] In an embodiment, the bus (720) communicatively couples the processor(s) (770) with the other memory, storage, and communication blocks. The bus (720) is, e.g., a Peripheral Component Interconnect (PCI)ZPCI 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 (770) to the system (108).

[0181] Optionally, operator and administrative interfaces, e.g., a display, keyboard, joystick, and a cursor control device, may also be coupled to the bus (720) to support direct operator interaction with the system (108). Other operators and administrative interfaces are provided through network connections connectedthrough the communication port (760). The components described above are meant only to exemplify various possibilities. In no way should the aforementioned exemplary illustration (700) limit the scope of the present disclosure.

[0182] In an exemplary embodiment, a computer program product comprising a non-transitory computer-readable medium is disclosed. The medium includes instructions that, when executed by one or more processors, cause the one or more processors to execute a method for discovering a network function (NF) in a communication network. The method includes receiving, by a requesting Network Repository Function (NRF), a discovery request to discover a target NF. The discovery request includes one or more discovery parameters associated with the target NF. The method further includes searching, by the requesting NRF, a local NRF database for an NF profile that corresponds to one or more discovery parameters. The method further includes applying, by the requesting NRF, a first routing policy provisioned at the requesting NRF upon failure to locate the NF profile in the local NRF database. The first routing policy includes a first routing logic to determine a first routing path. The method further includes forwarding, by the requesting NRF, the discovery request along the first routing path to a primary NRF. The method further includes searching, by the primary NRF, a primary NRF database for the NF profile based on the one or more discovery parameters. The method further includes, upon failure to locate the NF profile in the primary NRF database, applying, by the primary NRF a second routing policy provisioned at the primary NRF. The primary NRF includes a second routing logic to determine a second routing path. The method further includes forwarding, by the primary NRF, the discovery request along the second routing path to a secondary NRF to discover the target NF.

[0183] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made, and 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 disclosureherein, 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.

[0184] The present disclosure provides a technical advancement in Network Function (NF) discovery by enabling hierarchical, policy-based routing across multiple Network Repository Functions (NRFs). Unlike conventional methods limited to local responses, the present disclosure allows dynamic selection of the primary NRF and the secondary NRF using the one or more predefined discovery parameters such as Network Function Type (NFT), Slice / Service Type Identifier (S-NSSAI), Data Network Name (DNN), Public Land Mobile Network (PLMN) identifier, geographical region, or load-balancing metric. The present disclosure improves reliability, supports backup NF discovery, and enhances service availability in multi-PLMN and large-scale Fifth Generation (5G) deployments.ADVANTAGES OF THE PRESENT DISCLOSURE

[0185] The present disclosure described herein above has several technical advantages including, but not limited to, the realization of the system and the method that:

[0186] By enabling the NRF to recognize and route requests to secondary NFs across different locations, the network can maintain service continuity even if primary NFs fail. This ensures high availability for critical enterprise services.

[0187] Allowing NRFs to intelligently manage NF discovery based on parameters like DNN and Slice helps in optimizing the allocation and utilization of network resources, avoiding unnecessary load on local NFs.

[0188] The ability of NRFs to handle cross-PLMN common NFs ensures seamless integration and service delivery across different regions, enhancing the overall efficiency and coherence of the network.

[0189] Returning specific errors when expected parameters are not found helps in diagnosing issues quickly and transparently, facilitating faster resolution and improved network reliability.

[0190] With the capability to connect to NFs in different supercores, the network gains flexibility in deploying and scaling services according to demand, without being constrained by geographical limitations.

[0191] Enterprises relying on these services will experience more reliable and uninterrupted service, strengthening trust and potentially attracting more business customers due to the network’s robust failover capabilities.

Claims

CLAIMSWe claim:

1. A method (600) for discovering a network function (NF) in a communication network (106), the method (600) comprising: receiving (602), by a requesting Network Repository Function (NRF) (204), a discovery request to discover a target NF, the discovery request comprising one or more discovery parameters associated with the target NF; searching (604), by the requesting NRF (204), a local NRF database for an NF profile that corresponds to the one or more discovery parameters; upon failure to locate the NF profile in the local NRF database, applying (606), by the requesting NRF (204), a first routing policy provisioned at the requesting NRF (204), the first routing policy comprising a first routing logic to determine a first routing path; forwarding (608), by the requesting NRF (204), the discovery request along the first routing path to a primary NRF (206); searching (610), by the primary NRF (206), a primary NRF database for the NF profile based on the one or more discovery parameters; upon failure to locate the NF profile in the primary NRF database, applying (612), by the primary NRF (206), a second routing policy provisioned at the primary NRF (206), the primary NRF (206) comprising a second routing logic to determine a second routing path; and forwarding (614), by the primary NRF (206), the discovery request along the second routing path to a secondary NRF (208) to discover the target NF.

2. The method (600) as claimed in claim 1, comprising: searching, by the secondary NRF (208), a secondary NRF database for the NF profile based on the one or more discovery parameters; andsending, by the secondary NRF (208), a success response to the primary NRF (206) or the requesting NRF (204) upon locating the NF profile in the secondary database; and sending, by the secondary NRF (208), an error response to the primary NRF (206) or the requesting NRF (204) if the NF profile is not located in the secondary NRF database.

3. The method (600) as claimed in claim 2, comprising: applying, by the secondary NRF (208), a third routing policy provisioned at the secondary NRF (208) in response to determining that the NF profile is not available in the secondary NRF database, wherein the third routing policy comprises a third routing logic to determine a third routing path.

4. The method (600) as claimed in claim 2, comprising forwarding, by the primary NRF (206), the success response to the requesting NRF (204) in response to receiving the success response from the secondary NRF (208).

5. The method (600) as claimed in claim 1, wherein the NF profile is associated with the target NF.

6. The method (600) as claimed in claims 1 and 3, wherein: mapping, by the requesting NRF (204), the one or more discovery parameters against a first routing table configured at the requesting NRF (204) using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path; mapping, by the primary NRF (206), the one or more discovery parameters against a second routing table configured at the primary NRF (206) using the second routing logic, wherein the one or more discoveryparameters from the discovery request are mapped against the one or more predefined parameters provided in the second routing table to determine the second routing path; and mapping, by the secondary NRF (208), the one or more discovery parameters against a third routing table configured at the secondary NRF (208) using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path.

7. The method (600) as claimed in claim 1, comprising receiving, by the requesting NRF (204), the discovery request from a consumer NF (202).

8. The method (600) as claimed in claim 1, comprising: returning, by the requesting NRF (204), the error response to the consumer NF (202) when the NF profile is not discovered after applying the first routing path, the second routing path, and the third routing path.

9. The method (600) as claimed in claim 1, comprising: sending, by the requesting NRF (204), a response to the consumer NF (202) upon determining that the NF profile is not available in the requesting NRF database, wherein the response comprises of a routing information provided in the first routing policy provisioned at the requesting NRF (204); and redirecting, by the consumer NF (202), the discovery request to the primary NRF (206) based on the routing information sent by the requesting NRF (204).

10. The method (600) as claimed in claim 9, comprising: sending, by the primary NRF (206), a response to the consumer NF (202) upon determining that the NF profile is not available in the primaryNRF database, wherein the response comprises of a routing information provided in the second routing policy provisioned at the primary NRF (206); and redirecting, by the consumer NF (202), the discovery request to the secondary NRF (208) based on the routing information sent by the primary NRF (206).

11. The method (600) as claimed in claim 1, comprising: forwarding, by the requesting NRF (204), the discovery request to the primary NRF (206) using the first routing policy provisioned at the requesting NRF (204); and forwarding, by the primary NRF (206), the discovery request to the secondary NRF (208) using the second routing policy provisioned at the primary NRF upon determining that the NF profile is not located in the primary NRF database.

12. The method (600) as claimed in claim 1, comprising: selecting, by the requesting NRF (204), the primary NRF (206) to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF (204); and selecting, by the requesting NRF (204), the secondary NRF (208), to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF (204) after receiving the error response from the primary NRF (206).

13. The method (600) as claimed in claim 1, wherein the one or more discovery parameters comprise at least one of a Network Function Type (NFT), a Slice / Service Type Identifier (S-NSSAI), a Data Network Name (DNN), a Public Land Mobile Network (PLMN) identifier, a geographical region, or a load-balancing metric.

14. A system (108) for discovering a network function (NF) in a communication network (106), the system (108) comprising: a requesting Network Repository Function (NRF) (204) configured to: receive a discovery request to discover a target NF, the discovery request comprising one or more discovery parameters associated with the target NF; search a local NRF database for an NF profile that corresponds to the one or more discovery parameters; upon failure to locate the NF profile in the local NRF database, apply, a first routing policy provisioned at the requesting NRF (204), the first routing policy comprising a first routing logic to determine a first routing path; forward the discovery request along the first routing path to a primary NRF (206); the primary NRF (206), configured to: search a primary NRF database for the NF profile based on the one or more discovery parameters; upon failure to locate the NF profile in the primary NRF database, apply a second routing policy provisioned at the primary NRF (206), the primary NRF (206) comprising a second routing logic to determine a second routing path; and forward the discovery request along the second routing path to a secondary NRF (208) to discover the target NF.

15. The system (108) as claimed in claim 13, the secondary NRF (208) configured to: search a secondary NRF database for the NF profile based on the one or more discovery parameters; and send a success response to the primary NRF (206) or the requesting NRF (204) upon locating the NF profile in the secondary database; andsend an error response to the primary NRF (206) or the requesting NRF (204) if the NF profile is not located in the secondary NRF database.

16. The system (108) as claimed in claim 14, wherein the secondary NRF (208) applies a third routing policy provisioned at the secondary NRF (208) in response to determining that the NF profile is not available in the secondary NRF database, wherein the third routing policy comprises a third routing logic to determine a third routing path.

17. The system (108) as claimed in claim 14, wherein the primary NRF (206) forwards the success response to the requesting NRF (204) in response to receiving the success response from the secondary NRF (208).

18. The system (108) as claimed in claim 13, wherein the NF profile is associated with the target NF.

19. The system (108) as claimed in claims 13 and 15, wherein: the requesting NRF (204) is configured to perform mapping of the one or more discovery parameters against a first routing table configured at the requesting NRF (204) using the first routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the first routing table to determine the first routing path; the primary NRF (206) is configured to perform mapping of the one or more discovery parameters against a second routing table configured at the primary NRF (206) using the second routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the second routing table to determine the second routing path; and the secondary NRF (208) is configured to perform mapping of the one or more discovery parameters against a third routing table configured atthe secondary NRF (208) using the third routing logic, wherein the one or more discovery parameters from the discovery request are mapped against the one or more predefined parameters provided in the third routing table to determine the third routing path.

20. The system (108) as claimed in claim 13, wherein the requesting NRF (204) receives the discovery request from a consumer NF (202).

21. The system (108) as claimed in claim 13, wherein the requesting NRF (204) returns the error response to the consumer NF (202) when the NF profile is not discovered after applying the first routing path, the second routing path, and the third routing path.

22. The system (108) as claimed in claim 13, wherein: the requesting NRF (204) is configured to send a response to the consumer NF (202) upon determining that the NF profile is not available in the requesting NRF database, wherein the response comprises of a routing information provided in the first routing policy provisioned at the requesting NRF (204); and the consumer NF (202) is configured to redirect the discovery request to the primary NRF (206) based on the routing information sent by the requesting NRF (204).

23. The system (108) as claimed in claim 21, wherein: the primary NRF (206) is configured to send a response to the consumer NF (202) upon determining that the NF profile is not available in the primary NRF database, wherein the response comprises of a routing information provided in the second routing policy provisioned at the primary NRF (206); andthe consumer NF (202) is configured to redirect the discovery request to the secondary NRF (208) based on the routing information sent by the primary NRF (206).

24. The system (108) as claimed in claim 21, wherein: the requesting NRF (204) is configured to forward the discovery request to the primary NRF (206) using the first routing policy provisioned at the requesting NRF (204); and the primary NRF (206) is configured to forward the discovery request to the secondary NRF (208) using the second routing policy provisioned at the primary NRF (206) upon determining that the NF profile is not located in the primary NRF database.

25. The system (108) as claimed in claim 13, wherein the requesting NRF (204) is configured to: select the primary NRF (206) to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF (204); and select the secondary NRF (208) to forward the discovery request, wherein the selection is based on the first routing policy provisioned at the requesting NRF (204) after receiving the error response from the primary NRF (206).

26. The system (108) as claimed in claim 13, wherein the one or more discovery parameters comprise at least one of a Network Function Type (NFT), a Slice / Service Type Identifier (S-NSSAI), a Data Network Name (DNN), a Public Land Mobile Network (PLMN) identifier, a geographical region, or a load-balancing metric.

27. A computer program product comprising a non-transitory computer- readable medium comprising instructions that, when executed by one ormore processors, cause the one or more processors to execute a method (600) for discovering a network function (NF) in a communication network, the method (600) comprising: receiving (602), by a requesting Network Repository Function (NRF) (204), a discovery request to discover a target NF, the discovery request comprising one or more discovery parameters associated with the target NF; searching (604), by the requesting NRF (204), a local NRF database for an NF profile that corresponds to the one or more discovery parameters; upon failure to locate the NF profile in the local NRF database, applying (606), by the requesting NRF (204), a first routing policy provisioned at the requesting NRF (204), the first routing policy comprising a first routing logic to determine a first routing path; forwarding (608), by the requesting NRF (204), the discovery request along the first routing path to a primary NRF (206); searching (610), by the primary NRF (206), a primary NRF database for the NF profile based on the one or more discovery parameters; upon failure to locate the NF profile in the primary NRF database, applying (612), by the primary NRF (206), a second routing policy provisioned at the primary NRF (206), the primary NRF (206) comprising a second routing logic to determine a second routing path; and forwarding (614), by the primary NRF (206), the discovery request along the second routing path to a secondary NRF (208) to discover the target NF.

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