FORM 2
THE PATENTS ACT, 1970 (39 OF 1970)
& THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“METHOD AND SYSTEM FOR AUTOMATIC RE-REGISTRATION OF NETWORK FUNCTIONS IN A COMMUNICATION NETWORK”
We, Jio Platforms Limited, an Indian National, of Office - 101, Saffron, Nr. Centre Point, Panchwati 5 Rasta, Ambawadi, Ahmedabad - 380006, Gujarat, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

METHOD AND SYSTEM FOR AUTOMATIC RE-REGISTRATION OF NETWORK FUNCTIONS IN A COMMUNICATION NETWORK
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to the field of wireless
communication systems. More particularly, the present disclosure relates to methods and systems for automatic re-registration of network functions in a communication network.
BACKGROUND
[0002] 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.
[0003] Wireless communication technology has rapidly evolved over the past
few decades, with each generation bringing significant improvements and advancements. The first generation of wireless communication technology was based on analog technology and offered only voice services. However, with the advent of the second-generation (2G) technology, digital communication and data services became possible, and text messaging was introduced. 3G technology 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, better network coverage, and improved security. Currently, the fifth-generation (5G) technology is being deployed, promising even faster data speeds, low latency, and the ability to connect

multiple devices simultaneously. With each generation, wireless communication technology has become more advanced, sophisticated, and capable of delivering more services to its users.
[0004] In modern communication networks, the efficient management and
operation of network functions (NFs) are necessary for seamless service delivery. One of the core components in this architecture is the Network Repository Function (NRF), which maintains a repository of profiles for various NFs, making them discoverable and enabling communication among them. When an NF is ready for service, it registers its profile with the NRF, allowing other NFs to discover and interact with it. However, there are instances where, during regular operations such as updates or heartbeat checks, the NRF may respond with an error (such as "404 Not Found" error), indicating that the NF instance ID cannot be found in the NRF. This poses a significant challenge as the existing solutions do not specify the actions that an NF should take upon receiving such an error. Without a defined protocol for handling this situation, the affected NF could become undiscoverable, leading to potential service disruptions and degraded network performance. Moreover, existing techniques require manual intervention to resolve registration errors, which can be time-consuming and prone to human error. The manual process delays the re-establishment of NF profiles in the NRF, further affecting network efficiency. Additionally, the absence of an automatic rediscovery and resubscription process means that even if an NF is manually re-registered, there is no assurance that all necessary updates and changes that occurred during the downtime will be synchronized. This can lead to inconsistencies in the network state and further operational issues.
Thus, there exists an imperative need in the art to for a method and system for automatic re-registration of network functions in a communication network, which the present disclosure aims to address.

OBJECTS OF THE INVENTION
[0005] Some of the objects of the present disclosure, which at least one
embodiment disclosed herein satisfies are listed herein below.
[0006] It is an object of the present disclosure to provide a system and a method
for automatic re-registration of network functions in a communication network.
[0007] It is another object of the present disclosure to provide a solution that
defines the action needed at impacted NF (which has received 404 error) in terms of Discovery and Subscribe Service operations with NRF which are needed for service continuity.
SUMMARY OF THE DISCLOSURE
[0008] This section is provided to introduce certain aspects of the present
disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0009] According to an aspect of the present disclosure, a method for automatic
re-registration of network functions in a communication network is disclosed. The method includes transmitting, by a network function (NF), a request to a Network Repository Function (NRF) storing information associated with a plurality of NFs. The method further includes receiving, by the NF, an error message from the NRF based on the transmitted request. The method further includes determining, by the NF, a failure at NRF based on the received error message. The method further includes automatically transmitting, by the NF, a re-registration request to the NRF based on the determined failure. The method further includes transmitting, by the NF, a re-discovery request to the NRF to identify a set of NF instances required for

service continuity. Thereafter, the method includes transmitting, by the NF, a re-subscription request to the NRF to subscribe to status update for the identified set of NF instances.
[0010] In an aspect, the method includes transmitting, by the NF, an
unsubscribe request to the NRF for unsubscribing from previously held set of subscriptions related to the set of NF instances.
[0011] In an aspect, the method further includes transmitting, by the Network
Function Repository Function, a status information to the plurality of NFs to resume services.
[0012] In an aspect, the NF immediately transmit a re-registration request to
the NRF upon receiving the error message.
[0013] In an aspect, the error message is a "404 Not Found" message indicating
that the NRF cannot find an instance ID associated with the NF.
[0014] In an aspect, the re-registration request is transmitted immediately
following the determination of the failure at the NRF.
[0015] In an aspect, the method comprises receiving a confirmation message
from the NRF, acknowledging the successful re-registration of the NF.
[0016] According to another aspect of the present disclosure, a system for
automatic re-registration of network functions in a communication network is disclosed. The system includes a network function. The network function further includes a transmitting unit configured to transmit a request to a Network Repository Function (NRF) storing information associated with a plurality of NFs. The network function further includes a receiving unit connected at least to the

transmitting unit, the receiving unit configured to receive an error message from the NRF based on the transmitted request. The network function further includes a processing unit connected to at least the receiving unit, the processing unit configured to determine a failure at NRF based on the received error message. The transmitting unit is configured to automatically transmit a re-registration request to the NRF based on the determined failure; transmit a re-discovery request to the NRF to identify a set of NF instances required for service continuity; and transmit a re-subscription request to the NRF to subscribe to status update for the identified set of NF instances.
[0017] According to another aspect of the present disclosure, a user equipment
(UE) for automatic re-registration of network functions in a communication network is disclosed. The user equipment (UE) comprises a system. The system further comprises a network function. The network function comprises a transmitting unit configured to transmit a request to a Network Repository Function (NRF) storing information associated with a plurality of NFs. The network function includes a receiving unit configured to receive an error message from the NRF based on the transmitted request. The network function includes a processing unit configured to determine a failure at NRF based on the received error message. The transmitting unit is further configured to automatically transmit a re-registration request to the NRF based on the determined failure; transmit a re-discovery request to the NRF to identify a set of NF instances required for service continuity; and transmit a re-subscription request to the NRF to subscribe to status update for the identified set of NF instances.
[0018] According to yet another aspect, a non-transitory computer-readable
storage medium storing instruction for automatic re-registration of network functions in a communication network is disclosed. The storage medium comprising executable code which, when executed by one or more units of a system, causes: a transmitting unit to transmit a request to a Network Repository

Function (NRF) storing information associated with a plurality of NFs; a receiving unit connected at least to the transmitting unit, the receiving unit to receive an error message from the NRF based on the transmitted request; a processing unit connected to at least the receiving unit, the processing unit to determine a failure at NRF based on the received error message; the transmitting unit to: automatically transmit a re-registration request to the NRF based on the determined failure; transmit a re-discovery request to the NRF to identify a set of NF instances required for service continuity; and the transmitting unit configured to transmit a re-subscription request to the NRF to subscribe to status update for the identified set of NF instances.
BRIEF DESCRIPTION OF DRAWINGS
[0019] 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 disclosure of electrical components, electronic components or circuitry commonly used to implement such components.
[0020] FIG. 1 illustrates an exemplary block diagram representation of 5th
generation core (5GC) network architecture.
[0021] FIG. 2 illustrates an exemplary block diagram of a computer system
upon which the features of the present disclosure may be implemented in accordance with exemplary implementation of the present disclosure.

[0022] FIG. 3 illustrates an exemplary block diagram of a system for automatic
re-registration Network Functions (NFs) in a communication network, in accordance with exemplary embodiments of the present disclosure.
[0023] FIG. 4 illustrates an exemplary an exemplary sequence diagram for
automatic re-registration Network Functions (NFs) in a communication network case of NRF side failure, in accordance with exemplary embodiments of the present disclosure.
[0024] FIG. 5 illustrates an exemplary method flow diagram indicating the
process for automatic re-registration Network Functions (NFs) in a communication network, in accordance with exemplary embodiments of the present disclosure.
[0025] The foregoing shall be more apparent from the following more detailed
description of the disclosure.
DETAILED DESCRIPTION
[0026] 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 any of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Example embodiments of the present disclosure are described below, as illustrated in various drawings in

which like reference numerals refer to the same parts throughout the different drawings.
[0027] The ensuing description provides exemplary embodiments only, and is
5 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
10 of the disclosure as set forth.
[0028] It should be noted that the terms "mobile device", "user equipment",
"user device", “communication device”, “device” and similar terms are used interchangeably for the purpose of describing the invention. These terms are not
15 intended to limit the scope of the invention or imply any specific functionality or
limitations on the described embodiments. The use of these terms is solely for convenience and clarity of description. The invention is not limited to any particular type of device or equipment, and it should be understood that other equivalent terms or variations thereof may be used interchangeably without departing from the scope
20 of the invention as defined herein.
[0029] 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
25 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.
30
9

[0030] 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
5 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.
[0031] The word “exemplary” and/or “demonstrative” is used herein to mean
10 serving as an example, instance, or illustration. For the avoidance of doubt, the
subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques
15 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.
20
[0032] As used herein, an “electronic device”, or “portable electronic device”,
or “user device” or “communication device” or “user equipment” or “device” refers to any electrical, electronic, electromechanical and computing device. The user device is capable of receiving and/or transmitting one or parameters, performing
25 function/s, communicating with other user devices and transmitting data to the
other user devices. The user equipment may have a processor, a display, a memory, a battery and an input-means such as a hard keypad and/or a soft keypad. The user equipment may be capable of operating on any radio access technology including but not limited to IP-enabled communication, Zig Bee, Bluetooth, Bluetooth Low
30 Energy, Near Field Communication, Z-Wave, Wi-Fi, Wi-Fi direct, etc. For
10

instance, the user equipment may include, but not limited to, a mobile phone,
smartphone, virtual reality (VR) devices, augmented reality (AR) devices, laptop,
a general-purpose computer, desktop, personal digital assistant, tablet computer,
mainframe computer, or any other device as may be obvious to a person skilled in
5 the art for implementation of the features of the present disclosure.
[0033] Further, the user device may also comprise a “processor”
or “processing unit” includes processing unit, wherein processor refers to any logic circuitry for processing instructions. The processor may be a general-purpose
10 processor, a special purpose processor, a conventional processor, a digital signal
processor, a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits, Field Programmable Gate Array circuits, any other type of integrated circuits, etc. The processor may perform signal coding data processing,
15 input/output processing, and/or any other functionality that enables the working of
the system according to the present disclosure. More specifically, the processor is a hardware processor.
[0034] As portable electronic devices and wireless technologies continue to
20 improve and grow in popularity, the advancing wireless technologies for data
transfer are also expected to evolve and replace the older generations of
technologies. In the field of wireless data communications, the dynamic
advancement of various generations of cellular technology are also seen. The
development, in this respect, has been incremental in the order of second generation
25 (2G), third generation (3G), fourth generation (4G), and now fifth generation (5G),
and more such generations are expected to continue in the forthcoming time.
[0035] Radio Access Technology (RAT) refers to the technology used by
mobile devices/ user equipment (UE) to connect to a cellular network. It refers to
30 the specific protocol and standards that govern the way devices communicate with
11

base stations, which are responsible for providing the wireless connection. Further,
each RAT has its own set of protocols and standards for communication, which
define the frequency bands, modulation techniques, and other parameters used for
transmitting and receiving data. Examples of RATs include GSM (Global System
5 for Mobile Communications), CDMA (Code Division Multiple Access), UMTS
(Universal Mobile Telecommunications System), LTE (Long-Term Evolution),
and 5G. The choice of RAT depends on a variety of factors, including the network
infrastructure, the available spectrum, and the mobile device's/device's capabilities.
Mobile devices often support multiple RATs, allowing them to connect to different
10 types of networks and provide optimal performance based on the available network
resources.
[0036] As used herein, the subscription conditions for Network Functions
(NFs) include NF type, which specifies the category or role of the NF, such as
15 Session Management Function (SMF) or Access and Mobility Management
Function (AMF). Additionally, the services offered by the NF, detailing the specific functionalities or capabilities that the NF provides, such as session management, policy control, or mobility management. The list of subscriptions can also include other conditions such as geographical location, network slice instance, supported
20 interfaces, and operational status.
[0037] As used herein, set of subscriptions refers to notifications and updates
that a Network Function (NF) subscribes to, for maintaining efficient operation and seamless interaction within the network. The subscriptions can include from
25 example, status updates about the operational state of other NFs, configuration
changes that could impact interoperability, service availability information, load information for effective resource management, error reports for proactive issue resolution, policy updates for compliance and optimal performance, and subscription management notifications to keep track of new, renewed, or cancelled
30 subscriptions.
12

[0038] As used herein, set of NF instances refers to the network functions
within the network that an NF needs to interact with to perform it functions
effectively. The set of NF instances are identified based on their roles and
5 capabilities required for seamless network operation. For example, the Session
Management Function (SMF) for managing session states and user data sessions, the Access and Mobility Management Function (AMF) for handling user registration and mobility management, the Policy Control Function (PCF) for enforcing resource usage and service quality policies.
10
[0039] As discussed in the background section, when an NF is ready for
service, it registers its profile with the NRF, allowing other NFs to discover and interact with it. However, there are instances where, during regular operations such as updates or heartbeat checks, the NRF may respond with an error (such as "404
15 Not Found" error), indicating that the NF instance ID cannot be found in the NRF.
This poses a significant challenge as the existing solutions do not specify the actions that an NF should take upon receiving such an error. Without a defined protocol for handling the NF, the affected NF could become undiscoverable, leading to potential service disruptions and degraded network performance. Moreover, existing
20 techniques require manual intervention to resolve registration errors, which can be
time-consuming and prone to human error. The manual process delays the re-establishment of NF profiles in the NRF, further affecting network efficiency. Additionally, the absence of an automatic rediscovery and resubscription process means that even if an NF is manually re-registered, there is no assurance that all
25 necessary updates and changes that occurred during the downtime will be
synchronized. This can lead to inconsistencies in the network state and further operational issues.
[0040] The present disclosure aims to overcome the above-mentioned and
30 other existing problems in this field of technology by providing a method for
13

automatic re-registration, rediscovery, and resubscription of network functions
(NFs) in a communication network. The proposed solution as disclosed by the
present disclosure enables that when an NF receives a "404 Not Found" error from
the Network Repository Function (NRF) during regular operations such as updates
5 or heartbeat checks, it can autonomously address such errors without requiring
manual intervention. By defining specific actions that an NF should take upon receiving such an error, the disclosure addresses the lack of a defined protocol and mitigates the risk of the affected NF becoming undiscoverable. The automatic transmission of a re-registration request by the NF to the NRF immediately after
10 determining a failure based on the received error message enables quick re-
registration of the NF with the NRF, making it discoverable once again and allowing other NFs to interact with it. The automatic process eliminates the delays and potential errors associated with manual intervention, enhancing network efficiency and reliability. Additionally, the present disclosure includes a method for
15 the NF to automatically send a rediscovery request to the NRF to identify the
necessary NF instances required for service continuity such that any changes or updates that occurred during the downtime are identified and synchronized. Furthermore, the NF will also transmit a resubscription request to the NRF to subscribe to status updates for the identified set of NF instances, ensuring that it
20 remains up-to-date with the latest network information. The proposed not only
ensures that the NF can quickly recover from a "404 Not Found" error but also maintains consistency in the network state, addressing potential operational issues caused by unsynchronized updates. The method also allows the NF to transmit an unsubscribe request for previously held subscriptions, ensuring a clean and efficient
25 re-establishment of necessary profiles and services.
[0041] It would be appreciated by the person skilled in the art that by
automating the re-registration, rediscovery, and resubscription processes, the
present disclosure provides a robust and resilient solution to maintain NF
30 discoverability and service continuity to enhance the overall reliability and
14

performance of the communication network, ensuring uninterrupted service and efficient management of network resources.
[0042] Hereinafter, exemplary embodiments of the present disclosure will be
5 described with reference to the accompanying drawings.
[0043] FIG. 1 illustrates an exemplary block diagram representation of 5th
generation core (5GC) network architecture, in accordance with exemplary implementation of the present disclosure. As shown in FIG. 1, the 5GC network
10 architecture [100] includes a user equipment (UE) [102], a radio access network
(RAN) [104], an access and mobility management function (AMF) [106], a Session Management Function (SMF) [108], a Service Communication Proxy (SCP) [110], an Authentication Server Function (AUSF) [112], a Network Slice Specific Authentication and Authorization Function (NSSAAF) [114], a Network Slice
15 Selection Function (NSSF) [116], a Network Exposure Function (NEF) [118], a
Network Repository Function (NRF) [120], a Policy Control Function (PCF) [122], a Unified Data Management (UDM) [124], an application function (AF) [126], a User Plane Function (UPF) [128], a data network (DN) [130], wherein all the components are assumed to be connected to each other in a manner as obvious to
20 the person skilled in the art for implementing features of the present disclosure.
[0044] Radio Access Network (RAN) [104] is the part of a mobile
telecommunications system that connects user equipment (UE) [102] to the core
network (CN) and provides access to different types of networks (e.g., 5G network).
25 It consists of radio base stations and the radio access technologies that enable
wireless communication.
[0045] Access and Mobility Management Function (AMF) [106] is a 5G core
network function responsible for managing access and mobility aspects, such as UE
15

registration, connection, and reachability. It also handles mobility management procedures like handovers and paging.
[0046] Session Management Function (SMF) [108] is a 5G core network
5 function responsible for managing session-related aspects, such as establishing,
modifying, and releasing sessions. It coordinates with the User Plane Function
(UPF) for data forwarding and handles IP address allocation and QoS enforcement.
[0047] Service Communication Proxy (SCP) [110] is a network function in the
10 5G core network that facilitates communication between other network functions
by providing a secure and efficient messaging service. It acts as a mediator for service-based interfaces.
[0048] Authentication Server Function (AUSF) [112] is a network function in
15 the 5G core responsible for authenticating UEs during registration and providing
security services. It generates and verifies authentication vectors and tokens.
[0049] Network Slice Specific Authentication and Authorization Function
(NSSAAF) [114] is a network function that provides authentication and
20 authorization services specific to network slices. It ensures that UEs can access only
the slices for which they are authorized.
[0050] Network Slice Selection Function (NSSF) [116] is a network function
responsible for selecting the appropriate network slice for a UE based on factors
25 such as subscription, requested services, and network policies.
[0051] Network Exposure Function (NEF) [118] is a network function that
exposes capabilities and services of the 5G network to external applications, enabling integration with third-party services and applications. 30
16

[0052] Network Repository Function (NRF) [120] is a network function that
acts as a central repository for information about available network functions and services. It facilitates the discovery and dynamic registration of network functions.
5 [0053] Policy Control Function (PCF) [122] is a network function responsible
for policy control decisions, such as QoS, charging, and access control, based on subscriber information and network policies.
[0054] Unified Data Management (UDM) [124] is a network function that
10 centralizes the management of subscriber data, including authentication,
authorization, and subscription information.
[0055] Application Function (AF) [126] is a network function that represents
external applications interfacing with the 5G core network to access network
15 capabilities and services.
[0056] User Plane Function (UPF) [128] is a network function responsible for
handling user data traffic, including packet routing, forwarding, and QoS enforcement. 20
[0057] Data Network (DN) [130] refers to a network that provides data services
to user equipment (UE) in a telecommunications system. The data services may include but are not limited to Internet services, private data network related services.
25 [0058] FIG. 2 illustrates an exemplary block diagram of a computer system
[1000] upon which the features of the present disclosure may be implemented in accordance with exemplary implementation of the present disclosure. In an implementation, the computer system [1000] may also implement a method for automatic re-registration of network functions in a communication network. In
30 another implementation, the computer system [1000] itself implements the method
17

for automatic re-registration of network functions in a communication network using one or more units configured within the computer system [1000], wherein said one or more units are capable of implementing the features as disclosed in the present disclosure. 5
[0059] The computer system [1000] encompasses a wide range of electronic
devices capable of processing data and performing computations. Examples of computer system [1000] include, but are not limited only to, personal computers, laptops, tablets, smartphones, user equipment (UE), servers, and embedded
10 systems. The devices may operate independently or as part of a network and can
perform a variety of tasks such as data storage, retrieval, and analysis. Additionally, computer system [1000] may include peripheral devices, such as monitors, keyboards, and printers, as well as integrated components within larger electronic systems, showcasing their versatility in various technological applications.
15
[0060] The computer system [1000] may include a bus [1002] or other
communication mechanism for communicating information, and a processor [1004] coupled with bus [1002] for processing information. The processor [1004] may be, for example, a general-purpose microprocessor. The computer system [1000] may
20 also include a main memory [1006], such as a random-access memory (RAM), or
other dynamic storage device, coupled to the bus [1002] for storing information and instructions to be executed by the processor [1004]. The main memory [1006] also may be used for storing temporary variables or other intermediate information during execution of the instructions to be executed by the processor [1004]. Such
25 instructions, when stored in non-transitory storage media accessible to the processor
[1004], render the computer system [1000] into a special-purpose machine that is customized to perform the operations specified in the instructions. The computer system [1000] further includes a read only memory (ROM) [1008] or other static storage device coupled to the bus [1002] for storing static information and
30 instructions for the processor [1004].
18

[0061] A storage device [1010], such as a magnetic disk, optical disk, or solid-
state drive is provided and coupled to the bus [1002] for storing information and
instructions. The computer system [1000] may be coupled via the bus [1002] to a
5 display [1012], such as a cathode ray tube (CRT), Liquid crystal Display (LCD),
Light Emitting Diode (LED) display, Organic LED (OLED) display, etc. for displaying information to a computer user. An input device [1014], including alphanumeric and other keys, touch screen input means, etc. may be coupled to the bus [1002] for communicating information and command selections to the
10 processor [1004]. Another type of user input device may be a cursor controller
[1016], such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor [1004], and for controlling cursor movement on the display [1012]. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y),
15 that allow the device to specify positions in a plane.
[0062] The computer system [1000] may implement the techniques described
herein using customized hard-wired logic, one or more ASICs or FPGAs, firmware and/or program logic which in combination with the computer system [1000] causes
20 or programs the computer system [1000] to be a special-purpose machine.
According to one implementation, the techniques herein are performed by the computer system [1000] in response to the processor [1004] executing one or more sequences of one or more instructions contained in the main memory [1006]. Such instructions may be read into the main memory [1006] from another storage
25 medium, such as the storage device [1010]. Execution of the sequences of
instructions contained in the main memory [1006] causes the processor [1004] to perform the process steps described herein. In alternative implementations of the present disclosure, hard-wired circuitry may be used in place of or in combination with software instructions.
30
19

[0063] The computer system [1000] also may include a communication
interface [1018] coupled to the bus [1002]. The communication interface [1018]
provides a two-way data communication coupling to a network link [1020] that is
connected to a local network [1022]. For example, the communication interface
5 [1018] may be an integrated services digital network (ISDN) card, cable modem,
satellite modem, or a modem to provide a data communication connection to a
corresponding type of telephone line. As another example, the communication
interface [1018] may be a local area network (LAN) card to provide a data
communication connection to a compatible LAN. Wireless links may also be
10 implemented. In any such implementation, the communication interface [1018]
sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
[0064] The computer system [1000] can send messages and receive data,
15 including program code, through the network(s), the network link [1020] and the
communication interface [1018]. In the Internet example, a server [1030] might
transmit a requested code for an application program through the Internet [1028],
the ISP [1026], the host [1024], the local network [1022] and the communication
interface [1018]. The received code may be executed by the processor [1004] as it
20 is received, and/or stored in the storage device [1010], or other non-volatile storage
for later execution.
[0065] Referring to FIG. 3, an exemplary block diagram of a system [300] for
automatic re-registration of network functions in a communication network is
25 shown, in accordance with the exemplary embodiments of the present invention.
The system [300] comprises a network function (NF). The network function further comprises a transmitting unit [302], a receiving unit [304], and a processing unit [306]. Also, all of the components/ units of the system [300] are assumed to be connected to each other unless otherwise indicated below. As shown in the figures
30 all units shown within the system should also be assumed to be connected to each
20

other. Also, in FIG. 3 only a few units are shown, however, the system [300] may
comprise multiple such units or the system [300] may comprise any such numbers
of said units, as required to implement the features of the present disclosure.
Further, in an implementation, the system [300] may reside in a server or a network
5 entity.
[0066] The transmitting unit [302] is configured to transmit a request to a
Network Repository Function (NRF) [120] storing information associated with a plurality of NFs. For example, in a 5G network, the transmitting unit [302] might
10 utilize standardized communication protocols (such as HTTP/2 or RESTful APIs)
to send registration request for secure and reliable transmission of data between the NF and NRF [120]. When the NF is ready to register with the NRF [120], the transmitting unit [302] transmits a request (such as Nnrf_Management_NFRegister message). The request may include, but not limited only to the profile information
15 of the NF, including its instance ID, capabilities, and service parameters. The NRF
[120], which maintains a repository of NF profiles, uses the information to make the NF discoverable to other network functions of the network. The plurality of NFs include various 5G nodes defined in 3GPP standards. Examples of the plurality of NFs include, but are not limited only to Session Management Function (SMF), the
20 Access and Mobility Management Function (AMF), the Policy Control Function
(PCF), the User Plane Function (UPF) etc.
[0067] For example, a new NF is deployed in a 5G core network. Upon
initialization, the transmitting unit [302] within this NF sends a registration request
25 to the NRF [120]. The message includes details such as the NF's unique identifier,
supported services, and operational status. The NRF [120] receives the message, updates its repository, and confirms the registration, and thus enables other NFs in the network to discover and interact with the newly registered NF based on the stored profile information.
30
21

[0068] In addition to the registration, the request may also include periodic
updates (such as heartbeat message) and status messages. For example, during
routine operations, the NF might need to update its status or capabilities due to
configuration changes or software updates. The transmitting unit [302] in turn sends
5 the request (such as Nnrf_Management_NFUpdate message) to the NRF [120].
[0069] The receiving unit [304] connected at least to the transmitting unit
[302], the receiving unit [304] is configured to receive an error message from the NRF [120] based on the transmitted request. For example, when the NF sends a
10 registration request to the NRF [120] via the transmitting unit [302], the receiving
unit [304] is receives the response from the NRF [120]. If the NRF [120] detects an issue with the request, such as a missing or incorrect NF instance ID, it may respond with a "404 Not Found" error message. For example, an NF sends an update request to the NRF [120] to modify its profile information. The NRF [120] processes the
15 request and, if it cannot find the corresponding NF instance ID in the repository
then the NRF [120] sends back an error message (such as 404 Not Found) to the NF. Examples of the error message can include, but not limited only to different HTTP status codes such as "400 Bad Request," "403 Forbidden," and "404 Not Found.".
20
[0070] The processing unit [306] is connected to at least the receiving unit
[304], the processing unit [306] is configured to determine a failure at the NRF [120] [120] based on the received error message. When the receiving unit [304] receives an error (such as a "404 Not Found" error) from the NRF [120] it forwards
25 a message corresponding to the error to the processing unit [306]. The processing
unit [306] then interprets the error message to determine the nature and cause of the failure. For example, if the error message indicates that the NF instance ID cannot be found in the NRF [120], the processing unit [306] identifies this as a registration failure. The processing unit [306] is configured to determine failure based on a
30 predefined logic that maps the error codes to the failure. For example, upon
22

receiving the "404 Not Found" error, the processing unit [306] interprets it as a failure in the NRF [120] to locate the NF's profile, indicating that the NF is not currently registered.
5 [0071] For example, the NF is attempting to update its profile in the NRF [120].
If the NRF [120] responds with a "404 Not Found" error, the receiving unit [304] the processing unit [306] analyses the error message, identifies it as a failure in locating the NF instance ID, and determines that the NF is no longer registered in the NRF [120]. Further, the processing unit [306] can identify whether an error is
10 due to a temporary network issue, an incorrect request format, or a missing NF
instance ID. Exemplarily, the processing unit [306] may also log error occurrences. The error logs may provide valuable data for network administrators to analyse and improve network reliability and performance. For example, by examining the frequency and causes of "404 Not Found" errors, administrators can identify and
15 address underlying issues in the network infrastructure.
[0072] The transmitting unit [302] is further configured to automatically
transmit a re-registration request to the NRF [120] based on the determined failure. Upon receiving a failure determination from the processing unit [306], the
20 transmitting unit [302] initiates the re-registration process without requiring manual
intervention. The re-registration request is transmitted immediately following the determination of the failure at the NRF [120]. When the processing unit [306] determines the failure, such as a "404 Not Found" error indicating that the NF instance ID cannot be located in the NRF [120], it signals the transmitting unit [302]
25 to act. For example, an NF's registration is inadvertently deleted from the NRF
[120]. When the NF attempts to send an update or heartbeat message, it receives a "404 Not Found" error. The transmitting unit [302] then automatically transmits the request to the NRF [120], ensuring the NF is re-registered promptly. It would be appreciated by the person skilled in the art that by eliminating the need for manual
23

re-registration, the network can quickly recover from errors, reducing downtime and preventing potential service disruptions.
[0073] The transmitting unit [302] is further configured to transmit a re-
5 discovery request to the NRF [120] to identify a set of NF instances required for
service continuity. When an NF receives an error, such as a "404 Not Found" response from the NRF [120], the processing unit [306] determines that the NF's registration or information may be outdated or lost. Therefore, the transmitting unit [302] initiates a re-discovery process by sending the re-discovery request to the
10 NRF [120] to obtain updated information about other network functions that the NF
needs to interact with for maintaining seamless service operations. For example, suppose a User Plane Function (UPF) loses its registration in the NRF [120] due to a temporary issue. To restore its full operational capabilities, the UPF needs to reconnect with various control plane functions like the Session Management
15 Function (SMF) and the Policy Control Function (PCF). The transmitting unit [302]
sends a re-discovery request to the NRF [120], which then responds with detailed information about these control plane functions, including their current status, capabilities, and endpoints. For example, a Network Slice Selection Function (NSSF) loses its registration. The transmitting unit [302] sends a re-discovery
20 request to the NRF [120] to find all the necessary network slice instances required
for its operations. The NRF [120] provides the NSSF with updated details of these instances, allowing the NSSF to reconfigure itself and continue providing optimal network slice selection services.
25 [0074] The transmitting unit [302] is further configured to transmit a re-
subscription request to the NRF [120] to subscribe to status updates for the identified set of NF instances. When an NF experiences an error or disruption and subsequently performs a re-discovery of necessary NFs, it must also ensure that it remains updated on the status of these NFs. The re-subscription request may be sent
30 to the NRF [120] to receive notifications about the status of the identified NFs. The
24

status updates facilitates the NF to adapt to any changes in the network, such as NF
instance failures, updates, or configuration changes. For example, a Session
Management Function (SMF) needs to keep track of multiple User Plane Functions
(UPFs) to manage user sessions effectively. After an error causes the SMF to lose
5 its registration, it first re-registers and then re-discovers the UPFs. To ensure
ongoing service continuity, the transmitting unit [302] sends a re-subscription request to the NRF [120], requesting status updates for these UPFs. This way, the SMF can receive immediate notifications about any changes in the UPFs' status, such as instances going offline or coming back online.
10
[0075] The transmitting unit [302] is further configured to transmit an
unsubscribe request to the NRF [120] for unsubscribing from the previously held set of subscriptions related to the set of NF instances. For example, an SMF (Session Management Function) has several subscriptions to status updates from various
15 UPFs (User Plane Functions). After an error, the SMF re-registers and re-discovers
the UPFs it needs to interact with. Some of the UPFs it previously subscribed to might have been decommissioned or replaced by new instances. To avoid receiving unnecessary status updates and to ensure that the SMF is only monitoring the relevant UPFs, the transmitting unit [302] sends an unsubscribe request to the NRF
20 [120]. The unsubscribe request facilitates the NRF [120] to cancel the old
subscriptions that are no longer needed.
[0076] The transmitting unit [302] is configured to, by the Network Function
Repository Function (NRF) [120], transmit status information to the plurality of
25 NFs to resume services. For example, a control plane NF like the SMF (Session
Management Function) re-registers with the NRF [120] after experiencing an error. The NRF [120], upon receiving this re-registration, updates its records and generates status information reflecting the current state of the SMF. The transmitting unit [302] then transmits this status information to all NFs that have
30 subscribed to updates from the SMF. This includes other control plane functions,
25

user plane functions, and possibly application functions that depend on the SMF for
session management and policy enforcement. For example, an AMF loses
registration at the NRF [120] due to a temporary issue. Upon re-registering, the
NRF [120] updates its records with the AMF's latest status and the transmitting unit
5 [302] broadcasts this information to all relevant NFs. The NFs, such as the SMF
and PCF (Policy Control Function), receive the status updates and adjust their operations to ensure that user sessions and mobility management continue smoothly.
10 [0077] The receiving unit [304] is configured to receive a confirmation
message from the NRF [120], acknowledging the successful re-registration of the NF. For example, an SMF encounters an error that leads to its deregistration from the NRF [120]. After the SMF sends a re-registration request, the NRF [120] processes this request and, upon successful re-registration, sends a confirmation
15 message back to the SMF. The receiving unit [304] in the SMF is configured to
receive this confirmation message. Once the SMF receives this acknowledgment then facilitates in rediscovering necessary NFs and re-subscribing to status updates. The receipt of a confirmation message by the receiving unit [304] facilitates that the NF is again available in the network. For example, if an AMF re-registers and
20 receives the confirmation, it can immediately start managing user mobility and
session establishment processes, knowing that its status is recognized by the NRF [120] and other dependent NFs can discover and interact with it as needed.
[0078] Referring to FIG. 4 an exemplary sequence diagram for automatic re-
25 registration Network Functions (NFs) in a communication network case of NRF
[120] side failure is disclosed.
[0079] At step S1, the Network Function (NF) [402] initiates the process by
transmitting a request (such as Nnrf_Management_NFUpdate (Heartbeat)) to the
30 Network Repository Function (NRF) [120]. The request includes an NF Update or
26

a Heartbeat message for maintaining the NF's profile and status within the NRF [120].
[0080] At step S2, the NRF [120] processes the received request. If the NRF
5 [120] cannot find the corresponding nfInstanceID associated with the NF [402]
within its repository, it responds with a "404 Not Found" error message indicating that the NF's profile is not currently registered in the NRF [120].
[0081] At step S3, the NF [402] receives the "404 Not Found" error message
10 from the NRF [120]. The receiving unit [304] in the NF [402] receives the error
message, indicating that there has been a failure in locating the NF's [402] instance ID in the NRF [120].
[0082] At step S4, the processing unit [306] within the NF [402] analyses the
15 received error message to determine the failure at the NRF [120]. bBsed on the
determined failure, the transmitting unit [302] automatically sends a re-registration request (such as Nnrf_Management_NFRegister request from the NF [402] to the NRF [120]. The re-registration request includes the necessary profile information to re-register the NF [402] within the NRF [120].
20
[0083] At step S5, the NRF [120] processes the re-registration request and,
upon successful re-registration, and sends a response (such as '201 Created') back to the NF [402]. The receiving unit [304] receives the response, indicating that the NF's profile has been successfully created in the NRF [120].
25
[0084] At step S6, the NF [402] proceeds to transmit a re-discovery request to
the NRF [120] to identify a set of NF instances required for service continuity. The request includes, for example, an Nnrf_NFDiscovery_NFDiscover message that queries the NRF [120] for updated information about other NFs that the affected
30 NF [402] needs to interact with.
27

[0085] At step S7, the NRF [120] processes the re-discovery request and
responds with a '200 OK (Search Results)' message to the NF [402] comprising information about the identified set of NF instances required for service continuity 5
[0086] At step S8, the NF [402] transmits a re-subscription request (such as
Nnrf_Management_NFStatusSubscribe) to the NRF [120] to subscribe to status updates for the identified set of NF instances to obtain information about any status changes in the network. 10
[0087] At step S9, the NRF [120] processes the re-subscription request and,
upon successful processing, sends a '201 Created' response back to the NF [402] indicating that status updates have been successfully established.
15 [0088] At step S10, if there are previously held subscriptions that are no longer
relevant, the NF [402] sends an unsubscribe request (such as NFStatusUnSubscribe) to the NRF [120] to clean up old subscriptions and maintain an accurate list of necessary status updates.
20 [0089] At step S11, the NRF [120] processes the unsubscribe request and, upon
successful processing, sends a '204 No Content' response back to the NF [402] confirming that the old subscriptions have been successfully removed.
[0090] Referring to FIG. 5 an exemplary method flow diagram [500] indicating
25 a process for automatic re-registration of network function in a communication
network in accordance with exemplary embodiments of the present disclosure is shown. In an implementation the method [500] is performed by the system [300]. As shown in FIG. 5, the method [500] starts at step [502].
28

[0091] At step [504], the method [500] as disclosed by the present disclosure
comprises transmitting, by a network function (NF) [402], a request to a Network
Repository Function (NRF) [120] storing information associated with a plurality of
NFs. For example, the transmitting unit [302] might utilize communication
5 protocols (such as Hypertext Transfer Protocol/2 (HTTP/2) or HTTP) to send
registration request for secure and reliable transmission of data between the NF
[402] and NRF [120]. When the NF [402] is ready to register with the NRF [120],
the transmitting unit [302] transmits a request (such as
Nnrf_Management_NFRegister message). The request may include, but not limited
10 only to the profile information of the NF, including its instance ID, capabilities, and
service parameters. The NRF [120], which maintains a repository of NF [402] profiles, uses the information to make the NF [402] discoverable to other network functions of the network.
15 [0092] For example, a NF [402] is deployed in a 5G core network. Upon
initialization, the transmitting unit [302] within this NF [402] sends a registration request to the NRF [120]. The message includes details such as the NF's unique identifier, supported services, and operational status. The NRF [120] receives the message, updates its repository, and confirms the registration, and thus enables
20 other NFs in the network to discover and interact with the newly registered NF
[402] based on the stored profile information. In addition to the registration, the request may also include periodic updates (such as heartbeat message) and status messages. For example, during routine operations, the NF [402] might need to update its status or capabilities due to configuration changes or software updates.
25 The transmitting unit [302] in turn sends the request (such as
Nnrf_Management_NFUpdate message) to the NRF [120].
[0093] Next, at step [506], the method [500] as disclosed by the present
disclosure comprises receiving, by the NF [402], an error message from the NRF
30 [120] based on the transmitted request. For example, when the NF [402] sends a
29

registration request to the NRF [120] via the transmitting unit [302], the receiving
unit [304] is receives the response from the NRF [120]. If the NRF [120] detects an
issue with the request, such as a missing or incorrect NF instance ID, it may respond
with a "404 Not Found" error message. For example, an NF [402] sends an update
5 request to the NRF [120] to modify its profile information. The NRF [120]
processes the request and, if it cannot find the corresponding NF instance ID in the
repository then the NRF [120] sends back an error message (such as 404 Not Found)
to the NF. Examples of the error message can include, but not limited only to
different HTTP status codes such as "400 Bad Request," "403 Forbidden," and "404
10 Not Found.".
[0094] Next, at step [508], the method [500] as disclosed by the present
disclosure comprises determining, by the NF [402], a failure at NRF [120] based on the received error message. When the receiving unit [304] receives an error (such
15 as a "404 Not Found" error) from the NRF [120] it forwards a message
corresponding to the error to the processing unit [306]. The processing unit [306] then interprets the error message to determine the nature and cause of the failure. For example, if the error message indicates that the NF instance ID cannot be found in the NRF [120], the processing unit [306] identifies this as a registration failure.
20
[0095] For example, the NF [402] is attempting to update its profile in the NRF
[120]. If the NRF [120] responds with a "404 Not Found" error, the receiving unit [304] the processing unit [306] analyses the error message, identifies it as a failure in locating the NF instance ID, and determines that the NF [402] is no longer
25 registered in the NRF [120]. Further, the processing unit [306] can identify whether
an error is due to a temporary network issue, an incorrect request format, or a missing NF instance ID. Exemplarily, the processing unit [306] may also log error occurrences. The error logs may provide valuable data for network administrators to analyse and improve network reliability and performance. For example, by
30

examining the frequency and causes of "404 Not Found" errors, administrators can identify and address underlying issues in the network infrastructure.
[0096] Next, at step [510], the method [500] as disclosed by the present
5 disclosure comprises automatically transmitting, by the NF [402], a re-registration
request to the NRF [120] based on the determined failure. Upon receiving a failure determination from the processing unit [306], the transmitting unit [302] initiates the re-registration process without requiring manual intervention. The re-registration request is transmitted immediately following the determination of the
10 failure at the NRF [120]. When the processing unit [306] determines the failure,
such as a "404 Not Found" error indicating that the NF instance ID cannot be located in the NRF [120], it signals the transmitting unit [302] to act. For example, an NF's registration is inadvertently deleted from the NRF [120]. When the NF [402] attempts to send an update or heartbeat message, it receives a "404 Not Found"
15 error. The transmitting unit [302] then automatically transmits the request to the
NRF [120], ensuring the NF [402] is re-registered promptly. It would be appreciated by the person skilled in the art that by eliminating the need for manual re-registration, the network can quickly recover from errors, reducing downtime and preventing potential service disruptions.
20
[0097] Next, at step [512], the method [500] as disclosed by the present
disclosure comprises transmitting, by the NF [402], a re-discovery request to the NRF [120] to identify a set of NF instances required for service continuity. When an NF [402] receives an error, such as a "404 Not Found" response from the NRF
25 [120], the processing unit [306] determines that the NF's registration or information
may be outdated or lost. Therefore, the transmitting unit [302] initiates a re-discovery process by sending the re-discovery request to the NRF [120] to obtain updated information about other network functions that the NF [402] needs to interact with for maintaining seamless service operations. For example, suppose a
30 User Plane Function (UPF) loses its registration in the NRF [120] due to a
31

temporary issue. To restore its full operational capabilities, the UPF needs to
reconnect with various control plane functions like the Session Management
Function (SMF) and the Policy Control Function (PCF). The transmitting unit [302]
sends a re-discovery request to the NRF [120], which then responds with detailed
5 information about these control plane functions, including their current status,
capabilities, and endpoints. For example, a Network Slice Selection Function
(NSSF) loses its registration. The transmitting unit [302] sends a re-discovery
request to the NRF [120] to find all the necessary network slice instances required
for its operations. The NRF [120] provides the NSSF with updated details of these
10 instances, allowing the NSSF to reconfigure itself and continue providing optimal
network slice selection services.
[0098] Next, at step [514], the method [500] as disclosed by the present
disclosure comprises transmitting, by the NF [402], a re-subscription request to the
15 NRF [120] to subscribe to status update for the identified set of NF instances. When
an NF [402] experiences an error or disruption and subsequently performs a re-discovery of necessary NFs, it must also ensure that it remains updated on the status of these NFs. The re-subscription request may be sent to the NRF [120] to receive notifications about the status of the identified NFs. The status update facilitates the
20 NF [402] to adapt to any changes in the network, such as NF instance failures,
updates, or configuration changes. For example, a Session Management Function (SMF) needs to keep track of multiple User Plane Functions (UPFs) to manage user sessions effectively. After an error causes the SMF to lose its registration, it first re-registers and then re-discovers the UPFs. To ensure ongoing service continuity,
25 the transmitting unit [302] sends a re-subscription request to the NRF [120],
requesting status updates for these UPFs. This way, the SMF can receive immediate notifications about any changes in the UPFs' status, such as instances going offline or coming back online.
30 [0099] Thereafter, the method [500] terminates at step [516].
32

[0100] As is evident from the above, the present disclosure provides a
technically advanced solution for performing automatic NF [402] registration in
case of NRF [120] side failure. The present disclosure provides a solution that NF
5 [402] will reregister automatically into the NRF [120] which will in turn make the
NF [402] discoverable again and also the NRF [120] sends the updated profile to
all NFs that have subscribed. Furthermore, the present disclosure provides the other
action needed at impacted NF [402] (which has received 404 error) in terms of
discovery and subscribe service operations with NRF [120] which are needed for
10 service continuity.
[0101] According to another aspect of the present disclosure, a user equipment
(UE) [102] for automatic re-registration of network functions in a communication network is disclosed. The user equipment (UE) [102] comprises a system. The
15 system further comprises a network function [402]. The network function [402]
comprises a transmitting unit [302] configured to transmit a request to a Network Repository Function (NRF) [120] storing information associated with a plurality of NFs. The network function [402] includes a receiving unit [304] configured to receive an error message from the NRF [120] based on the transmitted request. The
20 network function [402] includes a processing unit [306] configured to determine a
failure at NRF [120] based on the received error message. The transmitting unit [302] is further configured to automatically transmit a re-registration request to the NRF [120] based on the determined failure; transmit a re-discovery request to the NRF [120] to identify a set of NF instances required for service continuity; and
25 transmit a re-subscription request to the NRF [120] to subscribe to status update for
the identified set of NF instances.
[0102] According to yet another aspect, a non-transitory computer-readable
storage medium storing instruction for automatic re-registration of network
30 functions in a communication network is disclosed. The storage medium
33

comprising executable code which, when executed by one or more units of a
system, causes: a transmitting unit [302] to transmit a request to a Network
Repository Function (NRF) [120] storing information associated with a plurality of
NFs; a receiving unit [304] connected at least to the transmitting unit, the receiving
5 unit [304] to receive an error message from the NRF [120] based on the transmitted
request; a processing unit [306] connected to at least the receiving unit [304], the
processing unit [306] to determine a failure at NRF [120] based on the received
error message; the transmitting unit [302] to: automatically transmit a re-
registration request to the NRF [120] based on the determined failure; transmit a re-
10 discovery request to the NRF [120] to identify a set of NF instances required for
service continuity; and the transmitting unit [302] configured to transmit a re-
subscription request to the NRF [120] to subscribe to status update for the identified
set of NF instances.
15 [0103] Further, in accordance with the present disclosure, it is to be
acknowledged that the functionality described for the various the components/units can be implemented interchangeably. While specific embodiments may disclose a particular functionality of these units for clarity, it is recognized that various configurations and combinations thereof are within the scope of the disclosure. The
20 functionality of specific units as disclosed in the disclosure should not be construed
as limiting the scope of the present disclosure. Consequently, alternative arrangements and substitutions of units, provided they achieve the intended functionality described herein, are considered to be encompassed within the scope of the present disclosure.
25
[0104] While considerable emphasis has been placed herein on the disclosed
embodiments, it will be appreciated that many embodiments can be made and that many changes can be made to the embodiments without departing from the principles of the present disclosure. These and other changes in the embodiments
30 of the present disclosure will be apparent to those skilled in the art, whereby it is to
34

be understood that the foregoing descriptive matter to be implemented is illustrative and non-limiting.
35

We Claim:
1. A method for automatic re-registration of network functions in a
communication network, the method comprising:
transmitting, by a network function (NF) [402], a request to a Network Repository Function (NRF) [120] storing information associated with a plurality of NFs;
receiving, by the NF [402], an error message from the NRF [120] based on the transmitted request;
determining, by the NF [402], a failure at NRF [120] based on the received error message;
automatically transmitting, by the NF [402], a re-registration request to the NRF [120] based on the determined failure;
transmitting, by the NF [402], a re-discovery request to the NRF [120] to identify a set of NF instances required for service continuity; and
transmitting, by the NF [402], a re-subscription request to the NRF [120] to subscribe to status update for the identified set of NF instances.
2. The method as claimed in claim 1, the method further comprising transmitting, by the NF [402], an unsubscribe request to the NRF [120] for unsubscribing from previously held set of subscriptions related to the set of NF instances.
3. The method as claimed in claim 1, the method further comprising transmitting, by the Network Function Repository Function, a status information to the plurality of NFs to resume services.
4. The method as claimed in claim 1, wherein the NF immediately transmit a re-registration request to the NRF [120] upon receiving the error message.

5. The method as claimed in claim 1, wherein the error message is a "404 Not Found" message indicating that the NRF [120] cannot find an instance ID associated with the NF.
6. The method as claimed in claim 1, wherein the re-registration request is transmitted immediately following the determination of the failure at the NRF [120].
7. The method as claimed in claim 1, further comprises receiving a confirmation message from the NRF [120], acknowledging the successful re-registration of the NF.
8. A system for automatic re-registration of network functions in a communication network, the system comprising:
a network function comprising:
a transmitting unit [302] configured to transmit a request to a Network Repository Function (NRF) [120] storing information associated with a plurality of NFs;
a receiving unit [304] connected at least to the transmitting unit [302], the receiving unit [304] configured to receive an error message from the NRF [120] based on the transmitted request;
a processing unit [306] connected to at least the receiving unit [304], the processing unit [306] configured to determine a failure at the NRF [120] based on the received error message;
the transmitting unit [302] configured to:
automatically transmit a re-registration request to the NRF
[120] based on the determined failure;
transmit a re-discovery request to the NRF [120] to identify
a set of NF instances required for service continuity; and

the transmitting unit [302] configured to transmit a re-subscription request to the NRF [120] to subscribe to status update for the identified set of NF instances.
9. The system as claimed in claim 8, comprises the transmitting unit [302] is configured to transmit an unsubscribe request to the NRF [120] for unsubscribing from previously held set of subscriptions related to the set of NF instances.
10. The system as claimed in claim 8, comprises the transmitting unit [302] is configured to, by the Network Function Repository Function, a status information to the plurality of NFs to resume services.
11. The system as claimed in claim 8, wherein the NF [402] immediately transmit a re-registration request to the NRF [120] upon receiving the error message.
12. The system as claimed in claim 8, wherein the error message is a "404 Not Found" message indicating that the NRF [120] cannot find an instance ID associated with the NF [402].
13. The system as claimed in claim 8, wherein the re-registration request is transmitted immediately following the determination of the failure at the NRF [120].
14. The system as claimed in claim 8, comprises the receiving unit [304] configured to receive a confirmation message from the NRF [120], acknowledging the successful re-registration of the NF [402].

15. A user equipment (UE) for automatic re-registration of network functions in a communication network, the UE comprising a system, the system further comprising:
a network function comprising:
a transmitting unit [302] configured to transmit a request to a Network Repository Function (NRF) [120] storing information associated with a plurality of NFs;
a receiving unit [304] configured to receive an error message from the NRF [120] based on the transmitted request;
a processing unit [306] configured to determine a failure at NRF [120] based on the received error message;
the transmitting unit [302] configured to automatically transmit a re-registration request to the NRF [120] based on the determined failure;
the transmitting unit [302] configured to transmit a re-discovery request to the NRF [120] to identify a set of NF instances required for service continuity; and
the transmitting unit [302] configured to transmit a re-subscription request to the NRF [120] to subscribe to status update for the identified set of NF instances.