System and method for maintaining service continuity between network entities

Abstract

The present disclosure discloses a method (400) for maintaining service continuity between a plurality of network entities, including receiving policy initiation messages by a network policy function (132); sending first set of subscribe messages by the network policy function (132) to a charging control function (134); determining a type of return message received from the charging control function (134); transmitting a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) when the return message is the error message, the first set of response messages comprises an error rule; sending a second set of subscribe messages by the network policy function (132) to the charging control function (134) based on policy update messages when the revalidation timer expires; and evaluating at least one PCC rule upon receiving the success message from the charging control function (134).

Description

SYSTEM AND METHOD FOR MAINTAINING SERVICE CONTINUITY BETWEEN NETWORK ENTITIESRESERVATION OF RIGHTS

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

[0002] The present disclosure relates to a field of telecommunication networks and specifically to a system and a method for maintaining service continuity during network connectivity issues between network entities such as, Policy Control Function (PCF) or Policy and Charging Rules Function (PCRF) and Charging Function (CHF) or Online Charging System (OCS).DEFINITION

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

[0004] The term PCF as used herein, refers to a Policy Control Function that is a functional element for policy control decision and flow-based charging control functionalities. The PCF provides functions such as, Policy rules for application and service data flow detection, gating, Quality of Service (QoS), and flow-based charging to Session Management Function (SMF).

[0005] The term PCRF as used herein, refers to a Policy and Charging Rules Function that is a component of the network core in telecommunications networks, particularly in the Evolved Packet Core (EPC) of 4G LTE networks. It plays a central role in defining quality policy rules and ensuring the competent application of real-time charging for user data.

[0006] The term OCS as used herein, refers to an Online charging system that allows a communication service provider to charge their customers, in real time, based on service usage.

[0007] The term CHF as used herein, refers to a Charging Function (CHF) that is a crucial component of 5G core network responsible for accurately calculating and allocating charges for various services and resources used by subscribers.BACKGROUND

[0008] 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.

[0009] In modem telecommunication networks, network policy functions such as, a Policy Control Function (PCF) in 5G or a Policy and Charging Rules Function (PCRF) in 4G plays a crucial role in managing and enforcing policies related to Quality of Service (QoS) and charging. These network policy functions interact with Charging Function (CHF) or Online Charging System (OCS) to monitor and control spending limit of subscribers in real time. This ensures that subscribers do not exceed their allowed spending limit and network resources are utilized efficiently.

[0010] As defined in 3GPP technical specification 29.513 / 29.213, an existing solution receives a Session Management (SM) Policy Control Create or Credit Control Request-Initial (CCR-I) message from a Session Management Function (SMF) or a Packet Data Network Gateway (PGW), and upon receiving the message, the network policy functions may trigger a Spending Limit Control (SLC) Subscribe or Sy interface Spending Limit Request (SLR) message towards the CHF or the OCS. The message requests information about the subscriber’s spending limits. Based on the received information, the network policy functions may provide Policy and Charging Control (PCC) / Session Rules towards the SMF or the PGW.

[0011] However, the existing solution often results in service disruption for the subscribers when the CHF or the OCS is unavailable or returns an error, which impacts user experience. Moreover, the existing solution lacks in dynamically attempting to revalidate SLC subscription after an initial failure.

[0012] Thus, there is a need of a solution that provides an improved mechanism to deal with change in flow of a negative scenario and provides a service to a customer based on business requirements, while simultaneously restoring normalcy in service continuity within a specified duration.OBJECTS OF THE PRESENT DISCLOSURE

[0013] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.

[0014] An object of the present disclosure is to provide a system and a method for providing service continuity during network connectivity issues between network policy functions such as a Policy Control Function (PCF) or a Policy Charging Rules Function (PCRF) and charging control functions such as a Charging Function (CHF) or an Online Charging System (OCS).

[0015] Another object of the present disclosure is to provide appropriate policy rules to a customer without any service interruption or need of customer to reconnect upon resolution of a network problem or a charging control function outage.

[0016] Another object of the present disclosure is to provide service continuity for cases where a charging control function is unavailable.

[0017] Another object of the present disclosure is to maintain a stable customer experience even in case of network outage of charging control functions or connectivity between the network policy functions and the charging control functions.SUMMARY

[0018] In an exemplary embodiment, the present invention discloses a method for maintaining service continuity between a plurality of network entities. The method includes a step of receiving one or more policy initiation messages from a session management function (SMF) by a network policy function. The method includes a step of communicating by the network policy function with a charging control function by sending a first set of subscribe messages based on the corresponding one or more policy initiation messages. The method includes a step of determining, by the processing unit, a type of return message received by the network policy function in response to the corresponding first set of subscribe messages from the charging control function. The return message includes one of, a success message or an error message. The method includes a step of transmitting a first set of response messages and a revalidation timer by the network policy function to the SMF upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule. The method includes a step of sending a second set of subscribe messages by the network policy function to the charging control function based on one or more policy update messages received from the SMF when the revalidation timer expires. The method includes a step of evaluating, by the network policy function, at leastone policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function.

[0019] In some embodiments, the network policy function is selected from a list of a Policy Control Function (PCF) or a Policy and Charging Rule Function (PCRF).

[0020] In some embodiments, the charging control function is selected from a list of a charging function (CHF) or an online charging system (OCS).

[0021] In some embodiments, the one or more policy initiation messages includes a Session Management (SM) policy control create message.

[0022] In some embodiments, the first set of subscribe messages includes an initial Spending Limit Control (SLC) subscribe message.

[0023] In some embodiments, the first set of response messages includes a Session Management (SM) policy control create response message.

[0024] In some embodiments, the second set of subscriber messages includes an updated Spending Limit Control (SLC) subscribe message.

[0025] In some embodiments, the one or more policy update messages comprises a Session Management (SM) policy control update message.

[0026] In some embodiments, the success message includes at least one updated policy counter information.

[0027] In some embodiments, the at least one evaluated PCC rule is updated based on the at least one updated policy counter information and stored session information associated with the one or more policy initiation messages.

[0028] In some embodiments, the method includes a step of transmitting the at least one updated PCC rule from the network policy function to the SMF.

[0029] In another exemplary embodiment, the present invention discloses a system for maintaining service continuity between a plurality of network entities. The system includes a receiving unit configured to receive one or more policy initiation messages from a session management function (SMF) by a network policy function. The system further includes a processing unit. The processing unit is configured to: communicate with a charging control function by the network policy function by sending a first set of subscribe messages based on the corresponding one or more policy initiation messages. The processing unit is configured to: determine a type of message received by the network policy function in response to the corresponding first set of subscribe messages from the charging control function. The return message includes one of, a success message or an error message. The processing unit is further configured to: transmit a first set of response messages and a revalidation timer by the network policy function to the SMF upon determining the received return message as the error message. The first set of response messages comprises at least one error rule. The processing unit is further configured to send a second set of subscribe messages by the network policy function to the charging control function based on one or more policy update messages received from the SMF when the revalidation timer expires. The processing unit is configured to evaluate at least one policy and charging control (PCC) rule by the network policy function upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function.

[0030] In some embodiments, the network policy function is selected from a list of a Policy Control Function (PCF) or a Policy and Charging Rule Function (PCRF), or a combination thereof.

[0031] In some embodiments, the charging control function is selected from a list of a charging function (CHF) or an online charging system (OCS).

[0032] In some embodiments, the one or more policy initiation messages includes a Session Management (SM) policy control create message.

[0033] In some embodiments, the first set of subscribe messages includes an initial Spending Limit Control (SLC) subscribe message.

[0034] In some embodiments, the first set of response messages includes a Session Management (SM) policy control create response message.

[0035] In some embodiments, the second set of subscriber messages includes an updated Spending Limit Control (SLC) subscribe message.

[0036] In some embodiments, the one or more policy update messages comprises a Session Management (SM) policy control update message.

[0037] In some embodiments, the success message includes at least one updated policy counter information.

[0038] In some embodiments, the at least one evaluated PCC rule is updated based on the at least one updated policy counter information and stored session information associated with the one or more policy initiation messages.

[0039] In some embodiments, the processing unit is configured to transmit the at least one updated PCC rule from the network policy function to the SMF.

[0040] In an exemplary embodiment, the present invention discloses a user equipment communicatively coupled with a network. The coupling includes steps of. receiving, by the network, a connection request from the user equipment (UE); sending, by the network, an acknowledgment of the connection request to the user equipment (UE); and transmitting a plurality of signals in response to the connection request. The network is configured for performing a method for maintaining service continuity between a plurality of network entities. The methodincludes a step of receiving one or more policy initiation messages from a session management function (SMF) by a network policy function. The method includes a step of communicating by the network policy function with a charging control function by sending a first set of subscribe messages based on the corresponding one or more policy initiation messages. The method includes a step of determining, by the processing unit, a type of return message received by the network policy function in response to the corresponding first set of subscribe messages from the charging control function. The return message includes one of, a success message or an error message. The method includes a step of transmitting a first set of response messages and a revalidation timer by the network policy function to the SMF upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule. The method includes a step of sending a second set of subscribe messages by the network policy function to the charging control function based on one or more policy update messages received from the SMF when the revalidation timer expires. The method includes a step of evaluating, by the network policy function, at least one policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function.

[0041] In an exemplary embodiment, the present invention discloses a computer program product comprising a non-transitory computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to perform a method for maintaining service continuity between a plurality of network entities. The method includes a step of receiving one or more policy initiation messages from a session management function (SMF) by a network policy function. The method includes a step of communicating by the network policy function with a charging control function by sending a first set of subscribe messages based on the corresponding one or more policy initiation messages. The method includes a step of determining, by the processing unit, a type of return message received by the network policy function in response to thecorresponding first set of subscribe messages from the charging control function. The return message includes one of, a success message or an error message. The method includes a step of transmitting a first set of response messages and a revalidation timer by the network policy function to the SMF upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule. The method includes a step of sending a second set of subscribe messages by the network policy function to the charging control function based on one or more policy update messages received from the SMF when the revalidation timer expires. The method includes a step of evaluating, by the network policy function, at least one policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function.BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In the figures, similar components and / or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

[0043] The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:

[0044] FIG. 1A illustrates an exemplary network architecture in which or with which embodiments of the present disclosure may be implemented;

[0045] FIG. IB illustrates an exemplary block diagram of a system, in accordance with an embodiment of the present disclosure;

[0046] FIG. 1C illustrates an exemplary sequence diagram depicting an error handling process for maintaining a service continuity between network entities, in accordance with an embodiment of the present disclosure;

[0047] FIG. 2 illustrates an exemplary diagram representing an interaction system for enabling an interaction between network entities through corresponding interfaces, in accordance with an embodiment of the present disclosure;

[0048] FIG. 3 illustrates an exemplary computer system in which or with which embodiments of the present disclosure may be implemented; and

[0049] FIG. 4 illustrates a flowchart of a method for maintaining a service continuity between network entities, in accordance with an embodiment of present disclosure.LIST OF REFERENCE NUMERALS100 - Network architecture102-1, 102-2. . . 102-N - User Equipment104-1, 104-2... 104-N - Users106 - System108 - Network110 - Receiving Unit112 - Memory114 - Interfacing Unit116 - Processing Unit118 - Database(s)120 - Communication Module122 - Response Determination Module124- Error Handling Module126 - Policy Evaluation Module128 - Sequence Diagram130 - Session Management Function (SMF)132 - Network Policy Function134 - Charging Control Function200 - Interaction System202 - Deep Packet Inspection (DPI) Function204 - Charging Function (CHF)206 - Binding Support Function (BSF)208 - Network Repository Function (NRF)210 - Access and Mobility Management Function (AMF)212 - Application Function (AF)214 - Online Charging System (OCS)216 - Packet Data Network Gateway (PGW)218 - Network Management System (NMS)220 - Subscriber Profile Repository (SPR)300 - Computer system310 - External storage device320 - Bus330 - Main memory340 - Read only memory350 - Mass storage device360 - Communication port(s)370 - Processor400 - MethodDETAILED DESCRIPTION

[0050] 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 notaddress 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The word “exemplary” and / or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and / or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive — in a manner similar to the term “comprising” as an open transition word — without precluding any additional or other elements.

[0055] 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” or “in some embodiments” 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.

[0056] 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.

[0057] Embodiments herein relate to a system and method for facilitating service continuity between network functions and charging control functions during network connectivity issues as well as during an outage or planned event at the charging control functions. The disclosed system and method use parameters that are defined in standard solutions and tweaks the parameters so that a customer service experience is not degraded across planned / unplanned outages.

[0058] Various embodiments of the present disclosure will be explained in detail with reference to FIGs. 1 to 4.

[0059] FIG. 1A illustrates an exemplary network architecture (100) in which or with which embodiments of the present disclosure may be implemented.

[0060] Referring to the FIG. 1 A, the network architecture (100) may include one or more computing devices or user equipment (102-1, 102-2. . . 102-N) that may be associated with one or more users (104-1, 104-2. . . 104-N) and a system (106) in an environment. In an embodiment, the one or more user equipment (102-1, 102- 2. . . 102-N) may be communicated to the system (106) through a network (108). A person of ordinary skill in the art will understand that the one or more user equipment (102-1, 102-2. .. 102-N) may be individually referred to as the user equipment (102) and collectively referred to as the user equipment (102). 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 equipment (102) are depicted in the FIG. 1A, however any number of the user equipment (102) may be included without departing from the scope of the ongoing description. Similarly. A person of ordinary skill in the art will understand that the one or more users (104-1, 104-2. . . 104-N) may be individually referred to as the user (104) and collectively referred to as the users (104).

[0061] In an embodiment, the user equipment (102) may include smart devices operating in a smart environment, for example, an Internet of Things (loT)system. In such an embodiment, the user equipment (102) may include, but 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, a smart security system, a smart home system, other devices for monitoring or interacting with or for the users (104) and / or entities, or any combination thereof. A person of ordinary skill in the art will appreciate that the user equipment (102) may include, but 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.

[0062] In an embodiment, the user equipment (102) may include, but 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 headmounted display computer device, a head-mounted camera device, a wristwatch computer device, and so on), a Global Positioning System (GPS) device, a laptop, a tablet computer, or another type of portable computer, a media playing device, a portable gaming system, and / or any other type of computer device with wireless communication capabilities, and the like.

[0063] In an embodiment, the user equipment (102) may include, but is not limited to, any electrical, electronic, electro -mechanical, or an equipment, or a combination of one or more of the above devices such as virtual reality (VR) devices, augmented reality (AR) devices, a general-purpose computer, a desktop, a personal digital assistant, a mainframe computer, or any other computing device. In another embodiment, the user equipment (102) 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 (104) or the entity such as a touchpad, a touch-enabled screen,an electronic pen, and the like. A person of ordinary skill in the art will appreciate that the user equipment (102) may not be restricted to the mentioned devices and various other devices may be used.

[0064] Referring to the FIG. 1A, the user equipment (102) may communicate with the system (106), for example, the system (106) for maintaining service continuity between a plurality of network entities. In an exemplary embodiment, the network entities may include, but are not limited to, Session Management Function (SMF) (130) (as shown in FIG. 1C), Packet Data Network Gateway (PGW) (216) (As shown in FIG. 2), Policy Control Function (PCF), Policy and Charging Rule Function (PCRF), Charging Function (CHF) (204) (As shown in FIG. 2), Online Charging System (OCS) (214) (As shown in FIG. 2), and so forth. Embodiments of the present invention are intended to include or otherwise cover any type of network entities, including known related art and / or later developed network entities.

[0065] In an embodiment, the system (106) may be configured to manage spending limit control (SLC) in a telecommunication network. The system (106) may include error handling and revalidation mechanisms, where a network policy function (132) (as shown in FIG. 1C) may install a Sy error rule and reattempt SLC subscription based on received session management (SM) policy control update (CCR-U) messages. This ensures continuous service delivery to subscribers during network issues or outages at a charging control function (134) (as shown in the FIG. 1C). In an embodiment, the network policy function (132) may include, but is not limited to, the PCF, the PCRF, and so forth. Similarly, in an exemplary embodiment, the charging control function (134) may be, but not limited to, the CHF (204), the OCS (214), and so forth.

[0066] In an embodiment, the network (108) may include at least one of a 5G network, 6G network, or the like. The network (108) may enable the user equipment (102) to communicate with other devices in the network architecture (100) and / or with the system (106). The network (108) may include a wireless cardor some other transceiver connection to facilitate this communication. In another embodiment, the network (108) 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, a Public Switched Telephone Network (PSTN), or the like.

[0067] Although the FIG. 1A shows exemplary components of the network architecture (100); however, in other embodiments, the network architecture (100) may include fewer components, different components, differently arranged components, or additional functional components than depicted in the FIG. 1A. 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).

[0068] FIG. IB illustrates an exemplary block diagram of the system (106), in accordance with an embodiment of the present disclosure.

[0069] In an embodiment, the system (106) may include a receiving unit (110), a memory (112), an interfacing unit (114), a processing unit (116) and a database (118). In an embodiment, the processing unit (116) may include a communication module (120), a response determination module (122), an error handling module (124), and a policy evaluation module (126).

[0070] In an embodiment, the receiving unit (110) may be configured to enable the network policy function (132) to receive one or more policy initiation messages from the SMF (130) (as shown in the FIG. 1C). The network policy function (132) may receive the policy initiation messages from the SMF (130) via a communication interface. The communication interface may be, but not limited to, N7 interface, S9 interface, and so forth. As used herein, the term “N7 interface” may refer to a standardized communication interface in 5G networks that connects the SMF (130) to the network policy function (132). Also, as used herein, the term“S9 interface” may refer to a standardized communication interface in the 5G networks that facilitates communication between the SMF (130) and the network policy function (132) to manage and enforce policy decisions related to subscriber sessions and charging rules. In an embodiment, the one or more policy initiation messages may include SM policy control create (CCR-I) message. In an exemplary embodiment, the SMF (130) may send the SM policy control create message to the network policy function (132) (as shown in the FIG. 1C) upon receiving a session initiation request from the user equipment (102) (as shown in the FIG. 1A). In an embodiment, the PGW (216) (as shown in FIG. 2) may be used in place of the SMF (130) for transmitting the SM policy control create (CCR-I) message to the network policy function (132).

[0071] The memory (112) may be configured to store computer-readable instructions or routines in a non-transitory computer readable storage medium. In an aspect, the memory (112) may be configured to store program instructions that may be executed to perform tasks associated with the system (106). The memory (112) may include any non-transitory storage device including, for example, but not limited to, a volatile memory such as a Random-Access Memory (RAM), or a nonvolatile memory such as an Erasable Programmable Read Only Memory (EPROM), a flash memory, and the like. Embodiments of the present invention are intended to include or otherwise type of the memory (112) including known related art and / or later developed technologies.

[0072] In an embodiment, the interfacing unit (114) may comprise a variety of interfaces, for example, interfaces for data input and output devices (VO), storage devices, and the like. The interfacing unit (114) may facilitate communication through the system (106). The interfacing unit (114) may also provide a communication pathway for various other units / modules of the system (106).

[0073] In an embodiment, the database (118) may offer functionality to manage, capture, store, and retrieve data. In an embodiment, the database (118) is configured to serve as a centralized repository for storing subscriber information.The database (118) is designed to interact seamlessly with other components of the system (106), such as the communication module (120), the response determination module (122), the error handling module (124), and the policy evaluation module (126), to support the functionality of the system (106) effectively. The database (118) may store the data that may be either stored or generated as a result of functionalities implemented by any of the components of the processing unit (116). In an embodiment, the database (118) may be separate from the system (106).

[0074] The modules are controlled by the processing unit (116), which executes the computer-readable instructions retrieved from the memory (112). The processing unit (116) further interacts with the interfacing unit (114) to facilitate user interaction and to provide options for managing and configuring the system (106). The processing unit (116) may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and / or any devices that process data based on operational instructions.

[0075] In an embodiment, the communication module (120) may be configured to receive one or more policy initiation messages from the receiving unit (HO).

[0076] In an embodiment, the communication module (120) may be configured to communicate with the charging control function (134) (as shown in FIG. 1C) by the network policy function (132) by sending a first set of subscribe messages based on the received policy initiation messages. In an embodiment, the network policy function (132) may be communicated with the charging control function (134) via the communication interface. In a preferred embodiment, the communication interface may be Sy interface. As used herein, the term “Sy interface” may refer to the standardized communication interface used in telecommunication networks that manages and controls spending limits and related policies for subscribers in real time. In an embodiment, the first set of subscribe messages may be an initial spending limit control (SLC) subscribe message. Inanother embodiment, the first set of subscribe messages may be an initial Spending Limit request (SLR) message. In an exemplary embodiment, the first set of subscribe messages may include a single subscribe message or multiple subscribe messages.

[0077] Further, in an embodiment, the response determination module (122) may be configured to enable the network policy function (132) to receive a return message from the charging control function (134). The return message may be received from the charging control function (134) in response to the corresponding first set of subscribe messages.

[0078] In an embodiment, the response determination module (122) may be configured to determine a type of the return message received by the network policy function (132) from the charging control function (134). The return message may be one of, a success message or an error message. In an embodiment, the network policy function (132) may examine the return message for a specific field that indicates the type of the return message. The specific field may be a result code indicating the success message or the error message. For example, the network policy function (132) checks the result code in the received return message. If the result code is equal to 2001, then the return message indicates the success message and if the result code is equal to 3002, then the return message indicates the error message.

[0079] The response determination module (122) may be configured to generate a revalidation signal when the received return message is determined as the error message. In an exemplary embodiment, the charging control function (134) may transmit the error message to the network policy function (132) during outage or network issues at the charging control function (134). In an exemplary embodiment, the error message may be provided in form of timeout or an error code (e.g., 3002 indicating unable to deliver, 5012 indicating diameter unable to comply, 404 indicating not found, and so forth). The response determination module (122)may be configured to transmit the generated revalidation signal to the error handling module (124).

[0080] In another embodiment, the response determination module (122) may be configured to generate a policy evaluation signal, when the received return message is determined as the success message. In an exemplary embodiment, the success message includes a policy counter information. In an exemplary embodiment, the policy counter information may be policy counter IDs. The response determination module (122) may be configured to transmit the generated policy evaluation signal to the policy evaluation module (126).

[0081] In an embodiment, the error handling module (124) may be configured to transmit a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) based on the received revalidation signal. In an embodiment, the first set of response messages and the revalidation timer may be transmitted to the SMF (130) via the communication interface such as, but not limited to, N7 interface, and so forth. In an embodiment, the N7 interface may use a diameter protocol that may be scalable and extensible protocol used for authentication, authorization and accounting (AAA). The first set of response message may be an SM policy control create response (CCA- I) message. The first set of response messages may include a single response message, or multiple response messages. In an embodiment, the response messages may depend on the first set of subscribe messages transmitted to the charging control function (134). In an embodiment, the first set of subscribe messages may be sent by the network policy function (132) to the charging control function (134) in order to initiate SLCs for a subscriber session and the first set of response messages may be sent by the charging control function (134) to the network policy function (132) in response to the initial SLC subscribe message.

[0082] In an embodiment, the first set of response messages may include at least one error rule that may be installed by the network policy function (132). In an exemplary embodiment, the error rule may be a Sy error rule. As used herein,the term “Sy error rule” may refer to a policy mechanism implemented by the network policy function (132) to handle error scenarios when attempting to communicate with the charging control function (134). Also, as used herein, the revalidation timer may be a specific duration set by the network policy function (132) during which the SMF (130) waits before reattempting a previously failed operation. As an example, the network policy function (132) may install the error rule and include the revalidation timer of a predefined time interval in the first set of response messages for transmitting to the SMF (130).

[0083] In an embodiment, the error handling module (124) may be configured to enable the SMF (130) to initiate the revalidation timer as specified by the network policy function (132). In an exemplary embodiment, during a revalidation period, a service may be provided to a subscriber with restricted policies as specified in the error rule. The error handling module (124) may be configured to enable the SMF (130) to transmit one or more policy update messages to the network policy function (132) upon expiration of the revalidation timer. In an exemplary embodiment, the policy update messages may be transmitted by the SMF (130) for reattempting a SLC subscription process. In an exemplary embodiment, the policy update messages may include SM policy control update message or Credit Control Request-Update (CCR-U) message.

[0084] In an embodiment, the error handling module (124) may be configured to check stored session information associated with the policy initiation messages by the network policy function (132) to determine that the previous SLC subscription attempt was unsuccessful. Based on the determination, the error handling module (124) may be configured to send a second set of subscribe messages by the network policy function (132) to the charging control function (134). In an exemplary embodiment, the second set of subscribe messages may include an updated Spending Limit Control (SLC) subscribe message. In an exemplary embodiment, the second set of subscribe messages may include a single subscribe message or multiple subscribe messages.

[0085] Further, in an embodiment, the error handling module (124) may be configured to enable the network policy function (132) to receive the return message in response to the second set of subscribe messages from the charging control function (134). The error handling module (124) may be configured to transmit the received return message to the response determination module (122).

[0086] In an embodiment, the response determination module (122) may be configured to determine the type of the return message received from the charging control function (134) in response to the second set of subscribe messages. The response determination module (122) may be configured to generate the revalidation signal when the received return message is determined as the error message and may transmit the generated revalidation signal to the error handling module (124) for installing the error rule again. In an embodiment, the second set of subscribe messages may be sent by the network policy function (132) to the charging control function (134) in order to update the SLCs for the subscriber session and the return message may be sent by the charging control function (134) to the network policy function (132) in response to the update SLC subscribe message.

[0087] In another embodiment, the response determination module (122) may be configured to generate the policy evaluation signal when the received return message is determined as the success message. In an embodiment, the success message includes updated policy counter information such as, new policy counter IDs (PCIDs). The response determination module (122) may be configured to transmit the generated policy evaluation signal to the policy evaluation module (126). As used herein, the policy counter information may be metrics used to track various aspects of the subscriber sessions such as, data usage, session duration, service interactions, and so forth. The policy counter information may be used by the network policy function (132) to monitor and manage how network resources are allocated and charged.

[0088] The policy evaluation module (126) may be configured to evaluate policy and charging control (PCC) rules by the network policy function (132) based on the received policy evaluation signal. In an embodiment, the policy evaluation module (126) may be configured to evaluate the PCC rules based on the received updated policy counter information when the success message is received in response to the second set of subscribe messages.

[0089] In an embodiment, the network policy function (132) may evaluate the PCC rules to determine whether the PCC rules need to be updated or not to ensure optimal service delivery and resource management. In an embodiment, the evaluation of the PCC rules may be performed by considering various factors such as, but not limited to, subscriber profiles, network conditions, any real time data related to the policy counters and the spending limits that may be received from the charging control function (134). In an embodiment, the PCC rules may be configured by network operators and may include policies related to QoS data usage limits, priority handling, charging rates, fair usage policies, and so forth. Based on the evaluated result, the network policy function (132) may update the PCC rules that are required to be updated using the updated policy counter information and the stored session information associated with the policy initiation messages. Further, the policy evaluation module (126) may be configured to transmit the updated PCC rules from the network policy function (132) to the SMF (130).

[0090] Although the FIG. IB shows an exemplary block diagram of the system (106); however, in other embodiments, the system (106) may include fewer components, different components, differently arranged components, or additional functional components than depicted in the FIG. IB. Additionally, or alternatively, one or more components of the system (106) may perform functions described as being performed by one or more other components of the system (106).

[0091] FIG. 1C illustrates a sequence diagram (128) depicting an errorhandling process for maintaining the service continuity between the network entities in accordance with an embodiment of the present disclosure.

[0092] In an embodiment, the sequence diagram (128) represents an interaction between the SMF (130), the network policy function (132), and the charging control function (134).

[0093] Initially, the SMF (130) transmits the at least one of the SM policy control create (CCR-I) messages to the network policy function (132) at step (136). Further, the network policy function (132) sends the SLC subscribe message to the charging control function (134) at step (138). In an event of the network issue or error, the charging control function (134) returns the error message to the network policy function (132).

[0094] Upon receiving the error message, the network policy function (132) installs the Sy Error Rule and sets the revalidation timer in the SM policy control create response (CCA- I) message and sends back the SM policy control create response message to the SMF (130) at step (140). The SMF (130) starts the revalidation timer and provides limited service based on the Sy Error Rule. When the revalidation timer expires, the SMF (130) sends the SM policy control update (CCR-U) message to the network policy function (132) at step (142).

[0095] The network policy function (132) checks the stored session information and sends the SLC update subscribe message to the charging control function (134) at step (144). Upon successfully processing the SLC update subscribe message, the charging control function (134) sends status and the updated policy counter information such as, the policy counter IDs (PCIDs) to the network policy function (132) at step (146). The network policy function (132) may evaluate and update the PCC rules based on the updated policy counter information and stored session information and transmit the updated PCC rules to the SMF (130) as the SM policy control update response at step (148).

[0096] FIG. 2 illustrates an exemplary diagram representing an interaction system (200) for enabling an interaction between the network entities through corresponding interfaces, in accordance with an embodiment of the present disclosure.

[0097] The network policy function (132) such as, the PCF and the PCRF may interact with various network entities through the interfaces to ensure seamless service delivery.

[0098] In an exemplary embodiment, the network policy function (132) may communicate with a Deep packet inspection (DPI) function (202) using a Sd interface. The DPI function (202) may be utilized to analyze network traffic at a granular level, enabling detailed traffic management and policy enforcement based on content and nature of data packets.

[0099] The network policy function (132) may communicate with the SMF (130) through N7 Interface. The network policy function (132) may provide the PCC rules to the SMF (130). In examples, the N7 interface is a function that facilitates communication between the SMF and PCF.

[0100] The network policy function (132) may communicate with the CHF (204) through N28 Interface. The network policy function (132) interacts with the CHF (204) to receive the updated policy counter information. In examples, the N28 interface facilitates communication between the SMF and the CHF. The N28 interface supports key charging and quota handling scenarios.

[0101] The network policy function (132) may communicate with a Binding Support Function (BSF) (206) through Nbsf Interface. The BSF (206) helps in binding application functions and their requests to the appropriate policy rules and sessions managed by the network policy function (132). In examples, the Nbsf interface is associated with the binding support function (BSF) providing packet data unit (PDU) session binding functionality.

[0102] The network policy function (132) may communicate with a Network Repository Function (NRF) (208) through a Nnrf Interface. The network policy function (132) queries the NRF (208) to discover other network functions and their capabilities, ensuring that it can interact with the appropriate functions to enforce the policies and manage sessions.

[0103] The network policy function (132) may communicate with an Access and Mobility Management Function (AMF) (210) through N15 Interface. The network policy function (132) provides the AMF (210) with policy decisions that affect user mobility, access management, and session continuity, ensuring consistent policy enforcement as the users (104) (as shown in the FIG. 1A) move across the network (108) (as shown in the FIG. 1A). In examples, the N15 interface connects the PCF and the AMF. In examples, in a non-roaming scenario, the N15 interface links the PCF and AMF directly. Otherwise, in a roaming scenario, the N15 connects the visited PCF (vPCF) in the visited network to the AMF in the home network. The N15 interface is configured to manage tasks related to policy control and access management, ensuring seamless communication for telecom services.

[0104] The network policy function (132) may communicate with an Application Function (AF) (212) through Rx Interface. The network policy function (132) receives application-level requests and requirements through the Rx interface, enabling it to apply appropriate QoS policies and resource allocations to support applications.

[0105] The network policy function (132) may communicate with the OCS (214) through Sy Interface. The network policy function (132) exchanges charging- related information with the OCS (214) to support real-time charging and apply the policies that affect how subscribers are billed for their usage. In examples, the Sy interface serves as a logical reference point within the packet core domain, situatedbetween the OCS and the PCRF. The Sy interface may be based on the Diameter protocol and allows the PCRF to obtain quota status from the OCS.

[0106] The network policy function (132) may communicate with the PGW (216) through Gx Interface. The network policy function (132) provides the PCC rules to the PGW (216), which enforces these rules for data sessions and managing the QoS. In examples, the Gx interface serves as a critical link between policy and charging enforcement function (PCEF) and the PCRF.

[0107] The network policy function (132) may communicate with a Network Management System (NMS) (218) and a Subscriber Profile Repository (SPR) (220). The network policy function (132) interacts with the NMS (218) for overall network management, monitoring, and configuration.

[0108] The network policy function (132) communicates with the SPR (220) to retrieve and update subscriber profile information, ensuring that the policy decisions are based on current subscriber information.

[0109] FIG. 3 illustrates an exemplary computer system (300) in which or with which embodiments of the present disclosure may be implemented. As shown in the FIG. 3, the computer system (300) may include an external storage device (310), a bus (320), a main memory (330), a read only memory (340), a mass storage device (350), a communication port (360), and a processor (370). A person skilled in the art will appreciate that the computer system (300) may include more than one processor (370) and the communication ports (360). The processor (370) may include various modules associated with embodiments of the present disclosure.

[0110] In an embodiment, the external storage device (310) may be any device that is commonly known in the art such as, but not limited to, a memory card, a memory stick, a solid-state drive, a hard disk drive (HDD), and so forth.

[0111] In an embodiment, the bus (320) may be communicatively coupled with the processor(s) (370) with the other memory, storage, and communicationblocks. The bus (320) may be, e.g., a Peripheral Component Interconnect (PCI) / PCI Extended (PCI-X) bus, a Small Computer System Interface (SCSI), a 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 (370) to the computer system (300).

[0112] In an embodiment, the main memory (330) may be a Random Access Memory (RAM), or any other dynamic storage device commonly known in the art. The Read-only memory (340) may be any static storage device(s) e.g., but not limited to, a Programmable Read Only Memory (PROM) chips for storing static information e.g., start-up or Basic Input / Output System (BIOS) instructions for the processor (370).

[0113] In an embodiment, the mass storage device (350) may be any current or future mass storage solution, which may be used to store information and / or instructions. Exemplary mass storage solutions include, but are not limited to, a Parallel Advanced Technology Attachment (PATA) or a 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).

[0114] Further, the communication port (360) may be any of an RS-232 port for use with a modem-based dialup connection, a 10 / 100 Ethernet port, a Gigabit or 10 Gigabit port using copper or fiber, a serial port, a parallel port, or other existing or future ports. The communication port (360) may be chosen depending on the network (108), such a Focal Area Network (FAN), Wide Area Network (WAN), or any network to which the computer system (300) connects.

[0115] Optionally, operator and administrative interfaces, e.g., a display, a keyboard, a joystick, and a cursor control device, may also be coupled to the bus (320) to support a direct operator interaction with the computer system (300). Otheroperator and administrative interfaces may be provided through network connections connected through the communication port (360). Components described above are meant only to exemplify various possibilities. In no way should the aforementioned exemplary computer system (300) limit the scope of the present disclosure.

[0116] FIG. 4 illustrates a flowchart of a method (400) for maintaining service continuity between a plurality of network entities, in accordance with an embodiment of present disclosure.

[0117] Step (402) includes a step of receiving one or more policy initiation messages from a session management function (SMF) (130) by a network policy function (132).

[0118] Step (404) includes a step of communicating by the network policy function (132) with a charging control function (134) by sending a first set of subscribe messages to the charging control function (134) based on the corresponding one or more policy initiation messages.

[0119] Step (406) includes a step of determining a type of return message received by the network policy function (132) in response to the corresponding first set of subscribe messages from the charging control function (134), wherein the return message comprises one of, a success message or an error message.

[0120] Step (408) includes a step of transmitting a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule.

[0121] Step (410) includes a step of sending a second set of subscribe messages by the network policy function (132) to the charging control function (134) based on one or more policy update messages received from the SMF (130) when the revalidation timer expires.

[0122] Step (412) includes a step of evaluating, by the network policy function (132), at least one policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function (134).

[0123] In an embodiment, the network policy function (132) is selected from a list of a Policy Control Function (PCF) or a Policy and Charging Rule Function (PCRF).

[0124] In some embodiments, the charging control function (134) is selected from a list of a charging function (CHF) (204) or an online charging system (OCS) (214).

[0125] In some embodiments, the one or more policy initiation messages includes a Session Management (SM) policy control create message.

[0126] In some embodiments, the first set of subscribe messages includes an initial Spending Limit Control (SLC) subscribe message.

[0127] In some embodiments, the first set of response messages includes a Session Management (SM) policy control create response message.

[0128] In some embodiments, the second set of subscriber messages includes an updated Spending Limit Control (SLC) subscribe message.

[0129] In some embodiments, the one or more policy update messages comprises a Session Management (SM) policy control update message.

[0130] In some embodiments, the success message includes at least one updated policy counter information.

[0131] In some embodiments, the at least one evaluated PCC rule is updated based on the at least one updated policy counter information and stored session information associated with the one or more policy initiation messages.

[0132] In some embodiments, the method (400) includes a step of transmitting the at least one updated PCC rule from the network policy function (132) to the SMF (130).

[0133] In an embodiment, the present disclosure discloses a user equipment (UE) communicatively coupled with a network. The coupling including a step of receiving, by the network, a connection request from the user equipment (UE). The coupling including a step of sending, by the network, an acknowledgment of the connection request to the UE. The coupling including a step of transmitting a plurality of signals in response to the connection request. The network is configured for implementing the method for maintaining service continuity between a plurality of network entities.

[0134] The present disclosure provides a significant technical advancement in the field of telecommunications network management, specifically addressing limitations found in existing solutions related to policy and charging control functions. Unlike conventional methods, the disclosed invention introduces an innovative approach to handle policy initiation and spending limit control between a Session Management Function (SMF) and a network policy function. By implementing an iterative revalidation mechanism upon timeout or error responses from a Charging Control Function, the invention improves network reliability and responsiveness. This approach optimizes resource allocation, enhances service quality, and ensures accurate billing through dynamic policy updates. As a result, network operators experience enhanced operational efficiency and subscriber satisfaction, achieving seamless service delivery and cost-effective network management.

[0135] While the foregoing describes various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the present disclosure is determined by the claims that follow. The present disclosure is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the present disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

[0136] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be implemented merely as illustrative of the disclosure and not as a limitation.ADVANTAGES OF THE PRESENT DISCLOSURE

[0137] The present disclosure provides a system and a method for providing service continuity during network connectivity issues between network policy functions such as a Policy Control Function (PCF) or a Policy Charging Rules Function (PCRF) and charging control functions such as a Charging Function (CHF) or an Online Charging System (OCS).

[0138] The present invention provides appropriate policy rules to a customer without any service interruption or need of customer to reconnect upon resolution of a network problem or a charging control function outage.

[0139] The present invention provides service continuity for cases where a charging control function is unavailable.

[0140] The present invention maintains a stable customer experience even in case of network outage of charging control functions or connectivity between the network policy functions and the charging control functions.

Claims

CLAIMS1. A method (400) for maintaining service continuity between a plurality of network entities, wherein the method (400) comprising steps of: receiving (402), by a receiving unit (110), one or more policy initiation messages from a session management function (SMF) (130) by a network policy function (132); communicating (404) by the network policy function (132) with a charging control function (134) by sending a first set of subscribe messages to the charging control function (134) based on the corresponding one or more policy initiation messages; determining (406) a type of return message received by the network policy function (132) in response to the corresponding first set of subscribe messages from the charging control function (134), wherein the return message comprises one of, a success message or an error message; transmitting (408) a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule; sending (410) a second set of subscribe messages by the network policy function (132) to the charging control function (134) based on one or more policy update messages received from the SMF (130) when the revalidation timer expires; and evaluating (412), by the network policy function (132), at least one policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function (134).

2. The method (400) as claimed in claim 1, wherein the network policy function (132) is selected from a list of a Policy Control Function (PCF) or a Policy and Charging Rule Function (PCRF).

3. The method (400) as claimed in claim 1, wherein the charging control function (134) is selected from a list of a charging function (CHF) (204) or an online charging system (OCS) (214).

4. The method (400) as claimed in claim 1, wherein the one or more policy initiation messages comprises a Session Management (SM) policy control create message.

5. The method (400) as claimed in claim 1, wherein the first set of subscribe messages comprises an initial Spending Limit Control (SLC) subscribe message.

6. The method (400) as claimed in claim 1, wherein the first set of response messages comprises a Session Management (SM) policy control create response message.

7. The method (400) as claimed in claim 1, wherein the second set of subscribe messages comprises an updated Spending Limit Control (SLC) subscribe message.

8. The method (400) as claimed in claim 1 , wherein the one or more policy update messages comprises a Session Management (SM) policy control update message.

9. The method (400) as claimed in claim 1, wherein the success message comprises at least one updated policy counter information.

10. The method (400) as claimed in claim 9, wherein the at least one evaluated PCC rule is updated based on the at least one updated policy counter information and stored session information associated with the one or more policy initiation messages.

11. The method (400) as claimed in claim 10, comprising a step of transmitting the at least one updated PCC rule from the network policy function (132) to the SMF (130).

12. A system (106) for maintaining service continuity between a plurality of network entities, wherein the system (106) comprising: a receiving unit (110) configured to receive one or more policy initiation messages from a session management function (SMF) (130) by a network policy function (132); a processing unit (116) configured to: communicate with a charging control function (134) by the network policy function (132) by sending a first set of subscribe messages based on the corresponding one or more policy initiation messages; determine a type of return message received by the network policy function (132) in response to the corresponding first set of subscribe messages from the charging control function (134), wherein the return message comprises one of, a success message or an error message; transmit a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule; send a second set of subscribe messages by the network policy function (132) to the charging control function (134) based on one or more policy update messages received from the SMF (130) when the revalidation timer expires; and evaluate at least one policy and charging control (PCC) rule by the network policy function (132) upon receiving the successmessage in response to the corresponding second set of subscribe messages from the charging control function (134).

13. The system (106) as claimed in claim 12, wherein the network policy function (132) is selected from a list of a Policy Control Function (PCF) or a Policy and Charging Rule Function (PCRF).

14. The system (106) as claimed in claim 12, wherein the charging control function (134) is selected from a list of a charging function (CHF) (204) or an online charging system (OCS) (214).

15. The system (106) as claimed in claim 12, wherein the one or more policy initiation messages comprises a Session Management (SM) policy control create message.

16. The system (106) as claimed in claim 12, wherein the first set of subscribe messages comprises an initial Spending Limit Control (SLC) subscribe message.

17. The system (106) as claimed in claim 12, wherein the first set of response messages comprises a Session Management (SM) policy control create response message.

18. The system (106) as claimed in claim 12, wherein the second set of subscribe messages comprises an updated Spending Limit Control (SLC) subscribe message.

19. The system (106) as claimed in claim 12, wherein the one or more policy update messages comprises a Session Management (SM) policy control update message.

20. The system (106) as claimed in claim 12, wherein the success message comprises at least one updated policy counter information.

21. The system (106) as claimed in claim 20, wherein the at least one evaluated PCC rule is updated based on the at least one updated policy counter information and stored session information associated with the one or more policy initiation messages.

22. The system (106) as claimed in claim 21, wherein the processing unit (116) is configured to transmit the at least one updated PCC rule from the network policy function (132) to the SMF (130).

23. A user equipment (102) communicatively coupled with a network (108), the coupling comprises steps of: receiving, by the network (108), a connection request from the user equipment (UE) (102); sending, by the network (108), an acknowledgment of the connection request to the UE (102); and transmitting a plurality of signals in response to the connection request, wherein the network (108) is configured for performing a method (400) for maintaining service continuity between a plurality of network entities as claimed in claim 1.

24. A computer program product comprising a non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform a method (400) for maintaining service continuity between a plurality of network entities, the method (400) comprising steps of: receiving (402) one or more policy initiation messages from a session management function (SMF) (130) by a network policy function (132); communicating (404) by the network policy function (132) with a charging control function (134) by sending a first set of subscribe messages to the charging control function (134) based on the corresponding one or more policy initiation messages;determining (406) a type of return message received by the network policy function (132) in response to the corresponding first set of subscribe messages from the charging control function (134), wherein the return message comprises one of, a success message or an error message; transmitting (408) a first set of response messages and a revalidation timer by the network policy function (132) to the SMF (130) upon determining the received return message as the error message, wherein the first set of response messages comprises at least one error rule; sending (410) a second set of subscribe messages by the network policy function (132) to the charging control function (134) based on one or more policy update messages received from the SMF (130) when the revalidation timer expires; and evaluating (412), by the network policy function (132), at least one policy and charging control (PCC) rule upon receiving the success message in response to the corresponding second set of subscribe messages from the charging control function (134)

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