Error causes for monitoring configuration in a communications network

Abstract

This disclosure provides a method for monitoring configuration in a communications network. The method comprises transmitting from a first network node to a third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure subscription request based on the indication; transmitting from the fourth network node to the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event; and transmitting from the third network node to the first network node a response message including an HTTP error code and the at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain.

Description

[0001] ERROR CAUSES FOR MONITORING CONFIGURATION IN A COMMUNICATIONS

[0002] NETWORK

[0003] TECHNICAL FIELD

[0004] The present invention generally relates to error handling in a communications network, and particularly, the invention relates to identifying and communicating errors associated with monitoring configurations in Fifth Generation Core (5GC) and Evolved Packet Core (EPC) networks.

[0005] BACKGROUND

[0006] In Fifth Generation Core (5GC) networks, external applications can subscribe to network events through the Network Exposure Function (NEF). The NEF facilitates this by subscribing to the Unified Data Management (UDM) using the Nudm_EventExposure_Subscribe service, allowing it to request notifications for one or multiple events.

[0007] Where both 4G and 5G networks coexist (dual 4G / 5G networks), and common exposure is supported, the UDM may forward the Event Exposure (EE) Subscription request to the Home Subscriber Server (HSS) using the Nhss_EventExposure_Subscribe service. This enables the monitoring of events within the Evolved Packet Core (EPC) of the 4G network.

[0008] When the NEF requests monitoring of multiple events, the UDM is responsible for creating the corresponding EE subscriptions. After processing the request, the UDM returns a result indicating success, partial success, or rejection. This response allows the NEF to take appropriate actions toward the Application Functions (AFs) that initiated the EE subscription request.

[0009] Figure 2 illustrates the subscription process for monitoring configurations and the various response cases when multiple monitoring configuration reports are requested from the UDM by a combined Service Capability Exposure Function and Network Exposure Function (SCEF+NEF) in a dual core network. The process flows are based on the Nudm_EventExposure and Nhss_EventExposure specifications defined by the 3rd Generation Partnership Project (3GPP).

[0010] In step 1 , the AF request NEF to Create MonitoringEventSubscription including multiple monitoring types (addnMonTypes).

[0011] In step 2, the combined SCEF+NEF in a dual core network requests EE Subscribe to UDM including multiple monitoring events (in monitoringConfiguration) and indicating that the Subscription request applies as well to EPC (with epcAppliedlnd=true).

[0012] In step 3, since the request applies to EPC as well, then UDM send EE Subscribe to HSS.

[0013] In a success case, in steps 4,5,6, in the case of successful response, all the requested monitoring configuration reports have been successfully created in UDM and in HSS. The successful create response from UDM and HSS includes a representation of the created subscription as confirmation of the accepted values.

[0014] In a partial success case, in step 4, in case of partial failure in EPC, not all requested events are successfully created in HSS, then in addition to the created monitoring configuration reports with the accepted values, the failed event configuration is included in “failedMonitoringConfigEpc” with additional information about the failed monitoring events and the cause for the failure.

[0015] In step 5, in case of partial failure in 5G, not all requested events are successfully created in UDM, then in addition to the created monitoring configuration reports with the accepted values, the failed event configuration is included in “failedMonitoringConfig” with additional information about the failed monitoring events and the cause for the failure.

[0016] In addition, if there is partial failure in EPC (step 4), “failedMonitoringConfigEpc” is as well included.

[0017] In step 6, in case of partial failure, either in EPC (step 4) or 5G (step 5) or in both, not all requested events are successfully created, then NEF returns success indicating the created “monitoringEventSubscription”.

[0018] A problematic aspect related to the partial success case is that with the current SCEF+NEF response to AS / SCS / AF (Application Server / Service Capability Server / Application Function) specified in 3GPP (step 6), is that only information about the accepted events is returned, meaning that in case there are different error reasons per monitoring configuration, AS / SCS / AF will not know which are the reasons why some of the events where not successfully created.

[0019] A further problematic aspect related to the error case is that in steps 4,5,6, in the case of error, meaning none of the requested monitoring configuration reports have been accepted, one single error is returned with a single cause for the failure.

[0020] A further problematic aspect is that with the current UDM (to SCEF+NEF) and HSS (to UDM) responses specified in 3GPP, is that it is only possible to indicate the reason of the failure for a single monitoring configuration / event, meaning that in case there are different error reasons per monitoring configuration / event, UDM and HSS shall randomly indicate one error for all the monitoring configurations / events. Therefore, the information provided to SCEF+NEF and AS / SCS / AF is not accurate, and it does not allow the AS / SCS / AF to properly react against errors for the different monitoring configurations / events.

[0021] For example, UDM / HSS may choose following errors:

[0022] - 501 UNSUPPORTED_MONITORING_EVENT_TYPE: this may be interpreted by AS / SCS / AF as none of the events are supported by UDM / HSS, but in reality, each monitoring configuration / event may have been discarded for different reasons.

[0023] - 403 MONITORING_NOT_ALLOWED: this may be interpreted by AS / SCS / AF as ALL the requested monitoring configurations / events are not allowed for the user, which may not be true, since as commented there may be a different error reason for each monitoring configuration / event.

[0024] - 400 INCORRECT_OPTIONAL_IE: this may be interpreted by AS / SCS / AF as the message is incorrect for all the events which again may not be true.

[0025] These errors are broad and do not provide details to take optimal actions to resolve them.

[0026] The same problem applies when there is only 5G network, i.e., AF sends an EE Subscription request to NEF and this one to UDM. SUMMARY

[0027] The invention is set out in the appended set of claims.

[0028] An object of the invention is to enable a mechanism in a 5G or 4G / 5G dual core network for an EE subscription that applies to multiple monitoring events, to provide an error cause with an error information per each monitoring event (instead of just one single error cause for the whole request) when same failure cause does not apply to all the monitoring events.

[0029] An aspect of the invention relates to a method performed by a first network node for monitoring configuration in a communications network, the method comprising transmitting from the first network node to a third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; and transmitting from the third network node to the first network node a response message including an HTTP error code and at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain. In some embodiments, further comprising receiving at the first network node from a second network node a MonitoringEventSubscription request including two or more monitoring events; and transmitting from the first network node to the second network node a response message including at least one cause of monitoring configuration failure for at least one monitoring event. In some embodiments, the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute. In some embodiments, further comprising receiving from the third network node at the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause. In some embodiments, further comprising aggregating at the first network node two or more error causes received from the third network node; and transmitting from the first network node to the second network node a response message including the aggregated causes. In some embodiments further comprising transmitting from the first network node to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure. In some embodiments, further comprising receiving from the third network node at the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains. In some embodiments, the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM.

[0030] An aspect of the invention relates to a method performed by a third network node for monitoring configuration in a communications network, the method comprising receiving from a first network node at the third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure subscription request based on the indication; receiving from the fourth network node at the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event; transmitting from the third network node to the first network node a response message including an HTTP error code and the at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain. In some embodiments, the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute. In some embodiments, further comprising determining at the third network node at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported. In some embodiments, further comprising aggregating at the third network node two or more error causes received from the fourth network node; and transmitting from the third network node to the first network node a response message including the aggregated errors and causes. In some embodiments, further comprising transmitting from the third network node to the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause. In some embodiments, further comprising transmitting from the third network node to the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains. In some embodiments, the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

[0031] An aspect of the invention relates to a method performed by a fourth network node for monitoring configuration in a communications network, the method comprising receiving from a third network node at the fourth network node an Event Exposure subscription request based on an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the fourth network node to the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event. In some embodiments, the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute. In some embodiments, the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

[0032] Other aspects of the invention relate to mobile network nodes, particularly a first network node (109, 700), a third network node (112, 800), a second network node (113), a fourth network node (116, 900) configured to perform the respective methods as described herein. Other aspects of the invention relate to computer program and computer program products.

[0033] In some embodiments, the first network node is a Network Exposure Function (NEF). In some embodiments, the third network node is a User Data Management (UDM). In some embodiments, the second network node is an Application Function (AF). In some embodiments, the fourth network node is a Home Subscriber Server (HSS).

[0034] Advantageously, the solution disclosed herein enables in a 5G or dual 4G / 5G network that the SCEF+NEF, NEF and AS / SCF / AF are provided with accurate information to take appropriate actions based on error cause for each event or for the whole request. That is, “UNSPECIFIED” Cause, indicates error information is provided for each event configuration, and then existing errors shall apply only when the same error cause applies for all the event configurations. For example:

[0035] 501 UNSUPPORTED_MONITORING_EVENT_TYPE: will be correctly interpreted as none of the events are supported by UDM / HSS;

[0036] 403 MONITORING_NOT_ALLOWED: will be correctly interpreted as ALL the requested events are not allowed for the user; or

[0037] 400 INCORRECT_OPTIONAL_IE: will be correctly interpreted as the message is incorrect for all the events. Further advantageously, the solution disclosed herein enables that the SCEF+NEF and NEF has enough information about the result of the monitoring configuration in EPC domain to decide whether a fallback to diameter is required or not.

[0038] Further advantageously, the solution disclosed herein enables that the AS / SCS / AF can make proper troubleshooting actions using valid and accurate error information provided by HSS / UDM via SCEF+NEF or NEF.

[0039] Additional objectives, features and advantages of the concepts disclosed herein will be apparent from the following description, claims and drawings, or may be learned by practice of the described technologies and concepts as set forth herein.

[0040] BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to best describe the manner in which the disclosed concepts may be implemented, as well as define other objects, advantages and features of the disclosure, a more particular description is provided below and is illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the invention and are not therefore to be considered to be limiting in scope, the examples will be described and explained with additional specificity and detail through the use of the accompanying drawings.

[0042] Figure 1 illustrates an example networked system in accordance with particular embodiments of the solution described herein.

[0043] Figure 2 illustrates an example signaling diagram showing a procedure according to particular embodiments of the solution described herein.

[0044] Figure 3 illustrates an example signaling diagram showing a procedure according to particular embodiments of the solution described herein.

[0045] Figure 4 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein.

[0046] Figure 5 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein. Figure 6 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein.

[0047] Figure 7 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0048] Figure 8 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0049] Figure 9 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0050] Figure 10 illustrates an example block diagram of a virtualized environment.

[0051] DETAILED DESCRIPTION

[0052] The invention will now be described in detail hereinafter with reference to the accompanying drawings, in which examples of embodiments or implementations of the invention are shown. The invention may, however, be embodied or implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present invention to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present / used in another embodiment. These embodiments of the disclosed subject matter are presented as teaching examples and are not to be construed as limiting the scope of the disclosed subject matter. For example, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter.

[0053] The example embodiments described herein arise in the context of a telecommunications network, including but not limited to a telecommunications network that conforms to and / or otherwise incorporates aspects of a fifth generation (5G) architecture. Figure 1 is an example networked system 100 in accordance with example embodiments of the present disclosure. Figure 1 specifically illustrates User Equipment (UE) 101 , which may be in communication with a (Radio) Access Network (RAN) 102 and Access and Mobility Management Function (AMF) 106 and User Plane Function (UPF) 103. The AMF 106 may, in turn, be in communication with core network services including Session Management Function (SMF) 107 and Policy Control Function (PCF) 111. The core network services may also be in communication with an Application Server / Application Function (AS / AF) 113. Other networked services also include Network Slice Selection Function (NSSF) 108, Authentication Server Function (AUSF) 105, User Data Management (UDM) 112, Network Exposure Function (NEF) 109, Network Repository Function (NRF) 110, Unified Data Repository (UDR) 114, Network Data Analytics Function (NWDAF) 115, and Data Network (DN) 104. In some example implementations of embodiments of the present disclosure, each one of the entities in the networked system 100 are considered to be a Network Function (NF). One or more additional instances of the NFs may be incorporated into the networked system.

[0054] The solution described herein aims to enable a mechanism in a 5G or 4G / 5G dual core network for an EE subscription that applies to multiple monitoring events, to provide error cause with error information per each monitoring event (instead of just one single error cause for the whole request) when same failure cause does not apply to all the monitoring events.

[0055] This disclosure provides a method for monitoring configuration in a communications network, specifically addressing error handling when multiple monitoring events are involved across both 5G Core (5GC) and Evolved Packet Core (EPC) domains. The method includes:

[0056] Transmitting from a first network node (e.g., Network Exposure Function, NEF) to a third network node (e.g., Unified Data Management, UDM) an Event Exposure (EE) subscription request that indicates the request applies to both EPC and 5GC for two or more monitoring events.

[0057] The third network node forwards this request to a fourth network node (e.g., Home Subscriber Server, HSS) based on the indication that EPC is also to be applied.

[0058] If monitoring configuration failures occur for any of the events, the fourth network node returns a response message to the third network node. This response includes an HTTP error code and specific causes of failure for each affected monitoring event.

[0059] The third network node aggregates any errors received and transmits a response back to the first network node, including the HTTP error code and detailed causes of failure for each event. Importantly, the response message specifies the domain (either EPC or 5GC) related to each monitoring configuration failure. The first network node then communicates these details to a second network node (e.g., Application Function, AF), enabling precise troubleshooting and corrective actions.

[0060] By providing detailed error causes for each monitoring event and specifying the affected domain, this method enhances error transparency and allows network functions and applications to respond appropriately to configuration issues in dual-core network environments.

[0061] The provided method for monitoring configuration in a communications network comprises transmitting from a first network node to a third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure subscription request based on the indication; transmitting from the fourth network node to the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event; transmitting from the third network node to the first network node a response message including an HTTP error code and the at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain. In some embodiments, further comprising receiving at the first network node from a second network node a MonitoringEventSubscription request including two or more monitoring events; and transmitting from the first network node to the second network node a response message including at least one cause of monitoring configuration failure for at least one monitoring event. In some embodiments, the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute. In some embodiments, further comprising determining at the third network node at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported. In some embodiments, further comprising aggregating at the third network node two or more error causes received from the fourth network node; and transmitting from the third network node to the first network node a response message including the aggregated errors and causes. In some embodiments, further comprising transmitting from the third network node to the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause. In some embodiments further comprising aggregating at the first network node two or more error causes received from the third network node; and transmitting from the first network node to the second network node a response message including the aggregated causes. In some embodiments, further comprising transmitting from the first network node to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure. In some embodiments, further comprising transmitting from the third network node to the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains. In some embodiments further comprising initiating at the second network node troubleshooting actions upon receiving the error causes from the first network node. In some embodiments, the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

[0062] This disclosure further provides a method for monitoring configuration in a communications network. The method comprises receiving at a first network node from a second network node a MonitoringEventSubscription request including two or more monitoring types; transmitting from the first network node to a third network node a subscription request, including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for the two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure Subscription request based on the indication; transmitting from the fourth network node to the third network node a response message including an HTTP Error Code including at least one cause of monitoring configuration failure for at least one monitoring event, particularly wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute; transmitting from the third network node to the first network node a response message including an HTTP Error Code including the at least one cause of monitoring configuration failure for at least one monitoring event; and transmitting from the first network node to the second network node a response message including the at least one cause of monitoring configuration failure for at least one monitoring event. In some embodiments, the method further comprises determining at the third network node at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported. In some embodiments, the method further comprises aggregating at the third network node two or more error causes received from the fourth network node; and transmitting from the third network node to the first network node a response message including the aggregated errors and causes. In some embodiments, the method further comprises transmitting from the third network node to the first network node an failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event and per domain, particularly including a UNSPECIFIED cause. In some embodiments, the method further comprises aggregating at the first network node two or more error causes received from the third network node; and transmitting from the first network node to the second network node a response message including the aggregated causes. In some embodiments, the method further comprises transmitting from the first network node to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure. In some embodiments, the method further comprises transmitting from the third network node to the first network node an HTTP Error Code including an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains. In some embodiments, the method further comprises initiating at the second network node troubleshooting actions upon receiving the error causes from the first network node. In some embodiments, the failedEventSubscriptions includes the domain, either EPC or 5G, related to the failed event. In some embodiments, the first network node is a NEF, the second network node is an AF, the third network node is an UDM, the fourth network node is an HSS.

[0063] This disclosure also provides mobile network nodes, particularly a first network node (109, 700), a third network node (112, 800), a second network node (113), a fourth network node (116, 900) configured to perform the respective methods as described herein. In some embodiments, the first network node is a Network Exposure Function (NEF) 109. In some embodiments, the third network node is a User Data Management (UDM) 112. In some embodiments, the second network node is an Application Function (AF) 113. In some embodiments, the fourth network node is a Home Subscriber Server (HSS) 116.

[0064] This disclosure also provides the corresponding computer program and computer program products comprising code, for example in the form of a computer program, that when run on processing circuitry of the mobile network nodes causes the mobile network nodes to perform the disclosed methods.

[0065] The solution and the features comprised therein are further described in what follows.

[0066] The solution disclosed herein proposes that in case UDM (or HSS for common exposure) receives an EE subscription request including multiple monitoring configuration / event reports, in case none of the requested events have been successfully configured in UDM (or for common exposure either in UDM or HSS), the HTTP Response returned includes a UNSPECIFIED_ERROR Cause, and additional information for each failed monitoring event providing the cause for the failure per event. With that information, the NEF (SCEF+NEF) and the AS / SCF / AF can take proper actions to solve each error and UDM / HSS behavior is clarified.

[0067] Advantageously, the solution disclosed herein enables in a 5G or dual 4G / 5G network that the SCEF+NEF, NEF and AS / SCF / AF are provided with accurate information to take appropriate actions based on error cause for each event or for the whole request. That is, “UNSPECIFIED” Cause, indicates error information is provided for each event configuration, and then existing errors shall apply only when the same error cause applies for all the event configurations. For example:

[0068] 501 UNSUPPORTED_MONITORING_EVENT_TYPE: will be correctly interpreted as none of the events are supported by UDM / HSS;

[0069] 403 MONITORING_NOT_ALLOWED: will be correctly interpreted as ALL the requested events are not allowed for the user; or

[0070] 400 INCORRECT_OPTIONAL_IE: will be correctly interpreted as the message is incorrect for all the events.

[0071] Further advantageously, the solution disclosed herein enables that the SCEF+NEF and NEF has enough information about the result of the monitoring configuration in EPC domain to decide whether a fallback to diameter is required or not.

[0072] Further advantageously, the solution disclosed herein enables that the AS / SCS / AF can make proper troubleshooting actions using valid and accurate error information provided by HSS / UDM via SCEF+NEF or NEF.

[0073] Hereinafter, drawings showing examples of embodiments of the solution are described in detail.

[0074] Figure 2 illustrates a procedure performed by a AS / SCS / AF (Application Server, Service Capability Server, or Application Function), SCEF+NEF (Service Capability Exposure Function and Network Exposure Function), UDM (Unified Data Management), and HSS (Home Subscriber Server). The steps of the procedure are the following:

[0075] Step 1 : The AS / SCS / AF transmits to the SCEF+NEF a Nnef 3gpp-monitoring-event request, which includes the parameters monitoringType and addMonTypes. This message initiates the monitoring event subscription process by requesting the type of monitoring and any additional monitoring types. Step 2: The SCEF+NEF transmits to the UDM a Nudm_EE_Subscribe request, including the parameters monitoringConfigurations and epcAppliedlnd=true. This indicates that the monitoring configurations are set and that EPC (Evolved Packet Core) is applied.

[0076] Step 3: If common 4G / 5G exposure is supported, the UDM creates related EPC EE (External Exposure) subscriptions in the EPC via the HSS. In this step, the UDM transmits to the HSS a Nhss_EE_Subscribe request.

[0077] Success Case:

[0078] Step 4: In the success case, the HSS responds to the UDM with a Nhss_EE_Subscribe response, which includes OK_CreatedEpcSubscription. This indicates that the EPC subscription has been successfully created.

[0079] Step 5: The UDM transmits to the SCEF+NEF a Nudm_EE_Subscribe response, which includes the CreatedEeSubscription. This confirms that the EE subscription has been successfully created.

[0080] Step 6: The SCEF+NEF transmits to the AS / SCS / AF a Nnef 3gpp-monitoring-event response, including the MonitoringEventSubscription. This final message confirms that the monitoring event subscription has been successfully completed.

[0081] Partial Success Case:

[0082] Step 4: In the partial success case, the HSS responds to the UDM with a Nhss_EE_Subscribe response, which includes the CreatedEpcSubscription along with optional failedMonitoringConfigs and failedMonitoringConfigsEpc. This indicates that while some subscriptions were successfully created, others failed.

[0083] Step 5: The UDM transmits to the SCEF+NEF a Nudm_EE_Subscribe response, including the CreatedEeSubscription, and also optionally includes failedMonitoringConfigs and failedMonitoringConfigsEpc. This message communicates that some monitoring configurations were successfully created, while others were not.

[0084] Step 6: The SCEF+NEF transmits to the AS / SCS / AF a Nnef 3gpp-monitoring-event response, including the MonitoringEventSubscription. This message confirms that the subscription was partially successful, with some configurations applied and others failing.

[0085] Error Case: Step 4: In the error case, the HSS responds to the UDM with a Nhss_EE_Subscribe response, which includes an HTTP error code and problemDetails. This indicates that the subscription request encountered an error.

[0086] Step 5: The UDM transmits to the SCEF+NEF a Nudm_EE_Subscribe response, which includes an HTTP error code and problemDetails. This confirms that the request failed due to an error.

[0087] Step 6: The SCEF+NEF transmits to the AS / SCS / AF a Nnef 3gpp-monitoring-event response, which includes an HTTP error code and problemDetails. This final message communicates that the subscription request was unsuccessful due to the encountered error.

[0088] Figure 3 is a signaling diagram illustrating a procedure for subscription to multiple monitoring configuration and updated error response. The procedure is performed by a first network node (109, 700), a third network node (112, 800), a second network node (113), a fourth network node (116, 900). In some embodiments, the first network node is a Network Exposure Function (NEF). In some embodiments, the third network node is a User Data Management (UDM). In some embodiments, the second network node is an Application Function (AF). In some embodiments, the fourth network node is a Home Subscriber Server (HSS). More particularly, the procedure is performed by a AS / SCS / AF (Application Server, Service Capability Server, or Application Function), SCEF+NEF (Service Capability

[0089] Exposure Function and Network Exposure Function), UDM (Unified Data Management), and HSS (Home Subscriber Server).

[0090] In step 1 , the AS / SCS / AF transmits to the SCEF+NEF a "Nnef 3gpp-monitoring-event request" message including the parameters "monitoringType" and "addMonTypes." This message initiates the request for monitoring a specific event type.

[0091] In step 2, the SCEF+NEF transmits to the UDM a "Nudm_EE_Subscribe request" message that includes the parameters "monitoringConfigurations" and "epcAppliedlnd=true." This message forwards the subscription request to the UDM with relevant monitoring configurations, indicating that EPC is applied.

[0092] In step 3, if common 4G / 5G exposure is supported, the UDM creates related EPC EE subscriptions in the EPC via the HSS by transmitting a "Nhss_EE_Subscribe request" message to the HSS. Partial Success Case:

[0093] In step 4, the HSS transmits to the UDM a "Nhss_EE_Subscribe response" message that includes the parameters "OK," "CreatedEpcSubscription," and optionally "failedMonitoringConfigs." This message confirms the creation of the EPC subscription.

[0094] In step 5, the UDM transmits to the SCEF+NEF a "Nudm_EE_Subscribe response" message that includes the parameters "OK," "CreatedEeSubscription," and optionally "failedMonitoringConfigs," indicating the successful creation of the monitoring subscription along with any failed monitoring configurations.

[0095] In step 6, the SCEF+NEF transmits to the AS / SCS / AF a "Nnef 3gpp-monitoring-event response" message that includes the parameters "OK," "MonitoringEventSubscription," and " failedEventsSubs," confirming the monitoring subscription with additional details on any failed event subscriptions.

[0096] Error Case:

[0097] In step 4, the HSS transmits to the UDM a "Nhss_EE_Subscribe response" message that includes an "HTTP Error Code" along with the parameters "problemDetails (CAUSE)" and "failedMonitoringConfigs." This message indicates a failure in creating the subscription due to an error.

[0098] In step 5, the UDM transmits to the SCEF+NEF a "Nudm_EE_Subscribe response" message that includes the parameters "HTTP Error Code," "problemDetails (CAUSE)," "failedMonitoringConfigs," and "failedMonitoringConfigsEpc," indicating that an error occurred during the subscription process, with additional information on failed configurations.

[0099] In step 6, the SCEF+NEF transmits to the AS / SCS / AF a "Nnef 3gpp-monitoring-event response" message that includes an "HTTP Error Code," "problemDetails (CAUSE)," and "failedEventSubs." This message confirms the error in the monitoring subscription, providing the relevant details and failed event subscriptions.

[0100] In some embodiments, all EE subscriptions may fail only in EPC, or only in 5G or in both.

[0101] Steps 1 , 2, and 3 correspond to steps 1 , 2 and 3 in Figure 2 respectively.

[0102] For the partial success case:

[0103] Steps 4,5 correspond to steps 4 and 5 in Figure 2 respectively. In step 6, in case of partial failure (either in EPC or in 5G or in both), not all requested events are successfully created, SCEF+NEF or NEF returns success indicating the created “monitoringEventSubscription”, additionally including a information element, failedEventSubscriptions which contains a list of failedEventSubscription. Each failedEventSubscription shall contain the failedEvent and the Cause of the failure.

[0104] Any event is applicable for both domains, and then for any event in case of common exposure, the EE subs needs to be created both in UDM and HSS. Then, it can fail in both domains, as considered in steps 4 and 5. In addition, the failure in each domain may be different. Therefore, the information provided in step 6 needs to include failure reason(s) and domain for each Event. The AS / SCS / AF is unable to react upon that, but this information is relevant for AS / SCS / AF to understand the criticality of the error.

[0105] For the error case:

[0106] The figure and the following description covers the most complete case: ALL EE subscriptions fail in both EPC and 5G (scenario 6 in Table 1).

[0107] In step 4, conditional to execution of step 3, the HSS tries to execute the requested EE subscription but due to different reasons, in this example it is considered that none of the required monitoring configuration reports can be configured in HSS. Based on this situation HSS returns a HTTP Error Code (e.g., 403 Forbidden) including ProblemDetails with Cause value “UNSPECIFIED” and additionally HSS includes information to provide the error cause for each of the failed monitoring configuration. As a possibility this information may be provided including existing failedMonitoringConfiguration (containing the failed event type and the failedCause) in the error response.

[0108] In step 5, following step 4 (if the request applied for EPC) or step 3 (if the request does not apply to EPC), UDM tries to execute the requested EE subscription in the 5G domain, but due to different reasons, in this example it is considered that none of the required monitoring configuration reports can be configured in UDM.

[0109] Since none of the 5G EE subscriptions (if the request does not apply to EPC) or neither 5G EE subscription nor 4G EE subscriptions (if the request applies to EPC) have been configured due to different reasons, UDM returns an HTTP Error Code (e.g. 403 Forbidden) including ProblemDetails including Cause value “UNSPECIFIED” and additionally including information to provide the error cause for each of the failed monitoring configuration. As a possibility this information may be provided including existing information element failedMonitoringConfiguration with the failed event type and the failedCause detected when trying to configure the event in the 5G domain. If step 3 and 4 are executed, UDM also includes information provided by HSS. As a possibility, this information may be provided by including existing information element failedMonitoringConfigurationEpc including the failure reasons as received from HSS in step 4.

[0110] In case HSS did not return failedMonitoringConfiguration information element in the error response (e.g. when HSS does not support the functionality described in this IvD), UDM shall generate related failedMonitoringConfigurationEpc including FailedCause as “UNSPECIFIED” or, if available, the Cause indicated by HSS in the ProblemDetails.

[0111] Table 1 covers solutions to additional scenarios for the different combinations depending on whether the EE subscription is successfully created for all events (all ok), or partially successfully created (partial ok), or none of the events are successfully created (all fail) in UDM and / or HSS. Based on that, the content of the response can vary as indicated in the table.

[0112] Table 1

[0113] Hereinafter, flowcharts showing examples of embodiments of the solution are described in detail.

[0114] The embodiments correspond to methods performed by and involving a first network node (109, 700), a third network node (112, 800), a second network node (113), a fourth network node (116, 900).

[0115] Figure 4 is a flowchart illustrating a method performed by the first network node for monitoring configuration in a communications network.

[0116] In step S-401 , the first network node receives from a second network node a MonitoringEventSubscription request including two or more monitoring types.

[0117] In step S-402, the first network node transmits to a third network node a subscription request, including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for the two or more monitoring events.

[0118] In step S-403, the first network node receives from the third network node a response message including an HTTP Error Code including the at least one cause of monitoring configuration failure for at least one monitoring event.

[0119] In step S-404, the first network node transmits to the second network node a response message including the at least one cause of monitoring configuration failure for at least one monitoring event.

[0120] In step S-405, the first network node receives from the third network node a response message including the aggregated errors and causes.

[0121] In step S-406, the first network node receives from the third network node an failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event and per domain, particularly including a UNSPECIFIED cause.

[0122] In step S-407, the first network node aggregates two or more error causes received from the third network node.

[0123] In step S-408, the first network node transmits to the second network node a response message including the aggregated causes.

[0124] In step S-409, the first network node transmits to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure. In step S-410, the first network node receives from the third network node an HTTP Error Code including an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains.

[0125] In some embodiments, the failedEventSubscriptions includes the domain, either EPC or 5G, related to the failed event.

[0126] In some embodiments, the first network node is a NEF, the second network node is an AF, the third network node is an UDM, the fourth network node is an HSS.

[0127] Figure 5 is a flowchart illustrating a method performed by the third network node for monitoring configuration in a communications network.

[0128] In step S-501 , the third network node receives from a first network node a subscription request, including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for the two or more monitoring events.

[0129] In step S-502, the third network node transmits to a fourth network node an Event Exposure Subscription request based on the indication.

[0130] In step S-503, the third network node receives from the fourth network node a response message including an HTTP Error Code including at least one cause of monitoring configuration failure for at least one monitoring event, particularly wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute.

[0131] In step S-504, the third network node transmits to the first network node a response message including an HTTP Error Code including the at least one cause of monitoring configuration failure for at least one monitoring event.

[0132] In step S-505, the third network node determines at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported.

[0133] In step S-506, the third network node aggregates two or more error causes received from the fourth network node.

[0134] In step S-507, the third network node transmits to the first network node a response message including the aggregated errors and causes.

[0135] In step S-508, the third network node transmits to the first network node an failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event and per domain, particularly including a UNSPECIFIED cause.

[0136] In step S-509, the third network node transmits to the first network node an HTTP Error Code including an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains.

[0137] In some embodiments, the failedEventSubscriptions includes the domain, either EPC or 5G, related to the failed event.

[0138] In some embodiments, the first network node is a NEF, the second network node is an AF, the third network node is an UDM, the fourth network node is an HSS.

[0139] Figure 6 is a flowchart illustrating a method performed by the fourth network node for monitoring configuration in a communications network.

[0140] In step S-601 , the fourth network node receives from a third network node an Event Exposure Subscription request based on the indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for the two or more monitoring events.

[0141] In step S-602, the fourth network node transmits to the third network node a response message including an HTTP Error Code including at least one cause of monitoring configuration failure for at least one monitoring event, particularly wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute.

[0142] In some embodiments, the failedEventSubscriptions includes the domain, either EPC or 5G, related to the failed event.

[0143] In some embodiments, the first network node is a NEF, the second network node is an AF, the third network node is an UDM, the fourth network node is an HSS.

[0144] Figure 7 is a block diagram illustrating elements of a mobile network node 700 of a mobile communications network. In some embodiments, the mobile network node 700 is a NEF 109. As shown, the mobile network node may include network interface circuitry 701 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 702 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 703 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 703 may include computer readable program code that when executed by the processing circuitry 702 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 702 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 702 and / or network interface circuitry 701 . For example, processing circuitry 702 may control network interface circuitry 701 to transmit communications through network interface circuitry 701 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 703, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 702, processing circuitry 702 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0145] Figure 8 is a block diagram illustrating elements of a mobile network node 800 of a mobile communications network. In some embodiments, the mobile network node 800 is a UDM 112. As shown, the mobile network node may include network interface circuitry 801 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 802 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 803 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 803 may include computer readable program code that when executed by the processing circuitry 802 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 802 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 802 and / or network interface circuitry 801 . For example, processing circuitry 802 may control network interface circuitry 801 to transmit communications through network interface circuitry 801 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 803, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 802, processing circuitry 802 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0146] Figure 9 is a block diagram illustrating elements of a mobile network node 900 of a mobile communications network. In some embodiments, the mobile network node 900 is a HSS 116. As shown, the mobile network node may include network interface circuitry 901 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 902 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 903 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 903 may include computer readable program code that when executed by the processing circuitry 902 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 902 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 902 and / or network interface circuitry 901 . For example, processing circuitry 902 may control network interface circuitry 901 to transmit communications through network interface circuitry 901 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 903, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 902, processing circuitry 902 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0147] Figure 10 is a block diagram illustrating a virtualization environment 1000 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1000 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1000 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface. Applications 1002 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0148] Hardware 1004 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1006 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1008a and 1008b (one or more of which may be generally referred to as VMs 1008), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1006 may present a virtual operating platform that appears like networking hardware to the VMs 1008.

[0149] The VMs 1008 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1006. Different embodiments of the instance of a virtual appliance 1002 may be implemented on one or more of VMs 1008, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0150] In the context of NFV, a VM 1008 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1008, and that part of hardware 1004 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1008 on top of the hardware 1004 and corresponds to the application 1002.

[0151] Hardware 1004 may be implemented in a standalone network node with generic or specific components. Hardware 1004 may implement some functions via virtualization. Alternatively, hardware 1004 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1010, which, among others, oversees lifecycle management of applications 1002. In some embodiments, hardware 1004 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1012 which may alternatively be used for communication between hardware nodes and radio units.

[0152] Embodiments within the scope of the present invention may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such tangible computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer- readable medium. Combinations of the above should also be included within the scope of the tangible computer-readable media.

[0153] Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in standalone or network environments. Generally, program modules include routines, programs, objects, components, and data structures that perform particular tasks or implement particular abstract data types. Computer executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represent examples of corresponding acts for implementing the functions described in such steps.

[0154] Those of skill in the art will appreciate that other embodiments of the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[0155] Communication at various stages of the described system can be performed through a local area network, a token ring network, the Internet, a corporate intranet, 802.11 series wireless signals, fiber-optic network, radio or microwave transmission, etc. Although the underlying communication technology may change, the fundamental principles described herein are still applicable.

[0156] The various embodiments described above are provided by way of illustration only and should not be construed to limit the invention. For example, the principles herein may be applied to any remotely controlled device. Further, those of skill in the art will recognize that communication between the remote the remotely controlled device need not be limited to communication over a local area network but can include communication over infrared channels, Bluetooth or any other suitable communication interface. Those skilled in the art will readily recognize various modifications and changes that may be made to the present invention without following the example embodiments and applications illustrated and described herein, and without departing from the scope of the present disclosure.

[0157] The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of example embodiments. 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 "includes," "including," "comprises," and "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, or components, and combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or components, and combinations thereof. Further, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to ""a / an / the element, apparatus, component, means, module, step, etc."" are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

[0158] ACRONYMS:

[0159] 3GPP 3rd Generation Partnership Project

[0160] 4G Fourth Generation

[0161] 5G Fifth Generation

[0162] 5GC 5G Core

[0163] AF Application Function

[0164] AS Application Server

[0165] DN Data Network

[0166] EE Event Exposure

[0167] EPC Evolved Packet Core

[0168] HSS Home Subscriber Server

[0169] HTTP Hypertext T ransfer Protocol

[0170] NEF Network Exposure Function

[0171] NF Network Function

[0172] NFV Network Function Virtualization

[0173] RAN Radio Access Network

[0174] SCEF Service Capability Exposure Function

[0175] SCS Service Capability Server

[0176] UE User Equipment

[0177] UDM Unified Data Management

[0178] UDR Unified Data Repository

[0179] VM Virtual Machine

[0180] VMM Virtual Machine Monitor

Claims

CLAIMS1 . A method for monitoring configuration in a communications network, the method comprising: transmitting from a first network node to a third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure subscription request based on the indication; transmitting from the fourth network node to the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event; transmitting from the third network node to the first network node a response message including an HTTP error code and the at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain.

2. The method of claim 1 , further comprising: receiving at the first network node from a second network node a MonitoringEventSubscription request including two or more monitoring events; and transmitting from the first network node to the second network node a response message including at least one cause of monitoring configuration failure for at least one monitoring event.

3. The method of any one of claims from claim 1 to claim 2, wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute.

4. The method of any one of claims from claim 1 to claim 3, further comprising: determining at the third network node at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported.

5. The method of any one of claims from claim 1 to claim 4, further comprising:aggregating at the third network node two or more error causes received from the fourth network node; and transmitting from the third network node to the first network node a response message including the aggregated errors and causes.

6. The method of any one of claims from claim 1 to claim 5, further comprising: transmitting from the third network node to the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause.

7. The method of any one of claims from claim 1 to claim 6, further comprising: aggregating at the first network node two or more error causes received from the third network node; and transmitting from the first network node to the second network node a response message including the aggregated causes.

8. The method of any one of claims from claim 1 to claim 7, further comprising: transmitting from the first network node to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure.

9. The method of any one of claims from claim 1 to claim 8, further comprising: transmitting from the third network node to the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains.

10. The method of any one of claims from claim 1 to claim 9, further comprising: initiating at the second network node troubleshooting actions upon receiving the error causes from the first network node.11 . The method of any one of claims from claim 1 to claim 11 , wherein the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

12. A method performed by a first network node for monitoring configuration in a communications network, the method comprising: transmitting from the first network node to a third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; and transmitting from the third network node to the first network node a response message including an HTTP error code and at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain.

13. The method of claim 12, further comprising: receiving at the first network node from a second network node a MonitoringEventSubscription request including two or more monitoring events; and transmitting from the first network node to the second network node a response message including at least one cause of monitoring configuration failure for at least one monitoring event.

14. The method of any one of claims from claim 12 to claim 13, wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute.

15. The method of any one of claims from claim 12 to claim 14, further comprising: receiving from the third network node at the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause.

16. The method of any one of claims from claim 12 to claim 15, further comprising: aggregating at the first network node two or more error causes received from the third network node; and transmitting from the first network node to the second network node a response message including the aggregated causes.

17. The method of any one of claims from claim 12 to claim 16, further comprising:transmitting from the first network node to the second network node a failedEventSubscriptions attribute including each failed event and the respective cause of failure.

18. The method of any one of claims from claim 12 to claim 17, further comprising: receiving from the third network node at the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains.

19. The method of any one of claims from claim 12 to claim 18, wherein the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM.

20. A method performed by a third network node for monitoring configuration in a communications network, the method comprising: receiving from a first network node at the third network node an Event Exposure subscription request including an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the third network node to a fourth network node an Event Exposure subscription request based on the indication; receiving from the fourth network node at the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event; transmitting from the third network node to the first network node a response message including an HTTP error code and the at least one cause of monitoring configuration failure for at least one monitoring event, wherein the response message indicates the domain related to the monitoring configuration failure, particularly wherein the domain is the EPC domain or the 5G domain.21 . The method of claim 20, wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute.

22. The method of any one of claims from claim 20 to claim 21 , further comprising: determining at the third network node at least one Event Exposure subscription to be created in EPC via HSS if common 4G / 5G exposure is supported.

23. The method of any one of claims from claim 20 to claim 22, further comprising: aggregating at the third network node two or more error causes received from the fourth network node; and transmitting from the third network node to the first network node a response message including the aggregated errors and causes.

24. The method of any one of claims from claim 20 to claim 23, further comprising: transmitting from the third network node to the first network node a failedMonitoringConfigurationEpc attribute when the fourth network node fails to provide specific error causes per failed event for the EPC domain, particularly including a UNSPECIFIED cause.

25. The method of any one of claims from claim 20 to claim 24, further comprising: transmitting from the third network node to the first network node an HTTP Error Code and an indication of a global failure where all event exposure subscriptions fail in both EPC and 5G domains.

26. The method of any one of claims from claim 20 to claim 25, wherein the first network node is a Network Exposure Function, NEF, the second network node is an Application Function, AF, the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

27. A method performed by a fourth network node for monitoring configuration in a communications network, the method comprising: receiving from a third network node at the fourth network node an Event Exposure subscription request based on an indication that the request applies to Evolved Packet Core, EPC, in addition to 5G Core, 5GC, for two or more monitoring events; transmitting from the fourth network node to the third network node a response message including a Hypertext Transfer Protocol, HTTP, error code and at least one cause of monitoring configuration failure for at least one monitoring event.

28. The method of claim 27, wherein the at least one cause of monitoring configuration failure is included in a failedMonitoringConfiguration attribute or a failedMonitoringConfigurationEpc attribute.

29. The method of any one of claims from claim 27 to claim 28, wherein the third network node is a Unified Data Management, UDM, the fourth network node is a Home Subscriber Server, HSS.

30. Apparatus for monitoring configuration in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 12 to claim 19.31 . Apparatus for monitoring configuration in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 20 to claim 26.

32. Apparatus for monitoring configuration in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 27 to claim 29.

33. A system comprising an apparatus as claimed in claim 30, an apparatus as claimed in claim 31 , and an apparatus as claimed in claim 32.

34. A computer-implemented system comprising one or more processors and one or more computer storage media storing computer-usable instructions that, when used by the one or more processors, cause the one or more processors to perform a method according to any one of claims from claim 12 to claim 29.

35. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to any of claims from claim 12 to claim 29.

36. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by a processor, causing the processor to perform the method according to any of claims from claim 12 to claim 29.

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