Feature discovery in non-direct subscription scenarios

Abstract

The invention relates to a method and a network node for feature discovery in a non-direct subscription scenario. A method at a first network node for determining whether one or more first features are to be used for notification from the first network node to a second network node is provided. The notification is subscribed by a non-direct subscription operation. The method comprises: receiving information indicating whether the second network node supports one or more first features or from which information from which whether the second network node supports one or more first features can be derived; and determining whether to use the one or more first features for the notification based at least on the received information.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to PCT International Application No. PCT / CN2022 / 102184, filed on June 29, 2022, entitled “Feature Discovery in Non-Direct Subscription Scenarios,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of telecommunications, and in particular, to a method and a network node for feature discovery in a non-direct subscription scenario. Background Art

[0003] With the development of electronic and communication technology, mobile devices such as mobile phones, smart phones, laptops, tablet computers, car devices, etc. have become an important part of our daily life. In order to support a large number of mobile devices, an efficient telecommunication system, such as the fifth generation system (5GS), will be required.

[0004] The 3rd Generation Partnership Project (3GPP) 5th Generation (5G) supports a discovery mechanism that enables a Core Network (CN) entity to discover a set of Network Function (NF) instances and NF Service instances for a specific NF service or NF type. Unless the expected NF and NF Service information is locally configured in the requester NF, the NF and NF Service discovery is achieved via the Network Repository Function (NRF).

[0005] In order to discover the requested NF type or NF service via NRF, the NF instance needs to be registered in NRF.

[0006] 3GPP 5G CN also supports a mechanism for negotiating optional features applicable to each 5G application programming interface (API). Both NF service consumers and NF service producers can directly negotiate support for optional features as part of the interface. Most 5G service-based interfaces (SBIs) negotiate support for optional functions when the NF service consumer first contacts the NF service producer for resource creation, as specified in clause 6.6 of 3GPP Technical Specification (TS) 29.500, V17.6.0. NF service consumers can also negotiate supported features as part of a data retrieval operation to obtain supported functions associated with the resource.

[0007] Furthermore, as stated in 3GPP TS 29.500, V17.6.0, "The NF instance shall register all the features it supports with the NRF to enable the NF Service Consumer to discover the NF Service Producer that supports a specific feature. The NF instance shall register all the features it supports as a NF Service Consumer in the corresponding default notification subscription in its NF profile with the NRF to enable the NF Service Producer to select the NF Service Consumer that supports a specific feature."

[0008] The 5G Core Network also allows a service consumer NF to explicitly or implicitly subscribe to notifications about data changes on any type of resource. A subscription can be implicit, i.e., it can exist without being explicitly created through a dedicated subscription operation (see TS29.501, V17.5.0, clause 4.6.2.2.1). There are two types of implicit subscriptions:

[0009] 1. An explicit operation exists (e.g., Npcf_SMPolicyControl_Create) and the corresponding notification is part of the same service process (e.g., Npcf_SMPolicy_Update, notification about matching events), and

[0010] 2. A subscription that exists without any explicit action. For example, at a unified data repository (UDR), any available unified data management (UDM) is implicitly subscribed to notifications about changes to the provided data; the UDR selects one of the appropriate available UDMs (discovered via NRF, taking into account the features supported by the UDM) and sends the notification using the callback uniform resource identifier (URI) provided by NRF during UDM discovery. Summary of the invention

[0011] There are other types of subscriptions where the NF Provider subscribes using a different service and path than the one used in the requested notification. Some other subscription examples applicable to this scenario related to the Policy and Charging Control (PCC) function are shown here:

[0012] - An Application Function (AF) may send a request to influence the Session Management Function (SMF) routing decision for user plane traffic of a Protocol Data Unit (PDU) session, as described in 3GPP TS 29.513, V17.6.0, clause 5.5.3. In this case, the AF uses the PCC framework (directly via the Policy Control Function (PCF), or using the Network Exposure Function (NEF) and UDR when not targeting a single User Equipment (UE) address) to indicate its requested subscription to SMF events (e.g., User Plane (UP) path changes). The SMF receives the subscription information provided in the PCC rules, i.e., the event and the AF / NEF notification URI. The SMF will notify the AF directly (for external applications, via the NEF).

[0013] - The AF may provide service parameter data to the PCF, which may generate UE Routing Selection Policy (URSP) rules for the UE. In addition, the AF may subscribe to receive notifications about the results of the URSP rule delivery. The AF subscription is indicated to the PCF as service parameter data (i.e., event and AF / NEF notification URIs) stored in the UDR.

[0014] In these cases, the NF that needs to be notified needs to provide the event and the notification URI through the PCC framework. The notification URI indicates the final recipient of the event notification.

[0015] However, there is currently no mechanism to negotiate between parties which features to use in indirect subscription notifications.

[0016] In order to solve or at least partially alleviate this problem, some embodiments of the present disclosure are provided below.

[0017] According to a first aspect of the present disclosure, a method at a first network node is provided, the method being used to determine whether one or more first features are to be used for a notification from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The method comprises: receiving information indicating whether the second network node supports the one or more first features or information from which it is possible to derive whether the second network node supports the one or more first features; and determining whether the one or more first features are to be used for the notification based at least on the received information.

[0018] In some embodiments, the non-direct subscription operation is a first service operation, the first service operation is associated with a first service, and the first service operation is invoked by a third network node in response to the second network node invoking a second service operation associated with the second service, and in some embodiments, the first service is different from the second service. In some embodiments, the third network node is different from the second network node. In some embodiments, at least one of the first service and the second service is provided by the third network node.

[0019] In some embodiments, the step of receiving the information includes at least one of the following: receiving a first message from a third network node, the first message indicating a notification URI pointing to the second network node; receiving a first message from the third network node, the first message indicating an NF instance identifier (ID) of the second network node; and receiving a first message from the third network node, the first message indicating zero or more second features supported by the second network node as an NF service consumer.

[0020] In some embodiments, when the first message indicates a notification URI pointing to the second network node, the step of determining whether to use one or more first features for the notification includes: sending a second message for discovering an NF instance to a fourth network node, the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features required by the first network node as an NF service consumer; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message. In some embodiments, the step of determining whether to use one or more first features for the notification further includes at least one of the following: determining to use one or more first features for the notification in response to at least receiving a third message indicating one NF instance from a fourth network node, and in response to determining that the one or more first features are one or more features associated with a first notification type among zero or more second features indicated by the third message, the first notification type indicating that the notification is subscribed to through an indirect subscription operation; and determining not to use one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node, or in response to determining that the one or more first features are not one or more features associated with the first notification type among zero or more second features indicated by the third message when the third message indicates one NF instance. In some embodiments, when the second message also indicates the first notification type, the step of determining whether to use one or more first features for the notification further includes at least one of the following: determining to use one or more first features for the notification in response to at least receiving a third message indicating one NF instance from the fourth network node; and determining not to use one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node.

[0021] In some embodiments, when a first message indicates a notification URI pointing to a second network node, the step of determining whether to use one or more first features for the notification includes: sending a second message to a fourth network node for discovering an NF instance, the NF instance having a notification URI matching the notification URI in its NF configuration file; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein, when the third message indicates one NF instance, the third message also indicates, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification also includes at least one of the following items: determining that the one or more first characteristics are to be used for the notification in response to at least receiving a third message indicating an NF instance from a fourth network node, and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, the first notification type indicating that the notification is subscribed to through a non-direct subscription operation; and determining not to use the one or more first characteristics for the notification in response to at least receiving a third message indicating that there is no NF instance from the fourth network node, or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance.

[0022] In some embodiments, when a first message indicates a notification URI pointing to a second network node, the step of determining whether to use one or more first features for the notification includes: sending a second message to a fourth network node for discovering an NF instance, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with a first notification type, the first notification type indicating that the notification is subscribed to through an indirect subscription operation; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein, when the third message indicates one NF instance, the third message also indicates, for the indicated NF instance and for the first notification type, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification also includes at least one of the following items: determining that one or more first characteristics are to be used for the notification at least in response to receiving a third message indicating an NF instance from a fourth network node and in response to determining that the one or more first characteristics are one or more of zero or more second characteristics; and determining not to use one or more first characteristics for the notification at least in response to receiving a third message indicating that there is no NF instance from the fourth network node or in response to determining that the one or more first characteristics are not one or more of zero or more second characteristics when the third message indicates an NF instance.

[0023] In some embodiments, when the first message indicates the NF instance ID of the second network node, the step of determining whether to use one or more first features for the notification includes: sending a second message for discovering an NF instance to a fourth network node, the NF instance having the NF instance ID indicated in the first message and supporting one or more first features required by the first network node as an NF service consumer; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message. In some embodiments, the step of determining whether to use one or more first features for the notification also includes at least one of the following items: determining to use one or more first features for the notification in response to at least receiving a third message indicating one NF instance from the fourth network node, and in response to determining that the one or more first features are one or more features associated with a first notification type among zero or more second features indicated by the third message, the first notification type indicating that the notification is subscribed through a non-direct subscription operation; and determining not to use one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node, or in response to determining that the one or more first features are not one or more features associated with a first notification type among zero or more second features indicated by the third message when the third message indicates one NF instance.

[0024] In some embodiments, when the first message indicates the NF instance ID of the second network node, the step of determining whether to use one or more first features for the notification includes: sending a second message for discovering an NF instance to a fourth network node, the NF instance having the NF instance ID indicated in the first message; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein, when the third message indicates one NF instance, the third message also indicates, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification also includes at least one of the following items: determining that the one or more first characteristics are to be used for the notification in response to at least receiving a third message indicating an NF instance from a fourth network node, and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, the first notification type indicating that the notification is subscribed to through a non-direct subscription operation; and determining not to use the one or more first characteristics for the notification in response to at least receiving a third message indicating that there is no NF instance from the fourth network node, or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance.

[0025] In some embodiments, when the first message indicates that the second network node as the NF service consumer supports zero or more second features, the step of determining whether to use one or more first features for the notification includes at least one of the following items: determining that the one or more first features are to be used for the notification at least in response to determining that the zero or more second features supported by the second network node include one or more first features; and determining not to use the one or more first features for the notification at least in response to determining that the zero or more second features supported by the second network node do not include one or more first features.

[0026] In some embodiments, before the step of determining whether to use one or more first features for the notification, the method further includes: sending a fourth message to a fourth network node, the fourth message indicating at least one of the following items: a notification URI pointing to the first network node and associated with the first notification type (which indicates that the notification is subscribed to through a non-direct subscription operation), zero or more third features supported by the first network node as an NF service producer, and the NF instance ID of the first network node.

[0027] In some embodiments, the method further comprises: sending a fifth message as the notification to the second network node, wherein the one or more first features are used based at least on a determination of whether the one or more first features are to be used for the notification. In some embodiments, the fifth message further indicates at least one of the following: a notification URI pointing to the first network node; an NF instance ID of the first network node; and zero or more third features supported by the first network node as an NF service producer.

[0028] In some embodiments, at least one of the following situations is true: the first network node is SMF; the second network node is NEF or AF; the third network node is PCF; the fourth network node is NRF; the first message is Npcf_SMPolicyControl_UpdateNotify request message; the second message is Nnrf_NFDiscovery_Request request message; the third message is Nnrf_NFDiscovery_Request response message; the fourth message is Nnrf_NFManagement_NFRegister request message; the fifth message is Nsmf_EventExposure_Notify request message.

[0029] According to a second aspect of the present disclosure, a first network node is provided. The first network node comprises: a processor; a memory storing instructions, which, when executed by the processor, causes the processor to perform any method in the method of the first aspect. In some embodiments, an SMF is deployed at the first network node.

[0030] According to a third aspect of the present disclosure, there is provided a first network node for determining whether to use one or more first features for a notification from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The first network node comprises: a receiving module configured to receive information indicating whether the second network node supports the one or more first features or information from which it is possible to derive whether the second network node supports the one or more first features; and a determining module configured to determine whether to use the one or more first features for the notification based at least on the received information. In some embodiments, the first network node further comprises one or more modules configured to perform any steps of any of the methods in the method of the first aspect.

[0031] According to a fourth aspect of the present disclosure, a method at a second network node is provided, the method being used to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The method comprises: sending information indicating whether the second network node supports the one or more first features or information from which it is possible to derive whether the second network node supports the one or more first features to a third network node different from the first network node.

[0032] In some embodiments, the non-direct subscription operation is a first service operation, the first service operation is associated with the first service, and the first service operation is called by the third network node in response to the second network node calling the second service operation associated with the second service, and in some embodiments, the first service is different from the second service. In some embodiments, the third network node is different from the second network node. In some embodiments, at least one of the first service and the second service is provided by the third network node. In some embodiments, the step of sending the information includes at least one of the following items: sending a sixth message indicating a notification URI to the third network node, the notification URI pointing to the second network node; sending a sixth message to the third network node, the sixth message indicating the NF instance ID of the second network node; and sending a sixth message to the third network node, the sixth message indicating zero or more second features supported by the second network node as an NF service consumer.

[0033] In some embodiments, before the step of sending the information, the method further includes: sending a seventh message to the fourth network node, the seventh message indicating at least one of the following items: a notification URI pointing to the second network node and associated with the first notification type (which indicates that the notification is subscribed to through a non-direct subscription operation), one or more second features supported by the second network node as an NF service consumer, and the NF instance ID of the second network node. In some embodiments, the method further includes: receiving a fifth message as the notification from the first network node, wherein the one or more first features are used based on at least the information sent to the third network node. In some embodiments, the fifth message also indicates at least one of the following items: another notification URI pointing to the first network node; the NF instance ID of the first network node; and zero or more third features supported by the first network node as an NF service producer.

[0034] In some embodiments, when the fifth message indicates another notification URI pointing to the first network node, the method further includes: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having a notification URI matching the other notification URI in its NF configuration file and supporting one or more fourth features required by the second network node as an NF service producer; and / or receiving a ninth message indicating zero or one NF instance from the fourth network node in response to the eighth message. In some embodiments, the method further includes at least one of the following items: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving a ninth message indicating one NF instance from the fourth network node; and determining not to use one or more fourth features for another notification in response to at least receiving a ninth message indicating no NF instance from the fourth network node.

[0035] In some embodiments, when the fifth message indicates another notification URI pointing to the first network node, the method further includes: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having a notification URI matching the other notification URI in its NF configuration file; and / or receiving a ninth message from the fourth network node in response to the eighth message, the ninth message indicating zero or one NF instance, wherein when the ninth message indicates one NF instance, the ninth message also indicates, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer. In some embodiments, the method further includes at least one of the following: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving the ninth message indicating one NF instance from the fourth network node, and in response to determining that the one or more fourth features are one or more of the zero or more third features; and determining not to use one or more fourth features for another notification in response to at least receiving the ninth message indicating no NF instance from the fourth network node, or in response to determining that the one or more fourth features are not one or more of the zero or more third features when the ninth message indicates one NF instance.

[0036] In some embodiments, when the fifth message indicates the NF instance ID of the first network node, the method further includes: sending an eighth message for discovering an NF instance to a fourth network node, the NF instance having the NF instance ID indicated in the fifth message and supporting one or more fourth features required by the second network node as an NF service producer; and / or receiving a ninth message indicating zero or one NF instance from the fourth network node in response to the eighth message. In some embodiments, the method further includes at least one of the following: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving a ninth message indicating one NF instance from the fourth network node; and determining not to use one or more fourth features for another notification in response to at least receiving a ninth message indicating no NF instance from the fourth network node.

[0037] In some embodiments, when the fifth message indicates the NF instance ID of the first network node, the method further includes: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having the NF instance ID indicated in the fifth message; and / or receiving a ninth message from the fourth network node in response to the eighth message, the ninth message indicating zero or one NF instance, wherein when the ninth message indicates one NF instance, the ninth message further indicates, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer. In some embodiments, the method further includes at least one of the following: determining to use the one or more fourth features for another notification from the second network node to the first network node in response to at least receiving the ninth message indicating one NF instance from the fourth network node, and in response to determining that the one or more fourth features are one or more of the zero or more third features; and determining not to use the one or more fourth features for another notification in response to at least receiving the ninth message indicating no NF instance from the fourth network node, or in response to determining that the one or more fourth features are not one or more of the zero or more third features when the ninth message indicates one NF instance.

[0038] In some embodiments, when the fifth message indicates zero or more third features supported by the first network node as an NF service producer, the method further includes at least one of the following: at least in response to determining that the zero or more third features supported by the first network node include one or more fourth features, determining that the one or more fourth features are to be used for another notification from the second network node to the first network node; and at least in response to determining that the zero or more third features supported by the first network node do not include one or more fourth features, determining not to use the one or more fourth features for another notification. In some embodiments, the method further includes: sending a tenth message as another notification to the first network node, wherein the one or more fourth features are used based at least on the determination of whether the one or more fourth features are to be used for another notification. In some embodiments, at least one of the following situations is true: the first network node is SMF; the second network node is NEF or AF; the third network node is PCF; the fourth network node is NRF; the fifth message is Nsmf_EventExposure_Notify request message; the sixth message is Npcf_PolicyAuthorization_Create request message, Npcf_PolicyAuthorization_Update request message or Npcf_PolicyAuthorization_Delete request message; the seventh message is Nnrf_NFManagement_NFRegister request message; the eighth message is Nnrf_NFDiscovery_Request request message; the ninth message is Nnrf_NFDiscovery_Request response message; and the tenth message is Nsmf_EventExposure_AppRelocationInfo request message.

[0039] According to a fifth aspect of the present disclosure, a second network node is provided. The second network node comprises: a processor; a memory storing instructions, which, when executed by the processor, causes the processor to perform any method in the method of the fourth aspect. In some embodiments, an NEF or an AF is deployed at the second network node.

[0040] According to a sixth aspect of the present disclosure, a second network node is provided, the second network node being used to facilitate a first network node in determining whether to use one or more first features for a notification from the first network node to search for a second network node. The notification is subscribed to through an indirect subscription operation. The second network node comprises: a sending module configured to send information indicating whether the second network node supports one or more first features or information from which it is possible to derive whether the second network node supports one or more first features to a third network node different from the first network node. In some embodiments, the second network node further comprises one or more modules configured to perform any steps of any method in the method of the fourth aspect.

[0041] According to a seventh aspect of the present disclosure, there is provided a method at a third network node for facilitating a first network node to determine whether to use one or more first features for a notification from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The method comprises: forwarding from the second network node to the first network node information indicating whether the second network node supports the one or more first features or information from which it is possible to derive whether the second network node supports the one or more first features.

[0042] In some embodiments, the non-direct subscription operation is a first service operation, the first service operation is associated with the first service, and the first service operation is called by the third network node in response to the second network node calling the second service operation associated with the second service, and in some embodiments, the first service is different from the second service. In some embodiments, the third network node is different from the second network node and / or the first network node. In some embodiments, at least one of the first service and the second service is provided by the third network node. In some embodiments, the step of forwarding the information includes at least one of the following items: receiving a sixth message from the second network node, the sixth message indicating a notification URI pointing to the second network node; and sending a first message indicating the notification URI to the first network node; receiving a sixth message indicating the NF instance ID of the second network node from the second network node, and sending a first message indicating the NF instance ID to the first network node; and receiving a sixth message from the second network node, the sixth message indicating zero or more second features supported by the second network node as a NF service consumer, and sending a first message indicating the zero or more second features to the first network node. In some embodiments, at least one of the following situations is true: the first network node is SMF; the second network node is NEF or AF; the third network node is PCF; the first message is Npcf_SMPolicyControl_UpdateNotify request message; the sixth message is Npcf_PolicyAuthorization_Create request message, Npcf_PolicyAuthorization_Update request message or Npcf_PolicyAuthorization_Delete request message.

[0043] According to an eighth aspect of the present disclosure, a third network node is provided. The third network node comprises: a processor; a memory storing instructions, which, when executed by the processor, causes the processor to execute any method in the seventh aspect. In some embodiments, a PCF is deployed at the third network node.

[0044] According to a ninth aspect of the present disclosure, there is provided a third network node for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The method comprises: a forwarding module configured to forward information indicating whether the second network node supports one or more first features or information from which it is possible to derive whether the second network node supports one or more first features from the second network node to the first network node. In some embodiments, the third network node further comprises one or more modules configured to perform any steps of any method in the method of the seventh aspect.

[0045] According to a tenth aspect of the present disclosure, a method at a fourth network node is provided, the method being used to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The method comprises: receiving first information from the first network node, from which it is possible to derive whether the second network node supports the one or more first features; determining second information based at least on the first information, the second information indicating whether the second network node supports the one or more first features; and sending the second information to the first network node.

[0046] In some embodiments, the indirect subscription operation is a first service operation that is associated with the first service, and the first service operation is called by the third network node in response to the second network node calling the second service operation associated with the second service. In some embodiments, the first service is different from the second service. In some embodiments, the third network node is different from the second network node and / or the first network node. In some embodiments, at least one of the first service and the second service is provided by the third network node. In some embodiments, the first information includes at least one of the following items: information indicating a notification URI pointing to the second network node; information indicating an NF instance ID of the second network node; information indicating one or more first characteristics; and information indicating a first notification type, the first notification type indicating that the notification is subscribed to through an indirect subscription operation.

[0047] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features required by the first network node as a NF service consumer, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at a fourth network node, the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features as a NF service consumer, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated in the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node, more than zero second features supported by the indicated NF instance as a NF service consumer.

[0048] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and supporting one or more first features required by the first network node and associated with the first notification type as a NF service consumer, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and supporting one or more first features associated with the first notification type as a NF service consumer, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node.

[0049] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI matching the notification URI in its NF configuration file, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at a fourth network node, the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated by the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node, zero or more second features supported by the indicated NF instance as an NF service consumer.

[0050] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated by the third message, the third message also indicates, for the first notification type, zero or more second features supported by the NF instance as an NF service consumer.

[0051] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having the NF instance ID of the second network node and supporting one or more first features required by the first network node as a NF service consumer, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at a fourth network node, the zero or one NF instance having the NF instance ID indicated in the second message and supporting one or more first features as a NF service consumer, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated in the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node, more than zero second features supported by the indicated NF instance as a NF service consumer.

[0052] In some embodiments, the step of receiving the first information includes: receiving a second message for discovering an NF instance from the first network node, the NF instance having an NF instance ID indicated in the first message, and / or wherein the step of determining the second information includes: determining zero or one NF instance from one or more NF instances registered at a fourth network node, the zero or one NF instance having the NF instance ID indicated in the second message, and / or wherein the step of sending the second information includes: sending a third message indicating zero or one NF instance to the first network node in response to the second message, and / or wherein, when one NF instance is determined and indicated by the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node, zero or more second features supported by the indicated NF instance as an NF service consumer.

[0053] In some embodiments, before the step of receiving the first information, the method also includes at least one of the following items: receiving a fourth message from the first network node, the fourth message indicating at least one of the following items: a notification URI pointing to the first network node and associated with the first notification type, zero or more third features supported by the first network node as an NF service producer, and the NF instance ID of the first network node; and receiving a seventh message from the second network node, the seventh message indicating at least one of the following items: a notification URI pointing to the second network node and associated with the first notification type, one or more second features supported by the second network node as an NF service consumer, and the NF instance ID of the second network node.

[0054] In some embodiments, the method further includes: receiving third information from the second network node, from which it is possible to derive whether the first network node supports one or more fourth features; and / or determining fourth information based at least on the third information, the fourth information indicating whether the first network node supports one or more fourth features; and / or sending the fourth information to the second network node. In some embodiments, the third information includes at least one of the following items: information indicating another notification URI pointing to the first network node; information indicating the NF instance ID of the first network node; information indicating one or more fourth features; and information indicating a first notification type, the first notification type indicating that the notification is subscribed through a non-direct subscription operation. In some embodiments, the step of receiving the third information includes: receiving an eighth message for discovering NF instances from the second network node, the NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features required by the second network node as a NF service producer, and / or wherein the step of determining the fourth information includes: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features as a NF service producer, and / or wherein the step of sending the fourth information includes: sending a ninth message indicating zero or one NF instance to the second network node.

[0055] In some embodiments, the step of receiving the third information includes: receiving an eighth message for discovering NF instances from the second network node, the eighth message having a notification URI in its NF profile that matches the other notification URI, and / or wherein the step of determining the fourth information includes: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI in its NF profile that matches the other notification URI, and / or wherein the step of sending the fourth information includes: sending a ninth message indicating zero or one NF instance to the second network node, and / or wherein, when one NF instance is determined and indicated by the ninth message, the ninth message also indicates zero or more third features supported by the indicated NF instance as an NF service producer.

[0056] In some embodiments, the step of receiving the third information includes: receiving an eighth message for discovering an NF instance from the second network node, the NF instance having the NF instance ID of the first network node and supporting one or more fourth features required by the second network node as a NF service producer, and / or wherein the step of determining the fourth information includes: determining zero or one NF instance from one or more NF instances registered with the fourth network node, the zero or one NF instance having the NF instance ID of the first network node and supporting one or more fourth features as a NF service producer, and / or wherein the step of sending the fourth information includes: sending a ninth message indicating zero or one NF instance to the second network node.

[0057] In some embodiments, the step of receiving the third information includes: receiving an eighth message for discovering NF instances from the second network node, the eighth message having the NF instance ID of the first network node, and / or wherein the step of determining the fourth information includes: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having the NF instance ID of the first network node, and / or wherein the step of sending the fourth information includes: sending a ninth message indicating zero or one NF instance to the second network node, and / or wherein, when one NF instance is determined and indicated by the ninth message, the ninth message also indicates zero or more third features supported by the indicated NF instance as an NF service producer.

[0058] In some embodiments, at least one of the following situations is true: the first network node is SMF; the second network node is NEF or AF; the fourth network node is NRF; the second message is Nnrf_NFDiscovery_Request request message; the third message is Nnrf_NFDiscovery_Request response message; the fourth message is Nnrf_NFManagement_NFRegister request message; the seventh message is Nnrf_NFManagement_NFRegister request message; the eighth message is Nnrf_NFDiscovery_Request request message; and the ninth message is Nnrf_NFDiscovery_Request response message.

[0059] According to an eleventh aspect of the present disclosure, a fourth network node is provided. The fourth network node comprises: a processor; a memory storing instructions, which, when executed by the processor, causes the processor to execute any method in the tenth aspect. In some embodiments, an NRF is deployed at the fourth network node.

[0060] According to the twelfth aspect of the present disclosure, there is provided a fourth network node, which is used to facilitate the first network node to determine whether to use one or more first features for notification from the first network node to the second network node. The notification is subscribed through an indirect subscription operation. The fourth network node includes: a receiving module, configured to receive first information from the first network node, from which it is possible to derive whether the second network node supports one or more first features; a determining module, configured to determine second information based at least on the first information, the second information indicating whether the second network node supports one or more first features; and a sending module, configured to send the second information to the first network node. In some embodiments, the fourth network node also includes one or more modules configured to perform any steps of any method in the method of the tenth aspect.

[0061] According to a thirteenth aspect of the present disclosure, there is provided a computer program comprising instructions. When the instructions are executed by at least one processor, the at least one processor executes any method of the methods of any one of the first aspect, the fourth aspect, the seventh aspect and the tenth aspect.

[0062] According to a fourteenth aspect of the present disclosure, there is provided a carrier comprising the computer program of the thirteenth aspect. In some embodiments, the carrier is one of an electrical signal, an optical signal, a radio signal or a computer-readable storage medium.

[0063] According to a fifteenth aspect of the present disclosure, a telecommunications system is provided, which is used to determine whether one or more first features are to be used for a notification from a first network node to a second network node. The notification is subscribed to by an indirect subscription operation. The telecommunications system includes: a second network node, configured to send second information indicating whether the second network node supports one or more first features to a third network node or first information from which it is possible to derive whether the second network node supports one or more first features; a third network node, configured to forward second information indicating whether the second network node supports one or more first features or first information from which it is possible to derive whether the second network node supports one or more first features from the second network node to the first network node; the first network node is configured to: receive second information indicating whether the second network node supports one or more first features or first information from which it is possible to derive whether the second network node supports one or more first features; and determine whether to use one or more first features for the notification based at least on the received information.

[0064] In some embodiments, when the first network node is configured to receive the first information, the telecommunications system further comprises: a fourth network node configured to: receive the first information from the first network node; determine the second information based at least on the first information; and send the second information to the first network node. In some embodiments, at least one of the following is true: the first network node is the first network node of the second aspect or the third aspect; the second network node is the second network node of the fifth aspect or the sixth aspect; the third network node is the third network node of the eighth aspect or the ninth aspect; and the fourth network node is the fourth network node of the eleventh aspect or the twelfth aspect.

[0065] Through some embodiments of the present disclosure, features to be used in indirect subscription notifications may be negotiated or otherwise determined between relevant parties. For example, a network function may be allowed to determine one or more features to be used in notifications to a selected NF (service) instance based on an indirect subscription (which occurs via a different path than the path used to report the notification, using a different service than the service used in the notification), or based on a previous notification, to know the features supported by the recipient of the notification. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The foregoing features and other features of the present disclosure will become more fully apparent from the following description and the appended claims in conjunction with the accompanying drawings. It should be understood that these drawings depict only several embodiments according to the present disclosure and therefore should not be considered to limit the scope of the present disclosure, which will be described with additional specificity and detail through the use of the accompanying drawings.

[0067] Figure 1 is a block diagram illustrating an exemplary telecommunications network to which feature discovery in a non-direct subscription scenario according to an embodiment of the present disclosure may be applied.

[0068] Figure 2A and Figure 2B is a diagram showing an exemplary process of feature discovery in a non-direct subscription scenario to which an embodiment of the present disclosure may be applied.

[0069] FIG. 3A to FIG. 3C is a diagram illustrating an exemplary process of feature discovery in a non-direct subscription scenario according to an embodiment of the present disclosure.

[0070] FIG. 4A to FIG. 4C is a diagram illustrating another exemplary process of feature discovery in a non-direct subscription scenario according to another embodiment of the present disclosure.

[0071] Figure 5A and Figure 5B is a diagram illustrating another exemplary process of feature discovery in a non-direct subscription scenario according to another embodiment of the present disclosure.

[0072] Figure 6 is a flow chart illustrating an exemplary method at a first network node for determining whether to use one or more first features for notification from the first network node to a second network node according to an embodiment of the present disclosure.

[0073] Figure 7 is a flow chart illustrating an exemplary method at a second network node for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to the second network node according to an embodiment of the present disclosure.

[0074] Figure 8 is a flow chart illustrating an exemplary method at a third network node for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to a second network node according to an embodiment of the present disclosure.

[0075] Fig. 9 is a flow chart illustrating an exemplary method at a fourth network node for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to a second network node according to an embodiment of the present disclosure.

[0076] Fig.10 Embodiments of arrangements which may be used in one or more network nodes according to embodiments of the present disclosure are schematically illustrated.

[0077] Fig.11 is a block diagram of an exemplary first network node according to an embodiment of the present disclosure.

[0078] Fig.12 is a block diagram of an exemplary second network node according to an embodiment of the present disclosure.

[0079] Fig.13 is a block diagram of an exemplary third network node according to an embodiment of the present disclosure.

[0080] Fig.14 is a block diagram of an exemplary fourth network node according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0081] The present disclosure is described below with reference to the embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are provided only for illustrative purposes and are not intended to limit the present disclosure. In addition, the description of known structures and technologies is omitted below to avoid unnecessarily obscuring the concept of the present disclosure.

[0082] Those skilled in the art will understand that the term "exemplary" is used herein to mean "illustrative" or "used as an example," and is not intended to imply that a particular embodiment is superior to another embodiment or that a particular feature is essential. Likewise, unless the context clearly indicates otherwise, the terms "first" and "second," and similar terms are used only to distinguish one particular instance of an item or feature from another particular instance, without indicating a particular order or arrangement. Furthermore, the term "step," as used herein, is intended to be synonymous with "operation" or "action." Unless the context or details of the operations being described clearly indicate otherwise, any description herein of a sequence of steps does not imply that the operations must be performed in a particular order, or even that the operations are performed in any order.

[0083] Unless expressly limited herein or understood from the context, conditional language used herein (e.g., "can," "should," "may," "for example," etc.) is generally intended to convey that some embodiments include some features, elements, and / or steps while other embodiments do not include the features, elements, and / or states. Therefore, such conditional language is generally not intended to imply that features, elements, and / or steps are necessary for one or more embodiments in any case, or to imply that one or more embodiments must include logic circuits to determine whether to include these features, elements, and / or states in any particular embodiment with or without author input or authorization, or to perform the features, elements, and / or states in any particular embodiment. In addition, the term "or" is used as an inclusive meaning (and not an exclusive meaning), so that when used, for example, to connect a list of elements, the term "or" represents one, a part, or all of the elements in the list. In addition, in addition to having its ordinary meaning, the term "each" used herein may mean any subset of the set of elements to which the term "each" is applied.

[0084] The term "based on" should be interpreted as "based at least in part on". The terms "one embodiment" and "embodiment" should be interpreted as "at least one embodiment". The term "another embodiment" should be interpreted as "at least one other embodiment". The following may include other definitions, both explicit and implicit. In addition, unless otherwise explicitly limited herein, statements such as phrases "at least one of X, Y, and Z" should be understood in conjunction with the context as generally used to express that an item, term, etc. can be X, Y, or Z, or a combination thereof.

[0085] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "one", "an" and "said" are intended to include plural forms unless the context clearly indicates otherwise. It will also be understood that when used in this article, the words "comprising", "having", "including" indicate the presence of stated features, elements and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. It will also be understood that unless clearly stated to the contrary, when used in this article, the terms "connected", "connected to", "connected to", etc. only mean that there is an electrical connection or communication connection between two elements and they can be directly or indirectly connected.

[0086] Of course, without departing from the scope and essential features of the present disclosure, the present disclosure may be implemented in other specific ways different from those set forth herein. One or more specific processes discussed below may be performed in any electronic device including one or more appropriately configured processing circuits, which in some embodiments may be embodied in one or more application specific integrated circuits (ASICs). In some embodiments, these processing circuits may include one or more microprocessors, microcontrollers, and / or digital signal processors programmed with appropriate software and / or firmware to implement one or more of the above operations and variations thereof. In some embodiments, these processing circuits may include custom hardware that performs one or more of the above functions. The proposed embodiments are therefore to be considered illustrative rather than restrictive in all respects.

[0087] Although several embodiments of the present disclosure will be shown in the drawings and described in the following detailed description, it will be understood that the disclosure is not limited to the disclosed embodiments, but is also capable of various rearrangements, modifications and substitutions without departing from the present disclosure as will be set forth and defined in the appended claims.

[0088] In addition, although the following description of some embodiments of the present disclosure is given in the context of a 5G system (5GS), the present disclosure is not limited thereto. In fact, as long as it involves feature discovery in a non-direct subscription scenario, the inventive concept of the present disclosure can be applied to any appropriate communication architecture, for example, it can be applied to global mobile communication system (GSM) / general packet radio service (GPRS), enhanced data rate for GSM evolution (EDGE), code division multiple access (CDMA), wideband CDMA (WCDMA), time division synchronous CDMA (TD-SCDMA), CDMA2000, world microwave access interoperability (WiMAX), wireless fidelity (Wi-Fi), long term evolution (LTE), evolved packet system (EPS), 5G new radio (NR), etc. Therefore, it can be easily understood by those skilled in the art that the terms used herein can also refer to their equivalents in any other infrastructure. For example, the term "user equipment" or "UE" used herein can refer to a mobile device, a mobile terminal, a mobile station, a user device, a user terminal, a wireless device, a wireless terminal, an Internet of Things (IoT) device, a vehicle, or any other equivalent. As another example, the term "network node" used in this document may refer to a base station, a base transceiver station, an access point, a hotspot, a Node B (NB), an evolved Node B (eNB), a gNB, a network element, a network function, or any other equivalent.

[0089] In addition, the following 3GPP documents are incorporated herein by reference in their entirety:

[0090] - 3GPP TS 29.500 V17.6.0 (2022-03), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 5G System; Technical Implementation of Service-Based Architecture; Stage 3 (Release 17)

[0091] - 3GPP TS 29.501 V17.5.0 (2022-03), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 5G System; Principles and Guidelines for Service Definition; Stage 3 (Release 17)

[0092] - 3GPP TS 29.510 V17.5.0 (2022-03), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 5G System; Network Function Repository Services; Stage 3 (Release 17); and

[0093] - 3GPP TS 29.513 V17.6.0 (2022-03), Technical Specification, 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 5G System; Policy and Charging Control Signaling Flows and QoS Parameter Mapping; Stage 3 (Release 17)

[0094] Figure 1 1 is a block diagram showing an exemplary telecommunications network 10 to which feature discovery in a non-direct subscription scenario according to an embodiment of the present disclosure may be applied. Although the telecommunications network 10 is a network defined in the context of 5GS, the present disclosure is not limited thereto.

[0095] like Figure 1 As shown, the network 10 may include one or more UEs 100 and a (radio) access network ((R)AN) 105, which may be a base station, NodeB, evolved NodeB (eNB), gNB or access network (AN) node, which provides the UE 100 with access to other parts of the network 10. In addition, the network 10 may include its core network portion, which includes (but is not limited to) an access and mobility management function (AMF) 110, an SMF 115, a PCF 120, an AF 125, a network slice selection function (NSSF) 130, a bundling support function (BSF) 135, a unified data management (UDM) 140, a NEF 145, an NRF 150, and one or more user plane functions (UPF) 155. As shown in FIG. Figure 1 As shown, these entities can communicate with each other via service-based interfaces (e.g., Namf, Nsmf, Npcf, etc.) and / or reference points (e.g., N1, N2, N3, N6, N9, etc.).

[0096] However, the present disclosure is not limited thereto. In some other embodiments, the network 10 may include additional network functions, fewer network functions, or Figure 1 Some variations of the existing network functions shown. For example, in a network with a 4G EPS architecture, the entity that performs these functions (e.g., PGW-C) can be connected to Figure 1 As another example, in a network with a hybrid 4G / 5G architecture, some of these entities may be different from the entities shown in FIG. Figure 1 Some entities shown are identical, while others may be different. Figure 1 The functions shown are not essential to the embodiments of the present disclosure. In other words, some of them may be missing in some embodiments of the present disclosure.

[0097] like Figure 1 As shown, UPF 155 is communicatively connected to a data network (DN) 160, which may be the Internet or is in turn communicatively connected to the Internet, so that UE 100 may ultimately communicate its user plane data with other devices outside network 10, for example, via RAN 105 and UPF 155.

[0098] The following will describe Figure 1Some network functions that may be involved in some embodiments of the present disclosure are shown.

[0099] In some embodiments, SMF 115 may support (but is not limited to) at least one of the following:

[0100] - Session management, such as session establishment, modification and release, including tunnel maintenance between UPF 155 and AN node 105.

[0101] - UE IP address allocation and management (optionally, including authorization). The UE IP address may be received from the UPF 155 or an external data network.

[0102] - Selection and control of User Plane (UP) functions, including controlling the UPF 155 to proxy Address Resolution Protocol (ARP) or IPv6 Neighbor Discovery, or forwarding all ARP / IPv6 Neighbor Solicitation traffic to the SMF 115 for Ethernet PDU sessions.

[0103] - Traffic steering is configured at UPF 155 to route the traffic to the correct destination.

[0104] In some embodiments, NEF 145 may support at least one of (but not limited to) the following:

[0105] - Exposure to capabilities and events:

[0106] NEF 145 may securely expose NF capabilities and events, for example to third parties, application functions 125, edge computing, etc., as described in clause 5.13 of TS 23.501.

[0107] NEF 145 uses a standardized interface (Nudr) to store information as structured data to / from the Unified Data Repository (UDR).

[0108] - Securely provide information from external applications to the 3GPP network:

[0109] It provides a way for application function 125 to securely provide information to the 3GPP network, such as expected UE behavior, 5G-VN group information, time synchronization service information, and service-specific information. In this case, NEF 145 can authenticate and authorize application function 125 and assist in limiting the flow of application function 125.

[0110] - Convert internal and external information:

[0111] Converts between information exchanged with the AF 125 and information exchanged with internal network functions. For example, converts between the AF service identifier and internal 5G core information such as Data Network Name (DNN), Single Network Slice Selection Assistance Information (S-NSSAI), as described in clause 5.6.7 of TS 23.501.

[0112] Specifically, the NEF 145 performs processing to shield the network and user sensitive information from the external AF 125 according to the network policy.

[0113] - NEF 145 receives information from other network functions (based on the exposed capabilities of the other network functions). NEF 145 stores the received information as structured data to the UDR using standardized interfaces. NEF 145 can access the stored information and "re-expose" it to other network functions and application functions 125 and use it for other purposes such as analysis.

[0114] In some embodiments, the AF 125 may interact with the 3GPP core network to provide services, such as supporting the following:

[0115] - The impact of the application on traffic routing (see clause 5.6.7 of TS 23.501);

[0116] - Access to NEF 145 (see clause 5.20 of TS 23.501);

[0117] - Interact with the Policy Framework for policy control (see clause 5.14 of TS 23.501).

[0118] Based on operator deployment, AF 125 that is deemed trustworthy by the operator may be allowed to interact directly with relevant network functions. AF 125 that is not allowed by the operator to directly access network functions shall interact with relevant network functions via NEF 145 using the external exposure framework (see clause 7.3 of TS 23.501).

[0119] In some embodiments, PCF 120 may support (but is not limited to) at least one of the following:

[0120] - Supports a unified policy framework to manage network behavior.

[0121] - Provide policy rules to the Control Plane (CP) functions to enforce these policy rules.

[0122] - Access subscription information in the UDR that is relevant to policy decisions.

[0123] In some embodiments, the NRF 150 may support (but not limited to) at least one of the following:

[0124] - Support service discovery function. Receive NF discovery request from NF instance or Service Communication Agent (SCP), and provide information of discovered NF instance to NF instance or SCP.

[0125] - Maintain NF profiles of available NF instances and their supported services.

[0126] - Notify subscribed NF service consumers or SCPs of newly registered / updated / deregistered NF and SCP instances and their potential NF services.

[0127] - Maintain the health of NF and SCP.

[0128] In some embodiments, BSF 135 may support (but is not limited to):

[0129] - Allows the PCF 120 to register / deregister itself and be discoverable by NF service consumers.

[0130] There may be both a PCF 120 for a PDU session and a PCF 120 for a UE. Each of them may separately and independently register itself at the BSF 135. Each of them may separately and independently be discovered by a consumer of the BSF 135.

[0131] With explicit subscription, characteristics can be negotiated between NF Service Consumer (NFsc) and NF Service Producer (NFsp) during creation of subscription resources. In this way, when NFsc sends notification to NFsp, the information related to the notified event can be according to the negotiated characteristics.

[0132] During the aforementioned implicit subscription of type 1, negotiation of characteristics may be performed as part of the service process, and notifications sent by NFsc may also be based on the negotiated characteristics.

[0133] For the implicit subscription of type 2 mentioned above, feature negotiation / awareness can be covered when NFsc can select a certain type of NFsp to send a notification "NF instance shall register all features it supports as NF service consumer in the corresponding default notification subscription in its NF profile to NRF, so that NF service producer can select NF service consumer supporting specific features".

[0134] For "other types of subscriptions" (referred to as indirect subscriptions in the rest of this disclosure) where the NFsc needs to interact with the NFsp providing its notification URI via different services and using different paths, no feature negotiation is specified.

[0135] As mentioned above, within the PCC framework there is a situation where the AF / NEF subscribes in the PCF or SMF to obtain notifications about certain events in the 5G core network. Figure 2A and Figure 2B An example of this situation is shown. Figure 2A and Figure 2B is a diagram showing an exemplary process of feature discovery in a non-direct subscription scenario to which an embodiment of the present disclosure may be applied.

[0136] As described in 3GPP TS 23.501 subclause 5.6.7, the AF 125 may send a request to influence the SMF routing decision for the user plane traffic of the PDU session. The AF 125 may also provide a subscription to SMF events (e.g., UP path changes) in its request.

[0137] In some embodiments, the AF 125 request is for a single UE address: Such a request may be routed to a single PCF 120 (by the AF 125 or NEF 145) using the BSF 135 or by configuration as described in subclause 5.5.3.2 of TS 29.513. Such a request is for an ongoing PDU session. Whether the AF 125 needs to use the NEF 145 depends on the local deployment.

[0138] like Figure 2A As shown, in 1A, AF 125 can send an AF request to PCF 120 via NEF 145.

[0139] At step S205a, to create a new AF request, the AF 125 may call the Nnef_TrafficInfluence_Create service operation to the NEF 145 by sending an HTTP POST request to the "Business Impact Subscription" resource. In addition, to update an existing AF request, the AF 125 may call the Nnef_TrafficInfluence_Update service operation by sending an HTTP PUT or PATCH request to the "Single Business Impact Subscription" resource. In addition, to delete an existing AF request, the AF 125 may call the Nnef_TrafficInfluence_Delete service operation by sending an HTTP DELETE request to the "Single Business Impact Subscription" resource.

[0140] At step S205b, upon receiving the AF request, the NEF 145 may authorize it and then perform mapping from the information provided by the AF 125 to the information required by the 5GC, as described in 3GPP TS 23.501 and 3GPP TS 23.502.

[0141] At steps S205c and S205d, if the PCF address is not available on the NEF 145 based on local configuration, the NEF 145 may invoke the Nbsf_Management_Discovery service operation specified in subclause 8.5.4 of TS 29.513 to obtain the PCF ID selected for the ongoing PDU Session identified by the single UE address in the AF Request.

[0142] At steps S205e and S205f, NEF 145 may forward the AF request to PCF 120. When the Nnef_TrafficInfluence_Create request is received in step S205a, NEF 145 may call Npcf_PolicyAuthorization_Create service operation by sending an HTTP POST request to the "Application Session" resource, as described in subclause 5.2.2.2.2.1 of TS 29.513. When the Nnef_TrafficInfluence_Update request is received in step S205a, NEF 145 may call Npcf_PolicyAuthorization_Update service operation by sending an HTTP PATCH request to the "Single Application Session Context" resource, as described in subclause 5.2.2.2.2.2 of TS 29.513. Upon receiving the Nnef_TrafficInfluence_Delete request in step S205a, the NEF 145 may invoke the Npcf_PolicyAuthorization_Delete service operation by sending an HTTP POST request to the "Single Application Session Context" resource, as described in subclause 5.2.2.2.2.3 of TS 29.513.

[0143] At step S205g, the NEF 145 may send an HTTP response message to the AF 125 accordingly.

[0144] like Figure 2A As shown, in 1B, AF 125 can send an AF request directly to PCF 120.

[0145] At steps S205a and S205b, if the PCF address is not available on the AF 125 based on local configuration, the AF 125 may invoke the Nbsf_Management_Discovery service operation as specified in subclause 8.5.4 of TS 29.513 to obtain the PCF ID selected for the ongoing PDU session identified by the single UE address in its request.

[0146] At steps S205c and S205d, to create a new AF request, the AF 125 may call the Npcf_PolicyAuthorization_Create service operation by sending an HTTP POST request to the "application session" resource, as described in subclause 5.2.2.2.2.1 of TS 29.513. In addition, to update an existing AF request, the AF 125 may call the Npcf_PolicyAuthorization_Update service operation by sending an HTTP PATCH request to the "single application session context" resource, as described in subclause 5.2.2.2.2.2 of TS 29.513. In addition, to remove an existing AF request, the AF 125 may call the Npcf_PolicyAuthorization_Delete service operation by sending an HTTP POST request to the "single application session context" resource, as described in subclause 5.2.2.2.2.3 of TS 29.513.

[0147] At steps S210 and S215, upon receiving the AF request, the PCF 120 may call the Npcf_SMPolicyControl_UpdateNotify service operation by sending an HTTP POST request to the callback URI "{notificationUri} / update" to update the SMF 115 with the corresponding PCC rules, as described in subclause 5.2.2.2.1 of TS 29.513. If the AF 125 subscribes to the UP path change event, the PCF 120 may include the relevant subscription information in the corresponding PCC rules.

[0148] - For Figure 2B As shown in case 4A, PCF 120 may include the notification URI pointing to NEF 145 and the notification correlation ID assigned by NEF 145 in the PCC rule.

[0149] - For Figure 2B As shown in case 4B, PCF 120 may include the notification URI pointing to AF 145 and the notification correlation ID assigned by AF 125 in the PCC rule.

[0150] If AF 125 unsubscribes from UP path change events, PCF 120 may remove the relevant subscription information from the corresponding PCC rules, as specified in 3GPP TS 29.512.

[0151] At step S215a, when SMF 115 successfully installs the PCC rules, SMF 115 may determine whether a UP path change needs to be enforced.

[0152] refer to Figure 2B , in 4A, in case 1A, if SMF 115 observes a PDU session related event to which AF 125 has subscribed, SMF 115 may send a notification to AF 125 via NEF 145.

[0153] At step S220a, if the SMF 115 observes a PDU session related event to which the AF 125 has subscribed, the SMF 115 may invoke the Nsmf_EventExposure_Notify service operation to the NEF 145 by sending an HTTP POST request to the callback URI "{notifUri}". If an indication that an AF answer is expected is included in the PCC rules, the SMF 115 may use the URI for the AF answer for notification, as described in 3GPP TS 29.508.

[0154] At step S220b, upon receiving the Nsmf_EventExposure_Notify service operation, the NEF 145 may perform information mapping (e.g., mapping of notification correlation ID to AF transaction ID) and call the Nnef_TrafficInfluence_Notify service operation to forward the notification to the AF 125 by sending an HTTP request to the callback URI "notificationDestination", as specified in 3GPP TS 29.522. If the notification from the SMF 115 includes a URI for AF answer, the NEF 145 may also use the URI for AF answer for notification, as specified in 3GPP TS 29.522.

[0155] At step S220 c , the AF 125 may send an HTTP “204 No Content” response to the NEF 145 .

[0156] At step S220d , the NEF 145 may send an HTTP “204 No Content” response to the SMF 115 .

[0157] At steps S220e and S220f, when a notification with a URI for AF reply is received from NEF 145, AF125 may call the Nnef_TrafficInfluence_AppRelocationInfo service operation to reply to the notification by sending an HTTP POST request to the callback URI “{afAckUri}”, and NEF 145 may send a “204 NoContent” response to AF 125.

[0158] At steps S220g and S220h, when the AF answer is received from the AF 125, in order to forward it to the SMF 115, the NEF 145 may call the Nsmf_EventExposure_AppRelocationInfo service operation by sending an HTTP POST request to the callback URI “{ackUri}”, and the SMF 115 may send a “204 No Content” response to the NEF 145. If the NEF 145 receives an indication that uplink traffic needs to be buffered to a target data network access identifier (DNAI), and the NEF 145 determines that the SMF 115 supports the “UL Buffering” function via the Nnrf_NFDiscovery service operation as defined in 3GPP TS 29.510, the NEF 145 may provide the SMF 115 with an indication that uplink traffic needs to be buffered to the target DNAI.

[0159] refer to Figure 2B , in 4B, in case 1B, if SMF 115 observes a PDU session related event to which AF 125 has subscribed, SMF 115 may send a notification directly to AF 125.

[0160] At steps S220a and S220b, the SMF 115 may directly invoke the Nsmf_EventExposure_Notify service operation to the AF 125 by sending an HTTP POST request to the callback URI “{notifUri}”, and the AF 125 may send a “204 No Content” response to the SMF 115. If an indication that an AF answer is expected is included in the PCC rules, the SMF 115 may provide a URI for the AF answer, as described in 3GPP TS 29.508.

[0161] At steps S220c and S220d, when a notification with a URI for AF reply is received from SMF 115, AF125 can reply to the notification by calling the Nsmf_EventExposure_AppRelocationInfo service operation by sending an HTTP POST request to the callback URI "{ackUri}", and SMF 115 can send a "204 NoContent" response to AF 125.

[0162] For simplicity, Figure 2A and Figure 2B Option B (i.e., 1B / 4B) in the description is used to describe the problem of feature discovery in non-direct subscription scenarios. The same problem will occur with Option A (i.e., 1A / 4A). In this case (i.e., Option A), the NEF 145 will face the problem described in Option B for the AF 125.

[0163] Considering option B, the indirect subscription is performed via steps S205c and S210 in 1B. The SMF 115 will receive an indication that it needs to notify the AF 125 directly of the event of the indirect subscription and the notification address to which the notification must be sent. The notification will be sent in Figure 2B It is performed in step S220a in 4B.

[0164] When the NF service producer (SMF 115 in the above example) needs to notify the NF service consumer (AF 125 in this example) of an event that is not directly subscribed, the NF service producer does not know whether the recipient of the notification supports the features required to successfully implement the function. That is, the SMF 115 does not know whether there is additional logic and information generated by the SMF 115 that should be provided to the NEF 145 / AF 125 based on the feature support.

[0165] Similarly, when the AF 125 subscribes indirectly to receive certain information (steps S205c (in 1B) and S210 in the above example), the AF 125 does not know whether the ultimate recipient of the subscription supports the features required to successfully perform the process (e.g., send additional instructions in a subsequent Nsmf_EventExposure_AppRelocationInfo request in step S220c in 4B). If any of the parties involved do not support the functionality, an error condition or false assumption may result.

[0166] As mentioned above, a network function can discover the features supported by another entity by directly negotiating the features in the interface or by consulting the NRF and selecting a NF instance with the appropriate feature level support.

[0167] However, the NF service producer that needs to initiate a notification to the selected NF (service) instance is not aware of the NF instance function support that is not directly subscribed without a subscription operation. Therefore, it is impossible to obtain the characteristics associated with the receiver of the notification.

[0168] In order to solve or at least alleviate the above problems, the present disclosure provides some embodiments, which may cover different alternatives.

[0169] Alternative A: Solution based on storage / discovery of notification URIs in NRF

[0170] The main ideas of this option are briefly described as follows:

[0171] 1) A NF instance that subscribes to receive notifications without using an explicit subscription operation (either using the indirect path or using a previously received notification request) will, in addition to registering the characteristics it supports as a NF consumer, also register the notification URI (which will be provided to the end entity that will initiate the notification) as a part of the default notification subscription within the NF profile.

[0172] 2) The NF instance that needs to initiate a notification based on an indirect subscription to the selected NF instance identified by the received Notification URI shall discover a NF instance that supports the required support functionality and has included a callback URI as part of the default notification subscription information, where, for the indicated service, the callback URI exactly matches the Notification URI provided in its NF configuration file.

[0173] If a NF instance matching the request is found, the NF instance will initiate the notification according to the supported features. If there is no NF instance matching the request, the NF service consumer will assume that the features are not supported and will act accordingly.

[0174] Will refer to FIG. 3A to FIG. 3C This alternative A is described in detail.

[0175] Alternative B: Solution based on sending NF instance ID via an indirect path

[0176] The main ideas of this option are as follows:

[0177] - A NF instance that subscribes to receive notifications without using an explicit subscription operation (either using the indirect path or using a previously received notification request) will register its NF instance ID as part of its NF profile and also register it as a supported feature for the NF consumer as part of the default notification subscription within the NF profile.

[0178] - A NF instance subscribing to an event notification via an indirect path shall use this indirect path to provide its NF instance identifier to the final NF instance that originated the notification.

[0179] - The NF instance that needs to initiate notification based on non-direct subscription will use the received NF instance ID to query the NRF for the NF profile related to the NF instance and find out the features supported by the NF instance within the default notification subscription.

[0180] Will combine FIG. 4A to FIG. 4C This alternative B is described in detail.

[0181] Alternative C: Solution based on sending features supported by the notified recipient NF instance via an indirect path case

[0182] The main ideas of this option are as follows:

[0183] - NF instances subscribing to event notifications via an indirect path use this indirect path to provide the features supported as NF service consumers in the relevant API to the end NF service producer.

[0184] - The NF instance that needs to initiate notification based on non-direct subscription (NF Service Producer) will identify the features supported by this NF instance (NF Service Consumer) received in the direct path.

[0185] Will combine FIG. 5A to FIG. 5B This alternative C is described in detail.

[0186] In addition, a textual proposal covering the above alternatives is provided as Appendix A below.

[0187] Through some embodiments of the present disclosure, it enables a network function (which needs to initiate a notification to a selected NF (service) instance) to know the features supported by the recipient of the notification based on an indirect subscription (which occurs via a different path than the path used to report the notification, using a different service than the service used in the notification), or based on a previous notification.

[0188] FIG. 3A to FIG. 3C is a diagram illustrating an exemplary process of feature discovery in a non-direct subscription scenario according to an embodiment of the present disclosure.

[0189] refer to Figure 3A , in 0A / 0B, at least one of the NEF 145, AF 125 and SMF 115 may register itself in the NRF 150, for example, by calling the Nnrf_NFManagement_NFRegister service operation.

[0190] For example, at steps S300a and S300b in 0A, NEF 145 may send a Nnrf_NFManagement_NFRegister request to NRF 150 to register itself in NRF 150, and upon successful registration, a Nnrf_NFManagement_NFRegister response may be sent back from NRF 150 to NEF 145. In some embodiments, the request may include at least one of: a notification URI associated with a particular notification type (pointing to or otherwise associated with NEF 145); and one or more features supported by NEF 145 as a service consumer. In some embodiments, the one or more features may be registered in the NRF 150 as “supportedFeatures” in one of the “defaultNotificationSubscriptions” of one of the “nfServices” of the “NFProfile” of the NEF 145, where the “notificationType” in one of the “defaultNotificationSubscriptions” may be “AF_INFLUENCE_EVENT_NOTIFICATION” or “EE_NON_DIRECT_SUBSC” (to be described below), where the “callbackUri” in one of the “defaultNotificationSubscriptions” may be the notification URI of the NEF 145. In some embodiments, one of the “nfServices” may be any service involved later, such as, for example, FIG. 3A to FIG. 3C "Nsmf_EventExposure" is shown. However, the present disclosure is not limited thereto.

[0191] Similarly, at steps S300a and S300b in 0B, the AF 125 may send a Nnrf_NFManagement_NFRegister request to the NRF 150 to register itself in the NRF 150, and upon successful registration, a Nnrf_NFManagement_NFRegister response may be sent back from the NRF 150 to the AF 125. In some embodiments, the request may include at least one of: a notification URI associated with a specific notification type (pointing to or otherwise associated with the AF 125); and one or more features supported by the AF 125 as a service consumer. In some embodiments, the one or more features may be registered in the NRF 150 as “supportedFeatures” in one of the “defaultNotificationSubscriptions” of one of the “nfServices” of the “NFProfile” of the AF 125, where the “notificationType” in one of the “defaultNotificationSubscriptions” may be “AF_INFLUENCE_EVENT_NOTIFICATION” or “EE_NON_DIRECT_SUBSC” (described below), where the “callbackUri” in one of the “defaultNotificationSubscriptions” may be the notification URI of the AF 125. In some embodiments, one of the “nfServices” may be any service involved later, such as, for example. FIG. 3A to FIG. 3C "Nsmf_EventExposure" is shown. However, the present disclosure is not limited thereto.

[0192] Similarly, at steps S300c and S300d in 0A and / or 0B, SMF 115 may also send a Nnrf_NFManagement_NFRegister request to NRF 150 to register itself in NRF 150, and upon successful registration, a Nnrf_NFManagement_NFRegister response may be sent back from NRF 150 to SMF 115. In some embodiments, the request may include at least one of: a notification URI associated with a specific notification type (pointing to SMF 115 or otherwise associated with SMF 115); and one or more features supported by SMF 115 as a service producer. In some embodiments, the one or more features may be registered in the NRF 150 as “supportedFeatures” in one of the “nfServices” in the “NFProfile” of the SMF 115, wherein the “notificationType” in one of the “defaultNotificationSubscriptions” in one of the “nfServices” in the “NFProfile” may be “AF_INFLUENCE_EVENT_NOTIFICATION” or “EE_NON_DIRECT_SUBSC” (described below), and wherein the “callbackUri” in one of the “defaultNotificationSubscriptions” may be the notification URI of the SMF 115. In some embodiments, one of the “nfServices” may be any service referred to later, such as, for example, FIG. 3A to FIG. 3C "Nsmf_EventExposure" is shown. However, the present disclosure is not limited thereto.

[0193] As defined in subclause 6.1.6.2.4 of TS 29.510, the default notification subscription in the NF profile includes the notification URI for which the network function instance will receive notifications and the features and related services it supports as a NF consumer. In some embodiments, the default notification subscription in the NF profile may include a new notification type (two alternative names are provided, one specific and one generic), as described above:

[0194]

[0195] For example, the request sent from the NEF 145, AF 125, and / or SMF 115 may include a notification URI associated with the new notification type (eg, AF_INFLUENCE_EVENT_NOTIFICATION or EE_NON_DIRECT_SUBSC).

[0196] However, the present disclosure is not limited thereto. In some other embodiments, another notification type name may be used. In addition, in some other embodiments, the NF instance may register a new notification type in a default notification subscription at a level different from the NFProfile. For example, the NF instance may register a new notification type in a default notification subscription at the NFService level, also as described above.

[0197] 1A / 1B and steps S310, S315 and S315a are the same as Figure 2A The steps in 1A / 1B shown and steps S210, S215 and S215a are substantially similar, and therefore, a detailed description thereof may be omitted for simplicity.

[0198] refer to Figure 3B , in box 3.5, before executing step S320a in 4A / 4B, at step S317a, SMF 115 may contact NRF 150 using Nnrf_NFDiscovery service to discover NEF (option A) / AF (option B) instances that support the features required for the service (e.g., SMF event exposure) and whose configuration files include notification URIs that exactly match the provided notification URIs. At step S317b, NRF 150 may provide NEF / AF instances that match the request. Thereafter, SMF 115 may continue the process based on the supported features. If no NF instance is provided, SMF 115 may continue the process assuming that these features are not supported.

[0199] Alternatively, in box ALT:3.5, at step S317a, the SMF 115 may contact the NRF 150 using the Nnrf_NFDiscovery service to discover a NEF / AF instance that includes in its configuration file a notification URI that exactly matches the provided notification URI for the indicated service. The SMF 115 may continue the process with the NEF 145 / AF 125 based on the features supported by the retrieved NEF / AF instance.

[0200] Furthermore, in box 3.5 and / or ALT:3.5, SMF 115 may also indicate a specific notification type that is the same as the notification type used in 0A / 0B, so that NRF 150 may use this parameter to narrow its search scope and provide a response more quickly.

[0201] Some steps in 4A / 4B (e.g., steps S320a, S320b, S320c, S320d, S320e, S320f, S320g, and S320h in 4A and steps S320a, S320b, S320c, and S320d in 4B) are similar to Figure 2B The steps shown (e.g., steps S220a, S220b, S220c, S220d, S220e, S220f, S220g, and S220h in 4A and steps S220a, S220b, S220c, and S220d in 4B) are similar, and therefore, a detailed description thereof may be omitted for simplicity.

[0202] However, if steps S320e and S320g in 4A and / or step S320c in 4B need to be initiated according to the current process, the NEF 145 and / or the AF 125 may contact the NRF 150 using the Nnrf_NFDiscovery service to discover an SMF instance that supports the features required for the service (SMF event exposure) and whose configuration file includes a notification URI that exactly matches the notification URI received in step S320a (both 4A and 4B).

[0203] For example, before executing step S320g in 4A, at step S320x1, NEF 145 can contact NRF 150 using the Nnrf_NFDiscovery service to discover an SMF instance that supports the features required for the service (SMF event exposure) and whose configuration file includes a notification URI that fully matches the provided notification URI. At step S320x2, NRF 150 can provide an SMF instance that matches the request. Afterwards, NEF 145 can continue the process based on the supported features. If no NF instance is provided, NEF 145 can continue the process assuming that these features are not supported.

[0204] Alternatively, at step S320y1, NEF 145 may contact NRF 150 using the Nnrf_NFDiscovery service to discover an SMF instance whose configuration file includes a notification URI that exactly matches the provided notification URI for the indicated service. NEF 145 may continue to perform the process with SMF 115 based on the features supported by the retrieved SMF instance.

[0205] Furthermore, in steps S320x1 and / or S320y1, the NEF 145 may also indicate a specific notification type that is the same as the notification type used in 0A / 0B, so that the NRF 150 may use the parameter to narrow its search range and provide a response more quickly.

[0206] Similarly, before executing step S320c in 4B, AF 125 can use Nnrf_NFDiscovery service to contact NRF 150 to discover SMF instances that support the features required for the service (SMF event exposure) and whose configuration files include notification URIs that fully match the provided notification URIs. At step S320x2, NRF 150 can provide SMF instances that match the request. Afterwards, AF 125 can continue the process based on the supported features. If no NF instance is provided, AF 125 can continue the process assuming that these features are not supported.

[0207] Alternatively, at step S320y1, AF 125 may contact NRF 150 using the Nnrf_NFDiscovery service to discover an SMF instance whose configuration file includes a notification URI that exactly matches the provided notification URI for the indicated service. AF 125 may continue to perform the process with SMF 115 based on the features supported by the retrieved SMF instance.

[0208] Furthermore, in steps S320x1 and / or S320y1, the AF 125 may also indicate a specific notification type that is the same as the notification type used in 0A / 0B, so that the NRF 150 may use the parameter to narrow its search range and provide a response more quickly.

[0209] pass FIG. 3A to FIG. 3C In the illustrated embodiment, at least one of the SMF 115, NEF 145, and AF 125 can discover the features supported by the other party as a service consumer / producer, and based on this, they can determine whether one or more features should be used in communicating with each other. In this way, the features to be used in non-direct subscription notifications can be negotiated or otherwise determined between the relevant parties.

[0210] FIG. 4A to FIG. 4C is a diagram illustrating another exemplary process of feature discovery in a non-direct subscription scenario according to another embodiment of the present disclosure. FIG. 4A to FIG. 4C The embodiment shown is somewhat similar to FIG. 3A to FIG. 3C The embodiments shown are similar.

[0211] For example, at steps S400a to S400d in 0A and / or 0B, at least one of the NEF 145, the AF 125, and the SMF 115 may use the Nnrf_NFManagement_NFRegister service operation to communicate with Figure 3AThe NF profile is registered in the NRF 150 in a similar manner as shown. The default notification subscription in the NF profile may include the notification URIs for which the network function instance will receive notifications and the features and related services it supports as an NF producer and / or NF consumer. The default notification subscription in the NF profile may include new notification types:

[0212]

[0213] FIG. 4A to FIG. 4C The embodiment shown differs from the embodiment shown in at least the following steps: FIG. 3A to FIG. 3C The embodiment shown.

[0214] For example, at step S405a and / or S405e in 1A and / or step 405c in 1B, an NF instance identifier for identifying the NF instance to receive the notification may be added in the corresponding message. In some embodiments, at step S405e in 1A, the NEF 145 may add its NF instance ID to the Npcf_PolicyAuthorization_Create / Update / Delete request message sent to the PCF 120. In some embodiments, at step S405a, the AF 125 may add its NF instance ID to the Nnef_TrafficInfluence_Create / Update / Delete request message sent to the NEF 145, and then at step S405e in 1A, the NEF 145 may add the received NF instance ID of the AF 125 to the Npcf_PolicyAuthorization_Create / Update / Delete request message sent to the PCF 120. In some embodiments, at step S405c in 1B, AF 125 may add its NF instance ID to the Npcf_PolicyAuthorization_Create / Update / Delete request message sent to PCF 120.

[0215] Through the received NF instance ID, at step S410, PCF 120 can send the NF instance ID received in the Npcf_SMPolicyControl_UpdateNotify request message to SMF 115, so that SMF 115 can know the NF instance ID of the recipient of the indirect subscription notification.

[0216] In addition, at block 3.5, before executing step S420a in 4A and / or 4B, at step S417a, SMF 115 may contact NRF 150 using the Nnrf_NFDiscovery service using the received NF instance ID and one or more features that SMF 115 needs to be supported by NEF 145 / AF 125 as a NF service consumer, in order to obtain the relevant NF profile. At step S417b, NRF 150 may provide the NF profile of the NEF / AF instance that matches the request. In some embodiments, SMF 115 may continue the process based on the features supported by the instance.

[0217] Alternatively, at block ALT:3.5, before executing step S420a in 4A and / or 4B, at step S417a, SMF 115 may contact NRF 150 using the received NF instance ID using the Nnrf_NFDiscovery service to obtain the relevant NF profile. At step S417b, NRF 150 may provide the NF profile of the NEF / AF instance matching the request. In some embodiments, SMF 115 may continue the process according to the features supported by the instance.

[0218] In addition, at steps S420a and S420b in 4A and step 420a in 4B, the NF instance identifier may be sent to the NEF 145 and / or the AF 125. If steps S420e and S420g in 4A and / or step 420c in 4B need to be initiated according to the current process, the NEF 145 and / or the AF 125 may obtain the NF instance ID provided by the SMF 115, and at step S420x1 or S420y1, contact the NRF 150 using the Nnrf_NFDiscovery service to discover the SMF profile of the provided instance. At step S420x2 or S420y2, the NRF 150 may provide the SMF profile of the instance that matches the request. The NEF 145 and / or the AF 125 may continue the process according to the supported features. If the NF instance is not provided, the NEF 145 and / or the AF 125 may continue the process under the assumption that no features are supported.

[0219] pass FIG. 4A to FIG. 4C In the illustrated embodiment, at least one of the SMF 115, NEF 145, and AF 125 can discover the features supported by the other party as a service consumer / producer, and based on this, they can determine whether one or more features should be used in communicating with each other. In this way, the features to be used in non-direct subscription notifications can be negotiated or otherwise determined between the relevant parties.

[0220] Figure 5A and Figure 5B FIG. 2 is a diagram showing another exemplary process of feature discovery in a non-direct subscription scenario according to another embodiment of the present disclosure. FIG. 3A to FIG. 3C The embodiment shown or FIG. 4A to FIG. 4C The embodiment shown is different. Figure 5A and Figure 5B In the embodiment shown, no additional signaling from / to the NRF 145 is required. Figure 2A and Figure 2B Compared to the illustrated embodiment, it is apparent that one or more features supported by one party will be explicitly indicated in messages sent to other parties involved in the interested service.

[0221] For example, at steps S505a and S505e in 1A and / or step 505c in 1B, the features supported by the NF instance (e.g., NEF 145 and / or AF 125) are explicitly indicated on the Nsmf API. Similarly, at steps 520a and 520b in 4A and / or step 520a in 4B, the supported features are explicitly indicated to NEF 145 and / or AF 125.

[0222] pass Figure 5A and Figure 5B In the illustrated embodiment, at least one of the SMF 115, NEF 145, and AF 125 can discover the features supported by the other party as a service consumer / producer, and based on this, they can determine whether one or more features should be used in communicating with each other. In this way, the features to be used in non-direct subscription notifications can be negotiated or otherwise determined between the relevant parties.

[0223] Figure 6 6 is a flow chart of an exemplary method 600 at a first network node, the exemplary method 600 being used to determine whether to use one or more first features for notifications from the first network node to a second network node. In some embodiments, the notification may be subscribed to through an indirect subscription operation. The method 600 may be performed by an SMF (e.g., SMF 115). The method 600 may include steps S610 and S620. However, the present disclosure is not limited thereto. In some other embodiments, the method 600 may include more steps, fewer steps, different steps, or any combination thereof. In addition, the steps of the method 600 may be performed in an order different from the order described herein. In addition, in some embodiments, the steps in the method 600 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in the method 600 may be combined into a single step.

[0224] The method 600 may start at step S610, where information indicating whether a second network node supports one or more first features may be received or information from which whether the second network node supports one or more first features may be derived.

[0225] At step S620, it may be determined whether to use one or more first features for the notification based at least on the received information.

[0226] In some embodiments, the indirect subscription operation may be a first service operation associated with the first service and invoked by the third network node in response to a second service operation associated with the second service. In some embodiments, the first service may be different from the second service. In some embodiments, the third network node may be different from the second network node. In some embodiments, at least one of the first service and the second service may be provided by the third network node.

[0227] In some embodiments, the step of receiving the information may include at least one of the following items: receiving a first message from a third network node, the first message indicating a notification URI pointing to the second network node; receiving a first message from the third network node, the first message indicating an NF instance identifier ID of the second network node; and receiving a first message from the third network node, the first message indicating zero or more second features supported by the second network node as an NF service consumer.

[0228] In some embodiments, when the first message indicates a notification URI pointing to the second network node, the step of determining whether to use one or more first features for the notification may include: sending a second message for discovering an NF instance to a fourth network node, the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features required by the first network node as an NF service consumer; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message. In some embodiments, the step of determining whether to use one or more first features for the notification may further include at least one of the following: determining to use one or more first features for the notification in response to at least receiving a third message indicating an NF instance from a fourth network node, and in response to determining that the one or more first features are one or more features associated with a first notification type among zero or more second features indicated by the third message, the first notification type indicating that the notification is subscribed to through an indirect subscription operation; and determining not to use the one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node, or in response to determining that the one or more first features are not one or more features associated with the first notification type among zero or more second features indicated by the third message when the third message indicates an NF instance. In some embodiments, when the second message also indicates the first notification type, the step of determining whether to use one or more first features for the notification may further include at least one of the following: determining to use one or more first features for the notification in response to at least receiving a third message indicating an NF instance from the fourth network node; and determining not to use the one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node.

[0229] In some embodiments, when a first message indicates a notification URI pointing to a second network node, the step of determining whether to use one or more first features for the notification may include: sending a second message to a fourth network node for discovering an NF instance, the NF instance having a notification URI matching the notification URI in its NF configuration file; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein, when the third message indicates one NF instance, the third message may also indicate, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification may also include at least one of the following items: determining that the one or more first characteristics are to be used for the notification in response to at least receiving a third message indicating an NF instance from a fourth network node, and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, the first notification type indicating that the notification is subscribed to through a non-direct subscription operation; and determining not to use the one or more first characteristics for the notification in response to at least receiving a third message indicating that there is no NF instance from the fourth network node, or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance.

[0230] In some embodiments, when a first message indicates a notification URI pointing to a second network node, the step of determining whether to use one or more first features for the notification may include: sending a second message to a fourth network node for discovering an NF instance, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with a first notification type, the first notification type indicating that the notification is subscribed to through an indirect subscription operation; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein, when the third message indicates one NF instance, the third message may also indicate, for the indicated NF instance and for the first notification type, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification may also include at least one of the following items: determining that one or more first characteristics are to be used for the notification at least in response to receiving a third message indicating an NF instance from a fourth network node and in response to determining that the one or more first characteristics are one or more characteristics among zero or more second characteristics; and determining not to use one or more first characteristics for the notification at least in response to receiving a third message indicating that there is no NF instance from the fourth network node or in response to determining that the one or more first characteristics are not one or more characteristics among zero or more second characteristics when the third message indicates an NF instance.

[0231] In some embodiments, when the first message indicates the NF instance ID of the second network node, the step of determining whether to use one or more first features for the notification may include: sending a second message for discovering an NF instance to a fourth network node, the NF instance having the NF instance ID indicated in the first message and supporting one or more first features required by the first network node as an NF service consumer; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message. In some embodiments, the step of determining whether to use one or more first features for the notification may also include at least one of the following items: determining to use one or more first features for the notification in response to at least receiving a third message indicating one NF instance from the fourth network node, and in response to determining that the one or more first features are one or more features associated with a first notification type among zero or more second features indicated by the third message, the first notification type indicating that the notification is subscribed through a non-direct subscription operation; and determining not to use one or more first features for the notification in response to at least receiving a third message indicating no NF instance from the fourth network node, or in response to determining that the one or more first features are not one or more features associated with a first notification type among zero or more second features indicated by the third message when the third message indicates one NF instance.

[0232] In some embodiments, when the first message indicates the NF instance ID of the second network node, the step of determining whether to use one or more first features for the notification may include: sending a second message for discovering an NF instance to a fourth network node, the NF instance having the NF instance ID indicated in the first message; and / or receiving a third message indicating zero or one NF instance from the fourth network node in response to the second message, wherein when the third message indicates one NF instance, the third message may also indicate, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer. In some embodiments, the step of determining whether to use one or more first characteristics for the notification may also include at least one of the following items: determining that the one or more first characteristics are to be used for the notification in response to at least receiving a third message indicating an NF instance from a fourth network node, and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, the first notification type indicating that the notification is subscribed to through a non-direct subscription operation; and determining not to use the one or more first characteristics for the notification in response to at least receiving a third message indicating that there is no NF instance from the fourth network node, or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance.

[0233] In some embodiments, when the first message indicates that the second network node as the NF service consumer supports zero or more second features, the step of determining whether to use one or more first features for the notification may include at least one of the following items: determining that the one or more first features are to be used for the notification at least in response to determining that the zero or more second features supported by the second network node include one or more first features; and determining not to use the one or more first features for the notification at least in response to determining that the zero or more second features supported by the second network node do not include one or more first features.

[0234] In some embodiments, before the step of determining whether to use one or more first features for the notification, method 600 may also include: sending a fourth message to a fourth network node, the fourth message indicating at least one of the following items: a notification URI pointing to the first network node and associated with the first notification type (which indicates that the notification is subscribed to through a non-direct subscription operation), zero or more third features supported by the first network node as an NF service producer, and the NF instance ID of the first network node.

[0235] In some embodiments, the method 600 may further include: sending a fifth message as the notification to the second network node, wherein the one or more first features are used based at least on the determination of whether the one or more first features are to be used for the notification. In some embodiments, the fifth message may further indicate at least one of the following items: a notification URI pointing to the first network node; an NF instance ID of the first network node; and zero or more third features supported by the first network node as an NF service producer.

[0236] In some embodiments, at least one of the following situations may be true: the first network node may be an SMF; the second network node may be an NEF or an AF; the third network node may be a PCF; the fourth network node may be an NRF; the first message may be an Npcf_SMPolicyControl_UpdateNotify request message; the second message may be an Nnrf_NFDiscovery_Request request message; the third message may be an Nnrf_NFDiscovery_Request response message; the fourth message may be an Nnrf_NFManagement_NFRegister request message; and the fifth message may be an Nsmf_EventExposure_Notify request message.

[0237] Figure 7 700 is a flow chart of an example method 700 at a second network node, the method 700 being used to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to the second network node. In some embodiments, the notification may be subscribed to through an indirect subscription operation. The method 700 may be performed by an NEF or an AF (e.g., NEF 145 or AF 125). The method 700 may include step S710. However, the present disclosure is not limited thereto. In some other embodiments, the method 700 may include more steps, different steps, or any combination thereof. In addition, the steps of the method 700 may be performed in an order different from the order described herein. In addition, in some embodiments, the steps in the method 700 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in the method 700 may be combined into a single step.

[0238] Method 700 may start at step S710, where information indicating whether a second network node supports one or more first features or information from which whether the second network node supports one or more first features can be sent to a third network node different from the first network node.

[0239] In some embodiments, the non-direct subscription operation may be a first service operation, which may be associated with the first service, and the first service operation may be called by the third network node in response to a second service operation associated with the second service. In some embodiments, the first service may be different from the second service. In some embodiments, the third network node may be different from the second network node. In some embodiments, at least one of the first service and the second service may be provided by the third network node. In some embodiments, the step of sending the information may include at least one of the following items: sending a sixth message indicating a notification URI to the third network node, the notification URI pointing to the second network node; sending a sixth message to the third network node, the sixth message indicating the NF instance ID of the second network node; and sending a sixth message to the third network node, the sixth message indicating zero or more second features supported by the second network node as an NF service consumer.

[0240] In some embodiments, before the step of sending the information, the method 700 may further include: sending a seventh message to the fourth network node, the seventh message indicating at least one of the following items: a notification URI pointing to the second network node and associated with the first notification type (which indicates that the notification is subscribed through a non-direct subscription operation), one or more second features supported by the second network node as an NF service consumer, and the NF instance ID of the second network node. In some embodiments, the method 700 may further include: receiving a fifth message as the notification from the first network node, wherein the one or more first features are used based at least on the information sent to the third network node. In some embodiments, the fifth message may further indicate at least one of the following items: another notification URI pointing to the first network node; the NF instance ID of the first network node; and zero or more third features supported by the first network node as an NF service producer.

[0241] In some embodiments, when the fifth message indicates another notification URI pointing to the first network node, the method 700 may further include: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having a notification URI matching the other notification URI in its NF configuration file and supporting one or more fourth features required by the second network node as an NF service producer; and / or receiving a ninth message indicating zero or one NF instance from the fourth network node in response to the eighth message. In some embodiments, the method 700 may further include at least one of the following items: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving a ninth message indicating one NF instance from the fourth network node; and determining not to use one or more fourth features for another notification in response to at least receiving a ninth message indicating no NF instance from the fourth network node.

[0242] In some embodiments, when the fifth message indicates another notification URI pointing to the first network node, the method 700 may further include: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having a notification URI matching the other notification URI in its NF configuration file; and / or receiving a ninth message from the fourth network node in response to the eighth message, the ninth message indicating zero or one NF instance, wherein when the ninth message indicates one NF instance, the ninth message may also indicate, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer. In some embodiments, the method 700 may further include at least one of the following items: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving the ninth message indicating one NF instance from the fourth network node, and in response to determining that the one or more fourth features are one or more of the zero or more third features; and determining not to use one or more fourth features for another notification in response to at least receiving the ninth message indicating no NF instance from the fourth network node, or in response to determining that the one or more fourth features are not one or more of the zero or more third features when the ninth message indicates one NF instance.

[0243] In some embodiments, when the fifth message indicates the NF instance ID of the first network node, the method 700 may further include: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having the NF instance ID indicated in the fifth message and supporting one or more fourth features required by the second network node as an NF service producer; and / or receiving a ninth message indicating zero or one NF instance from the fourth network node in response to the eighth message. In some embodiments, the method 700 may further include at least one of the following items: determining to use one or more fourth features for another notification from the second network node to the first network node in response to at least receiving a ninth message indicating one NF instance from the fourth network node; and determining not to use one or more fourth features for another notification in response to at least receiving a ninth message indicating no NF instance from the fourth network node.

[0244] In some embodiments, when the fifth message indicates the NF instance ID of the first network node, the method 700 may further include: sending an eighth message for discovering an NF instance to the fourth network node, the NF instance having the NF instance ID indicated in the fifth message; and / or receiving a ninth message from the fourth network node in response to the eighth message, the ninth message indicating zero or one NF instance, wherein when the ninth message indicates one NF instance, the ninth message may further indicate, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer. In some embodiments, the method 700 may further include at least one of the following items: determining to use the one or more fourth features for another notification from the second network node to the first network node in response to at least receiving the ninth message indicating one NF instance from the fourth network node, and in response to determining that the one or more fourth features are one or more of the zero or more third features; and determining not to use the one or more fourth features for another notification in response to at least receiving the ninth message indicating no NF instance from the fourth network node, or in response to determining that the one or more fourth features are not one or more of the zero or more third features when the ninth message indicates one NF instance.

[0245] In some embodiments, when the fifth message indicates zero or more third features supported by the first network node as an NF service producer, the method 700 may further include at least one of the following items: at least in response to determining that the zero or more third features supported by the first network node include one or more fourth features, determining that the one or more fourth features are to be used for another notification from the second network node to the first network node; and at least in response to determining that the zero or more third features supported by the first network node do not include one or more fourth features, determining not to use the one or more fourth features for another notification. In some embodiments, the method 700 may further include: sending a tenth message as another notification to the first network node, wherein the one or more fourth features are used based at least on the determination of whether the one or more fourth features are to be used for another notification. In some embodiments, at least one of the following situations may be true: the first network node may be an SMF; the second network node may be an NEF or an AF; the third network node may be a PCF; the fourth network node may be an NRF; the fifth message may be an Nsmf_EventExposure_Notify request message; the sixth message may be an Npcf_PolicyAuthorization_Create request message, an Npcf_PolicyAuthorization_Update request message, or an Npcf_PolicyAuthorization_Delete request message; the seventh message may be an Nnrf_NFManagement_NFRegister request message; the eighth message may be an Nnrf_NFDiscovery_Request request message; the ninth message may be an Nnrf_NFDiscovery_Request response message; and the tenth message may be an Nsmf_EventExposure_AppRelocationInfo request message.

[0246] Figure 8 800 is a flow chart of an exemplary method 800 at a third network node, the exemplary method 800 being used to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node. In some embodiments, the notification may be subscribed to through an indirect subscription operation. The method 800 may be performed by a PCF (e.g., PCF 120). The method 800 may include step S810. However, the present disclosure is not limited thereto. In some other embodiments, the method 800 may include more steps, different steps, or any combination thereof. In addition, the steps of the method 800 may be performed in an order different from the order described herein. In addition, in some embodiments, the steps in the method 800 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in the method 800 may be combined into a single step.

[0247] The method 800 may start at step S810, where information indicating whether a second network node supports one or more first features may be forwarded to a first network node or information from which whether the second network node supports one or more first features may be derived.

[0248] In some embodiments, the non-direct subscription operation may be a first service operation, which may be associated with the first service, and the first service operation may be called by the third network node in response to a second service operation associated with the second service. In some embodiments, the first service may be different from the second service. In some embodiments, the third network node may be different from the second network node and / or the first network node. In some embodiments, at least one of the first service and the second service may be provided by the third network node. In some embodiments, the step of forwarding the information may include at least one of the following items: receiving a sixth message from the second network node, the sixth message indicating a notification URI pointing to the second network node; and sending a first message indicating the notification URI to the first network node; receiving a sixth message indicating the NF instance ID of the second network node from the second network node, and sending a first message indicating the NF instance ID to the first network node; and receiving a sixth message from the second network node, the sixth message indicating zero or more second features supported by the second network node as a NF service consumer, and sending a first message indicating the zero or more second features to the first network node. In some embodiments, at least one of the following situations may be true: the first network node may be an SMF; the second network node may be an NEF or an AF; the third network node may be a PCF; the first message may be an Npcf_SMPolicyControl_UpdateNotify request message; and the sixth message may be an Npcf_PolicyAuthorization_Create request message, an Npcf_PolicyAuthorization_Update request message, or an Npcf_PolicyAuthorization_Delete request message.

[0249] Fig. 9is a flow chart of an exemplary method 900 at a fourth network node, the exemplary method 900 being used to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node. In some embodiments, the notification may be subscribed to through a non-direct subscription operation. Method 900 may be performed by an NRF (e.g., NRF 150). Method 900 may include steps S910, S920, and S930. However, the present disclosure is not limited thereto. In some other embodiments, method 900 may include more steps, fewer steps, different steps, or any combination thereof. In addition, the steps of method 900 may be performed in an order different from the order described herein. In addition, in some embodiments, the steps in method 900 may be split into multiple sub-steps and performed by different entities, and / or multiple steps in method 900 may be combined into a single step.

[0250] The method 900 may start at step S910 , where first information may be received from a first network node, from which it may be derived whether a second network node supports one or more first features.

[0251] At step S920, second information may be determined based at least on the first information, the second information indicating whether the second network node supports one or more first features.

[0252] At step S930, second information may be sent to the first network node.

[0253] In some embodiments, the indirect subscription operation may be a first service operation, which may be associated with the first service and may be called by a third network node in response to a second service operation associated with the second service. In some embodiments, the first service may be different from the second service. In some embodiments, the third network node may be different from the second network node and / or the first network node. In some embodiments, at least one of the first service and the second service may be provided by a third network node. In some embodiments, the first information may include at least one of the following items: information indicating a notification URI pointing to the second network node; information indicating an NF instance ID of the second network node; information indicating one or more first features; and information indicating a first notification type, the first notification type indicating that the notification is subscribed to via an indirect subscription operation.

[0254] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features required by the first network node as a NF service consumer, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features as a NF service consumer, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated in the third message, the third message may also indicate, for each notification type registered by the indicated NF instance at the fourth network node, more than zero second features supported by the indicated NF instance as a NF service consumer.

[0255] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and supporting one or more first features required by the first network node and associated with the first notification type as a NF service consumer, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and supporting one or more first features associated with the first notification type as a NF service consumer, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node.

[0256] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI matching the notification URI in its NF configuration file, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated by the third message, the third message may also indicate, for each notification type registered by the indicated NF instance at the fourth network node, zero or more second features supported by the indicated NF instance as an NF service consumer.

[0257] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated by the third message, the third message may also indicate, for the first notification type, zero or more second features supported by the NF instance as an NF service consumer.

[0258] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having the NF instance ID of the second network node and supporting one or more first features required by the first network node as a NF service consumer, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having the NF instance ID indicated in the second message and supporting one or more first features as a NF service consumer, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node, and / or wherein, when one NF instance is determined and indicated in the third message, the third message may also indicate, for each notification type registered by the indicated NF instance at the fourth network node, more than zero second features supported by the indicated NF instance as a NF service consumer.

[0259] In some embodiments, the step of receiving the first information may include: receiving a second message for discovering an NF instance from the first network node, the NF instance having an NF instance ID indicated in the first message, and / or wherein the step of determining the second information may include: determining zero or one NF instance from one or more NF instances registered at a fourth network node, the zero or one NF instance having an NF instance ID indicated in the second message, and / or wherein the step of sending the second information may include: sending a third message indicating zero or one NF instance to the first network node in response to the second message, and / or wherein, when one NF instance is determined and indicated by the third message, the third message may also indicate, for each notification type registered by the indicated NF instance at the fourth network node, zero or more second features supported by the indicated NF instance as an NF service consumer.

[0260] In some embodiments, before the step of receiving the first information, method 900 may also include at least one of the following items: receiving a fourth message from the first network node, the fourth message indicating at least one of the following items: a notification URI pointing to the first network node and associated with the first notification type, zero or more third features supported by the first network node as an NF service producer, and the NF instance ID of the first network node; and receiving a seventh message from the second network node, the seventh message indicating at least one of the following items: a notification URI pointing to the second network node and associated with the first notification type, one or more second features supported by the second network node as an NF service consumer, and the NF instance ID of the second network node.

[0261] In some embodiments, the method 900 may further include: receiving third information from the second network node, from which it is possible to derive whether the first network node supports one or more fourth features; and / or determining fourth information based at least on the third information, the fourth information indicating whether the first network node supports one or more fourth features; and / or sending the fourth information to the second network node. In some embodiments, the third information may include at least one of the following items: information indicating another notification URI pointing to the first network node; information indicating the NF instance ID of the first network node; information indicating one or more fourth features; and information indicating a first notification type, the first notification type indicating that the notification is subscribed through an indirect subscription operation. In some embodiments, the step of receiving the third information may include: receiving an eighth message for discovering NF instances from the second network node, the NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features required by the second network node as a NF service producer, and / or wherein the step of determining the fourth information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features as a NF service producer, and / or wherein the step of sending the fourth information may include: sending a ninth message indicating zero or one NF instance to the second network node.

[0262] In some embodiments, the step of receiving the third information may include: receiving an eighth message for discovering NF instances from the second network node, the eighth message having a notification URI matching the other notification URI in its NF profile, and / or wherein the step of determining the fourth information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having a notification URI matching the other notification URI in its NF profile, and / or wherein the step of sending the fourth information may include: sending a ninth message indicating zero or one NF instance to the second network node, and / or wherein, when one NF instance is determined and indicated by the ninth message, the ninth message may also indicate zero or more third features supported by the indicated NF instance as an NF service producer.

[0263] In some embodiments, the step of receiving the third information may include: receiving an eighth message for discovering an NF instance from the second network node, the NF instance having the NF instance ID of the first network node and supporting one or more fourth features required by the second network node as a NF service producer, and / or wherein the step of determining the fourth information may include: determining zero or one NF instance from one or more NF instances registered with the fourth network node, the zero or one NF instance having the NF instance ID of the first network node and supporting one or more fourth features as a NF service producer, and / or wherein the step of sending the fourth information may include: sending a ninth message indicating zero or one NF instance to the second network node.

[0264] In some embodiments, the step of receiving the third information may include: receiving an eighth message for discovering NF instances from the second network node, the eighth message having the NF instance ID of the first network node, and / or wherein the step of determining the fourth information may include: determining zero or one NF instance from one or more NF instances registered at the fourth network node, the zero or one NF instance having the NF instance ID of the first network node, and / or wherein the step of sending the fourth information may include: sending a ninth message indicating zero or one NF instance to the second network node, and / or wherein, when one NF instance is determined and indicated by the ninth message, the ninth message may also indicate zero or more third features supported by the indicated NF instance as an NF service producer.

[0265] In some embodiments, at least one of the following situations may be true: the first network node may be an SMF; the second network node may be an NEF or an AF; the fourth network node may be an NRF; the second message may be an Nnrf_NFDiscovery_Request request message; the third message may be an Nnrf_NFDiscovery_Request response message; the fourth message may be an Nnrf_NFManagement_NFRegister request message; the seventh message may be an Nnrf_NFManagement_NFRegister request message; the eighth message may be an Nnrf_NFDiscovery_Request request message; and the ninth message may be an Nnrf_NFDiscovery_Request response message.

[0266] Fig.10Schematically illustrates an embodiment of an arrangement that can be used in one or more network nodes (e.g., SMF, NEF / AF, PCF and / or NRF) according to an embodiment of the present disclosure. The arrangement 1000 includes a processing unit 1006, for example, having a digital signal processor (DSP) or a central processing unit (CPU). The processing unit 1006 can be a single unit or multiple units for performing different actions of the processes described herein. The arrangement 1000 can also include an input unit 1002 for receiving signals from other entities, and an output unit 1004 for providing signals to other entities. The input unit 1002 and the output unit 1004 can be arranged as an integrated entity or a separate entity.

[0267] Furthermore, the arrangement 1000 may include at least one computer program product 1008 in the form of a non-volatile or volatile memory, such as an electrically erasable programmable read-only memory (EEPROM), a flash memory and / or a hard drive. The computer program product 1008 includes a computer program 1010, which includes code / computer-readable instructions that, when executed by the processing unit 1006 in the arrangement 1000, causes the arrangement 1000 or a network node including the arrangement 1000 to perform, for example, the above-described operations in conjunction with Figures 2A to 9 acts or any other variations of the processes described.

[0268] The computer program 1010 may be configured as computer program code constructed in computer program modules 1010A and 1010B. Thus, in an exemplary embodiment, when the arrangement 1000 is used in a first network node to determine whether one or more first features are to be used for a notification from the first network node to a second network node and the notification is subscribed to by an indirect subscription operation, the code in the computer program of the arrangement 1000 comprises: a module 1010A configured to receive information indicating whether the second network node supports the one or more first features or information from which it can be derived whether the second network node supports the one or more first features; and a module 1010B configured to determine whether the one or more first features are to be used for the notification based at least on the received information. In some embodiments, the first network node may comprise a module configured to perform a reference Figure 6 One or more further modules of one or more steps of any of the methods described.

[0269] Additionally or alternatively, the computer program 1010 may be configured as a computer program code constructed in a computer program module 1010C. Thus, in an exemplary embodiment, when the arrangement 1000 is used in a second network node to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to the second network node and the notifications are subscribed to by an indirect subscription operation, the code in the computer program of the arrangement 1000 comprises: a module 1010C configured to send information indicating whether the second network node supports the one or more first features or information from which it can be derived whether the second network node supports the one or more first features to a third network node different from the first network node. In some embodiments, the second network node may include a module configured to perform a reference Figure 7 One or more further modules of one or more steps of any of the methods described.

[0270] Additionally or alternatively, the computer program 1010 may be configured as a computer program code constructed in a computer program module 1010D. Thus, in an exemplary embodiment, when the arrangement 1000 is used in a third network node to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node and the notifications are subscribed to by an indirect subscription operation, the code in the computer program of the arrangement 1000 comprises: a module 1010D configured to forward information indicating whether the second network node supports the one or more first features or information from which it can be derived whether the second network node supports the one or more first features from the second network node to the first network node. In some embodiments, the third network node may comprise a module configured to perform a reference Figure 8 One or more further modules of one or more steps of any of the methods described.

[0271] Additionally or alternatively, the computer program 1010 may be configured as computer program code constructed in computer program modules 1010E, 1010F, and 1010G. Thus, in an exemplary embodiment, when the arrangement 1000 is used in a fourth network node to facilitate a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node and the notification is subscribed to by an indirect subscription operation, the code in the computer program of the arrangement 1000 includes: a module 1010E configured to receive first information from the first network node, from which it is possible to derive whether the second network node supports the one or more first features; a module 1010F configured to determine second information based at least on the first information, the second information indicating whether the second network node supports the one or more first features; and a module 1010G configured to send the second information to the first network node. In some embodiments, the fourth network node may include a module configured to perform a reference Fig. 9 One or more further modules of one or more steps of any of the methods described.

[0272] A computer program module can basically execute Figures 2A to 9 In other words, when different computer program modules are executed in the processing unit 1006, they may correspond to different modules in the network node.

[0273] Although the above combination Fig.10 The code means in the disclosed embodiments are implemented as computer program modules (which, when executed in a processor, cause the arrangement to perform the actions described above in conjunction with the above figures), but in alternative embodiments, at least one code means may be at least partially implemented as a hardware circuit.

[0274] The processor may be a single CPU (central processing unit), but may also include two or more processing units. For example, the processor may include a general-purpose microprocessor; an instruction set processor and / or an associated chipset and / or a dedicated microprocessor, such as an application-specific integrated circuit (ASIC). The processor may also include on-board memory for cache purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may include a computer-readable medium on which the computer program is stored. For example, the computer program product may be a flash memory, a random access memory (RAM), a read-only memory (ROM) or an EEPROM, and the above-mentioned computer program modules may be distributed on different computer program products in the form of memory within the network node in an alternative embodiment.

[0275] Corresponding to the method 600 described above, an exemplary first network node for determining whether to use one or more first features for notification from the first network node to the second network node is provided. In some embodiments, the notification may be subscribed to through an indirect subscription operation. Fig.11 1 is a block diagram of a first network node 1100 according to an embodiment of the present disclosure. In some embodiments, the first network node 1100 may be, for example, an SMF 115.

[0276] The first network node 1100 may be configured to perform the above Fig.11 The method 600 is described. Fig.11 As shown, the first network node 1100 may include: a receiving module 1000, configured to receive information indicating whether the second network node supports one or more first features or information from which whether the second network node supports one or more first features can be derived; and a determination module 1120, configured to determine whether to use one or more first features for the notification based at least on the received information.

[0277] The modules 1110 and / or 1120 described above may be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of the following: a processor or microprocessor and appropriate software and a memory for storing software, a programmable logic device (PLD) or other electronic components or a device configured to perform the above and, for example, Figure 6 In addition, the first network node 1100 may include one or more additional modules, each of which may execute the reference Figure 6 Any of the steps of method 600 described.

[0278] Corresponding to the method 700 described above, an exemplary second network node is provided for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to the second network node. In some embodiments, the notification may be subscribed to through an indirect subscription operation. Fig.12 is a block diagram of a second network node 1200 according to an embodiment of the present disclosure. In some embodiments, the second network node 1200 may be, for example, a NEF 145 or an AF 125.

[0279] The second network node 1200 may be configured to perform the above combined Fig.10 The method 700 is described. Fig.12 As shown, the second network node 1200 may include a sending module 1210 configured to send information indicating whether the second network node supports one or more first features or information from which whether the second network node supports one or more first features can be derived to a third network node different from the first network node.

[0280] The module 1210 described above can be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of the following: a processor or microprocessor and appropriate software and a memory for storing software, a PLD or other electronic component or a device configured to perform the above and, for example, Figure 7 In addition, the second network node 1200 may include one or more additional modules, each of which may execute the reference Figure 7 Any of the steps of method 700 described.

[0281] Corresponding to the method 800 described above, an exemplary third network node is provided for facilitating a first network node to determine whether to use one or more first features for notification from the first network node to a second network node. In some embodiments, the notification may be subscribed to through an indirect subscription operation. Fig.13 1 is a block diagram of a third network node 1300 according to an embodiment of the present disclosure. In some embodiments, the third network node 1300 may be, for example, the PCF 120.

[0282] The third network node 1300 may be configured to perform the above combined Figure 8 The method 800 is described. Fig.13 As shown, the third network node 1300 may include a forwarding module 1310 configured to forward information indicating whether the second network node supports one or more first features or information from which it can be derived whether the second network node supports one or more first features from the second network node to the first network node.

[0283] The module 1310 described above can be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of the following: a processor or microprocessor and appropriate software and a memory for storing software, a PLD or other electronic component or a device configured to perform the above and, for example, Figure 8 In addition, the third network node 1300 may include one or more additional modules, each of which may execute the reference Figure 8 Any of the steps of method 800 described.

[0284] Corresponding to the method 900 described above, an exemplary fourth network node for facilitating a first network node to determine whether to use one or more first features for notifications from the first network node to a second network node is provided. In some embodiments, notifications may be subscribed to through an indirect subscription operation. Fig.14 1 is a block diagram of a fourth network node 1400 according to an embodiment of the present disclosure. In some embodiments, the fourth network node 1400 may be, for example, the NRF 150.

[0285] The fourth network node 1400 may be configured to perform the above combination Fig. 9 The method 900 is described. Fig.14 As shown, the fourth network node 1400 may include: a receiving module 1410, configured to receive first information from the first network node, from which it is possible to derive whether the second network node supports one or more first features; a determining module 1420, configured to determine second information based at least on the first information, the second information indicating whether the second network node supports one or more first features; and a sending module 1430, configured to send the second information to the first network node.

[0286] The modules 1410, 1420 and / or 1430 described above may be implemented as a pure hardware solution or a combination of software and hardware, for example, by one or more of the following: a processor or microprocessor and appropriate software and a memory for storing the software, a PLD or other electronic component or a device configured to perform the above and, for example, Fig. 9 In addition, the first network node 1400 may include one or more additional modules, each of which may execute the reference Fig. 9 Any of the steps of method 900 described.

[0287] The present disclosure has been described above with reference to the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. A person skilled in the art may make various modifications and variations without departing from the scope of the present disclosure, wherein these modifications and variations all fall within the scope of the present disclosure.

[0288] Appendix A

[0289] 3GPP TSG-CT WG3 Meeting #123e C3-224xxx

[0290] Electronic Conference, August 18-26, 2022

[0291] Source: Ericsson

[0292] Title: Support for negotiation of characteristics when subscribing to notifications via an indirect path

[0293] Documents: Discussion and Agreement

[0294] Agenda item: 17.xx (CT3)

[0295] Work item / version: eEDGE_5GC / Release 17

[0296] Summary of contributions:

[0297] The handling of negotiation of supported features between peers in scenarios where notifications are subscribed indirectly via an indirect path cannot be addressed using the mechanisms defined in TS 29.500. CT3 has considered using NRF for this purpose. However, the current specification of the Nnrf service does not allow discovery of features supported by a specific NF instance when only the notification URI associated with the instance is known. This paper proposes three solutions to address this issue with the goal of reaching agreement on one of the solutions for introduction in the specification.

[0298] 1. Introduction

[0299] The 5G Core Network allows a service consumer NF to explicitly or implicitly subscribe to notifications about data changes on any type of resource. An implicit subscription is a subscription that is not explicitly created through a dedicated subscription operation (see TS 29.501, clause 4.6.2.2.1).

[0300] There are also other types of subscriptions where the NF Provider subscribes using a different service and path than the one used in the requested notification. Some examples of subscriptions applicable to this scenario related to the PCC functionality are shown here:

[0301] - The AF can send a request to influence the SMF's routing decision for the user plane traffic of a PDU Session, as described in 3GPP TS29.513, clause 5.5.3. In this case, the AF uses the PCC framework (directly via the PCF or using the NEF and UDR when not targeting a single UE address) to indicate its subscription to SMF events (e.g. UP path change). The SMF receives the subscription information provided in the PCC rules, i.e. the event and the AF / NEF notification URI. The SMF will notify the AF directly (for external applications, via the NEF).

[0302] - The AF may provide service parameter data to the PCF, which may generate URSP rules for the UE as described in 3GPP TS29.513, clause 5.5.8. In addition, the AF may subscribe to receive notifications about the results of the URSP rule delivery. The AF subscription is indicated to the PCF as service parameter data (i.e., events and AF / NEF notification URIs) stored in the UDR, i.e., the service parameter data provided in the UDR includes the events and AF / NEF notification URIs.

[0303] In these cases, the network function that needs to be notified needs to provide the event and the notification URI through the PCC framework. The notification URI indicates the final recipient of the event notification.

[0304] It is possible that the NF (service) consumer needs to initiate a new notification as a response to a notification generated as a result of an indirect subscription (i.e., a callback to a received notification). In the first case above (see e.g. TS 29.513, clause 5.5.3, steps (4b, 4c)), the AF / NEF may need to interact with the SMF upon receiving a notification about a UP path change, in response to the fact that application relocation is possible.

[0305] 3GPP 5G CN supports a mechanism for negotiating optional features applicable to each 5G API. Both NF Service Consumer and NF Service Producer can directly negotiate support for optional features as part of the interface, as described in subclause 6.6 of 3GPP TS29.500. This negotiation requires direct interaction between peers and occurs during resource creation or resource data retrieval. Therefore, for the above scenario, the network function cannot utilize this mechanism because there is no direct communication to negotiate the features.

[0306] 3GPP 5G CN also supports a discovery mechanism that enables core network entities to discover a set of NF instances and NF service instances for a specific NF service or NF type. NF service discovery is implemented via the Network Repository Function (NRF). NRF saves information about the NF (service) profiles of NF (service) instances that have been previously registered. Features supported by NF (service) instances as NF service producers and NF service consumers can be stored as part of the NF profile.

[0307] CT3 has discussed feature negotiation for these specific cases in the context of edge computing, and decided to use NRF so that the sender of a notification / callback can discover the features supported by the receiver before initiating the notification. For example, in TS29.513, clause 5.5.3.2, steps 4e to 4h:

[0308] If the NEF determines that the SMF has been contacted via the Nnrf_NFDiscovery service as defined in 3GPP TS 29.510

[51] Operation supports the "EASIPreplacement" feature, The NEF then notifies the SMF of the EAS IP replacement information as described in 3GPP TS 29.508[8]. The AF may provide the NEF with an indication of the need to buffer uplink traffic to the target DNAI. Then, if The NEF determines that the SMF supports the Nnrf_NFDiscovery service operation as defined in 3GPP TS 29.510

[51] . "ULBuffering" feature, The NEF then notifies the SMF of the indication as described in 3GPP TS 29.508[8].

[0309] The network function in the above CT3 scenario only knows the notification URI to which the notification will be sent. However, the NRF cannot discover the NF profile associated with the notification URI.

[0310] Therefore, some additional provisions may be required in the NRF and / or PCC framework in order to implement the previously agreed solutions.

[0311] 2. Discussion

[0312] 2.1 Overview

[0313] In order for a network function to discover the features supported by another network function:

[0314] - It needs to initiate notification to the NF that has subscribed via the indirect path

[0315] - It needs to initiate a notification (callback) to this NF as a response to a previous notification that occurred based on a subscription via an indirect path

[0316] Different alternatives are possible:

[0317] Alternative A: Solution based on registering the Notification URI as part of the NF Service Profile in NRF.

[0318] Alternative B: Solution based on registering the NF Instance Identifier as part of the NF Service Profile in NRF.

[0319] Alternative C: Solution based on using indirect path and Notify request to send supported features list. No NRF required.

[0320] 2.2 Alternative A: NotificationUri-based solution

[0321] The solution proposes that a network function that indirectly subscribes to receive direct notifications from a certain network function registers the notification URI (which is sent through the indirect path (PCC framework in CT3 scenario)) along with the features supported as a NF service consumer. For the case of callbacks to the received indirect subscription-based notifications, the network function that originates the notification also registers the notification URI as part of the NF profile.

[0322] In the case where AF affects service routing, AF / NEF registers the same notification URI sent to SMF via PCF in NRF. When SMF needs to initiate notification to AF / NEF, it will use the received notification URI to contact NRF to obtain the features supported by AF / NEF as NF service consumer.

[0323] Similarly, when NEF / AF needs to interact with SMF (callback on received notification), NEF / AF will contact NRF using the received SMF notification URI (not included in the existing NRF-specified process) to obtain the features supported by SMF as NF Service Producer.

[0324] 2.3 Alternative B: NfInstanceId-based solution

[0325] This solution is similar to the previous one but more straightforward as it identifies the characteristic backed by the real NF instance ID that initiated the indirect subscription.

[0326] The solution proposes that: A network function that subscribes indirectly to receive direct notifications registers its NF instance ID along with the features it supports as a NF service consumer. In addition, the NF instance ID should always be sent from the notification receiver to the notification initiator via the PCC framework. An NF instance that initiates a notification based on an indirect subscription and expects to receive new notifications from the receiver registers the NF profile of its NF instance ID in the NRF along with the features it supports as a NF service provider using the existing procedures.

[0327] In case of AF affecting service routing, AF / NEF registers the same NF instance ID that it will send to SMF via PCF along with the features it supports as a NF service consumer in NRF. When SMF needs to initiate notification to AF / NEF, it will contact NRF using the received NF instance ID to obtain the features that AF / NEF supports as a NF service consumer.

[0328] When the SMF expects further interaction from the NEF as a result of the triggered notification, the SMF includes the NF instance ID in the notification request together with the SMF notification URI. When the AF / NEF needs to initiate subsequent notifications to the SMF, it will use the received NF instance ID to contact the NRF to obtain the supported features of the SMF instance for the Nsmf_EventExposure service.

[0329] 2.3 Alternative C: Solution based on sending supported features via PCC

[0330] This solution proposes an indirect subscription to receive direct notifications from another network function. A network function sends a list of supported features via an indirect path. In the scenario where the AF affects the service routing, the AF / NEF includes the supported features in the interaction with the PCF and / or UDR and propagates it to the SMF. Based on this information, the SMF can easily find out which features the NEF / AF supports and can provide the negotiated features to the AF / NEF in the notification request.

[0331] The alternative may also be based on the definition of capabilities or functions rather than the current definition of features. Certain attributes of the information conveyed may be provided as part of the distributed payload.

[0332] This solution does not require any interaction with NRF.

[0333] 2.4 Analysis

[0334] The first alternative and the second alternative are based on the same principle, although using different information elements.

[0335] Alternative A requires associating the features supported by the NF service consumer / producer with their corresponding notification URIs in the NRF. The notification URI will also be used as a query parameter during the discovery process.

[0336] Alternative B requires the introduction of NF Instance ID in different interfaces affected by the indirect subscription path, so that the originator of the notification can use it to query the NRF for the supported features. The NF Instance ID should also be added as part of the payload to be sent by the sender of the notification (which requires a callback to the notification request), so that the receiver can use it to query the NRF to find out the features it supports.

[0337] Alternative C does not have any impact on the Nnrf service. Instead, the service operations that use the indirect path to pass the notification URI will need to be modified to introduce features supported by the NF service consumer. In a callback scenario, the sender of the notification that will require the attached callback will have to communicate the negotiated supported features to the receiver of the notification and the initiator of the callback. This alternative can be modified to pass the "capability" or "function" as specific data instead of the current definition of the feature.

[0338] Alternatives A and B are beyond the scope of CT3 and require in-depth analysis from CT4 to check their feasibility. Once TS 29.510 is amended according to the final solution, the possible impact on CT3 will be considered.

[0339] 3. Conclusion

[0340] To solve the problem of discovering supported features between two peers without direct supported feature negotiation, three alternatives are proposed.

[0341] It is recommended that CT3 discuss and agree on a solution that is more suitable for the CT3 scenario. If Alternative A or B is considered the preferred option, it is recommended to contact CT4 so that they analyze the impact and introduce the required amendments in TS 29.510 as needed, and then adjust the CT3 specification accordingly.

[0342] Ericsson is happy to contribute depending on the final agreed solution.

Claims

1. A method (600) at a first network node (115), the method for determining whether to use one or more first characteristics for a notification from the first network node (115) to a second network node (125, 145), the notification being subscribed to via an indirect subscription operation, the method (600) comprising: receiving (S310, S410, S510, S610) information indicating whether the second network node (125, 145) supports the one or more first features or information from which it is derivable whether the second network node (125, 145) supports the one or more first features; as well as A determination is made ( S317 a / S317 b , S417 a / S417 b , S620 ) based at least on the received information whether the one or more first features are to be used for the notification.

2. The method (600) according to claim 1, wherein: The indirect subscription operation is a first service operation, the first service operation being associated with a first service and being invoked by a third network node (120) in response to the second network node invoking a second service operation associated with a second service, wherein the first service is different from the second service, The third network node (120) is different from the second network node (125, 145).

3. The method (600) according to claim 2, wherein: At least one of the first service and the second service is provided by the third network node (120).

4. The method (600) according to any one of claims 1 to 3, wherein: The step of receiving (S310, S410, S510, S610) the information includes at least one of the following: - receiving (S310) a first message from the third network node (120), the first message indicating a notification uniform resource identifier URI directed to the second network node (125, 145); - receiving (S410) a first message from the third network node (120), the first message indicating a network function NF instance identifier ID of the second network node (125, 145); and - receiving (S510) a first message from the third network node (120), the first message indicating zero or more second features supported by the second network node (125, 145) as a NF service consumer.

5. The method (600) according to any one of claims 1 to 4, wherein: When the first message indicates a notification URI pointing to the second network node (125, 145), the step of determining (S317a / S317b, S620) whether the one or more first features are to be used for the notification comprises: sending (S317a) a second message for discovering a NF instance to a fourth network node (150), the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting the one or more first features required by the first network node (115) as a NF service consumer; and / or In response to the second message, a third message indicating zero or one NF instance is received (S317b) from the fourth network node (150).

6. The method (600) according to claim 5, wherein: The step of determining (S317a / S317b, S620) whether to use the one or more first features for the notification further comprises at least one of the following: In response to at least receiving a third message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, determining that the one or more first characteristics are to be used for the notification, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation; and At least in response to receiving a third message indicating that there is no NF instance from the fourth network node (150), or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance, it is determined that the one or more first characteristics are not used for the notification.

7. The method (600) of claim 5, wherein: When the second message also indicates the first notification type, the step of determining (S317a / S317b, S620) whether to use the one or more first features for the notification further includes at least one of the following: determining to use the one or more first features for the notification in response to at least receiving a third message indicating an NF instance from the fourth network node (150); as well as In response to at least receiving a third message from the fourth network node (150) indicating that there is no NF instance, it is determined not to use the one or more first features for the notification.

8. The method (600) according to any one of claims 1 to 4, wherein: When the first message indicates a notification URI pointing to the second network node (125, 145), the step of determining (S317a / S317b, S620) whether the one or more first features are to be used for the notification comprises: sending (S317a) to a fourth network node (150) a second message for discovering a NF instance, said NF instance having a notification URI matching said notification URI in its NF configuration file; and / or receiving (S317b) a third message indicating zero or one NF instance from the fourth network node (150) in response to the second message, Wherein, when the third message indicates an NF instance, the third message also indicates, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer.

9. The method (600) of claim 8, wherein: The step of determining (S317a / S317b, S620) whether to use the one or more first features for the notification further comprises at least one of the following: In response to at least receiving a third message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, determining that the one or more first characteristics are to be used for the notification, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation; and At least in response to receiving a third message indicating that there is no NF instance from the fourth network node (150), or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance, it is determined that the one or more first characteristics are not used for the notification.

10. The method (600) according to any one of claims 1 to 4, wherein: When the first message indicates a notification URI pointing to the second network node (125, 145), the step of determining (S317a / S317b, S620) whether the one or more first features are to be used for the notification comprises: sending (S317a) to a fourth network node (150) a second message for discovering a NF instance, the NF instance having in its NF configuration file a notification URI matching the notification URI and associated with a first notification type, the first notification type indicating that the notification is subscribed to via an indirect subscription operation; and / or receiving (S317b) a third message indicating zero or one NF instance from the fourth network node (150) in response to the second message, When the third message indicates an NF instance, the third message also indicates, for the indicated NF instance and for the first notification type, zero or more second features supported by the indicated NF instance as an NF service consumer.

11. The method (600) according to claim 10, wherein: The step of determining (S317a / S317b, S620) whether to use the one or more first features for the notification further comprises at least one of the following: In response to at least receiving a third message indicating an NF instance from the fourth network node (150) and in response to determining that the one or more first characteristics are one or more characteristics of the zero or more second characteristics, determining that the one or more first characteristics are to be used for the notification; as well as At least in response to receiving a third message indicating that there is no NF instance from the fourth network node (150) or in response to determining that the one or more first characteristics are not one or more characteristics of the zero or more second characteristics when the third message indicates an NF instance, it is determined not to use the one or more first characteristics for the notification.

12. The method (600) according to any one of claims 1 to 11, wherein: When the first message indicates the NF instance ID of the second network node (125, 145), the step of determining (S417a / S417b, S620) whether the one or more first characteristics are to be used for the notification comprises: sending (S417a) a second message for discovering a NF instance to a fourth network node (150), the NF instance having the NF instance ID indicated in the first message and supporting one or more first features required by the first network node (115) as a NF service consumer; and / or In response to the second message, a third message indicating zero or one NF instance is received (S417b) from the fourth network node (150).

13. The method (600) of claim 12, wherein: The step of determining (S417a / S417b, S620) whether to use the one or more first features for the notification further comprises at least one of the following: In response to at least receiving a third message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, determining that the one or more first characteristics are to be used for the notification, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation; and At least in response to receiving a third message indicating that there is no NF instance from the fourth network node (150), or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance, it is determined that the one or more first characteristics are not used for the notification.

14. The method (600) according to any one of claims 1 to 11, wherein: When the first message indicates the NF instance ID of the second network node (125, 145), the step of determining (S417a / S417b, S620) whether the one or more first characteristics are to be used for the notification comprises: sending (S417a) to a fourth network node (150) a second message for discovering a NF instance having the NF instance ID indicated in the first message; and / or receiving (S417b) a third message indicating zero or one NF instance from the fourth network node (150) in response to the second message, Wherein, when the third message indicates an NF instance, the third message also indicates, for the indicated NF instance and for each notification type indicated by the third message, zero or more second features supported by the indicated NF instance as an NF service consumer.

15. The method (600) of claim 14, wherein: The step of determining (S417a / S417b, S620) whether to use the one or more first features for the notification further comprises at least one of the following: In response to at least receiving a third message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more first characteristics are one or more characteristics associated with a first notification type among zero or more second characteristics indicated by the third message, determining that the one or more first characteristics are to be used for the notification, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation; and At least in response to receiving a third message indicating that there is no NF instance from the fourth network node (150), or in response to determining that the one or more first characteristics are not one or more characteristics associated with the first notification type among zero or more second characteristics indicated by the third message when the third message indicates an NF instance, it is determined that the one or more first characteristics are not used for the notification.

16. The method (600) according to any one of claims 1 to 15, wherein: When the first message indicates zero or more second features supported by the second network node (125, 145) as a NF service consumer, the step of determining (S620) whether the one or more first features are to be used for the notification comprises at least one of the following: In response to at least determining that the zero or more second features supported by the second network node (125, 145) include the one or more first features, determining that the one or more first features are to be used for the notification; as well as In response at least to determining that the zero or more second features supported by the second network node (125, 145) do not include the one or more first features, determining not to use the one or more first features for the notification.

17. The method (600) according to any one of claims 1 to 16, wherein: Before the step of determining (S317a / S317b, S417a / S417b, S620) whether the one or more first features are to be used for the notification, the method (600) further comprises: A fourth message is sent (S300c, S400c) to the fourth network node (150), the fourth message indicating at least one of the following items: - a notification URI pointing to the first network node (115) and associated with a first notification type, the first notification type indicating that the notification is subscribed to via an indirect subscription operation, - zero or more third features supported by said first network node (115) as a NF service producer, and - NF instance ID of the first network node (115).

18. The method (600) according to any one of claims 1 to 17, further comprising: A fifth message is sent (S320a, S420a, S520a) as the notification to the second network node (125, 145), wherein the one or more first features are used based at least on a determination of whether the one or more first features are to be used for the notification.

19. The method (600) of claim 18, wherein: The fifth message further indicates at least one of the following: - a notification URI pointing to said first network node (115); - NF instance ID of the first network node (115); and - zero or more third features supported by said first network node (115) as a NF service producer.

20. The method (600) according to any one of claims 1 to 19, wherein: At least one of the terms is true: - the first network node (115) is a session management function SMF; - the second network node (125, 145) is a network exposure function NEF or an application function AF; - the third network node (120) is a policy control function PCF; - said fourth network node (150) is a Network Repository Function NRF; - The first message is a Npcf_SMPolicyControl_UpdateNotify request message; - The second message is a Nnrf_NFDiscovery_Request message; - The third message is a Nnrf_NFDiscovery_Request response message; - the fourth message is a Nnrf_NFManagement_NFRegister request message; and - The fifth message is a Nsmf_EventExposure_Notify request message.

21. A first network node (115, 1000, 1100), comprising: Processor (1006); A memory (1008) storing instructions which, when executed by the processor (1006), cause the processor (1006) to perform the method (600) according to any one of claims 1 to 20.

22. The first network node (115, 1000, 1100) according to claim 21, wherein A session management function (SMF) is deployed at the first network node (115).

23. A method (700) at a second network node (125, 145), the method for facilitating a first network node (115) to determine whether to use one or more first characteristics for notifications from the first network node (115) to the second network node (125, 145), the notifications being subscribed to via an indirect subscription operation, the method (700) comprising: Information indicating whether the second network node (125, 145) supports the one or more first features or information from which whether the second network node (125, 145) supports the one or more first features is sent (S305e in 1A, S305c in 1B, S405e in 1A, S405c in 1B, S505e in 1A, S505c in 1B, S710) to a third network node (120) different from the first network node (115).

24. The method (700) of claim 23, wherein: The indirect subscription operation is a first service operation, the first service operation being associated with a first service and being invoked by the third network node (120) in response to the second network node invoking a second service operation associated with a second service, wherein the first service is different from the second service, The third network node (120) is different from the second network node (125, 145).

25. The method (700) of claim 24, wherein: At least one of the first service and the second service is provided by the third network node (120).

26. The method (700) according to any one of claims 23 to 25, wherein: The step of sending (S305e in 1A, S305c in 1B, S405e in 1A, S405c in 1B, S505e in 1A, S505c in 1B, S710) the information includes at least one of the following items: - sending (S305e in 1A, S305c in 1B) a sixth message to the third network node (120), the sixth message indicating a notification URI pointing to the second network node (125, 145); - sending (S405e in 1A, S405c in 1B) a sixth message to the third network node (120), the sixth message indicating the NF instance ID of the second network node (125, 145); and - Sending (S505e in 1A, S505c in 1B) a sixth message to the third network node (120), the sixth message indicating zero or more second features supported by the second network node (125, 145) as a NF service consumer.

27. The method (700) according to any one of claims 23 to 26, wherein: Before the step of sending (S305e in 1A, S305c in 1B, S405e in 1A, S405c in 1B, S505e in 1A, S505c in 1B, S710) the information, the method (700) further includes: A seventh message is sent (S300a, S400a) to a fourth network node (150), the seventh message indicating at least one of the following items: - a notification URI pointing to the second network node (125, 145) and associated with a first notification type, the first notification type indicating that the notification is subscribed to via an indirect subscription operation, - one or more second features supported by said second network node (125, 145) as a NF service consumer, and - NF instance ID of the second network node (125, 145).

28. The method (700) according to any one of claims 23 to 27, further comprising: A fifth message is received (S320a, S420a, S520a) as the notification from the first network node (115), wherein the one or more first features are used based on at least the information sent to the third network node (120).

29. The method (700) of claim 28, wherein the fifth message further indicates at least one of the following: - another notification URI pointing to said first network node (115); - NF instance ID of the first network node (115); and - zero or more third features supported by said first network node (115) as a NF service producer.

30. The method (700) according to claim 28 or 29, wherein: When the fifth message indicates another notification URI pointing to the first network node (115), the method (700) further comprises: sending (S320x1) an eighth message for discovering an NF instance to a fourth network node (150), the NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features required by the second network node (125, 145) as a NF service producer; and / or In response to the eighth message, a ninth message indicating zero or one NF instance is received (S320x2) from the fourth network node (150).

31. The method (700) of claim 30, further comprising at least one of the following: In response to at least receiving a ninth message indicating an NF instance from the fourth network node (150), determining that the one or more fourth characteristics are to be used for another notification from the second network node (125, 145) to the first network node (115); and At least in response to receiving a ninth message from the fourth network node (150) indicating that there is no NF instance, it is determined not to use the one or more fourth characteristics for the further notification.

32. The method (700) of claim 28 or 29, wherein: When the fifth message indicates another notification URI pointing to the first network node (115), the method (700) further comprises: sending (S320y1) an eighth message for discovering a NF instance to the fourth network node (150), the NF instance having a notification URI matching the other notification URI in its NF configuration file; and / or In response to the eighth message, receiving (S320y2) a ninth message indicating zero or one NF instance from the fourth network node (150), When the ninth message indicates an NF instance, the ninth message also indicates, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer.

33. The method (700) of claim 32, further comprising at least one of the following: In response to at least receiving a ninth message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more fourth characteristics are one or more characteristics of zero or more third characteristics, determining that the one or more fourth characteristics are to be used for another notification from the second network node (125, 145) to the first network node (115); and At least in response to receiving a ninth message indicating no NF instance from the fourth network node (150), or in response to determining that the one or more fourth characteristics are not one or more of the zero or more third characteristics when the ninth message indicates one NF instance, it is determined not to use the one or more fourth characteristics for the other notification.

34. The method (700) according to any one of claims 28 to 33, wherein: When the fifth message indicates the NF instance ID of the first network node (115), the method (700) further comprises: sending (S420x1) an eighth message for discovering a NF instance to a fourth network node (150), the NF instance having the NF instance ID indicated in the fifth message and supporting one or more fourth features required by the second network node (125, 145) as a NF service producer; and / or In response to the eighth message, a ninth message indicating zero or one NF instance is received (S420x2) from the fourth network node (150).

35. The method (700) of claim 34, further comprising at least one of the following: In response to at least receiving a ninth message indicating an NF instance from the fourth network node (150), determining that the one or more fourth characteristics are to be used for another notification from the second network node (125, 145) to the first network node (115); and At least in response to receiving a ninth message from the fourth network node (150) indicating that there is no NF instance, it is determined not to use the one or more fourth characteristics for the further notification.

36. The method (700) according to any one of claims 28 to 33, wherein: When the fifth message indicates the NF instance ID of the first network node (115), the method (700) further comprises: Sending (S420y1) an eighth message for discovering a NF instance to a fourth network node (150), the NF instance having the NF instance ID indicated in the fifth message; and / or In response to the eighth message, receiving (S420y2) a ninth message indicating zero or one NF instance from the fourth network node (150), When the ninth message indicates an NF instance, the ninth message also indicates, for the indicated NF instance, zero or more third features supported by the indicated NF instance as an NF service producer.

37. The method (700) of claim 36, further comprising at least one of the following: In response to at least receiving a ninth message indicating an NF instance from the fourth network node (150), and in response to determining that the one or more fourth characteristics are one or more characteristics of zero or more third characteristics, determining that the one or more fourth characteristics are to be used for another notification from the second network node (125, 145) to the first network node (115); and At least in response to receiving a ninth message indicating no NF instance from the fourth network node (150), or in response to determining that the one or more fourth characteristics are not one or more of the zero or more third characteristics when the ninth message indicates one NF instance, it is determined not to use the one or more fourth characteristics for the other notification.

38. The method (700) according to any one of claims 28 to 37, wherein: When the fifth message indicates zero or more third features supported by the first network node (115) as a NF service producer, the method (700) further comprises at least one of the following: In response to at least determining that the zero or more third features supported by the first network node (115) include the one or more fourth features, determining that the one or more fourth features are to be used for another notification from the second network node (125, 145) to the first network node (115); and At least in response to determining that the zero or more third features supported by the first network node (115) do not include the one or more fourth features, determining not to use the one or more fourth features for the another notification.

39. The method (700) according to any one of claims 28 to 38, further comprising: sending (S320g in 4A, S320c in 4B, S420g in 4A, S420c in 4B, S520g in 4A, S520c in 4B) a tenth message as the further notification to the first network node (115), wherein the one or more fourth characteristics are used at least based on a determination of whether the one or more fourth characteristics are to be used for the further notification.

40. The method (700) according to any one of claims 23 to 39, wherein: At least one of the terms is true: - the first network node (115) is a SMF; - the second network node (125, 145) is a NEF or an AF; - the third network node (120) is a PCF; - the fourth network node (150) is an NRF; - The fifth message is a Nsmf_EventExposure_Notify request message; - The sixth message is a Npcf_PolicyAuthorization_Create request message, a Npcf_PolicyAuthorization_Update request message or a Npcf_PolicyAuthorization_Delete request message; - The seventh message is a Nnrf_NFManagement_NFRegister request message; - The eighth message is a Nnrf_NFDiscovery_Request message; - The ninth message is a Nnrf_NFDiscovery_Request response message; and - The tenth message is the Nsmf_EventExposure_AppRelocationInfo request message.

41. A second network node (125, 145, 1000, 1200), comprising: Processor (1006); A memory (1008) storing instructions which, when executed by the processor (1006), cause the processor (1006) to perform the method (700) according to any one of claims 23 to 40.

42. The second network node (125, 145, 1000, 1200) according to claim 41, wherein A network exposure function NEF or an application function AF is deployed at the second network node (125, 145).

43. A method (800) at a third network node (120), the method for facilitating a first network node (115) to determine whether to use one or more first characteristics for notifications from the first network node (115) to a second network node (125, 145), the notifications being subscribed to via an indirect subscription operation, the method (800) comprising: Information indicating whether the second network node (125, 145) supports the one or more first features or information from which whether the second network node (125, 145) supports the one or more first features is forwarded (S305e in 1A / S305c / S310 in 1B, S405e in 1A / S405c / S410 in 1B, S505e in 1A / S505c / S510 in 1B, S810) to the first network node (115).

44. The method (800) of claim 43, wherein: The indirect subscription operation is a first service operation, the first service operation being associated with a first service and being invoked by the third network node (120) in response to the second network node invoking a second service operation associated with a second service, wherein the first service is different from the second service, The third network node (120) is different from the second network node (125, 145) and / or the first network node (115).

45. The method (800) of claim 44, wherein: At least one of the first service and the second service is provided by the third network node (120).

46. ​​The method (800) according to any one of claims 43 to 45, wherein: The step of forwarding (S305e in 1A / S305c / S310 in 1B, S405e in 1A / S405c / S410 in 1B, S505e in 1A / S505c / S510 in 1B, S810) the information includes at least one of the following: - receiving (S305e in 1A / S305c in 1B) a sixth message indicating a notification URI from the second network node (125, 145), the notification URI pointing to the second network node (125, 145), and sending (S310) a first message indicating the notification URI to the first network node (115); - receiving (S405e in 1A / S405c in 1B) a sixth message indicating the NF instance ID of the second network node (125, 145) from the second network node (125, 145), and sending (S410) a first message indicating the NF instance ID to the first network node (115); and - receiving (S505e in 1A / S505c in 1B) a sixth message from the second network node (125, 145) indicating zero or more second features supported by the second network node (125, 145) as a NF service consumer, and sending (S510) a first message indicating the zero or more second features to the first network node (115).

47. The method (800) according to any one of claims 43 to 46, wherein: At least one of the terms is true: - the first network node (115) is a SMF; - the second network node (125, 145) is a NEF or an AF; - the third network node (120) is a PCF; - The first message is a Npcf_SMPolicyControl_UpdateNotify request message; as well as - The sixth message is a Npcf_PolicyAuthorization_Create request message, a Npcf_PolicyAuthorization_Update request message or a Npcf_PolicyAuthorization_Delete request message.

48. A third network node (120, 1000, 1300), comprising: Processor (1006); A memory (1008) storing instructions which, when executed by the processor (1006), cause the processor (1006) to perform the method (800) according to any one of claims 43 to 47.

49. The third network node (120, 1000, 1300) according to claim 48, wherein A policy control function (PCF) is deployed at the third network node (120).

50. A method (900) at a fourth network node (150), the method for facilitating a first network node (115) to determine whether to use one or more first characteristics for notifications from the first network node (115) to a second network node (125, 145), the notifications being subscribed to via an indirect subscription operation, the method (900) comprising: receiving (S317a, S417a, S910) first information from the first network node (115), from which it can be derived whether the second network node (125, 145) supports the one or more first features; determining (S920) second information based at least on the first information, the second information indicating whether the second network node (125, 145) supports the one or more first features; as well as The second information is sent (S317b, S417b, S930) to the first network node (115).

51. The method (900) of claim 50, wherein: The indirect subscription operation is a first service operation, the first service operation being associated with a first service and being invoked by a third network node (120) in response to the second network node invoking a second service operation associated with a second service, wherein the first service is different from the second service, The third network node (120) is different from the second network node (125, 145) and / or the first network node (115).

52. The method (900) of claim 51, wherein: At least one of the first service and the second service is provided by the third network node (120).

53. The method (900) according to any one of claims 50 to 52, wherein: The first information includes at least one of the following items: - information indicating a notification URI pointing to the second network node (125, 145); - information indicating the NF instance ID of the second network node (125, 145); - information indicative of said one or more first characteristics; as well as - Information indicating a first notification type, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation.

54. The method (900) according to any one of claims 50 to 53, wherein: The step of receiving (S317a, S417a, S910) the first information comprises: receiving (S317a) a second message for discovering a NF instance from the first network node (115), the NF instance having a notification URI matching the notification URI in its NF configuration file and supporting one or more first features required by the first network node (115) as a NF service consumer; and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file and supporting the one or more first features as a NF service consumer, and / or The step of sending (S317b, S417b, S930) the second information comprises: sending (S317b) a third message indicating the zero or one NF instance to the first network node (115), and / or Wherein, when an NF instance is determined and indicated in the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node (150), zero or more second features supported by the indicated NF instance as an NF service consumer.

55. The method (900) according to any one of claims 50 to 53, wherein: The step of receiving (S317a, S417a, S910) the first information comprises: receiving (S317a) from the first network node (115) a second message for discovering a NF instance, the NF instance having in its NF configuration file a notification URI that matches the notification URI and is associated with the first notification type, and supporting one or more first features required by the first network node (115) and associated with the first notification type as a NF service consumer, and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI matching the notification URI and associated with the first notification type in its NF configuration file, and supporting one or more first features associated with the first notification type as a NF service consumer, and / or The step of sending (S317b, S417b, S930) the second information comprises: sending (S317b) a third message indicating the zero or one NF instance to the first network node (115).

56. The method (900) according to any one of claims 50 to 53, wherein: The step of receiving (S317a, S417a, S910) said first information comprises: receiving (S317a) from said first network node (115) a second message for discovering a NF instance, said NF instance having in its NF configuration file a notification URI matching said notification URI, and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI matching the notification URI in its NF configuration file, and / or The step of sending (S317b, S417b, S930) the second information comprises: sending (S317b) a third message indicating the zero or one NF instance to the first network node (115), and / or Wherein, when an NF instance is determined and indicated by the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node (150), zero or more second features supported by the indicated NF instance as an NF service consumer.

57. The method (900) according to any one of claims 50 to 53, wherein: The step of receiving (S317a, S417a, S910) said first information comprises: receiving (S317a) from said first network node (115) a second message for discovering a NF instance, said NF instance having in its NF configuration file a notification URI matching said notification URI and associated with said first notification type, and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI in its NF configuration file that matches the notification URI and is associated with the first notification type, and / or The step of sending (S317b, S417b, S930) the second information comprises: sending (S317b) a third message indicating the zero or one NF instance to the first network node (115), and / or Wherein, when an NF instance is determined and indicated by the third message, the third message also indicates, for the first notification type, zero or more second features supported by the indicated NF instance as an NF service consumer.

58. The method (900) according to any one of claims 50 to 57, wherein: The step of receiving (S317a, S417a, S910) the first information comprises: receiving (S417a) a second message for discovering a NF instance from the first network node (115), the NF instance having the NF instance ID of the second network node (125, 145) and supporting one or more first features required by the first network node (115) as a NF service consumer, and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having the NF instance ID indicated in the second message and supporting the one or more first features as a NF service consumer, and / or The step of sending (S317b, S417b, S930) the second information comprises: sending (S417b) a third message indicating the zero or one NF instance to the first network node (115), and / or Wherein, when an NF instance is determined and indicated in the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node (150), zero or more second features supported by the indicated NF instance as an NF service consumer.

59. The method (900) according to any one of claims 50 to 57, wherein: The step of receiving (S317a, S417a, S910) the first information comprises: receiving (S417a) a second message for discovering a NF instance from the first network node (115), the NF instance having the NF instance ID indicated in the first message, and / or The step of determining (S920) the second information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having the NF instance ID indicated in the second message, and / or The step of sending (S317b, S417b, S930) the second information comprises: in response to the second message, sending (S417b) a third message indicating zero or one NF instance to the first network node (115), and / or Wherein, when an NF instance is determined and indicated by the third message, the third message also indicates, for each notification type registered by the indicated NF instance at the fourth network node (150), zero or more second features supported by the indicated NF instance as an NF service consumer.

60. The method (900) according to any one of claims 50 to 59, wherein: Before the step of receiving (S317a, S417a, S910) the first information, the method (900) further includes at least one of the following items: receiving (S300c, S400c) a fourth message from the first network node (115), the fourth message indicating at least one of the following: a notification URI pointing to the first network node (115) and associated with the first notification type, zero or more third features supported by the first network node (115) as a NF service producer, and a NF instance ID of the first network node (115); and A seventh message is received (S300a, S400a) from the second network node (125, 145), the seventh message indicating at least one of the following items: a notification URI pointing to the second network node (125, 145) and associated with the first notification type, one or more second features supported by the second network node (125, 145) as a NF service consumer, and an NF instance ID of the second network node (125, 145).

61. The method (900) according to any one of claims 50 to 60, further comprising: receiving (S320x1, S320y1, S420x1, S420y1) third information from the second network node (125, 145), from which it can be derived whether the first network node (115) supports one or more fourth features; and / or determining fourth information based at least on the third information, the fourth information indicating whether the first network node (115) supports the one or more fourth features; and / or The fourth information is sent (S320x2, S320y2, S420x2, S420y2) to the second network node (125, 145).

62. The method (900) of claim 61, wherein: The third information includes at least one of the following items: - information indicating another notification URI pointing to the first network node (115); - information indicating the NF instance ID of the first network node (115); - information indicative of said one or more fourth characteristics; as well as - Information indicating a first notification type, wherein the first notification type indicates that the notification is subscribed to through an indirect subscription operation.

63. The method (900) of claim 61 or 62, wherein: The step of receiving (S320x1, S320y1, S420x1, S420y1) the third information comprises: receiving (S320x1) an eighth message for discovering an NF instance from the second network node (125, 145), the NF instance having a notification URI matching the other notification URI in its NF profile and supporting one or more fourth features required by the second network node (125, 145) as a NF service producer, and / or The step of determining the fourth information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI matching the other notification URI in its NF configuration file and supporting the one or more fourth features as a NF service producer, and / or Therein, sending (S320x2, S320y2, S420x2, S420y2) the fourth information includes: sending (S320x2) a ninth message indicating the zero or one NF instance to the second network node (125, 145).

64. The method (900) of claim 61 or 62, wherein: The step of receiving (S320x1, S320y1, S420x1, S420y1) the third information comprises: receiving (S320y1) an eighth message for discovering a NF instance from the second network node (125, 145), the NF instance having a notification URI in its configuration file that matches the other notification URI, and / or The step of determining the fourth information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having a notification URI matching the other notification URI in its NF configuration file, and / or Wherein, sending (S320x2, S320y2, S420x2, S420y2) the fourth information includes: sending (S320y2) a ninth message indicating the zero or one NF instance to the second network node (125, 145), and / or Wherein, when an NF instance is determined and indicated by the ninth message, the ninth message also indicates zero or more third features supported by the indicated NF instance as an NF service producer.

65. The method (900) according to any one of claims 61 to 64, wherein: The step of receiving (S320x1, S320y1, S420x1, S420y1) the third information comprises: receiving (S420x1) an eighth message for discovering a NF instance from the second network node (125, 145), the NF instance having the NF instance ID of the first network node (115) and supporting one or more fourth features required by the second network node (125, 145) as a NF service producer, and / or The step of determining the fourth information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance ID having the NF instance ID of the first network node (115) and supporting the one or more fourth features as an NF service producer, and / or Wherein, sending (S320x2, S320y2, S420x2, S420y2) the fourth information includes: sending (S420x2) a ninth message indicating the zero or one NF instance to the second network node (125, 145).

66. The method (900) according to any one of claims 61 to 64, wherein: The step of receiving (S320x1, S320y1, S420x1, S420y1) the third information comprises: receiving (S420y1) an eighth message for discovering a NF instance from the second network node (125, 145), the NF instance having the NF instance ID of the first network node (115), and / or The step of determining the fourth information comprises: determining zero or one NF instance from one or more NF instances registered at the fourth network node (150), the zero or one NF instance having the NF instance ID of the first network node (115), and / or Wherein, sending (S320x2, S320y2, S420x2, S420y2) the fourth information includes: sending (S420y2) a ninth message indicating the zero or one NF instance to the second network node (125, 145), and / or Wherein, when an NF instance is determined and indicated by the ninth message, the ninth message also indicates zero or more third features supported by the indicated NF instance as an NF service producer.

67. The method (900) according to any one of claims 50 to 66, wherein: At least one of the terms is true: - the first network node (115) is a SMF; - the second network node (125, 145) is a NEF or an AF; - the fourth network node (150) is an NRF; - The second message is a Nnrf_NFDiscovery_Request message; - The third message is a Nnrf_NFDiscovery_Request response message; - The fourth message is a Nnrf_NFManagement_NFRegister request message; - The seventh message is a Nnrf_NFManagement_NFRegister request message; - The eighth message is a Nnrf_NFDiscovery_Request message; and - The ninth message is the Nnrf_NFDiscovery_Request response message.

68. A fourth network node (150, 1000, 1400), comprising: Processor (1006); A memory (1008) storing instructions which, when executed by the processor (1006), cause the processor (1006) to perform the method (900) according to any one of claims 50 to 67.

69. The fourth network node (150, 1000, 1400) according to claim 68, wherein A network repository function NRF is deployed at the fourth network node (150).

70. A computer program (1010) comprising instructions which, when executed by at least one processor (1006), cause the at least one processor (1006) to perform the method (600, 700, 800, 900) according to any one of claims 1 to 20, 23 to 40, 43 to 47 and 50 to 67.

71. A carrier (1008) comprising a computer program (1010) according to claim 70, wherein The carrier (1008) is one of an electric signal, an optical signal, a radio signal or a computer-readable storage medium.

72. A telecommunications system (10) for determining whether to use one or more first features for a notification from a first network node (115) to a second network node (125, 145), the notification being subscribed to via an indirect subscription operation, the telecommunications system comprising: a second network node (125, 145) configured to send, to a third network node (120), second information indicating whether the second network node (125, 145) supports one or more first features or first information from which it can be derived whether the second network node (125, 145) supports the one or more first features; a third network node (120) configured to forward, from the second network node (125, 145) to the first network node (115), the second information indicating whether the second network node (125, 145) supports the one or more first features or the first information from which it can be derived whether the second network node (125, 145) supports the one or more first features; The first network node (115) is configured to: receiving the second information indicating whether the second network node (125, 145) supports the one or more first features or the first information from which it can be derived whether the second network node (125, 145) supports the one or more first features; as well as A determination is made based at least on the received information whether to use the one or more first characteristics for the notification.

73. The telecommunication system (10) according to claim 72, wherein: When the first network node (115) is configured to receive the first information, the telecommunication system further comprises: The fourth network node (150) is configured to: receiving the first information from the first network node (115); determining the second information based at least on the first information; and The second information is sent to the first network node (115).

74. The telecommunication system (10) according to claim 72 or 73, wherein: At least one of the terms is true: - the first network node (115) is a first network node (115) according to claim 21 or 22; - the second network node (125, 145) is a second network node (125, 145) according to claim 41 or 42; - the third network node (120) is a third network node (120) according to claim 48 or 49; and - The fourth network node (150) is a fourth network node (150) according to claim 68 or 69.

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