CN111031517A

CN111031517A - Message notification method, device, network element, system and storage medium

Info

Publication number: CN111031517A
Application number: CN201811341759.0A
Authority: CN
Inventors: 洪英杰
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2018-10-10
Filing date: 2018-11-12
Publication date: 2020-04-17
Also published as: WO2020098622A1

Abstract

The embodiment of the invention provides a message notification method, a device, a network element, a system and a storage medium, wherein after receiving a request sent by a third-party application AF and used for subscribing a UE reachable event after downlink data failure, a first request for subscribing the UE reachable event after downlink data failure is sent to a target network element according to the request, the first request comprises an application identifier of the AF, so that the target network element can generate the first subscribed event which can be reached by the UE after the downlink data failure corresponding to the AF is failed; after receiving the downlink data failure sent by the target network element, the UE can reach the notification, and the AF corresponding to the application identifier contained in the downlink data failure UE can be sent with the notification message that the UE can reach the notification in a targeted manner, so that the pertinence of sending the UE can reach the notification message can be improved, and the utilization rate of network resources can be improved.

Description

Message notification method, device, network element, system and storage medium

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method, an apparatus, a network element, a system, and a storage medium for notifying a message.

Background

In the related art, transmitting data from an AF (Application Function, which refers to a non-3 GPP third party Application) to a UE (user equipment) is DownLink data (DL data) transmission. The UE is not always in a connected state for reasons such as power saving. While the AF is not known for how the UE is in. Therefore, in order to effectively perform DL data transmission, the following method is adopted in the related art: assuming that all AFs subscribe to the UE availabilityafter DDN failed event (which may also be referred to as UE reachable event after downlink data failure or UE reachable state subscription event, which is hereinafter collectively referred to as UE reachable event after downlink data failure); a certain AF sends Downlink Data at a certain time, after receiving the Downlink Data, a UPF (user plane Function) network element sends a DDN (Downlink Data Notify) message to an AMF (Access Management Function) network element to Notify the AMF that Downlink Data exist and UE needs to be awakened, and if the AMF cannot awaken the UE, a DDN failure response is returned; when the UE state changes from unreachable to reachable, the AMF may directly send a UE reachable notification message to all AFs subscribing to the UE reachable event after the downlink data failure. However, not all AFs subscribed to the UE reachable status subscription event need to receive the notification message that the UE is reachable. For example, in an exemplary case, only the AF that sends the downlink data service requirement needs to receive the notification message that the UE is reachable. Therefore, it is not necessary to send UE reachable notification messages to all AFs subscribing to UE reachable events after downlink data failure, and network resources are wasted.

Disclosure of Invention

The message notification method, the device, the network element, the system and the storage medium provided by the embodiment of the invention mainly solve the problem that when the related technology sends the notification message that the UE can reach, the notification message that the UE can reach is directly sent to all AF subscribing the UE reaching event after the downlink data fails.

To solve the foregoing technical problem, an embodiment of the present invention provides a message notification method, including:

receiving a first request for subscribing a UE reachable event after downlink data failure, and generating a first subscription event reachable by the UE after the downlink data failure according to the first request, wherein the first request comprises an application identifier of a third-party application AF, an identifier NEF ID of a network open function NEF network element and an event reference identifier of the first subscription event which are mutually associated;

and receiving a UE reachable notification after the downlink data of the target UE corresponding to the application identifier fails, and sending the UE reachable notification after the downlink data fails to the NEF network element according to the first subscription event.

To solve the foregoing technical problem, an embodiment of the present invention further provides a message notification apparatus, including:

a third event subscription processing module, configured to receive a first request for subscribing to a UE reachable event after a downlink data failure, and generate a first subscription event that the UE can reach after the downlink data failure according to the first request, where the first request includes an application identifier of an AF, an identifier NEF ID of an NEF network element, and an event reference identifier of the first subscription event, which are associated with each other;

and a fifth notification sending module, configured to receive a UE reachable notification after the downlink data of the target UE corresponding to the application identifier fails, and send the UE reachable notification after the downlink data fails to the NEF network element according to the first subscription event.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides a message notification method, including:

receiving a request sent by AF and used for subscribing UE reachable events after downlink data failure;

sending a first request for subscribing the UE reachable event after the downlink data subscription failure to the AMF network element, and sending a second request for subscribing the application data detection event to the SMF network element;

receiving an application data detection notification sent by the SMF network element, and storing an application identifier in the application data detection notification in an application identifier list;

receiving a UE reachable notification after the downlink data sent by the AMF network element fails;

and sending UE reachable notification after the failure of downlink data to AF corresponding to the application identifier contained in the application identifier list.

receiving a second request for subscribing an application data detection event sent by an NEF network element, and generating a second subscription event for application data detection according to the second request, wherein the second request comprises an application identifier of an AF (auto-ranging) and an identifier NEF ID of the NEF network element;

requesting a User Plane Function (UPF) network element to activate application data detection of the AF corresponding to the application identifier;

receiving an application data detection notification sent by the UPF network element, wherein the application data detection notification comprises an application identifier of the AF which sends the downlink data;

and sending the application data detection notice to the NEF network element.

a second request receiving module, configured to receive a request, sent by an AF, for subscribing to a UE reachable event after a failure of downlink data subscription;

a second event subscription request module, configured to send, to the AMF network element according to the request, a first request for subscribing to a UE reachable event after the failure of downlink data subscription, and send, to the SMF network element, a second request for subscribing to an application data detection event;

a second notification receiving module, configured to receive an application data detection notification sent by the SMF network element, and store an application identifier in the application data detection notification in an application identifier list; and a UE reachable notification after failure of receiving the downlink data sent by the AMF network element;

and the second notification sending module is used for sending the UE reachable notification after the failure of sending the downlink data to the AF corresponding to the application identifier contained in the application identifier list.

a fourth request receiving module, configured to receive a second request for subscribing to an application data detection event, where the second request includes an application identifier of an AF and an identifier NEF ID of the NEF network element;

a second event subscription processing module, configured to generate a second subscription event for application data detection according to the second request, and to request, according to the second subscription event, the UPF network element to activate application data detection of the AF corresponding to the application identifier;

and a fourth notification sending module, configured to receive an application data detection notification sent by the UPF network element, where the application data detection notification includes an application identifier of an AF that has sent downlink data, and send the application data detection notification to the NEF network element.

sending a first request of UE reachable events after the failure of subscribing the downlink data to a target network element according to the request, wherein the first request comprises an identifier NEF ID of the NEF network element and an application identifier of the AF;

receiving a UE reachable notification after downlink data failure sent by the target network element, wherein the UE reachable notification after downlink data failure comprises an AF application identifier corresponding to UE which is changed from unreachable to reachable;

and sending the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier contained in the UE reachable notification after the downlink data failure.

a first request receiving module, configured to receive a request sent by an AF for subscribing to a UE reachable event after a failure of downlink data;

a first event subscription request module, configured to send, to a target network element, a first request for subscribing to a UE reachable event after a failure of downlink data subscription according to the request, where the first request includes an identifier NEF ID of a network open function NEF network element and an application identifier of the AF;

a first notification receiving module, configured to receive a UE reachable notification after a downlink data failure sent by the target network element, where the UE reachable notification after the downlink data failure includes an application identifier of an AF corresponding to a UE that is changed from unreachable to reachable;

and the first notification sending module is used for sending the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier contained in the UE reachable notification after the downlink data failure.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides an SMF network element, including a first processor, a first memory, and a first communication bus;

the first communication bus is used for connecting the first processor and the first memory;

the first processor is configured to execute a first computer program stored in the first memory to implement the steps of the message notification method as described above;

alternatively, the first processor is configured to execute a second computer program stored in the first memory to implement the steps of the message notification method as described above.

In order to solve the foregoing technical problem, an embodiment of the present invention further provides an NEF network element, including a second processor, a second memory, and a second communication bus;

the second communication bus is used for connecting the second processor and the second memory;

the second processor is configured to execute a third computer program stored in the second memory to implement the steps of the message notification method as described above;

or the second processor is configured to execute a fourth computer program stored in the second memory to implement the steps of the message notification method as described above.

In order to solve the above technical problem, an embodiment of the present invention further provides a communication system, where the communication system includes a target network element and an NEF network element;

the target network element is used for receiving a first request for subscribing the UE reachable event after the downlink data failure, and generating a first subscription event which can be reached by the UE after the downlink data failure according to the first request, wherein the first request comprises an application identifier of an AF (application function), an identifier NEF ID (network element identifier) of an NEF (network element identifier) and an event reference identifier of a first subscription event, and the first subscription event is associated with the event reference identifier of the first subscription event; and the network element is used for receiving a UE reachable notification after the downlink data of the target UE corresponding to the application identifier fails, and sending the UE reachable notification after the downlink data fails to the NEF network element according to the first subscription event;

and the NEF network element is used for sending the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier contained in the UE reachable notification after the downlink data failure.

To solve the above technical problem, embodiments of the present invention further provide a computer-readable storage medium for storing one or more first computer programs, which are executable by one or more processors to implement the steps of the message notification method as described above;

or, the computer readable storage medium is for storing one or more second computer programs, which are executable by one or more processors to implement the steps of the message notification method as described above;

or, the computer readable storage medium is for storing one or more third computer programs, which are executable by one or more processors to implement the steps of the message notification method as described above;

alternatively, the computer readable storage medium is used to store one or more fourth computer programs, which are executable by one or more processors to implement the steps of the message notification method as described above.

According to the message notification method, the device, the network element, the system and the storage medium provided by the embodiment of the invention, after receiving a request sent by a third party Application AF and used for subscribing the UE reachable event after the downlink data fails, a first request for subscribing the UE reachable event after the downlink data fails is sent to a target network element according to the request, wherein the first request comprises an identifier NEF ID of a NEF (network exposure Function) network element and an Application identifier Application ID of the AF, so that the target network element can generate the first subscribed event which can be reached by the UE after the downlink data corresponding to the AF fails; after receiving the downlink data failure sent by the target network element, the UE can reach the notification, and sends a notification message that the UE can reach (for example, the UE can reach the notification after the downlink data failure) to the AF corresponding to the application identifier included in the UE can reach the notification after the downlink data failure in a targeted manner, instead of directly sending the notification message to all AFs subscribing to the UE reachable event after the downlink data failure, so that the sending pertinence of the UE can be improved, and the utilization rate of network resources is improved.

Additional features and corresponding advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a flowchart illustrating a message notification method according to a first embodiment of the present invention;

fig. 2 is a schematic diagram of a network basic architecture according to a second embodiment of the present invention;

fig. 3 is a schematic view illustrating a flow of subscribing to an event according to a second embodiment of the present invention;

fig. 4 is a schematic view illustrating a flow of subscribing to an event according to a third embodiment of the present invention;

fig. 5 is a schematic diagram illustrating a UE reachable notification message notification flow according to a fourth embodiment of the present invention;

fig. 6 is a schematic structural diagram of a message notification apparatus according to a fifth embodiment of the present invention;

fig. 7 is a flowchart illustrating a message notification method at an NEF network element side according to a sixth embodiment of the present invention;

fig. 8 is a flowchart illustrating a sixth embodiment of the present invention for clearing an application id;

fig. 9 is a flowchart illustrating an identification process according to a sixth embodiment of the present invention;

fig. 10 is a schematic structural diagram of a message notification apparatus on the NEF network element side according to a sixth embodiment of the present invention;

fig. 11 is a flowchart illustrating a message notification method on an AMF network element side according to a sixth embodiment of the present invention;

fig. 12 is a schematic diagram of a processing flow of a third subscription event at an AMF network element side according to a sixth embodiment of the present invention;

fig. 13 is a schematic structural diagram of a message notification apparatus on an AMF network element side according to a sixth embodiment of the present invention;

fig. 14 is a flowchart illustrating a message notification method at an SMF network element side according to a sixth embodiment of the present invention;

fig. 15 is a schematic structural diagram of a message notification apparatus on an SMF network element side according to a sixth embodiment of the present invention;

fig. 16 is a first schematic view illustrating a subscription event flow according to a seventh embodiment of the present invention;

fig. 17 is a schematic view illustrating a second flow of subscribing to an event according to a seventh embodiment of the present invention;

fig. 18 is a schematic diagram illustrating a UE reachable notification message notification flow according to a seventh embodiment of the present invention;

fig. 19 is a flowchart illustrating a message notification method at an NEF network element side according to an eighth embodiment of the present invention;

fig. 20 is a flowchart illustrating a message notification method at a target network element side according to an eighth embodiment of the present invention;

fig. 21 is a schematic structural diagram of a message notification apparatus according to an eighth embodiment of the present invention;

fig. 22 is a schematic structural diagram of an SMF network element according to the ninth embodiment of the present invention;

fig. 23 is a schematic structural diagram of an NEF network element according to the ninth embodiment of the present invention;

fig. 24 is a schematic structural diagram of an AMF network element according to a ninth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The first embodiment is as follows:

the present embodiment provides a message notification method, where a target network element associates and corresponds a first subscription event of a UE reachable event (i.e., a UE availability after DDN failed event) in a first request when generating a first subscription event of a downlink data failure according to the first request, where the first subscription event is associated with an Application identifier (i.e., an Application ID, and it should be understood that the Application identifier in this embodiment may be any information that uniquely identifies/identifies an AF) of the AF in the first request; when a target network element detects that a target UE corresponding to an AF subscribed to a first subscription event is changed from unreachable to reachable, a UE reachable notification (namely a notification message that the UE can reach) sent after downlink data failure includes an application identifier of the AF; thus, the NEF network element can pertinently send a notification message that the UE is reachable to the AF corresponding to the application identifier according to the application identifier in the UE reachable notification after the downlink data fails; the rationality of sending the notification message which can be reached by the UE and the utilization rate of network resources are improved.

In this embodiment, taking a target network element as an SMF network element as an example, a method for notifying according to a message is provided, where the SMF network element generates a first subscription event that the UE can reach after a failure of downlink data according to a first request, where the first request includes an application identifier of an AF, an identifier NEF ID of the NEF network element, and an event reference identifier of the first subscription event, which are associated with each other, and the generated first subscription event may be associated with the event reference identifier; thus, when the SMF subsequently receives the UE reachable notification after the downlink data failure, the SMF may send the UE reachable notification after the downlink data failure (i.e., a UE reachable notification message) to the NEF network element corresponding to the NEF ID according to the previously generated first subscription event, and send the AF corresponding to the Application ID (the Application ID included in the UE reachable notification after the downlink data failure) through the NEF network element, so that the pertinence of sending the UE reachable notification after the downlink data failure may be improved, and the network resource utilization rate may be improved.

The message notification method provided in this embodiment includes a first subscription event generation process and a notification process of UE reachable notification after downlink data failure, where an exemplary message notification method is shown in fig. 1, and includes:

s101: the first request is used for receiving a first request for receiving a UE reachable event after the downlink data failure, and generating a first subscription event which is reachable by the UE after the downlink data failure according to the first request, wherein the first request comprises an application identifier of an AF (application function), an identifier NEF ID (network element identifier) of a NEF (network element) and an event reference identifier of the first subscription event, and the first subscription event can be associated with the event reference identifier.

In this embodiment, the first request includes an event reference identifier of the first subscription event, an identifier Application ID of the third party Application AF, and an identifier NEF ID of the network open function NEF network element, which are associated with each other, where the target UE is a target UE corresponding to the AF in the first request, that is, a target receiving object of downlink data sent by the AF. The first subscription event generated in S101 is associated with the event reference identifier of the first subscription event in the first request. And optionally S101 may be performed by an SMF network element.

In an example of this embodiment, the NEF network element may trigger, according to a request of the third-party application AF, to send a first request for generating a UE reachable event after a failure of downlink data to the SMF network element, so that the SMF network element generates a first subscription event for monitoring a UE reachable state. And optionally, the event reference identifier of the first subscription event included in the first request may be generated by the NEF network element.

For example, in one example, the request sent by the NEF network element may include, but is not limited to including, at least one of the following requests:

an Event open subscription request from the AF, for example, includes, but is not limited to, Event Exposure _ subscribe.

Correspondingly, in one example, the first request may include, but is not limited to, at least one of the following requests:

an Event open subscription request from a UDM network element, for example including but not limited to an Event expose _ Subscribe request;

the session policy control Update notification request from the PCF network element includes, for example, but is not limited to, an SM PolicyControl _ Update notification request.

S102: and the UE reachable notification is used for receiving the UE reachable notification after the downlink data of the target UE corresponding to the application identifier fails, and sending the UE reachable notification after the downlink data fails to the NEF network element according to the first subscription event.

In an example in this embodiment, in the process of generating the first subscription event, the SMF network element may further configure the UPF network element to perform AF packet detection, that is, send a message to the UPF, and activate the Application data detection function corresponding to the Application ID. The SMF network element can issue a PFD (Packet Flow Description) corresponding to the Application ID to the UPF network element; optionally, the SMF network element may also issue the Application ID to the UPF, and at this time, the UPF network element may perform packet detection according to the locally configured PFD corresponding to the Application ID.

In an example of this embodiment, the SMF network element may control, through the first notification identifier, whether each first subscription event needs to report the UE reachable notification after the downlink data failure, and therefore, in an example of this embodiment, when the SMF network element generates the first subscription event, the method may further include:

a first notification flag, for example but not limited to, a notification flag, is generated, and the generated first notification flag is set to be associated with an event reference flag of the first subscription event in the first request. Optionally, when the value of the first notification identifier may be set to be a first preset value, the UE may reach the notification after the first subscription event associated with the event reference identifier of the first subscription event associated with the first notification identifier needs to report the failure of the downlink data; optionally, when the value of the first notification identifier is not the first preset value, the UE may reach the notification after the reporting of the downlink data fails, which may characterize the first subscription event associated with the event reference identifier of the first subscription event associated with the first notification identifier. It should be understood that, in this embodiment, a specific value of the first preset value may be flexibly set, for example, may be set to "1" or "yes", or may be set to another value, as long as the UE can reach the notification after the first subscription event associated with the event reference identifier that can represent the first subscription event associated with the first notification identifier needs to report the failure of downlink data.

In an example of this embodiment, in the process of generating the first subscription event, the value of the generated first notification identifier may be temporarily not set, or directly set as the first preset value by default. And the method can be flexibly set according to a specific application scene.

In one example of this embodiment, the SMF network element may set the value of the first notification flag in, but is not limited to, the following example manner. For example, before the SMF network element receives the reachable notification, the SMF network element receives an Application data detection notification including a corresponding Application ID sent by the UPF, and may set the notification flag corresponding to the Application ID to a first preset value when it is determined that the target UE to be delivered by the AF corresponding to the Application ID is currently unreachable. The application data detection notification in this embodiment includes, but is not limited to: at least one of an N4Report message and a Data Notification message. In addition, in this embodiment, the N4Report message and the Data Notification message may be sent to the SMF network element through, but not limited to, the UPF.

Therefore, in an example of this embodiment, before sending the UE reachable notification after the downlink data failure to the NEF network element corresponding to the NEF ID in S102, the method may further include:

and judging whether the first notification identifier (the first notification identifier is a first notification identifier corresponding to the event reference identifier of the first subscription event associated with the NEF ID in S102) is a first preset value at present, if so, sending the UE reachable notification after the downlink data fails to the NEF network element corresponding to the NEF ID, so that the NEF network element sends the AF corresponding to the Application ID according to the association relationship between the Application ID and the event reference identifier of the first subscription event.

Optionally, in an example of this embodiment, the SMF network element obtains the UE reachable notification after the downlink data fails by requesting to subscribe to the UE reachable event from the AMF network element, and after receiving the first subscription event requested by the SMF network element, the AMF network element controls whether the UE reachable notification needs to be sent to the SMF network element by setting the notification identifier. For example, when the AMF network element pages the UE according to the request of the SMF network element, a second notification flag associated with the SMF network element may be set, for example, but not limited to, a UE availability Notify SMF flag, and when a value of the second notification flag is set to a first preset value, the indication needs to be reported to the associated SMF, that is, the indication indicates that the state of the target UE needs to be notified when the state of the target UE is changed from unreachable availability. Therefore, in an example of this embodiment, after the downlink data failure in S102, the UE reachable notification is that the AMF network element sends the current value of the second notification identifier associated with the SMF network element to the SMF when detecting that the state of the target UE changes from unreachable availability to reachable availability, and the current value of the second notification identifier associated with the SMF network element is the first preset value. And the second notification identifier UE is set by the AMF network element after detecting that the state of the target UE is unreachable and receiving the event subscription message of the SMF. For example, an example of a setup process may include, but is not limited to: when the SMF network element receives an Application data detection notice including an Application ID from a UPF network element, and the SMF network element learns that a user is not reachable currently, setting a first notice identifier corresponding to the Application ID as a first preset value; if the SMF network element learns that the user is not reachable currently and the AMF network element is not subscribed with the user reachable state notification at that time, the SMF subscribes the event of the UE reachable state notification to the AMF network element; when receiving a notification request for subscribing the UE reachable state from the SMF network element, the AMF network element sets a value of a second notification identifier associated with the SMF network element to a first preset value, so as to represent that the AMF network element needs to send a message notification to the SMF network element when detecting that the state of the target UE changes from unreachable to reachable.

As can be seen, by the message notification method provided in this embodiment, the UE reachable notification after the downlink data failure can be sent only to the AF that has sent the downlink data service requirement, instead of to all AFs that have subscribed to the first subscription event in the UE reachable state, so that the pertinence and intelligence of sending the UE reachable notification after the downlink data failure are improved, and the network resource utilization rate is improved.

Example two:

for convenience of understanding, the present embodiment is described with reference to an application scenario of a specific network architecture diagram as an example on the basis of the second embodiment.

In order to maintain the competitiveness of the third generation mobile communication system in the communication field, provide faster, lower delay, and more personalized mobile communication services for users, and at the same time, reduce the operation cost of operators, the 3GPP (3rd generation partnership Project) standard working group is dedicated to the research of the next generation wireless mobile access network. In the next generation Radio Access Network, a Core Network with unified Access to a plurality of Radio networks is supported, and it is desirable that a Radio Access Network (RAN) and a Core Network (CN) have a coupling relationship as reduced as possible, that is, a terminal can be accessed to a unified CN regardless of the RAN Access technology. Core network functions of next generation networks support service-based interfaces in order to support more flexible deployment, wherein an exemplary network basic architecture is shown in fig. 2, where the main nfs (network function) includes but is not limited to the following:

the AMF belongs to a common control plane function in a core network and terminates NAS messages between all users and the network. A user UE may have only one AMF, which is responsible for user mobility management, UE status (e.g., reachability) management, etc.

SMF, which is responsible for but not limited to session establishment, modification, deletion, PCF charging and policy execution and other functions;

the PCF is responsible for, but not limited to, formulating policies for the terminal, including routing policies, quality of service policies, charging policies, etc., according to the subscription of the user, the current location of the UE, and the information related to the application.

The UDM has a unified data management function and can be used for but not limited to permanent storage of user subscription data and other functions;

UDR (Unified Data Repository), which may be used for, but is not limited to, storing user subscription Data, policy Data, etc. managed by UDMs and PCFs.

UPF, belonging to the function of user plane in core Network, it is anchor point of user plane in core Network, it is interface for Data transmission with external Network (DN, Data Network), and executes the execution of PCF strategy rule of user plane;

NEF (not shown in the figure) for exposing the capability and event of 3GPP NFs to other NF or third party application AF, providing AF to pre-configure 3GPP NFs capability, implementing 3GPP network and external network information mapping, etc.;

AF in this example refers to a non-3 GPP third party application; dn (data network) refers to a non-3 GPP external network; 5G-AN (Access network) refers to a 5G access network.

For convenience of understanding, based on the network infrastructure application scenario shown in fig. 2, the present embodiment is exemplified by a method for performing AF application packet detection on an SMF network element by first subscribing to an event and making a UPF, which is shown in fig. 3 and includes:

s301: each AF may Subscribe to a notification Event (i.e., Subscribe to a UE Availability after DDNfailed Event) through the NEF network element, for example, the AF may send a Nnef _ Event _ Exposure _ describe request to Subscribe to an Availability after DDN failure Event of a target UE corresponding to the AF, and the Nnef _ Event _ Exposure _ describe may include an indication of subscribing to the Availability after DDN failure Event and an Application ID including the AF. The message also includes a target UE identity, which may indicate a single user or a group of users. The target UE identity may also optionally include an IP address.

Upon receiving the Nnef _ Event _ Exposure _ Subscribe request, the NEF network element may generate an Event reference identifier NEF _ reference _ ID1 for the first subscribed Event, which is associated with the Application ID in the Nnef _ Event _ Exposure _ Subscribe request.

S302: the NEF network element generates a first subscription event from the UDM network element according to the target UE identifier; for example, the NEF network element may send a numdeveexposure _ Subscribe request (i.e., a type of first request) to the UDM network element, which may include an indication to Subscribe to an Availability after DDN failure Event, an Application ID of the AF, NEF _ reference _ ID1, and optionally, an NEF ID of the NEF network element.

S303: and the UDM network element finds out the context related to the user according to the target UE identification, selects a proper SMF network element in the user context, and then performs UE availability after DDN failed event subscription on the SMF network element. For example, the UDM network element may send an Nsmf _ Event _ expose _ describe request to the SMF network element, which may include an indication of a subscription to an Availability after DDN failure Event, Application ID, NEF _ reference _ ID 1.

The SMF generates a first subscription event for monitoring the reachable state of the UE, and optionally can set whether to send a notification flag for starting monitoring of the first notification identifier (if the notification flag is 'No', the UE reachable notification is not sent after the downlink data of the first subscription event fails, and if the notification flag is 'yes' (namely a first preset value), the UE reachable notification is sent after the downlink data of the first subscription event fails).

S304: and the SMF network element configures the UPF network element to perform AF data packet detection.

And the SMF network element activates Application packet detection aiming at the Application ID on the UPF network element according to the subscription request (namely, the second request) of the UDM network element. For example, the SMF network element may send N4session establishment/Modification Request (Application ID, PFD) to the UPF network element, and in the N4session establishment/Modification Request, the SMF network element may issue a PFD (Packet Flow Description) corresponding to the Application ID to the UPF. The SMF may also issue the Application ID to the UPF, and at this time, the UPF performs packet detection according to the locally configured PFD corresponding to the Application ID.

S305: the SMF network element sends a response message, e.g., Nsmf _ EventExposure _ subscribes, to the UDM network element.

S306: the UDM network element sends a response message, e.g., nutm EventExposure subscribes, to the NEF network element.

S307: the NEF network element sends a response message, e.g., Nnef _ EventExposure _ subscribes, to the AF.

Alternatively, steps S306 and S307 may be transmitted before step S303.

The AF application packet detection can be performed on the SMF network element by the first subscription event and the configuration UPF in the manner shown in fig. 3.

Example three:

based on the application scenario of the network basic architecture shown in fig. 2, the following description is given by taking a method for performing AF application packet detection on a first subscription event and a UPF made on an SMF network element as an example, and as shown in fig. 4, the method includes:

s401: each AF may Subscribe to a notification Event (i.e., Subscribe to a UE Availability after DDNfailed Event) through the NEF network element, for example, the AF may send a Nnef _ Event _ Exposure _ describe request to Subscribe to an Availability after DDN failure Event of a target UE corresponding to the AF, and the Nnef _ Event _ Exposure _ describe may include an indication of subscribing to the Availability after DDN failure Event and an Application ID including the AF.

S402: the NEF finds out a corresponding PCF network element according to the target UE identification and other information, and the PCF network element generates a related first subscription event; for example, the NEF network element may send an Npcf _ PolicyAuthorization _ Create (i.e., an example first request) to the PCF network element, which may include an indication to subscribe to an Availability afterDDN failure event, an Application ID of the AF, a NEF _ reference _ ID1, and optionally, a NEF ID of the NEF network element.

S403: the PCF network element finds out the context and the relevant session related to the user according to the target UE identification and other information, and then performs an Availability after DDN failure event (namely a UE validity monitoring event) subscription on the SMF network element of the session. For example, the PCF network element may send an Npcf _ SMPolicyControl _ UpdateNotify to the SMF network element, which may include an indication to subscribe to an Availability after DDN failure event, Application ID, NEF reference ID 1.

S404: and the SMF network element configures the UPF network element to perform AF data packet detection.

And the SMF network element activates Application packet detection aiming at the Application ID on the UPF network element according to the subscription request of the UDM network element. For example, the SMF network element may send N4Session Establishment/Modification Request (Application ID, PFD) to the UPF network element, and in the N4Session Establishment/Modification Request, the SMF network element may issue a PFD (Packet Flow Description) corresponding to the Application ID to the UPF. The SMF may also issue the Application ID to the UPF, and at this time, the UPF performs packet detection according to the locally configured PFD corresponding to the Application ID.

S405: the SMF network element sends a response message, e.g., Npcf _ SMPolicyControl _ UpdateNotify, to the PCF network element.

S406: the PCF network element sends a response message, e.g. numdm _ EventExposure _ subscribes, to the NEF network element.

S407: the NEF network element sends a response message, e.g. Npcf _ PolicyAuthorization _ Createresponse, to the AF.

Alternatively, steps S406 and S407 may be transmitted before step S403.

In the manner shown in fig. 4, the AF application packet detection can be performed on the SMF network element by the first subscription event and the configuration UPF.

Example four:

in this embodiment, on the basis of the foregoing embodiment, a process of a method for a UPF network element to send a notification to an SMF network element when detecting an AF application data packet, and for the SMF network element to report a UE availability notification message to an AF is provided as an example for description, and as shown in fig. 5, the process includes:

s501: the AF sends downlink data, and the UE in fig. 5 is a target UE corresponding to the AF.

S502: the UPF network element sends Downlink Data Notification to the SMF network element, and optionally, the Downlink Data Notification may carry, but is not limited to, at least one of QoS flow, ARP (Allocation and retention Priority), and other information. The UPF network element detects that the AF is sending downlink Data according to the packet detection, and then sends an N4Report message to the SMF network element to Report the detected Application ID (of course, in an example, the UPF network element may directly Report the detected Application ID to the SMF through Data Notification). After receiving the N4Report message or the Data Notification message, if the SMF network element already knows that the target UE corresponding to the AF corresponding to the Application ID is in an unreachable state, the SMF network element sets the Notification flag of the AF to yes, where the Notification flag and the NEF _ reference _ ID1 are associated. If the SMF network element already knows that the target UE corresponding to the AF corresponding to the Application ID is in a reachable state, the notification flag of the AF can be set to be negative; and optionally may also clear the ApplicationID.

S503: if the SMF network element does not know that the user is in the unreachable state, the SMF network element requests the AMF network element, instructing the AMF network element to page the target UE (for example, see S5031 in fig. 5, at this time, DDN failure).

S504: and the AMF network element judges that the paging target UE has no response or fails, and then the AMF network element sends a DDN failure response to the SMF network element.

S505: the SMF learns that the user is not reachable currently, then sends a message to the AMF requesting to subscribe to the user reachable notification, and after receiving the message, the AMF sets a second notification flag associated with the SMF network element in S503, where the value of the Availability notification SMF flag is "yes", and is used to indicate that the SMF network element needs to be notified when the target UE state becomes Availability. In another example, the tape subscription request may be carried in step S503, so that the SMF does not need to resend the subscription message to the AMF.

S506: in S5061, the AMF network element detects that the target UE status becomes available, and sends a UE status reachable notification message to the SMF network element according to the second notification flag UE available notification SMF flag set in S505.

S507: the SMF network element determines AF needing to be notified according to the setting of a first notification flag, and sends a UE state reachable notification message to the NEF network element corresponding to the NEF ID according to the NEF _ Reference _ ID1 and the NEF ID of an event Reference identifier of a first subscription event; for example, in one example, the SMF network element may be implemented by sending an Nsmf _ EventExposure _ Notify to the NEF network element.

S508: and the NEF network element sends the UE reachable notification to the AF corresponding to the Application ID after the received downlink data fails. For example, in one example, the NEF network element may be implemented by sending a Nnef _ EventExposure _ Notify to the AF.

Example five:

the present embodiment also provides a message notification apparatus, which may be disposed in an SMF network element, as shown in fig. 6, and includes:

the third event subscription processing module 601 receives a first request for generating a first subscription event for monitoring the reachable state of the target UE, and generates the first subscription event for monitoring the reachable state of the target UE, that is, a UE availability after DDN failed event subscribed to the target UE.

In this embodiment, the first request includes an event reference identifier of a first subscription event, an identifier Application ID of a third party Application AF, and an NEF identifier NEF ID of a network open function NEF network element, which are associated with each other, and the third event subscription processing module 601 associates the generated first subscription event with the event reference identifier of the first subscription event in the first request.

In an example of this embodiment, the NEF network element may trigger, according to the second request of the third-party application AF, to send, to the session management function SMF network element, a first request for generating a first subscription event for monitoring the UE reachable state, so that the SMF network element generates the first subscription event for monitoring the UE reachable state. And optionally, the event reference identifier of the first subscription event included in the first request may be generated by the NEF network element.

For example, in one example, the second request may include, but is not limited to including, at least one of:

Correspondingly, in an example, the first request received by the third event subscription processing module 601 includes at least one of the following requests:

an Event open subscription request from a UDM (Unified Data Management) network element, for example including but not limited to an Event expose _ Subscribe request.

A session Policy Control Update notification request from a PCF (Policy Control Function) network element, including, but not limited to, an SM Policy Control _ Update notification request, for example.

A fifth notification sending module 602, configured to receive a UE reachable notification after the downlink data of the target UE fails, and send the UE reachable notification after the downlink data fails to an NEF network element corresponding to the NEF ID associated with the first subscription event according to the first subscription event generated by the third event subscription processing module 601, so that the NEF network element sends, according to the association relationship between the Application ID and the event reference identifier of the first subscription event, an AF corresponding to the Application ID.

In an example in this embodiment, in the process that the third event subscription processing module 601 generates the first subscription event, the UPF network element may be further configured to perform packet detection, that is, the Application packet detection for the Application ID is activated on the UPF network element. The third event subscription processing module 601 may issue a PFD (Packet FlowDescription ) corresponding to the Application ID to the UPF network element; optionally, the third event subscription processing module 601 may also issue the Application ID to the UPF network element, and at this time, the UPF network element may perform packet detection according to the locally configured PFD corresponding to the Application ID.

In an example of this embodiment, the third event subscription processing module 601 may control, through the first notification identifier, whether each first subscription event needs to report the UE reachable notification after the downlink data failure, and therefore, in an example of this embodiment, when the third event subscription processing module 601 generates the first subscription event that monitors the UE reachable state, the method further includes:

and generating a first notification identifier, such as a notification flag, and setting the generated first notification identifier to be associated with the event reference identifier of the first subscription event in the first request. Optionally, when the value of the first notification identifier may be set to be a first preset value, the UE may reach the notification after the first subscription event associated with the event reference identifier of the first subscription event associated with the first notification identifier needs to report the failure of the downlink data; optionally, when the value of the first notification identifier is not the first preset value, the UE may reach the notification after the reporting of the downlink data fails, which may characterize the first subscription event associated with the event reference identifier of the first subscription event associated with the first notification identifier.

In an example of this embodiment, the third event subscription processing module 601 may temporarily set a value of the generated first notification identifier or directly default to the first preset value in the process of generating the first subscription event. And the method can be flexibly set according to a specific application scene.

In an example of the present embodiment, the third event subscription processing module 601 may set the value of the notification flag in, but is not limited to, the following example manner. For example, before the third event subscription processing module 601 receives the reachable notification, the third event subscription processing module 601 receives an Application data detection notification including a corresponding Application ID sent by the UPF network element, and when it is determined that the target UE to be delivered by the AF corresponding to the Application ID is currently unreachable, may set the first notification identifier corresponding to the Application ID to be the first preset value. The downlink application data detection notification in this embodiment includes, but is not limited to: at least one of an N4Report message and a Data Notification message.

Therefore, in an example of this embodiment, before the UE reachable notification after the downlink data failure is sent to the NEF network element corresponding to the NEF ID in the fifth notification sending module 602, the fifth notification sending module may be further configured to determine whether the first notification identifier is the first preset value currently, and if so, send the UE reachable notification after the downlink data failure to the NEF network element corresponding to the NEF ID, so that the NEF network element sends the UE reachable notification to the AF corresponding to the Application ID according to the association relationship between the Application ID and the event reference identifier of the first subscription event.

In an example of this embodiment, the AMF network element may also control whether the reachable notification needs to be sent to the third event subscription processing module 601 by setting the notification identifier. For example, when the AMF network element pages the UE according to the request of the SMF network element, if the user is not reachable and a subscription request of a user reachable notification of the SMF network element is received, a second notification flag UE Availability notification SMF flag associated with the SMF network element may be set, and when the value of the UE Availability notification SMF flag is set to be a first preset value, it is characterized that the associated SMF needs to be reported, that is, it is indicated that the associated SMF needs to be notified when the state of the target UE changes from unreachable Availability to reachable Availability. Therefore, optionally, in an example of the present embodiment, the reachable notification received by the fifth notification sending module 602 may be that the AMF network element changes the status of the target UE from unreachable availability to reachable availability when detecting that the status of the target UE is changed. And the second notification identifier, for example, the UE Availability Notify SMF flag, is sent to the SMF by the AMF when the current value of the second notification identifier is the first preset value. The second notification identifier UE, Availability notification SMF flag, is set after the AMF network element detects that the state of the target UE is unarchability and receives an event subscription message of SMF.

The functions of the third event subscription processing module 601 and the fifth notification sending module 602 in this embodiment may be implemented by, but are not limited to, a processor or a controller of an SMF network element, and with the message notification apparatus provided in this embodiment, the UE reachable notification after the downlink data failure may be sent only to the AF that has sent the downlink data service requirement, instead of to all AFs that subscribe to the first subscription event in the UE reachable state, so that the pertinence and intelligence of sending the UE reachable notification after the downlink data failure are improved, and the utilization rate of network resources is improved.

Example six:

the message notification method provided in this embodiment, on the NEF network element side, as shown in fig. 7, may include, but is not limited to, the following steps:

s701: receiving a request sent by an AF for subscribing to a UE reachable event (i.e., UE availabilityafter DDN failure) after a failure of downlink data, where the request message may include a target UE identity and an Application identity Application ID.

In this example, the AF may also send a request for a UE reachable event after a failure to subscribe to downlink data through various interactive messages with the NEF network element.

S702: and sending a first request for subscribing the UE reachable event after the downlink data fails to be sent to the AMF network element according to the received request, and sending a second request for subscribing the application data detection event (namely the downlink data packet detection event) to the SMF network element.

In this embodiment, the execution sequence of sending the first request to the AMF network element and sending the second request to the SMF network element by the NEF network element is not strictly limited, and the two requests may be executed in parallel, or the first request may be sent to the AMF network element first and then the second request may be sent to the SMF network element; or the second request is sent to the SMF network element first, and then the first request is sent to the AMF network element.

In this embodiment, the first request may include, but is not limited to, an application identifier of the AF and an identifier NEF ID of the NEF network element, and the functions of the first request are as described above, and are not described herein again. The second request may also include an application identifier of the AF and an identifier NEFID of the NEF network element, so that a second subscription event detected by the application data generated by the SMF network element according to the second request may be associated with the application identifier of the AF and the identifier NEF ID of the NEF network element, and the SMF network element may instruct, according to the second subscription event, the UPF network element to activate application data detection (i.e., downlink packet detection) of the AF corresponding to the corresponding application identifier; and when receiving a notification sent by the UPF and detecting that a certain AF sends downlink data, determining a corresponding second subscription event according to the application identifier in the notification and the association relationship, sending an application data detection notification to a NEF network element corresponding to a corresponding NEF ID according to the determined second subscription event and the association relationship, and including the corresponding application identifier in the sent application data detection notification.

In this embodiment, the sending, to the AMF network element, the first request for the UE reachable event after the failure of subscribing to the downlink data may include, but is not limited to, at least one of the following manners:

sending a first request to an AMF network element through an event open subscription request of a UDM (Unified Data Management) network element;

in this embodiment, the sending of the second request for subscribing to the application data detection to the SMF network element may include, but is not limited to, at least one of the following manners:

sending a first request to an SMF network element through an event open subscription request of a UDM (Unified Data Management) network element;

sending a first request to an SMF network element through a session Policy Control update notification request of a Policy Control Function (PCF) network element.

S703: and receiving an application data detection notice sent by the SMF network element, and storing an application identifier in the application data detection notice in an application identifier list.

It should be understood that the present embodiment is not limited to storing/caching the application identifier in the application data detection notification (i.e. detecting the application identifier of each AF that has sent the downlink data) through the application identifier list. In addition, the application identification list in this embodiment may adopt various lists that can be used to store identification information.

S704: and the UE can reach the notice after the failure of receiving the downlink data sent by the AMF network element.

As shown above, the UE reachable notification after the downlink data failure may include an application identifier of an AF corresponding to the UE that is changed from the unreachable state to the reachable state.

It should be understood that the execution sequence of S703 and S704 in this embodiment is not strictly limited by the timing sequence; and the two can be executed in parallel or not.

S705: and sending UE reachable notification after the failure of downlink data to AF corresponding to the application identifier contained in the application identifier list.

In this step, the UE reachable notification after failure of sending downlink data to the AF corresponding to the application identifier included in the application identifier list includes, but is not limited to, one of the following:

directly sending a UE reachable notification after failure of downlink data transmission to the AF corresponding to the application identifier contained in the application identifier list, and optionally clearing the application identifier list after transmission;

sending the UE reachable notification after the downlink data failure to AF corresponding to the application identification contained in the UE reachable notification after the downlink data failure in the application identification list; for example, the application identifier is extracted from the UE reachable notification after the received downlink data fails, and then when the application identifier that is the same as the application identifier is selected from the application identifier list, the UE reachable notification after the downlink data fails is sent to the AF corresponding to the application identifier.

In this embodiment, for an AF that has sent downlink data, a target UE corresponding to the AF may be in an reachable state when the target UE sends the downlink data, and for such an AF, the UE may not be reachable after the failure of sending the downlink data to the target UE; therefore, optionally, in order to further improve the accuracy of resource utilization and message notification control, for this type of AF, a clearing mechanism may be employed to clear its application identity from the above-mentioned application identity list. For example, referring to fig. 8, an exemplary manner may further include, but is not limited to, after receiving the application data detection notification sent by the SMF network element:

s801: and sending a third request for subscribing the UE reachable event to the AMF network element.

The UE reachable event in this embodiment refers to one of two methods: the method comprises the following steps: the UE is currently reachable or not at the time of detection, and does not care about the previous state of the UE. That is, at the time before the UE corresponding to the application identifier in the application data detection notification is reachable or not, the UE may be in a reachable state or in an unreachable state, and only after the detection or the start of the detection, the UE is reachable from unreachable; in either case, the UE reachable notification is fed back as long as UE reachability is detected. The second method comprises the following steps: whether the current state of the UE can be reached during detection or not is judged, and if the current state of the UE can be reached, a UE reaching notice is fed back; and if the current state of the UE is unreachable, feeding back a UE unreachable notice.

In this embodiment, the sending of the third request for subscribing to the UE reachable event to the AMF network element includes but is not limited to:

and sending a third request to the AMF network element through the event open subscription request of the UDM network element.

S802: and when the UE reachable notification sent by the AMF network element is received, clearing the application identifier contained in the application identifier list.

In this embodiment, the clearing of the application identifier list includes but is not limited to one of the following:

removing all application identifications in the application identification list;

and clearing the application identifications in the application list, which are the same as the application identifications contained in the UE reachable notification.

As shown above, the UE reachable notification sent by the AMF network element for a certain UE may be sent when the UE becomes reachable from unreachable, or may be sent when the UE is in a reachable state when the corresponding AF sends downlink data (that is, a DDN failure event does not occur). Therefore, in order to avoid mistakenly clearing the AF corresponding to the UE that is in the unreachable reachable state, the present embodiment may further employ an identification mechanism to avoid the above situation. For example, referring to fig. 9, an identification process, before clearing the application identifier included in the application identifier list after receiving the UE reachable notification sent by the AMF network element, may further include:

s901: the timing is started from when the UE reachable notification is received.

In one example, the NEF network element may set a timer by which to time.

S902: and when the timing value reaches a set time value, if the UE can reach the notice after the failure of the downlink data is not received, clearing the application identifier contained in the application identifier list.

In this step, if the UE reachable notification after the downlink data failure is received, the UE reachable notification after the downlink data failure is sent to the AF corresponding to the application identifier included in the application identifier list.

The present embodiment also provides a message notification apparatus that can be disposed in a NEF network element, and certainly can also be disposed in other network elements that can communicate with an AF, where each module included in the message notification apparatus can implement, but is not limited to, the corresponding function in the foregoing method, and the function of each module can be implemented by, but is not limited to, a processor or a controller of the network element. Referring to fig. 10, the message notification apparatus in the present embodiment includes, but is not limited to:

a second request receiving module 1001, configured to receive a request, sent by an AF, for subscribing to a UE reachable event after a failure of downlink data subscription.

A second event subscription requesting module 1002, configured to send, to the AMF network element, a first request for subscribing to the UE reachable event after the downlink data failure according to the request received by the second request receiving module 1001, and send, to the SMF network element, a second request for subscribing to the application data detection event.

A second notification receiving module 1003, configured to receive an application data detection notification sent by an SMF network element, and store an application identifier in the application data detection notification in an application identifier list; and the UE reachable notification is used for receiving the downlink data failure sent by the AMF network element.

A second notification sending module 1004, configured to send a UE reachable notification after failure of sending downlink data to an AF corresponding to an application identifier included in the application identifier list, and optionally, may further be configured to clear the application identifier list;

in an example of this embodiment, the second event subscription request module 1002 may be further configured to send a third request for subscribing to the UE reachable event to the AMF network element.

The second notification receiving module 1003 may further be configured to clear the application identifier included in the application identifier list when receiving the UE reachable notification sent by the AMF network element.

Optionally, in this embodiment, the second notification receiving module 1003 may be further configured to start timing when the UE reachable notification is received before the application identifier included in the application identifier list is cleared after the UE reachable notification sent by the AMF network element is received. The second notification receiving module 1003 may further be configured to clear the application identifier included in the application identifier list if the UE can reach the notification after failing to receive the downlink data when the timing value reaches the set time value; if the UE reachable notification after the downlink data failure is received, the UE reachable notification after the downlink data failure can be sent to the AF corresponding to the application identifier through the second notification sending module 1004.

The message notification method provided in this embodiment, on the AMF network element side, as shown in fig. 11, may include, but is not limited to, the following steps:

s1101: receiving a first request sent by a NEF network element and used for subscribing the UE reachable event after the downlink data failure, and generating the first subscription event that the UE can reach after the downlink data failure according to the first request.

As shown above, the first request may include the application identifier of the AF and the NEF ID of the NEF network element, and the first subscription event may be associated with the application identifier of the AF and the NEF ID of the NEF network element in the first request; optionally, in an example, an event reference identifier of an associated first subscription event may also be generated for the first subscription event, so as to facilitate management of each first subscription event. For example, when a certain UE detects that the UE becomes reachable from unreachable, the UE reachable notification may further include an event reference identifier of a corresponding first subscription event after the sent downlink data fails, so that the receiver recognizes that the received notification is a notification corresponding to the first subscription event according to the event reference identifier of the first subscription event.

S1102: and when detecting that the target UE is changed from unreachable to reachable according to the first subscription event, sending a UE reachable notification after downlink data failure to the NEF network element, wherein the UE reachable notification after the downlink data failure can comprise an application identifier.

That is, in this step, the AMF network element may send, according to the first subscription event, a UE reachable notification after failure of downlink data to the NEF network element corresponding to the NEF ID corresponding to the first subscription event when it is detected that the target UE corresponding to the first subscription event is changed from unreachable to reachable, where the sent UE reachable notification after failure of downlink data may include the application identifier corresponding to the first subscription event.

On the AMF network element side, the message notification method provided in this embodiment is shown in fig. 12, which may further include, but is not limited to, the following steps:

s1201: and receiving a third request for subscribing the UE reachable event sent by the NEF network element, and generating a third subscribed event which can be reached by the UE according to the third request, wherein the third request can comprise an application identifier in the application data detection notification.

S1202: and when detecting that the target UE in the third request is reachable according to the third subscription event, sending a UE reachable notification to the NEF network element.

As shown in the foregoing analysis, in this step, the AMF network element detects that the UE is reachable, where the UE may be changed from unreachable to reachable, or may be in a reachable state when the UE sends downlink data through its corresponding AF.

Optionally, in an example, an event reference identifier of an associated third subscription event may also be generated for the third subscription event, so as to facilitate management of each third subscription event. For example, when the AMF network element determines that a certain UE is reachable according to the third event, the sent UE reachable notification may include an event reference identifier of the corresponding third subscription event, so that the receiver recognizes that the received notification is a notification corresponding to the third subscription event according to the event reference identifier of the third subscription event.

The present embodiment also provides a message notification apparatus that can be disposed in the AMF network element, and certainly can also be disposed in other network elements that can directly or indirectly detect the UE reachable state, where each module included in the message notification apparatus can implement, but is not limited to, a corresponding function in the foregoing method, and the function of each module can be implemented, but is not limited to, by a processor or a controller of the network element. Referring to fig. 13, the message notification apparatus in the present embodiment includes, but is not limited to:

a third request receiving module 1301, configured to receive a first request sent by an NEF network element and used for subscribing to a UE reachable event after a failure of downlink data, where the first request includes an application identifier of an AF and an identifier NEF ID of the NEF network element;

a first event subscription processing module 1302, configured to generate, according to the first request received by the third request receiving module 1301, a first subscription event that the UE can reach after the downlink data failure.

A third notification sending module 1303, configured to send, according to the first subscription event, a UE reachable notification after a failure of downlink data to the NEF network element when detecting that the UE corresponding to the application identifier is reachable from unreachable, where the UE reachable notification after the failure of the downlink data includes the application identifier.

In an example of this embodiment, the third request receiving module 1301 may be further configured to receive a third request for subscribing to a UE reachable event sent by the NEF network element; the third request comprises an application identifier in the application data detection notification;

the first event subscription processing module 1302 is further configured to generate a third subscription event that the UE is reachable according to the third request;

the third notification sending module 1303 is further configured to send a UE reachable notification to the NEF network element when detecting that the UE corresponding to the application identifier in the third request is reachable according to the third subscription event.

The message notification method provided in this embodiment, on the SMF network element side, as shown in fig. 14, may include, but is not limited to, the following steps:

s1401: and receiving a second request for subscribing the application data detection event sent by the NEF network element, and generating a second subscription event for application data detection according to the second request, wherein the second request comprises the application identifier of the AF and the identifier NEFID of the NEF network element.

Optionally, in an example, an event reference identifier of an associated second subscription event may also be generated for the second subscription event, so as to facilitate management of each second subscription event. For example, when a certain AF detects that it has sent downlink data, the subsequently sent application data detection notification may include an event reference identifier of a corresponding second subscription event, so that the receiving side recognizes that the received notification is a notification corresponding to the second subscription event according to the event reference identifier of the second subscription event.

S1402: and indicating the UPF network element to activate the application data detection of the AF corresponding to the application identifier according to the second subscription event. And the UPF network element can detect the application data, namely the downlink data packet, of the corresponding AF according to the indication.

S1403: and receiving an application data detection notice sent by the UPF network element, wherein the application data detection notice comprises an application identifier of the AF which sends the downlink data.

S1404: and sending the received application data detection notice to the NEF network element.

The present embodiment also provides a message notification apparatus that can be disposed in an SMF network element, and certainly can also be disposed in other network elements that can directly detect or indirectly detect AF downlink data, where each module included in the message notification apparatus can implement, but is not limited to, a corresponding function in the foregoing method, and the function of each module can be implemented, but is not limited to, by a processor or a controller of the network element. Referring to fig. 15, the message notification apparatus in the present embodiment includes, but is not limited to:

a fourth request receiving module 1501, configured to receive a second request for subscribing to an application data detection event sent by an NEF network element, where the second request includes an application identifier of an AF and an identifier NEF ID of the NEF network element.

A second event subscription processing module 1502, configured to generate a second subscription event of application data detection according to the second request, and instruct, according to the second subscription event, the user plane function UPF network element to activate application data detection of the AF corresponding to the application identifier.

A fourth notification sending module 1503, configured to receive the application data detection notification sent by the UPF network element, and send the application data detection notification to a corresponding NEF network element (that is, the NEF network element corresponding to the application identifier in the notification), where the application data detection notification includes the application identifier of the AF that has sent the downlink data.

Example seven:

based on the network infrastructure application scenario shown in fig. 2, the following description of this embodiment is given by using a method for detecting a UE reachable event (i.e., a UE availability after DDN failed to subscribe to downlink data on an AMF network element) and an AF application packet activated by an SMF network element.

One example of this is shown in fig. 16, which includes:

s1601: each AF may Subscribe to a UE Availability after DDN failed event by sending a request (hereinafter referred to as an event subscription request) to the NEF network element, for example, the AF may send a Nnef _ EventExposure _ Subscribe to a UE Availability after DDN failed event of a UE corresponding to the AF, and the Nnef _ EventExposure _ Subscribe request may include an indication of subscribing to the UE Availability after DDN failed event, an application identifier of the AF, and optionally, a target UE identifier corresponding to the AF. The target UE identity may indicate a single user or may indicate a group of users. The target UE identity may optionally include an IP address. The Application identifier of the AF refers to information that can be used to characterize the AF identity, such as Application identifier Application ID, port information, IP address information, and the like.

Upon receiving the Nnef _ EventExposure _ Subscribe request of each AF, the NEF network element may generate an event reference identifier NEF _ reference _ ID, which may be associated with the Application ID in the Nnef _ EventExposure _ Subscribe.

S1602: the NEF network element finds the UDM network element according to the target UE identification in the event subscription request, and generates a subscription event to the UDM network element; for example, the NEF network element may send a numdm _ EventExposure _ Subscribe request (i.e., an example first request) to the UDM network element, which may include an indication to Subscribe to the Availability after DDN failure event, the Application ID of the AF, the NEF _ reference _ ID, and optionally, the NEF ID of the NEF network element.

S1603: the UDM network element performs UE availability after DDN failure event subscription to the AMF network element, for example, the UDM network element may send a Namf _ EventExposure _ Subscribe request (i.e., an exemplary first request sending manner) to the AMF network element, where the request may include an indication of subscribing to the UE availability after DDN failure event, an Application ID, an NEF ID, and an NEF _ reference _ ID (i.e., an event reference identifier of the first subscription event); the AMF network element may generate the first subscription event according to the Namf _ EventExposure _ Subscribe request.

S1604: and the UDM network element finds out a session context related to the user according to the target UE identification, finds out an SMF (home network roaming condition, namely hSMF or home SMF) network element registered by the user in the user context, and then performs application data detection event subscription on the SMF network element. For example, the UDM network element may send an Nsmf _ EventExposure _ Subscribe request (i.e., an example second request) to the SMF network element, which may include an indication of a subscribed Application data detection event, an Application ID, an NEF _ reference _ ID (i.e., an event reference identifier for a second subscribed event), and the SMF network element may generate the second subscribed event based on the Nsmf _ EventExposure _ Subscribe request.

S1605: and the SMF network element configures UPF (home network roaming scene, namely hUPF or home UPF) network elements to execute AF data packet detection corresponding to the Application ID.

And the SMF network element activates downlink data packet detection aiming at the Application ID on the UPF network element according to the Nsmf _ EventExpo _ Subscripte request of the UDM network element. For example, the SMF network element may send N4session establishment/Modification Request (Application ID, PFD) to the UPF network element, and in the N4session establishment/Modification Request, the SMF network element may issue a PFD (Packet Flow Description) corresponding to the Application ID to the UPF. The SMF may also issue the Application ID to the UPF, and at this time, the UPF performs packet detection according to the locally configured PFD corresponding to the Application ID.

S1606: the SMF network element sends a response message, e.g., Nsmf _ EventExposure _ subscribes, to the UDM network element.

S1607: the UDM network element sends a response message, e.g., nutm EventExposure subscribes, to the NEF network element.

S1608: the NEF network element sends a response message, e.g., Nnef _ EventExposure _ subscribes, to the AF.

The present embodiment also provides an example, referring to fig. 17, that the generating of the second subscription event for detecting the application data packet at the SMF network element may also be implemented, where the second subscription event includes:

s1701: each AF may Subscribe to an event by sending a request (hereinafter referred to as an event subscription request) to the NEF network element, e.g., the AF may send a Nnef _ EventExposure _ Subscribe request, which may include the AF's Application identification Application ID and corresponding UE information (e.g., including but not limited to the IP address of the UE), to Subscribe to an Application data detection event corresponding to the AF.

S1702: if the UE can reach the PCF Network element of the PDU session related to the UE, the NEF Network element requests the PCF Network element to detect an event subscription by using the IP address of the UE in the event subscription request, or DNN (Data Network Name) and S-NSSAI (subscribed Network Slice Selection assistance information) information, for example, the NEF may send an Npcf _ policy authorization _ Subscribe request, where the request message carries an event reference identifier, an Application identifier Application ID, and an NEF Network element identifier.

If the NEF network element does not find the PCF network element of the session related to the user UE, the NEF saves the subscription event in the UDR (Unified Data Repository), and when the user creates a PDU session, the PCF network element receives the subscription event from the UDR.

S1703, the PCF network element issues a policy control and charging rule (PCC rule) to the SMF network element to request to report an Application data detection event, wherein the PCC rule comprises an Application ID, an event reference identifier and an NEF network element identifier which need to be detected. The pcresult is sent to the SMF network element, for example, by a session policy control update notification request message Npcf _ SMPolicyControl _ UpdateNotify.

S1704, the SMF network element creates an application data detection subscription event (i.e. the second subscription event), where the event includes an event reference identifier of the second subscription event and an NEF network element identifier; meanwhile, the SMF network element sends and executes AF aiming at the Application ID identification to the UPF network element for Application data detection. For example, the SMF network element may send an N4Session Establishment/Modification Request (Application ID, PFD) to the UPF network element, and in the N4Session Establishment/Modification Request, the SMF network element may send a PFD (Packet Flow Description) corresponding to the Application ID to the UPF. The SMF can also issue the Application ID to the UPF, and the UPF performs data packet detection according to the locally configured PFD corresponding to the Application ID

For convenience of understanding, the following description is made in conjunction with a notification flow diagram of a UE reachable notification message, and is shown in fig. 18, where the notification flow diagram includes:

s1800: according to the configuration, the application data detection is carried out by the hUPF network element (hereinafter referred to as hUPF) according to the PDF.

S1801: and the AF sends the downlink data to the hUPF network element.

S1802: and the hUPF network element detects the downlink Data sent by the AF identified by the Application ID, and sends an N4report or Data Notification (Data Notification) message to notify the hSMF network element.

S1803: the hSMF notifies an NEF network element (hereinafter abbreviated as NEF) according to a second subscription event of the AF, that the AF sends data Nsmf _ evendexposure _ notify (application id), where the message carries an application identifier of the AF.

S1804: the NEF stores the identification Application ID of the detected AF to an Application ID list, if the NEF receives the notification of the hSMF and comprises a plurality of Application IDs, all the Application IDs can be directly stored in the Application ID list, and if the subsequent hSMF continues to report the detected Application ID, the NEF network element adds the subsequent Application ID to the Application ID list.

S1805: the NEF generates a new NEF Reference ID (i.e. the event Reference event identifier of the third subscription event), and sends a UE reachable monitor subscription event request to a UDM network element (hereinafter referred to as UDM).

S1806: when receiving the NEF request message, the UDM sends a request to the AMF to subscribe to the UE reachable state event Namf _ EventExposure _ describe (UE availability status, NEF ID, NEF Reference _ ID), that is, the third subscription event.

S1807: the hUPF sends downstream data to the visiting UPF (vUPF or visit UPF).

S1808: the vUPF caches the downlink Data, sends a Data Notification to the access SMF (vSMF or visit SMF), and then sends the Data Notification to the AMF.

S1809: the AMF pages the paging destination UE.

It should be understood that the above-described S1807 to S1809 may be executed in parallel with the steps S182 to S186.

S1810: if the AMF paging succeeds or the AMF knows that the UE status is reachable, performing S1811-S1812; otherwise, jump to S1813.

S1811: according to the third subscription event, the AMF sends a UE reachable notification message to the NEF Namf _ EventExposure _ notify.

S1812: the NEF receives the UE reachable notification of the third subscription event, which indicates that the user is currently reachable, all downlink data can be sent to the UE, and DDN Failure does not occur, so that the AF does not need to be notified, and then the NEF clears the Application ID list in S1804. (as shown in the above real-time data, for the NEF network element, when receiving the notification message of the third subscription event, the NEF cannot determine whether the message is received in S1812 or S1816, so when the NEF network element receives the message of the third subscription event, as in S1816, a timer is set locally, before the timer expires, if the notification of the first subscription event is not received, the Application ID list in S1804 is cleared, and if the notification of the first subscription event is received before the timer expires, the processing is performed according to S1816).

S1813: if the paging fails, the AMF sends DDN failure to the vSMF. The vSMF may instruct the vUPF to drop or save downstream data.

S1814: the AMF detects that the UE is reachable when the UE connects to the network next time. The AMF sends a UE reachable notification message Namf _ EventExposure _ notify (UE reachability) to the NEF according to the third subscription event.

S1815: meanwhile, the AMF judges that the user is the UE availability DDN Failure currently, and then the AMF sends the UE availability after DDN Failure to the NEF Namf _ EventExposure _ notify (UE availability after DDN Failure) according to the first subscription event.

S1816: if the NEF network element receives the UE availability after DDN failure of the first subscription event, the NEF sends the UE availability after DDN failure event to the AF corresponding to the Application ID list stored in S1804. Because S1814 and S1815 may be sent simultaneously from the AMF, if the NEF receives the user reachable notification of the third subscription event first, the NEF may set a timer locally, and before the timer times out, if the event notification of the first subscription event is received, send the UE availability after DDN failure event to the AF; if the notification of the first subscription event is not received before the timer times out, it is explained that the notification of S1812 is received, and the process is performed as S1812.

S1817: the NEF sends UE availabilityafter DDN failure notification message to the AF.

Example eight:

For easy understanding, the present embodiment is described with reference to a flow of a message notification method as an example, and a method flow at the NEF network element side is described in the present embodiment. It should be understood, however, that the following method steps are not limited to be performed by NEF network elements, but may be performed by other network elements that may communicate with an AF. The message notification method in this example is shown in fig. 19, and may include, but is not limited to:

s1901: receiving a request sent by an AF for subscribing to a UE reachable event (UE availabilityafter DDN failed event) after a failure of downlink data subscription.

In this example, the AF may send a request for a UE reachable Event after a subscription failure through various interactive messages (including signaling) with the NEF network element, for example, including but not limited to Nnef _ Event _ Exposure _ subscriber request.

In this embodiment, the request sent by the AF for subscribing to the UE reachable event after the downlink data failure may include the Application identifier Application ID of the AF, or may not include the Application identifier of the AF, and after the NEF network element receives the request, the AF Application identifier is extracted according to the sender of the request.

S1902: the first request for the UE reachable event after the failure of subscribing to the downlink data is sent to the target network element according to the request received in S1901, where the first request includes an identifier NEF ID of the NEF network element (it should be understood that NEFID in this embodiment may be any information that uniquely identifies/identifies the NEF network element) and an application identifier of the AF.

Because the first request sent to the target network element includes the identifier NEF ID of the NEF network element and the application identifier of the AF, when the target network element generates the first subscription event that the UE can reach after the downlink data failure according to the first request, the generated first subscription event can be correspondingly associated with the identifier NEF ID of the NEF network element and the application identifier of the AF; when detecting that a certain UE is changed from unreachable to reachable, the subsequent target network element may determine, according to the corresponding association relationship, an application identifier of the AF corresponding to the UE and an NEF ID corresponding to the application identifier of the AF, thereby determining an NEF network element to which the AF is accessed, and sending a UE reachable notification to the corresponding NEF network element after the downlink data of the UE fails.

In this embodiment, the target network element may include, but is not limited to, at least one of an AMF network element and an SMF (Session management function) network element. And it should be understood that the target network element may be, besides the AMF network element and the SMF network element in the above examples, any other network element capable of detecting or communicatively connecting with a network element capable of detecting a UE reachable status, such as a UDM (Unified Data Management) network element, a PCF (Policy Control Function) network element, and the like.

S1903: and receiving a UE reachable notification after the downlink data sent by the target network element fails, wherein the UE reachable notification after the downlink data fails comprises an AF application identifier corresponding to the UE which is changed from unreachable to reachable.

In this embodiment, the UE reachable notification is sent when the target network element detects that a target UE corresponding to an AF subscribed to the first subscription event is reachable from unreachable after the downlink data fails. And the reachable state of the UE can be directly detected by a target network element or detected by other network elements, and the detection result is sent to the target network element, so that the target network element determines the reachable state of the UE according to the detection result.

S1904: sending the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier contained in the UE reachable notification after the downlink data failure; and for other AF, UE can reach the notice after the downlink data fails not to be sent, so that the communication requirement can be met, and the utilization rate of network resources can be improved.

In this example, on the target network element side, the flow of the message notification method is shown in fig. 20, which may include but is not limited to:

s2001: receiving a first request sent by a NEF network element and used for subscribing the UE reachable event after the downlink data failure, and generating the first subscription event that the UE can reach after the downlink data failure according to the first request.

As indicated above, the first request includes the application identifier of the AF and the identification NEF ID of the NEF network element, and the first subscription event may be associated with the application identifier of the AF and the identification NEF ID of the NEF network element in the first request.

S2002: and when detecting that the UE corresponding to the corresponding application identifier is changed from unreachable to reachable according to the first subscription event, sending a UE reachable notification after downlink data failure to the corresponding NEF network element, wherein the UE reachable notification after the downlink data failure comprises the application identifier.

That is, in this step, the target network element may send, according to the first subscription event, a UE reachable notification after the failure of the downlink data to the NEF network element corresponding to the NEF ID corresponding to the first subscription event when detecting that the UE corresponding to the application identifier corresponding to the first subscription event is changed from unreachable to reachable, where the UE reachable notification after the failure of the downlink data includes the application identifier corresponding to the first subscription event.

As shown above, the target network element in this embodiment may include, but is not limited to, at least one of an AMF network element and an SMF network element. And in some examples, but not limited to UDM network elements, PCF network elements, etc. may also be employed.

The present embodiment also provides a message notification apparatus, which may be disposed in a NEF network element, or in another network element capable of communicating with an AF, where each module included in the message notification apparatus may implement, but is not limited to, a corresponding function in the foregoing method, and the function of each module may be implemented by, but is not limited to, a processor or a controller of the network element. Referring to fig. 21, the message notification apparatus in the present embodiment includes, but is not limited to:

a first request receiving module 2101, configured to receive a request sent by an AF for subscribing to a UE reachable event after a failure of downlink data;

a first event subscription request module 2102, configured to send, to a target network element, a first request for subscribing to a UE reachable event after the failure of downlink data according to the request received by the first request receiving module 2101, where the first request includes an identifier NEF ID of a NEF network element having a network open function and an application identifier of the AF;

a first notification receiving module 2103, configured to receive a UE reachable notification after a downlink data failure sent by a target network element, where the UE reachable notification after the downlink data failure includes an application identifier of an AF corresponding to a UE that is changed from unreachable to reachable;

a first notification sending module 2104, configured to send the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier included in the UE reachable notification after the downlink data failure.

By the message notification method and the device provided by the embodiment, the UE reachable notification message can be sent to the AF in a targeted manner, and compared with the related art in which the UE reachable notification message is directly sent to all AFs subscribing to the UE reachable event after the downlink data failure, the accuracy and reliability of communication and the utilization rate of network resources can be improved.

Example nine:

the present embodiment also provides an SMF network element, as shown in fig. 22, including a first processor 2201, a first memory 2202, and a first communication bus 2203;

a first communication bus 2203 is used to connect the first processor 2201 with the first memory 2202;

the first processor 2201 is configured to execute a first computer program stored in the first memory 2202 to implement, but not limited to, the steps of the message notification method as shown in embodiment one above;

alternatively, the first processor 2201 is configured to execute a second computer program stored in the first memory 2202 to implement, but not limited to, the steps of the message notification method as shown in the above embodiment eight.

The present embodiment also provides a NEF network element, as shown in fig. 23, including a second processor 2301, a second memory 2302, and a second communication bus 2303;

the second communication bus 2303 is used to connect the second processor 2301 and the second memory 2302;

the second processor 2301 is used to execute the third computer program stored in the second memory 2302 to implement, but not limited to, the steps of the message notification method as shown in the above embodiments six to seven;

or the second processor is configured to execute a fourth computer program stored in the second memory to implement the steps of the message notification method as shown in embodiment eight above.

The embodiment also provides an AMF network element, as shown in fig. 24, including a third processor 2401, a third memory 2402 and a third communication bus 2403;

a third communication bus 2403 for connecting the third processor 2401 and the third memory 2402;

the third processor 2401 is configured to execute a fifth computer program stored in the third memory 2402 to implement, but not limited to, the steps of the message notification method as shown in the above embodiments six to seven;

alternatively, the third processor 2401 is configured to execute a sixth computer program stored in the third memory 2402 to implement, but not limited to, the steps of the message notification method as shown in the above embodiment eight.

The embodiment also provides a communication system, which comprises a target network element and an NEF network element; the target network element may be an AMF network element or an SMF network element, etc.

The target network element is used for receiving a first request for UE reachable events after downlink data failure, and generating a first subscription event which can be reached by the UE after the downlink data failure according to the first request, wherein the first request comprises an application identifier of an AF (application function), an identifier NEF ID (network element identifier) of an NEF network element and an event reference identifier of the first subscription event, and the first subscription event is associated with the event reference identifier of the first subscription event; the UE reachability notification is used for receiving the UE reachability notification after the downlink data of the target UE corresponding to the application identifier fails, and sending the UE reachability notification after the downlink data fails to the NEF network element according to the first subscription event;

The present embodiments also provide a computer-readable storage medium including volatile or non-volatile, removable or non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, computer program modules or other data. Computer-readable storage media include, but are not limited to, RAM (Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash Memory or other Memory technology, CD-ROM (Compact disk Read-Only Memory), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer.

In one example, the computer readable storage medium in this embodiment is used to store one or more first computer programs, which are executable by one or more processors to implement the steps of the message notification method in the first embodiment as described above;

alternatively, the computer readable storage medium is used for storing one or more second computer programs, which can be executed by one or more processors to implement, but not limited to, the steps of the message notification method as shown in the above embodiment eight;

alternatively, the computer readable storage medium is used for storing one or more third computer programs, which can be executed by one or more processors to implement, but are not limited to, the steps of the message notification method as shown in the above embodiments six to seven;

alternatively, the computer readable storage medium is used for storing one or more fourth computer programs, which can be executed by one or more processors to implement, but not limited to, the steps of the message notification method as shown in the above embodiment eight;

alternatively, the computer readable storage medium is used for storing one or more fifth computer programs, which can be executed by one or more processors to implement, but are not limited to, the steps of the message notification method as shown in the above embodiments six to seven;

alternatively, the computer readable storage medium is used for storing one or more fifth computer programs, and the one or more sixth computer programs are executable by one or more processors to implement, but are not limited to, the steps of the message notification method as shown in the above embodiment eight.

The present embodiment also provides a computer program (or computer software), which can be distributed on a computer-readable medium and executed by a computing device to implement at least one step of the message notification method as shown in the above embodiments; and in some cases at least one of the steps shown or described may be performed in an order different than that described in the embodiments above.

The present embodiments also provide a computer program product comprising a computer readable means on which a computer program as shown above is stored. The computer readable means in this embodiment may include a computer readable storage medium as shown above.

It will be apparent to those skilled in the art that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software (which may be implemented in computer program code executable by a computing device), firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed by several physical components in cooperation. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit.

In addition, communication media typically embodies computer readable instructions, data structures, computer program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to one of ordinary skill in the art. Thus, the present invention is not limited to any specific combination of hardware and software.

The foregoing is a more detailed description of embodiments of the present invention, and the present invention is not to be considered limited to such descriptions. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A message notification method, comprising:

2. The message notification method according to claim 1, wherein when the first subscription event reachable by the UE after the failure of generating the downlink data is generated, the method further comprises:

and generating a first notification identifier, wherein the first notification identifier is associated with the event reference identifier of the first subscription event, and when the value of the first notification identifier is a first preset value, the UE can reach the notification after the downlink data reporting of the first subscription event associated with the event reference identifier representing the first subscription event fails.

3. The message notification method of claim 2, wherein the UE reachable notification after the downlink data failure is sent by the AMF network element when detecting that the state of the target UE changes from unreachable to reachable, and the second notification identifier corresponding to the first subscription event has a current value equal to a first preset value.

4. The message notification method as claimed in claim 3, wherein before the UE reachable notification after the failure of receiving the downlink data, further comprising:

and sending a message to a UPF network element, and activating an application data detection function corresponding to the application identifier.

5. The message notification method as claimed in claim 4, wherein before the UE reachable notification after the failure of receiving the downlink data, further comprising:

and receiving an application data detection notification including an application identifier from the UPF network element, and if the fact that the target UE to be issued by the AF corresponding to the application identifier is not reachable currently is determined, setting a first notification identifier corresponding to an event reference identifier of a first subscription event associated with the application identifier as a first preset value.

6. The message notification method as claimed in claim 5, wherein before the UE reachable notification after the failure of receiving the downlink data, further comprising:

and when determining that the target UE to be issued by the AF corresponding to the application identifier is not reachable currently, sending a message to the AMF network element and subscribing the reachable state event of the target UE.

7. The message notification method as claimed in any of claims 2-6, wherein before sending the UE reachable notification after the downlink data failure to the NEF network element, further comprising:

and judging whether the first notification identifier is a first preset value at present.

8. The message notification method of any of claims 1-6, wherein the first request comprises at least one of:

an event open subscription request from a Unified Data Management (UDM) network element;

a session policy control update notification request from a policy control function, PCF, network element.

9. A message notification apparatus, comprising:

10. The message notification apparatus as claimed in claim 9, wherein when the third event subscription processing module generates the first subscription event that the UE can reach after the downlink data failure, the third event subscription processing module is further configured to:

11. A message notification method, comprising:

12. The message notification method of claim 11, wherein after receiving the application data detection notification sent by the SMF network element, further comprising:

sending a third request for subscribing the UE reachable event to the AMF network element;

and when a UE reachable notification sent by the AMF network element is received, clearing the application identifier list.

13. The message notification method as claimed in claim 12, wherein before clearing the application identification list, further comprising:

starting timing from when the UE reachable notification is received;

and when the timing value reaches a set time value, if the UE can reach the notice after the failure of the downlink data is not received, clearing the application identifier list.

14. The message notification method as claimed in claim 12, wherein clearing the application identification list comprises one of:

removing all the application identifications in the application identification list;

and clearing the application identifiers in the application list, which are the same as the application identifiers contained in the UE reachable notification.

15. The message notification method according to any of claims 11-14, wherein the UE reachable notification after failure of sending downlink data to the AF corresponding to the application identifier included in the application identifier list comprises one of:

sending UE reachable notification after failure of downlink data to AF corresponding to all application identifications contained in the application identification list;

and sending the UE reachable notification after the downlink data failure to the AF corresponding to the application identifier contained in the UE reachable notification after the downlink data failure in the application identifier list.

16. The message notification method of any of claims 11-14, wherein sending the first request or the third request for subscription to an AMF network element comprises at least one of:

sending a first request or a third request to the AMF network element through an event open subscription request of a Unified Data Management (UDM) network element;

and/or sending the second request for subscription to the SMF network element comprises at least one of:

sending a second request to the SMF network element through an event open subscription request of the UDM network element;

and sending a second request to the SMF network element through a session policy control update notification request of the PCF network element.

17. A message notification method, comprising:

receiving a second request for subscribing an application data detection event sent by an NEF network element, and generating a second subscription event for application data detection according to the second request, wherein the second request comprises an AF application identifier and an NEFID identifier of the NEF network element;

and sending the application data detection notice to the NEF network element.

18. The message notification method of claim 17, wherein receiving the second request for subscribing to the application data detection event sent by the NEF network element comprises at least one of:

receiving the second request through an event open subscription request of the UDM network element;

and receiving the second request through a session policy control update notification request of the PCF network element.

19. A message notification apparatus, comprising:

20. The message notification apparatus of claim 19,

the second event subscription request module is further configured to send a third request for subscribing to a UE reachable event to the AMF network element;

the second notification receiving module is further configured to clear the application identifier list when receiving a UE reachable notification sent by the AMF network element.

21. A message notification apparatus, comprising:

22. A message notification method, comprising:

23. The message notification method of claim 22, wherein the target network element comprises at least one of:

accessing an AMF network element;

and a Session Management Function (SMF) network element.

24. A message notification apparatus, comprising:

25. An SMF network element comprising a first processor, a first memory and a first communication bus;

the first processor is configured to execute a first computer program stored in the first memory to implement the steps of the message notification method according to any of claims 1-8;

or the like, or, alternatively,

the first processor is adapted to execute a second computer program stored in the first memory to implement the steps of the message notification method as claimed in claim 17 or 18.

26. A NEF network element comprising a second processor, a second memory, and a second communication bus;

the second processor is adapted to execute a third computer program stored in the second memory to implement the steps of the message notification method according to any of claims 11-16;

or the like, or, alternatively,

the second processor is adapted to execute a fourth computer program stored in the second memory to implement the steps of the message notification method as claimed in claim 22 or 23.

27. A communication system, characterized in that the communication system comprises a target network element and a NEF network element;

28. A computer-readable storage medium for storing one or more first computer programs, the one or more first computer programs being executable by one or more processors for performing the steps of the message notification method as claimed in any one of claims 1-8;

or the like, or, alternatively,

the computer readable storage medium for storing one or more second computer programs executable by one or more processors for implementing the steps of the message notification method as claimed in claim 17 or 18;

or the like, or, alternatively,

the computer readable storage medium for storing one or more third computer programs, the one or more third computer programs being executable by one or more processors for implementing the steps of the message notification method as claimed in any one of claims 11-16;

or the like, or, alternatively,

the computer readable storage medium is for storing one or more fourth computer programs which are executable by one or more processors to implement the steps of the message notification method as claimed in claim 22 or 23.