CN117693074A

CN117693074A - Communication method, network element device, medium, and program product

Info

Publication number: CN117693074A
Application number: CN202211071713.8A
Authority: CN
Inventors: 涂小勇; 刘俊羿
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2022-09-02
Filing date: 2022-09-02
Publication date: 2024-03-12
Also published as: WO2024046148A1

Abstract

The embodiment of the application provides a communication method, network element equipment, medium and program product, which are used for notifying the cancellation of SMF connection release when AMF interrupts N2 connection release flow so as to keep the connection resources among network element functional entities consistent; therefore, the service success rate of the user under the condition of long-time inactivity is improved, and the service experience of the user is improved.

Description

Communication method, network element device, medium, and program product

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communications method, a network element device, a medium, and a program product.

Background

Mobile communication has now evolved to the 5G stage, and the main feature of the 5G network architecture is a service-based architecture. In a 5G network, the radio access network (Radio Access Network, RAN) actively triggers N2 connection release when it finds that the user is inactive for a long period of time.

In the related art, after the RAN triggers the N2 connection release, an N2 connection release notification is sent to the access and mobility management function (Access and Mobility Management Function, AMF), and after the AMF receives the notification, the session management function (Session Management Function, SMF) and the user plane function (User Plane Function, UPF) are notified to release the corresponding N3 connection. If the AMF has downlink signaling to be delivered to a user or the RAN in the release process, the connection release process is terminated, so that the resource states of the SMF and UPF sides are not synchronous with the AMF and the RAN sides, and the resources of different network elements are not matched, thereby causing communication failure.

Disclosure of Invention

The embodiment of the application provides a communication method, network element equipment, a medium and a program product, which aim to ensure uniform resources among different network elements and improve user service experience.

In a first aspect, an embodiment of the present application provides a communication method applied to an access and mobility management function network element AMF, where the method includes: sending a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection; receiving a downlink signaling trigger message; sending a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection canceling release; a first cancel connection release response message is received, wherein the first cancel connection release response message is used for notifying the AMF that the connection release of the SMF has been cancelled or notifying the AMF that the connection release of the SMF has been completed.

In a second aspect, an embodiment of the present application provides a communication method, applied to a session management function network element SMF, where the method includes: receiving a first connection release request message, wherein the first connection release request message is used for indicating the SMF to release connection; and receiving a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel the connection canceling release.

In a third aspect, an embodiment of the present application provides a communication method, applied to a user plane function network element UPF, where the method includes: receiving a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating the UPF to cancel connection canceling release; and sending a second connection canceling release response message.

In a fourth aspect, embodiments of the present application provide a communication method, where the method includes: the method comprises the steps that an access and mobile management function network element (AMF) sends a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection; the session management function network element SMF receives a first connection release request message; the AMF receives a downlink signaling trigger message; the AMF sends a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection release; the SMF receives a first connection canceling release request message; the SMF sends a first connection release cancellation response message, where the first connection release cancellation response message is used to notify the AMF that a connection release of the SMF has been cancelled or to notify the AMF that a connection release of the SMF has been completed; the AMF receives the first cancel connection release response message.

In a fifth aspect, an embodiment of the present application provides a network element device, including: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the communication method as in any of the above aspects when the computer program is executed.

In a sixth aspect, embodiments of the present application provide a computer-readable storage medium storing computer-executable instructions that when executed by a computer implement a communication method as in any of the above aspects.

In a seventh aspect, embodiments of the present application provide a computer program product comprising a computer program or computer instructions stored in a computer-readable storage medium, the computer program or computer instructions being read from the computer-readable storage medium by a processor of a computer device, the processor executing the computer program or computer instructions causing the computer device to perform a communication method as in any one of the above aspects.

According to the embodiment of the application, the AMF sends the first connection release cancellation request message to the SMF to inform the SMF that the connection release corresponding to the previous first connection release request message needs to be cancelled, so that the SMF side can timely know whether the current connection release is cancelled or not, connection resources among different network elements are kept consistent, and user service experience is improved.

Drawings

Fig. 1 is a diagram of a 5G network architecture provided in the related art;

fig. 2 is a flowchart for releasing an N2 connection provided in the related art;

FIG. 3 is a flow chart of a related art provided for releasing an N2 connection from being interrupted;

FIG. 4 is a diagram of an application network architecture according to an embodiment of the present application;

FIG. 5 is a flow chart of a communication method according to an embodiment of the present application;

FIG. 6 is a flow chart of a communication method according to another embodiment of the present application;

FIG. 7 is a flow chart of AMF and SMF function negotiation according to an embodiment of the present application;

FIG. 8 is a flow chart of a communication method according to another embodiment of the present application;

FIG. 9 is a flow chart of SMF and UPF function negotiation provided in an embodiment of the present application;

FIG. 10 is a flow chart of a communication method according to another embodiment of the present application;

fig. 11 is an interactive flowchart of SMF confirmation cancellation connection release according to an embodiment of the present application;

fig. 12 (a) is an interaction flow chart in the case of the SMF release connection provided in an embodiment of the present application;

FIG. 12 (b) is an interactive flow chart of the subsequent flow of FIG. 12 (a);

fig. 13 is an interaction flow chart in a case where an SMF releases a connection according to another embodiment of the present application;

fig. 14 is a schematic structural diagram of a network element device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical methods and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It should be noted that although a logical order is illustrated in the flowchart, in some cases, the steps illustrated or described may be performed in an order different from that in the flowchart. The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

In the description of the embodiments of the present application, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly, and those skilled in the art may reasonably determine the specific meaning of the terms in the embodiments of the present application in combination with the specific contents of the technical solutions. The words "further," "exemplary," or "optionally" in the embodiments herein are used to indicate by way of example, illustration, or description that the embodiment is not to be interpreted as preferred or advantageous over other embodiments or designs. The use of the words "further," "exemplary," or "optionally" and the like is intended to present the relevant concepts in a concrete fashion.

The embodiment of the application can be applied to network element functional entities of a core network. The embodiments of the present application are not particularly limited.

As shown in fig. 1, a conventional 5G network architecture generally includes, but is not limited to, the following network elements:

the terminal (UE) mainly accesses the 5G network through a wireless air interface and obtains service, and the terminal exchanges information with the base station through the air interface and exchanges information with the Access and mobile management function of the core network through Non-Access Stratum (NAS) signaling.

And the wireless access network is responsible for air interface resource scheduling and air interface connection management of the terminal access network.

Access and mobility management functions: the core network control plane entity is mainly responsible for user mobility management, including registration and temporary identifier allocation; maintaining IDLE (IDLE) and connection (CONNECT) states and state transitions; switching in CONNECT state; and triggering functions such as paging and the like in the user IDLE state.

Authentication server function (Authentication Server Function, AUSF): the core network control plane entity is mainly responsible for authentication and authorization of the user to ensure that the user is a legal user.

A unified data management function (Unified Data Management, UDM) is a core network control plane entity, home subscriber server, which permanently stores subscriber subscription data.

Session management function: the core network control plane entity is mainly responsible for maintaining protocol data unit Session (Protocol Data Unit Session, PDU Session), distributing user IP address, and having quality of service (Quality of Service, qoS) control and charging functions; and the user IDLE receives the downlink data packet for caching and informs the AMF of paging the user and other functions.

User plane function: the core network user plane functional entity is responsible for forwarding the user data message, and also performs statistics on the user data message for charging and other functions.

Policy control function (Policy Control Functionality, PCF): the core network control plane entity is responsible for the functional entities of access and mobility management policies, UE policies, session management policies and charging rules. The functional entity generates access and mobility management policies, UE routing policies, qoS rules and charging rules for user data delivery, etc. mainly according to service information and user subscription information, and configuration information of an operator.

Capacity open function (Network Exposure Function, NEF): the core network control plane entity is responsible for the outward opening of the mobile network capability.

Network function library functions (NF Repository Function, NRF): the core network control plane entity is responsible for dynamic registration of service capabilities of network functions and network function discovery.

Network slice selection function (Network Slice Selection Function, NSSF): the core network control plane entity is responsible for the selection of the target network slice instance (Network Slice Instance, NSI).

Application function (Application Function, AF): an application entity is responsible for providing specific services for users.

In a 5G network, the connection state of the UE includes: idle state, connected state, inactive state.

Idle state: the RAN has no context information for the UE, and the RAN has no air-interface RRC connection (radio resource control layer, radio Resource Control, RRC) for the UE and no N2 connection with the AMF.

And (3) connection state: the RAN has the context information of the UE, and the RAN has an air interface RRC connection of the UE and an N2 connection with the AMF.

Inactive state: the RAN has the context information of the UE, the RAN has an N2 connection with the AMF, but the RAN has no air interface RRC connection of the UE.

As shown in fig. 2, when the RAN finds that the user is inactive for a long time and there is no uplink and downlink data or signaling, the RAN actively triggers N2 connection release, which specifically includes the following steps:

step S101: an N2 connection release request; when the RAN discovers that a User (UE) is not active for a long time and has no uplink and downlink data or other reasons, initiating an N2 connection release flow; the RAN sends an N2 connection release request message to the AMF, and carries a cause value and a PDU Session ID; the cause value is set to user inactive. The PDU Session ID is used to characterize the PDU Session with the N3 UP connection corresponding to the N2 connection.

Step S102: updating the SM context request; for each PDU session with an N3UP connection, the AMF sends an update SM context request message to the SMF informing the SMF of the N3UP connection deactivation.

Step S103: an N4 session modification request; the SMF sends an N4 session modification request message to the UPF informing the UPF of N3UP connection deactivation.

Step S104: an N4 session modification response; after the UPF deactivates the N3UP connection, the UPF returns an N4 session modification response message to the SMF.

Step S105: updating SM context response; the SMF returns an update SM context response message to the AMF to inform the AMF that the release of the N3UP connection corresponding to the N2 connection to be released is completed.

Step S106: n2 connect release command; after the AMF receives the updated SM context response messages returned by all SMFs, the AMF sends an N2 connection release command (UE context release command) message to the RAN.

Step S107: n2 connection release is completed; the RAN completes the release of the N2 connection and returns an N2 connection release complete (UE context release complete) message to the AMF.

It can be appreciated that in a normal N2 connection release procedure, the N3UP connection corresponding to the N2 connection needs to be released synchronously. However, in the RAN triggered N2 connection release procedure, if the AMF finds that there is a downlink signaling to be delivered to the UE and/or the RAN, the AMF may terminate the N2 connection release procedure.

As shown in fig. 3, a specific procedure for triggering N2 connection release at AMF terminating RAN is as follows:

step S201: n2 connection release request.

When the RAN discovers that a User (UE) has no activity for a long time, no uplink and downlink data or other reasons, initiating an N2 connection release process, and sending an N2 connection release request message to an AMF by the RAN, wherein the N2 connection release request message carries a reason value and a PDU Session ID; the cause value is set to user inactive. The PDU Session ID is used to characterize the PDU Session with the N3 UP connection corresponding to the N2 connection.

Step S202: the SM context request is updated.

If the AMF finds that the request message has been sent to the RAN after receiving the N2 connection release request, and is waiting for a response message of the RAN, the AMF may directly discard the N2 connection release request.

If the AMF does not discard the N2 connection release request message, the AMF sends an update SM context request message to the SMF for each PDU session with an N3 UP connection, informing the SMF of N3 UP connection deactivation.

Step S203: the AMF receives messages that other network element functional entities trigger to UE and/or RAN to send downlink signaling.

When the AMF is waiting for the SMF to return the SM context update response message, if receiving the message of other network element function entity NF, downlink signaling to UE and/or RAN needs to be triggered, such as NAS message from UDM to UE, NAS message from PCF to UE, NAS message from SMSF to UE, PDU session modification request triggered by SMF, etc., the AMF terminates the N2 connection release procedure triggered by RAN, and processes the received message of other NF.

As can be seen from the above flow, in the existing flow, if the AMF receives a message sent by other NF and triggering downlink signaling to the UE and/or RAN during the process of waiting for the SMF and/or UPF to deactivate the N3 UP connection, the release of the N2 connection will be cancelled, but the SMF will not be notified that the release of the N2 connection has been cancelled, at this time, the SMF and UPF will still release the corresponding N3 UP connection, but the RAN side will cancel the release of the N2 connection, which results in non-uniform resources between the network elements, unable to communicate normally, and unable to quickly reestablish a communication link to resume normal communication function due to non-uniform resources between the network element sides.

The embodiment of the application provides a communication method, network element equipment, medium and program product, which are used for notifying the release cancellation of SMF connection when AMF interrupts N2 connection release flow, so as to keep the connection resources among SMF, UPF and RAN consistent; therefore, the service success rate of the user under the condition of long-time inactivity is improved, and the service experience of the user is improved.

Embodiments of the present application are further described below with reference to the accompanying drawings.

Fig. 4 is an application network architecture diagram of a communication method according to an embodiment of the present application. As shown in fig. 4, the system architecture may include, but is not limited to, UE, RAN, AMF, SMF, UPF.

The UE is respectively in communication connection with the AMF and the RAN, wherein the UE and the AMF are connected through an N1 interface, and the N1 interface is a signaling interface between the UE and the AMF.

The AMFs are respectively in communication connection with UE, SMF, RAN, wherein the AMFs are connected with the RAN through an N2 interface, and the N2 interface is a signaling interface between the RAN and the AMF.

The RAN is respectively in communication connection with the UE, the AMF and the UPF, wherein the RAN and the UPF are connected through an N3 interface, and the N3 interface is an interface between the RAN and the UPF and is mainly used for transmitting uplink and downlink user plane data between the RAN and the UPF.

The SMF is respectively connected with the AMF and the UPF in a communication way, wherein the SMF and the UPF are continuously connected through an N4 interface, and the N4 interface is an interface between the SMF and the UPF and is used for transmitting control plane information between the SMF and the UPF.

The communication method of the application at least comprises the following steps:

the AMF sends a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection;

the SMF receives a first connection release request message;

the AMF receives the downlink signaling trigger message;

the AMF sends a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection canceling;

The SMF receives a first connection canceling release request message;

the SMF sends a first connection canceling release response message; wherein the first cancel connection release response message AMF notifies the SMF that the connection release of the SMF has been cancelled for notifying the AMF that the connection release of the SMF has been cancelled or for notifying the AMF that the connection release of the SMF has been completed;

the AMF receives a first cancel connection release response message.

In some possible embodiments, the downlink signaling trigger message is used to inform the AMF that there is currently an NF to send a message to the UE or RAN. For example, the UDM to UE NAS message, PCF to UE NAS message, sms network function element (Short Message Service Function, SMSF) to UE NAS message, SMF triggered PDU session modification request, etc., where AMF terminates RAN triggered N2 connection release procedure, processing received other NF messages.

In some possible embodiments, in the connection release process, when NF sends a message to UE or RAN, for example, a NAS message from UDM to UE, a NAS message from PCF to UE, a NAS message from SMSF to UE, an SMF triggered PDU session modification request, etc., at this time, AMF receives a downlink signaling trigger message, after AMF receives the trigger message, the N2 connection release process is terminated, and connection release is cancelled.

In some possible embodiments, the first connection release request message is used to instruct the SMF to deactivate the N3 UP connection corresponding to the N2 connection to be released.

In some possible embodiments, the first cancel connection release request message carries an indication informing the SMF to cancel the deactivation of the N3 UP connection, and after the SMF receives the first cancel connection release request message, the SMF terminates the flow of deactivating the N3 UP connection. After the SMF terminates the flow of deactivating the N3 UP connection, sending a second connection canceling release request message to the UPF, wherein the second connection canceling release request message is used for indicating the UPF to cancel releasing the N3 UP connection; if the UPF receives the second connection canceling release request message and receives the instruction for deactivating the N3 UP connection, the deactivation is terminated, and the deactivated connection is recovered; if the UPF receives the second connection canceling release request message and does not receive the instruction of deactivating the N3 UP connection, the connection is kept normally available. After the UPF receives the second connection canceling release request message, the UPF confirms that the corresponding N3 UP connection is normally available, and sends a second connection canceling release response message to the SMF, wherein the second connection canceling release response message is used for informing that the N3 UP connection is normally available. The SMF receives the second connection canceling response message, confirms that the N3 UP connection is normally available, namely the connection canceling is cancelled, and sends a first connection canceling response message to the AMF, wherein the first connection canceling response message is used for notifying the AMF that the connection canceling is cancelled, and the connection is normally available.

After the AMF interrupts the N2 connection release, the SMF is simultaneously informed to cancel the release of the corresponding N3 UP connection, so that the communication connection between the functional entities of the network elements is normally available, the resources are consistent, and the communication can be normally carried out.

In some possible embodiments, the AMF may further perform a function negotiation with the SMF before sending the first connection release cancellation request message to the SMF, confirming that the SMF supports the connection release cancellation function. Before sending a message indicating connection release cancellation to the UPF, the SMF performs a function negotiation with the UPF to confirm that the UPF supports the connection release cancellation function.

In some possible implementations, after the SMF receives the first cancel connection release request message, the SMF acknowledges that the N3 UP connection continues to be deactivated. After the SMF confirms that the N3 UP connection is continuously deactivated, the SMF and the UPF continuously perform a deactivation flow. The SMF sends a first connection canceling response message to the AMF, wherein the first connection canceling response message is used for notifying the AMF that the SMF releases the N3 UP connection message. The SMF may further send a message delivery request message to the AMF, where the message delivery request message carries a PDU session resource release request message corresponding to the N3 UP connection, and the message delivery request message is further configured to instruct the AMF to forward the carried PDU session resource release request message corresponding to the N3 UP connection to the RAN. After the AMF receives the message delivery request message, the AMF forwards the PDU session resource release request message in the message delivery request message to the RAN, and returns a message delivery response message to the SMF. After receiving the PDU conversation resource release request message corresponding to the N3 UP connection, the RAN releases the corresponding PDU conversation resource, wherein the released PDU conversation resource corresponds to the released N3 UP connection; after releasing the PDU session resources, the RAN sends a PDU session resource release response message to the AMF. The AMF receives the PDU session resource release response message and forwards it to the SMF. The SMF responds.

Under the condition that the SMF continues to deactivate the N3UP connection, the RAN side is informed to release the corresponding PDU session resources, so that the resource unification among different network element functional entities is ensured; at this time, although the connection is released, the reconnection can be performed quickly because the resources are kept consistent, so that the user experience is ensured, and the situation that normal communication and reconnection cannot be performed under the condition that the resources are not uniform is avoided.

In some possible implementations, after the SMF receives the first cancel connection release request message, the SMF acknowledges that the N3UP connection continues to be deactivated. After the SMF confirms that the N3UP connection is continuously deactivated, the SMF and the UPF continuously perform a deactivation flow. The SMF sends a first connection canceling response message to the AMF, wherein the first connection canceling response message is used for notifying the AMF that the N3UP connection message is released. After the AMF receives the first connection canceling response message, confirming that the N3UP connection at the SMF side and the UPF side is released; the AMF sends a second connection release request message to the RAN, where the second connection release request message is used to instruct the RAN to release PDU session resources corresponding to the N3UP connection, and it can be understood that the N3UP connection is the same as the N3UP connection included in the first connection cancellation release request message. The RAN receives the second connection release request message, releases the corresponding PDU session resource, and returns a second connection release response message to the AMF.

Under the condition that the SMF continues to deactivate the N3 UP connection, when the AMF receives that the SMF finishes the release of the N3 UP connection, the AMF directly informs the RAN side to release the corresponding PDU session resource, so as to ensure the resource unification among different network element functional entities; at this time, although the connection is released, the reconnection can be performed quickly because the resources are kept consistent, so that the user experience is ensured, and the situation that normal communication and reconnection cannot be performed under the condition that the resources are not uniform is avoided.

According to the scheme, when the AMF interrupts N2 connection release, a connection release cancellation notification is sent to the SMF, so that the SMF synchronously executes a flow of receiving the connection release cancellation notification, resources among network element functional entities at different sides are kept uniform, normal operation of communication service is ensured, and user service experience is improved.

Fig. 5 is a flowchart of a communication method according to an embodiment of the present application. As shown in fig. 5, the communication method may be used for an AMF network element functional entity. In the embodiment of fig. 5, the communication method may include, but is not limited to, step S2100, step S2200, step S2300, and step S2400.

Step S2100: and sending a first connection release request message, wherein the first connection release request message is used for indicating the session management function network element SMF to release connection.

When the UE has no activity for a long time, no uplink and downlink data or other reasons, the RAN actively triggers the N2 connection release procedure and sends an N2 connection release request message to the AMF, and after the AMF receives the message, the AMF sends a first connection release request message to the SMF for indicating the SMF to synchronously release the N3 UP connection, so as to complete the release of the N2 connection and the PDU session resources corresponding to the N2 connection.

The first connection release request message is used to instruct the SMF to deactivate the N3 UP connection corresponding to the N2 connection to be released. The connection release of the SMF, that is, the process of the SMF deactivating the N3 UP connection corresponding to the N2 connection to be released, includes the following steps: the SMF sends an N4 session modification request message to the UPF, wherein the N4 session modification request message carries an instruction for notifying the UPF to deactivate the corresponding N3 UP connection; after the UPF completes the deactivation of the corresponding N3 UP connection according to the N4 session modification request message, an N4 session modification response message is returned to the SMF.

When the SMF completes the connection release, i.e., the N3 UP connection is deactivated, the connection state of the AMF and the UE is changed from the CM-Connected state to the CM-Idle state. The CM-Connected state indicates that the UE and the AMF have NAS signaling connection on an N1 interface, and the CM-Idle state indicates that the UE does not establish NAS signaling connection with the AMF on N1, does not have access network signaling connection, and is Connected with N2 and N3.

Step S2200: and receiving a downlink signaling trigger message.

The AMF receives a downlink signaling trigger message, wherein the downlink signaling trigger message is used for notifying that the AMF currently has NF to send a message to the UE or the RAN. For example, the UDM to UE NAS message, PCF to UE NAS message, sms network function element (Short Message Service Function, SMSF) to UE NAS message, SMF triggered PDU session modification request, etc., where AMF terminates RAN triggered N2 connection release procedure, processing received other NF messages.

In some possible embodiments, in the connection release process, when NF needs to send a message to UE or RAN, for example, a NAS message from UDM to UE, a NAS message from PCF to UE, a NAS message from SMSF to UE, an SMF triggered PDU session modification request, etc., in order to ensure that other NF can send a downlink message to UE or RAN normally, at this time, AMF receives a downlink signaling trigger message, after AMF receives the trigger message, the connection release process is terminated, and connection release is cancelled.

Step S2300: and sending a first connection canceling request message, wherein the first connection canceling request message is used for indicating the SMF to cancel the connection canceling.

After the AMF informs the SMF to release the N3 UP connection, when the AMF cancels the N2 connection release initiated by the RAN, the AMF sends a first connection canceling release request message to the SMF at the moment so that the N2 connection and the N3 UP connection cancel release, and the resource unification among network element functional entities is ensured.

In some possible embodiments, the RAN may carry a PDU session ID when sending an N2 connection release request to the AMF, for identifying a PDU session with an N3 UP connection; the AMF generates a first connection canceling release request message according to the PUD session ID, wherein the first connection canceling release request message comprises PDU sessions each having an N3 UP connection acquired from the N2 connection canceling release request message and an indication message for informing the SMF to deactivate the corresponding N3 UP connection.

In some possible implementations, the first cancel connection release request message includes an indication of release cancellation of the N3 UP connection for each PDU session in the previously sent first connection release request.

Step S2400: a first cancel connection release response message is received, wherein the first cancel connection release response message AMF informs the SMF that the connection release of the SMF has been cancelled, informs the AMF that the connection release of the SMF has been cancelled, or informs the AMF that the connection release of the SMF has been completed.

After the SMF receives a first connection canceling release request message sent by the AMF, the SMF confirms whether to continue to release the connection, if the SMF continues to release the connection, the connection is released, namely after the connection release process is completed, the SMF informs the AMF that the N3 connection between the UPF and the RAN is released through a first connection canceling release response message, and the connection state of the AMF and the UE is changed from a CM-Connected state to a CM-Idle state; if the SMF cancels the release, the SMF informs the AMF through a first cancel connection release response message, the connection state of the AMF and the UE maintains the CM-Connected state, and the N3 connection between the UPF and the RAN is still available.

In some possible embodiments, in case the first cancel connection release response message comprises an acknowledge connection release cancellation, i.e. the first cancel connection release response message AMF informs the SMF that the connection release of the SMF has been cancelled for informing the AMF that the connection release of the SMF has been cancelled. When the SMF receives a first connection canceling release request message sent by the AMF and confirms connection canceling release, the SMF generates a second connection canceling release request message, wherein the second connection canceling release request message carries an N3 UP connection canceling instruction and sends the second connection canceling release request message to the UPF; the UPF receives a second connection canceling release request message, if the corresponding N3 UP connection is released, the connection is restored, and after the UPF confirms that the N3 UP connection is normally available, the UPF returns a second connection canceling release response message to the SMF; after the SMF receives the second connection canceling response message, the SMF confirms that the N3 UP connection is normally available, namely the connection canceling is cancelled, generates a first connection canceling response message and sends the first connection canceling response message to the AMF, informs the AMF that the N3 UP connection canceling is cancelled, and the connection is normally available.

By indicating the SMF to cancel the release of the N3 UP connection, the unified resources among the functional entities of the network elements are ensured, and the session is normally available.

In some possible embodiments, in a case where the connection release cancellation response operation includes confirming that the connection is released, that is, the first cancellation connection release response message is used to notify the AMF that the connection release of the SMF is completed, step S2300 includes: sending a second connection release request message, wherein the second connection release request message is used for indicating the Radio Access Network (RAN) to release connection; a second connection release response message is received.

After the AMF receives the first connection canceling release response message sent by the SMF and confirms that the SMF has completed connection release, the AMF sends a second connection canceling release request message to the RAN, where the second connection canceling release request message is used to instruct the RAN to release PDU session resources corresponding to the N3 UP connection, and it can be understood that the N3 UP connection is the same as the N3 UP connection included in the first connection canceling release request message. And the RAN finishes the release of the corresponding PDU session resources according to the received second connection release request message and generates a second connection release response message to inform the AMF that the release of the PDU session resources is finished.

When the SMF does not support the connection release cancel function or needs to continue to release the N3 UP connection for other reasons, after confirming that the SMF still releases the connection, the AMF synchronously informs the RAN to release the corresponding PDU session information, so that resources among network element functional entities at different sides are unified, and the situation that the resources are not unified, namely normal conversation and reconnection are not possible is avoided.

In some possible embodiments, in a case where the connection release cancellation response operation includes confirming that the connection is released, that is, the first cancellation connection release response message is used to notify the AMF that the connection release of the SMF is completed, step S2300 includes: receiving a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message; sending a message delivery response message; transmitting a PDU session resource release request message, wherein the PDU session resource release request message is used for indicating the RAN to release PDU session resources; receiving a PDU session resource release response message; sending an update context request message, wherein the update context request message is used for notifying the SMF that PDU session resource release of the RAN is completed; an update context response message is received.

The SMF receives a first connection canceling release request message sent by the AMF, and still continues to release the connection, the SMF continues to execute the flow of releasing the N3 UP connection with the UPF, and returns a first connection canceling release response message to inform the AMF that the N3 UP connection is released; and the SMF also sends a message delivery request message to the AMF, wherein the message delivery request message carries a PDU session resource release request. The AMF obtains PDU conversation resource release request information according to the message delivery request information, and the AMF forwards the PDU conversation resource release request information to the RAN; the RAN releases the corresponding PDU session resources according to the request message, including releasing the corresponding N2 connection, and returns a PDU session resource release response message to the AMF. After receiving the PDU session resource release response message, the AMF sends update context request information to the SMF to inform the SMF that the PDU session resource at the RAN side is released.

Under the condition that the SMF continues to release the N3 UP connection, a PDU session resource release request is sent to the RAN, so that session resources at the RAN side are correspondingly released, the uniformity of resources among functional entities of each network element is maintained, reconnection can be rapidly carried out, and the service experience of a user is ensured; and the situation that normal communication cannot be performed and reconnection cannot be performed due to non-uniform resources among network element functional entities is avoided.

In some possible embodiments, before step S2300, the AMF confirms whether the SMF supports the connection release cancellation function according to preset local configuration information; if the SMF supports the connection release cancellation function, the related flow of step S2300 and subsequent cancellation of connection release is performed.

In some possible embodiments, the AMF may also perform a function negotiation with the SMF prior to step 2300: transmitting a first support connection release cancellation function confirmation request message, wherein the first support connection release cancellation function confirmation request message is used for confirming that the SMF supports a connection release cancellation function; a first support connection release cancellation function acknowledgement response message is received.

The AMF sends a first connection support release cancellation function confirmation request message to the SMF, and when the SMF receives the message, if the SMF supports the connection release cancellation function, the AMF returns a first connection support release cancellation function confirmation response message to the AMF, wherein the first connection support release cancellation function confirmation response message carries a message representing that the SMF supports the connection release cancellation function; the function negotiation is completed.

Fig. 6 is a flowchart of a communication method provided in another embodiment of the present application. As shown in fig. 6, the communication method may be used for SMF network element functional entities. In the embodiment of fig. 6, the communication method may include, but is not limited to, step S3100, step S3200.

Step S3100: a first connection release request message is received, wherein the first connection release request message is used to instruct the SMF to release the connection.

Step S3200: a first cancel connection release request message is received, wherein the first cancel connection release request message is used to instruct the SMF to cancel the release connection.

It can be appreciated that the method corresponds to the communication method applied to the AMF network element functional entity.

In some possible embodiments, step S3200 includes, prior to: the SMF receives a first request message for confirming the connection release cancellation function, which is sent by the AMF, wherein the first request message for confirming the connection release cancellation function is used for confirming that the SMF supports the connection release cancellation function; the SMF sends a first support connection release cancellation function acknowledgement response message to the AMF.

In some possible embodiments, step S3200 then comprises: the SMF sends a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating a user plane function network element UPF to cancel connection release; the SMF receives a second connection canceling release response message; the SMF sends a first cancel connection release response message, where the first cancel connection release response message is used to notify the AMF that the connection release of the SMF has been cancelled.

After the SMF receives the first connection canceling request message, it confirms canceling the N3 UP connection canceling, and the SMF sends a second connection canceling request message to the UPF. The UPF receives the second connection canceling release request message, executes connection canceling release operation, and if the connection is released at the moment, the UPF resumes the connection and confirms that the connection is normally available; if the connection is not released at this time, the UPF confirms that the connection is normally available. And after the UPF confirms that the connection is normally available, namely the connection release is cancelled, a second connection release cancellation response message is sent to the SMF to inform the SMF that the connection release is cancelled and the connection is normally available. After receiving the second connection canceling response message, the SMF sends a first connection canceling response message to the AMF to inform the AMF that the connection canceling is cancelled and the connection is normally available.

The SMF is informed of the need of canceling the connection release through the first connection canceling request message, and then the SMF correspondingly informs the UPF of canceling the connection release, so that the unification of session resources among the functional entities of the network elements is realized, and the normal session is ensured.

In some possible embodiments, before the SMF sends the second connection release cancellation request message to the UPF, the SMF confirms that the UPF supports the connection release cancellation function according to preset local configuration information.

In some possible embodiments, before the SMF sends the second connection release cancellation request message to the UPF, performing a function negotiation between the SMF and the UPF to confirm that the UPF supports the connection release cancellation function, including: the SMF sends a second request message for confirming the connection release cancellation function to the UPF, wherein the second request message for confirming the connection release cancellation function is used for confirming the UPF; returning a second support connection release cancellation function acknowledgement response message to the SMF by the UPF in the case of support of the connection release cancellation function; the SMF receives the second support connection release cancellation function acknowledgement response message, acknowledging that the UPF supports the connection release cancellation function.

In some possible embodiments, step S3200 may be followed by: the SMF sends a first cancel connection release response message, where the first cancel connection release response message is used to notify the AMF that the connection release of the SMF is completed.

In some possible embodiments, after the SMF sends the first cancel connection release response message, the SMF further includes: the SMF sends a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message; SMF receives the message delivery response message; the SMF receives an update context request message, wherein the update context request message is used for notifying the RAN of the completion of PDU session resource release; the SMF sends an update context response message. It is understood that the step flow on the SMF side corresponds to the step flow on the AMF side, and is not developed in detail herein.

As shown in fig. 7, in some possible embodiments, before receiving the connection release cancellation indication message sent by the AMF, the function negotiation between the SMF and the AMF includes: the SMF receives a confirmation request message of supporting the connection release cancellation function sent by the AMF; in case of supporting the connection release cancellation function, the SMF transmits an acknowledgement response message to the AMF.

In some possible embodiments, in a case where the connection release cancellation function is supported, when the connection release instruction message is received, the SMF performs the connection release operation after a preset time. When the SMF supports a connection release cancellation function, the SMF delays to clear connection information when receiving a connection release indication message, and if the SMF receives the connection release cancellation indication message at the moment, the SMF can quickly recover connection and confirm that the connection is normal; and if the SMF does not receive the connection release cancellation indication message after exceeding the preset time period, clearing the connection information to finish connection release.

Fig. 8 is a flowchart of a communication method according to an embodiment of the present application. As shown in fig. 8, the communication method may be used for a UPF network element functional entity. In the embodiment of fig. 8, the communication method may include, but is not limited to, step S4100, step S4200.

Step S4100: receiving a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating UPF to cancel connection canceling release;

step S4200: and sending a second connection canceling release response message.

It is conceivable that steps 4100 to 4200 are related corresponding side steps to the communication method applied to the AMF network element function entity and the communication method applied to the SMF network element function entity, and are not specifically described herein.

In some possible embodiments, before step S4100, comprising: the UPF receives a second connection release request message, wherein the second connection release request message is used for indicating the UPF to release the connection; the UPF sends a second connection release response message. I.e. the UPF receives a request to cancel the connection release after receiving the connection release request.

In some possible embodiments, before step S4100, comprising: the UPF receives a second request message for confirming the support connection release cancellation function, wherein the second request message for confirming the support connection release cancellation function of the UPF; the UPF sends a second support connection release cancellation function acknowledgement response message. As shown in fig. 9, the function negotiation between the UPF and the SMF includes: the UPF receives a confirmation request message of supporting the connection release cancellation function sent by the SMF; in the case where the UPF supports the connection release cancellation function, the UPF transmits an acknowledgement response message to the SMF.

In some possible embodiments, when the UPF receives a message carrying a connection release instruction sent by the SMF under the condition that the UPF supports a connection release cancellation function, the UPF delays to clear connection information, and if the UPF receives a modification request message at this time, the UPF can quickly resume connection and confirm that the connection is normal, wherein the modification request message carries the connection release cancellation instruction; if the UPF exceeds the preset time period and still does not receive the modification request message carrying the connection release cancellation instruction sent by the SMF, the connection information is cleared, and the connection release is completed.

Fig. 10 is a flowchart of a communication method according to an embodiment of the present application. As shown in fig. 10, the communication method can be used for a 5G communication network architecture. In the embodiment of fig. 10, the communication method may include, but is not limited to, step S5100, step S5200, step S5300, step S5400, step S5500, step S5600, step S5700.

Step S5100: the AMF sends a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection;

step S5200: the SMF receives a first connection release request message;

step S5300: the AMF receives the downlink signaling trigger message;

Step S5400: the AMF sends a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection canceling;

step S5500: the SMF receives a first connection canceling release request message;

step S5600: the SMF sends a first connection canceling release response message; wherein the first cancel connection release response message is used for notifying the AMF that the connection release of the SMF is cancelled; or for informing the AMF that the connection release of the SMF is completed;

step S5700: the AMF receives a first cancel connection release response message.

In some possible embodiments, when the first cancel connection release response message is used to notify the AMF that the connection release of the SMF has been cancelled; the step S5600 includes, before: the SMF sends a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating the UPF to cancel connection canceling release; the UPF receives a second connection canceling release request message; the UPF sends a second connection canceling response message, wherein the second connection canceling response message is used for notifying the SMF that the connection is released; the SMF receives a second cancel connection release response message.

In some possible embodiments, when the first cancel connection release response message is used to notify the AMF that the connection release of the SMF is completed; step S5700 is followed by: the AMF sends a second connection release request message, wherein the second connection release request message is used for indicating the RAN to release the connection; the RAN receives a second connection release request message; the RAN sends a second connection release response message, wherein the second connection release response message is used for notifying the AMF that the connection release is completed; the AMF receives the second connection release response message.

In some possible embodiments, when the first cancel connection release response message is used to notify the AMF that the connection release of the SMF is completed; step S5700 is followed by: the SMF sends a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message; the AMF receives a message delivery request message; the AMF sends a PDU session resource release request message, wherein the PDU session resource release request message is used for indicating the RAN to release PDU session resources; the RAN receives PDU session resource release request information; the RAN sends PDU session resource release response information, wherein the PDU session resource release response information is used for notifying an AMF, and the RAN finishes PDU session resource release; AMF receives PDU session resource release response message; AMF sends request message for updating context; wherein the update context request message is used to notify the SMF that PDU session resource release of the RAN is completed; the SMF receives the update context request message; SMF sends update context response message; the AMF receives the update context response message.

It will be appreciated that further details of the communication method of this embodiment have been described in the foregoing section, and will not be described here.

The communication method of the present application will be further described with reference to specific examples, and it should be understood that the following implementation is merely illustrative of the solution of the present application and is not intended to be limiting.

Fig. 11 is an interactive flowchart of SMF acknowledgment cancellation connection release according to an embodiment of the present application. Next, with reference to fig. 11, a complete interaction flow in the case where the AMF interrupts N2 connection release, and the SMF performs confirmation of canceling the connection release will be described.

Step S301: the RAN sends an N2 connection release request to the ANF; when the RAN finds that the user is inactive for a long time or other reasons, the RAN initiates an N2 connection release process; the RAN sends an N2 connection release request message to the AMF carrying the cause value and PDU Session ID. The cause value is set to user inactive. The PDU Session ID is used to identify the PDU Session with the N3 UP connection.

Step S302: the AMF sends an update context request to the SMF; for each PDU session with an N3 UP connection obtained from step S301, the AMF sends an update SM context request message to the SMF informing the SMF of the synchronous release of the N3 UP connection.

Step S303: the SMF sends an N4 session modification request to the UPF; the SMF sends an N4 session modification request message to the UPF, where the message carries an indication of the release of the N3 UP connection.

Step S304: the UPF sends an N4 session modification response to the SMF; after the UPF performs the indication of the N3 UP connection release, the UPF returns an N4 session modification response message to the SMF.

Step S305: the SMF returns an update SM context response message to the AMF.

Step S306: AMF terminates RAN-triggered N2 connection release; if the AMF is waiting for the SMF to return the SM context update response message (i.e. between step S302 and step S305), and receives a message of other NF, downlink signaling to the UE and/or RAN needs to be triggered, such as a NAS message from UDM to UE, a NAS message from PCF to UE, a NAS message from SMSF to UE, an SMF-triggered PDU session modification request, etc., the AMF terminates the RAN-triggered N2 connection release procedure, and processes the received message of other NF.

Step S307: the AMF sends an update SM context request (connection release cancel instruction) to the SMF; for each PDU session for which an update SM context request message was sent during the previous RAN-triggered N2 connection release, the AMF sends a new update SM context request message to the SMF, with an N3 UP connection release cancelled indication in the message.

Step S308: SMF cancels connection release; the SMF acknowledges continued use of the N3 UP connection and cancels the connection release.

Step S309: the SMF sends an N4 session modification request to the UPF; the SMF sends an N4 session modification request message to the UPF, wherein the message carries an N3 UP connection release cancelled instruction.

Step S310: the UPF sends an N4 session modification response to the SMF; after the UPF receives the N4 session modification request, the UPF restores the N3 UP connection, and the UPF confirms that the N3 UP connection is normally available, and returns an N4 session modification response message to the SMF.

Step S311: the SMF returns an updated SM context response message to the AMF; the SMF receives the N4 session modification response message, confirms that the N3 UP connection is normally available, and returns an update SM context response message to the AMF.

Fig. 12 (a) and 12 (b) are interaction flowcharts in the case of the SMF release connection provided in an embodiment of the present application. The following describes a complete interaction flow in the case where the AMF interrupts N2 connection release and the SMF performs confirmation to continue to release the connection, with reference to fig. 12 (a) and 12 (b).

Step S401: the RAN sends an N2 connection release request to the AMF; when the RAN finds that the user is inactive for a long time or other reasons, the RAN initiates an N2 connection release process; the RAN sends an N2 connection release request message to the AMF, wherein the N2 connection release request message carries a reason value and a PDU Session ID; the cause value is set to user inactive and the PDU Session ID is used to identify the PDU Session with the N3 UP connection.

Step S402: the AMF sends an SM context update request to the SMF; for each PDU session with an N3 UP connection obtained from step S401, the AMF sends an update SM context request message to the SMF informing the SMF of the synchronous release of the N3 UP connection.

Step S403: the SMF sends an N4 session modification request to the UPF; the SMF sends an N4 session modification request message to the UPF, wherein the N4 session modification request message carries an indication of N3 UP connection release.

Step S404: the UPF sends an N4 session modification response to the SMF; after the UPF performs the indication of the N3 UP connection release, the UPF returns an N4 session modification response message to the SMF.

Step S405: the SMF returns an update SM context response message to the AMF.

Step S406: AMF terminates RAN-triggered N2 connection release; if the AMF is waiting for the SMF to return the SM context update response message (i.e. between step S402 and step S405), and receives a message of the other network element functional entity NF, downlink signaling to the UE and/or RAN needs to be triggered, for example, a NAS message of UDM to UE, a NAS message of PCF to UE, a NAS message of SMSF to UE, an SMF triggered PDU session modification request, etc., the AMF terminates the RAN triggered N2 connection release procedure, and processes the received message of other NF.

Step S407: the AMF sends an update SM context request (connection release cancel instruction) to the SMF; for each PDU session for which an update SM context request message was sent during the previous RAN-triggered N2 connection release, the AMF sends a new update SM context request message to the SMF, with an N3 UP connection release cancelled indication in the message.

Step S408: SMF releases the connection; the SMF continues to execute the procedure related to releasing the N3 UP connection as by step S403-step S404.

Step S409: the SMF returns an update SM context response message to the AMF informing the AMF that the N3 UP connection has been released.

Step S410: the SMF sends an N1N2 message delivery request to the AMF; the N1N2 delivery request message carries N2 container information, and the N2 container information carries PDU session resource release request message.

Step S411: the AMF returns an N1N2 message delivery response message to the SMF.

Step S412: AMF sends PDU session resource release request to RAN; the AMF obtains PDU session resource release request message from the N1N2 message delivery request and forwards it to the RAN.

Step S413: the RAN releases PDU session resources; after receiving the PDU session resource release request message, the RAN performs PDU session resource release.

Step S414: the RAN returns a PDU session resource release response message to the AMF.

Step S415: the AMF sends an update context request to the SMF; the update context request message carries an N2 container, and the N2 container carries information in a PDU session resource release response message, so as to inform the SMF that the PDU session resource on the RAN side has been released.

Step S416: the SMF returns an update context response message to the AMF.

Fig. 13 is an interaction flow chart in a case where an SMF releases a connection according to another embodiment of the present application. Next, with reference to fig. 13, a complete interaction flow in the case where the AMF interrupts N2 connection release, and the SMF performs confirmation to continue the release of the connection will be described.

Step S501: the RAN sends an N2 connection release request to the AMF; when the RAN finds that the user is inactive for a long time or other reasons, the RAN initiates an N2 connection release process; the RAN sends an N2 connection release request message to the AMF, wherein the N2 connection release request message carries a reason value and a PDU Session ID; the cause value is set to user inactive and the PDU Session ID is used to identify the PDU Session with the N3 UP connection.

Step S502: the AMF sends an SM context update request to the SMF; for each PDU session with an N3 UP connection obtained from step S501, the AMF sends an update SM context request message to the SMF informing the SMF of the synchronous release of the N3 UP connection.

Step S503: the SMF sends an N4 session modification request to the UPF; the SMF sends an N4 session modification request message to the UPF, wherein the N4 session modification request message carries an indication of N3 UP connection release.

Step S504: the UPF sends an N4 session modification response to the SMF; after the UPF performs the indication of the N3 UP connection release, the UPF returns an N4 session modification response message to the SMF.

Step S505: the SMF returns an update SM context response message to the AMF.

Step S506: AMF terminates RAN-triggered N2 connection release; if the AMF is waiting for the SMF to return the SM context update response message (i.e. between step S502 and step S505), and receives a message of the other network element functional entity NF, downlink signaling to the UE and/or RAN needs to be triggered, such as a NAS message from UDM to UE, a NAS message from PCF to UE, a NAS message from SMSF to UE, an SMF triggered PDU session modification request, etc., the AMF terminates the RAN triggered N2 connection release procedure, and processes the received message of other NF.

Step S507: AMF sends an N3 UP connection release request to RAN; for each PDU session in which an update SM context request message is sent in the previous RAN-triggered N2 connection release process, the AMF sends an N3 UP connection release request message to the RAN, and the message carries a corresponding PDU session ID for releasing the N3 UP connection.

Step S508: the RAN releases PDU session resources; the RAN releases the corresponding PDU session resources according to the corresponding PDU session ID of the N3 UP connection to be released, which is obtained in the step S507, so as to be unified with the SMF side resources.

Step S509: the RAN returns an N3 UP connection release response message to the AMF.

Fig. 14 is a schematic structural diagram of a network element device according to an embodiment of the present application. As shown in fig. 14, the apparatus includes a memory 1100, a processor 1200, and a communication device 1300. The number of the memories 1100 and the processors 1200 may be one or more, and one memory 1100 and one processor 1200 are exemplified in fig. 14; the memory 1100 and the processor 1200 in the device may be connected by a bus or otherwise, for example in fig. 14.

The memory 1100 is a computer readable storage medium, and may be used to store a software program, a computer executable program, and modules, such as program instructions/modules corresponding to the communication methods provided in any of the embodiments of the present application. The processor 1200 implements the communication methods described above by running software programs, instructions, and modules stored in the memory 1110.

The memory 1100 may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, at least one application program required for functions. In addition, memory 1100 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some examples, memory 1100 may further include memory located remotely from processor 1200, which may be connected to the device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The communication device 1300 is configured to perform information transmission and reception communication according to control of the processor 1200.

In one embodiment, the communications apparatus 1300 includes a receiver 1310, a transmitter 1320. Receiver 1310 is a module or combination of devices in a network element that performs data reception. Transmitter 1320 is a module or combination of devices in a network element that performs data transmission.

An embodiment of the present application also provides a computer-readable storage medium storing computer-executable instructions for performing a communication method as provided in any embodiment of the present application.

An embodiment of the present application further provides a computer program product, including a computer program or computer instructions, where the computer program or computer instructions are stored in a computer readable storage medium, and where a processor of a computer device reads the computer program or computer instructions from the computer readable storage medium, and where the processor executes the computer program or computer instructions, so that the computer device performs a communication method as provided in any embodiment of the present application.

The system architecture and the application scenario described in the embodiments of the present application are for more clearly describing the technical solution of the embodiments of the present application, and do not constitute a limitation on the technical solution provided by the embodiments of the present application, and those skilled in the art can know that, with the evolution of the system architecture and the appearance of a new application scenario, the technical solution provided by the embodiments of the present application is equally applicable to similar technical problems.

Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof.

In a hardware implementation, the division between the 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 cooperatively by several physical components. 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. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, 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. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, 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 used in this specification, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components may reside within a process or thread of execution and a component may be localized on one computer or distributed between 2 or more computers. Furthermore, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local or remote processes such as in accordance with a signal having one or more data packets (e.g., data from two components interacting with one another in a local system, distributed system, or across a network such as the internet with other systems by way of the signal).

Some embodiments of the present application are described above with reference to the accompanying drawings, and thus do not limit the scope of the claims of the present application. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the present application shall fall within the scope of the claims of the present application.

Claims

1. A communication method, applied to an access and mobility management function network element AMF, the method comprising:

sending a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection;

receiving a downlink signaling trigger message;

sending a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection canceling release;

a first cancel connection release response message is received, wherein the first cancel connection release response message is used for notifying the AMF that the connection release of the SMF has been cancelled or notifying the AMF that the connection release of the SMF has been completed.

2. The method of claim 1, wherein receiving the downlink signaling trigger message comprises:

and receiving a downlink signaling trigger message sent by the network element functional entity NF.

3. The method of claim 1, wherein in the case where the first cancel connection release response message is used to notify the AMF that connection release of the SMF is completed, the method further comprises:

sending a second connection release request message, wherein the second connection release request message is used for indicating a Radio Access Network (RAN) to release connection;

A second connection release response message is received.

4. The method of claim 1, wherein in the case where the first cancel connection release response message is used to notify the AMF that connection release of the SMF is completed, the method further comprises:

receiving a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message;

sending a message delivery response message;

transmitting the PDU session resource release request message, wherein the PDU session resource release request message is used for indicating the RAN to release PDU session resources;

receiving a PDU session resource release response message;

sending an update context request message, wherein the update context request message is used for notifying the SMF that PDU session resource release of the RAN is completed;

an update context response message is received.

5. The method of claim 1, wherein prior to the sending the first cancel connection release request message, the method further comprises:

a first request message for confirming the release of the connection cancellation function is sent, wherein the request message for confirming the release of the connection cancellation function is used for confirming the SMF to support the release of the connection cancellation function;

A first support connection release cancellation function acknowledgement response message is received.

6. A communication method, applied to a session management function network element SMF, the method comprising:

receiving a first connection release request message, wherein the first connection release request message is used for indicating the SMF to release connection;

and receiving a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel the connection canceling release.

7. The method of claim 6, wherein after the receiving the first cancel connection release request message, the method further comprises:

sending a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating a user plane function network element UPF to cancel connection release;

receiving a second cancel connection release response message;

and sending a first connection canceling response message, wherein the first connection canceling response message is used for notifying an access and mobility management function network element (AMF) that the connection canceling of the SMF is canceled.

8. The method of claim 6, wherein after the receiving the first cancel connection release request message, the method further comprises:

And sending a first connection canceling response message, wherein the first connection canceling response message is used for notifying an AMF that the connection of the SMF is completed.

9. The method of claim 8, wherein after the receiving the first cancel connection release request message, the method further comprises:

sending a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message;

receiving a message delivery response message;

receiving an update context request message, wherein the update context request message is used for notifying the SMF that PDU session resource release of a Radio Access Network (RAN) is completed;

and sending an update context response message.

10. The method of claim 6, wherein prior to receiving the first cancel connection release request message, the method further comprises:

receiving a first request message for confirming the release of the connection cancellation function, wherein the first request message is used for confirming the release of the connection cancellation function by the SMF;

and sending a first support connection release cancellation function acknowledgement response message.

11. The method of claim 7, wherein prior to sending the second cancel connection release request message, the method further comprises:

a second request message for confirming the release of the connection cancellation function is sent, wherein the second request message for confirming the release of the connection cancellation function is used for confirming the release of the connection cancellation function by the UPF;

a second support connection release cancellation function acknowledgement response message is received.

12. A communication method, applied to a user plane function network element UPF, the method comprising:

receiving a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating the UPF to cancel connection canceling release;

and sending a second connection canceling release response message.

13. The method of claim 12, wherein prior to receiving the second cancel connection release request message, the method further comprises:

receiving a second connection release request message, wherein the second connection release request message is used for indicating the UPF to release connection;

and sending a second connection release response message.

14. The method of claim 12, wherein prior to receiving the second cancel connection release request message, the method further comprises:

Receiving a second request message for confirming the release of the connection cancellation function, wherein the second request message is used for confirming the release of the connection cancellation function by the UPF;

and sending a second support connection release cancellation function acknowledgement response message.

15. A method of communication, the method comprising:

the method comprises the steps that an access and mobile management function network element (AMF) sends a first connection release request message, wherein the first connection release request message is used for indicating a session management function network element (SMF) to release connection;

the session management function network element SMF receives a first connection release request message;

the AMF receives a downlink signaling trigger message;

the AMF sends a first connection canceling release request message, wherein the first connection canceling release request message is used for indicating the SMF to cancel connection release;

the SMF receives a first connection canceling release request message;

the SMF sends a first connection release cancellation response message, where the first connection release cancellation response message is used to notify the AMF that a connection release of the SMF has been cancelled or to notify the AMF that a connection release of the SMF has been completed;

The AMF receives the first cancel connection release response message.

16. The method of claim 15, wherein in the case where the first cancel connection release response message is used to notify the AMF that connection release of the SMF has been canceled, the method further comprises:

the SMF sends a second connection canceling release request message, wherein the second connection canceling release request message is used for indicating a user plane function network element UPF to cancel connection canceling;

the UPF receives the second connection canceling release request message;

the UPF sends a second connection canceling response message, wherein the second connection canceling response message is used for notifying the SMF that the connection is released;

the SMF receives the second cancel connection release response message.

17. The method of claim 15, wherein in the case where the first cancel connection release response message is used to notify the AMF that connection release of the SMF is completed, after the AMF receives the first cancel connection release response message, the method further comprises:

the AMF sends a second connection release request message, wherein the second connection release request message is used for indicating a Radio Access Network (RAN) to release connection;

The RAN receives the second connection release request message;

the RAN sends a second connection release response message, wherein the second connection release response message is used for informing the AMF that the connection release of the RAN is completed;

the AMF receives the second connection release response message.

18. The method of claim 15, wherein, in the case where the first cancel connection release response message is used to notify the AMF that connection release of the SMF is completed, the AMF receives the first cancel connection release response message, the method further comprises:

the SMF sends a message delivery request message, wherein the message delivery request message carries a protocol data unit PDU session resource release request message;

the AMF receives the message delivery request message;

the AMF sends the PDU session resource release request message, wherein the PDU session resource release request message is used for indicating the RAN to release PDU session resources;

the RAN receives the PDU session resource release request message;

the RAN sends PDU session resource release response information, wherein the PDU session resource release response information is used for notifying the AMF that PDU session resource release of the RAN is completed;

The AMF receives the PDU session resource release response message;

the AMF sends an update context request message, wherein the update context request message is used for notifying the SMF that PDU session resource release of the RAN is completed;

the SMF receives the update context request message;

the SMF sends an update context response message;

the AMF receives the update context response message.

19. A network element device, comprising: memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the communication method according to any of claims 1 to 18 when executing the computer program.

20. A computer readable storage medium storing computer executable instructions which when executed by a computer implement a method of communication as claimed in any one of claims 1 to 18.

21. A computer program product comprising a computer program or computer instructions, characterized in that the computer program or the computer instructions are stored in a computer-readable storage medium, from which the computer program or the computer instructions are read by a processor of a computer device, which processor executes the computer program or the computer instructions, so that the computer device performs the communication method according to any one of claims 1 to 18.