CN110140333B - Method and terminal for session management - Google Patents

Abstract

The embodiments of the present application relate to a method and a terminal for session management. The method includes: the terminal receives a first message sent by the access and mobility management function entity AMF, the first message includes or does not include information of the LADN; the terminal determines according to the first message that the available state of the LADN changes; the terminal modifies or releases the described PDU session. Through the embodiments of the present application, the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state is reduced, and the information caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN is also reduced. to waste.

Description

Method and terminal for session management

technical field

The embodiments of the present application relate to the field of communication technologies, and in particular, to a method and terminal for session management.

Background technique

In the 5G network, the concept of Local Area Data Network (LADN) is introduced into the terminal. During the registration procedure (Registration Procedure) of the terminal, the access and mobility management function (AMF) provides the terminal with LADN information (for example, LADN availability information), the LADN availability information includes the LADN data network name (LADN data network name, LADN DNN) and the LADN service area (LADN Service Area), the LADN service area is the terminal A set of specific tracking areas (TA) in the registration area. When the terminal is located in the LADN Service Area, a protocol data unit (PDU) session with the LADN can be established. When the terminal moves out of the LADN Servcie After Area, data transmission based on LADN cannot be realized.

Usually the Access and Mobility Management Function (AMF) provides the Session Management Function (SMF) with information about whether the terminal is in the LADN Service Area, so that the SMF can determine whether the terminal can establish a session to access the LADN, or Manage the currently established LADN session, so as to ensure that the terminal can transmit LADN-based data only when it is in the LADN Service Area.

After the SMF determines that the terminal moves out of the service area of the LADN, it can notify the user plane function (UPF) to discard the downlink data of the session accessing the LADN or stop sending the downlink data notification (DDN) related to the session to the SMF. ), however, data loss may occur when the terminal is in an idle state. After the SMF determines that the terminal moves out of the LADN service area, the SMF does not notify the UPF to discard the downlink data of the session or stop sending the DDN related to the session to the SMF. In this case, signaling resources may be wasted.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a method and device for session management. In order to realize the management of the session accessing the LADN, the problem of data loss or signaling waste is reduced.

In a first aspect, a method for session management is provided. Wherein, the terminal has a PDU session accessing the LADN, and the method includes: the terminal receives, in a first registration area (registration area, RA), a first message sent by the access and mobility management function entity AMF, where the first message includes or The information of the LADN is not included; wherein, the first RA is the current registration area of the terminal; the terminal determines that the availability state of the LADN has changed according to the first message; the terminal modifies or releases the PDU session. The first message may be a registration accept message (RegistrationAccept) or a UE configuration update command message (UE Configration Update Command), and the information of the LADN may be available information of the LADN. Through the embodiments of this application, for a LADN session, when a terminal enters a registration area for information that does not support LADN from a registration area that supports LADN, the terminal modifies or releases the PDU session, or the terminal uses information that does not support LADN to modify or release the PDU session. When the registration area of the LADN enters the registration area that supports LADN information, the terminal modifies the PDU session, thereby reducing the need for the network device to access the LADN because the registration area does not include LADN information when the terminal is in an idle state. There is a waste of signaling caused by paging the terminal due to the arrival of downlink data in the session.

It can be understood that the first message does not include LADN information, specifically, there may be no LADN information in the first message, or the LADN information in the first message is empty, or the first message includes other indication information indicating that there is no LADN. information, the present invention is not specifically limited.

It should be noted that the existence of a PDU session for the terminal to access the LADN may mean that the terminal saves the context of the PDU session for access to the LADN, where the context of the PDU session may include one or more of the following: the identifier of the PDU session; The session service continuity (SSC) mode of the session; the type of the PDU session (eg IP type), ethernet type, unstructured type, etc.; the data network name (data network) corresponding to the PDU session name, DNN); network slice information corresponding to the PDU session (such as single network slice selection information (S-NSSAI)), network slice identifier (NSI), etc.; the quality of service flow identifier (QoS) of the PDU session flow identifier, QFI), QoS parameters corresponding to the QoS flow, such as 5G quality of service indicator (5G QoS indicator, 5QI), guaranteed flow bit rate (GFBR), maximum flow bit rate (maximum flow bit rate, MFBR) ), the session aggregate maximum bit rate (Session-AMBR), the radio bearer information corresponding to the PDU session, such as the data radio bearer (DRB), which can also refer to the UE establishing a PDU session accessing the LADN , the terminal can transmit uplink and downlink data through the PDU session. Specifically, the PDU session accessing the LAND means that the DNN attribute corresponding to the PDU session is LADN DNN.

In a first optional implementation of the first aspect, the terminal determines that the availability state of the LADN changes according to the first message, including: when the first message does not include the information of the LADN, further, the When the terminal determines that the second registration area includes the LADN information, the terminal determines that the LADN information in the registration area has changed; or, when the first message does not include the LADN information, and the first registration area When the information of the LADN is included before receiving the first message, the terminal determines that the information of the LADN in the registration area has changed; wherein, the first registration area is the current registration area of the terminal, and the The second registration area is the registration area before the terminal enters the current registration area.

In a second optional implementation of the first aspect, modifying the PDU session by the terminal includes: the terminal sends a first session modification request message to the SMF, where the first session modification request message includes a first indication, and the first indication is used for Information indicating when the first RA does not include the LADN. It can be understood that the terminal also needs to access to the SMF the identifier of the PDU session of the LADN, and the identifier of the PDU session may be included in the first session modification request message, or may be included in the NAS message sent by the terminal to the AMF, It is then forwarded by AMF to SMF. The embodiment of the present application can realize that the PDU session is managed based on the current registration area and the service area of the LADN, and the granularity is relatively fine.

In a third optional implementation of the first aspect, releasing the PDU session by the terminal includes: the terminal sending a session release request message to the session management entity SMF. The embodiments of the present application can realize that when the terminal is located outside the service area of the LADN, the terminal initiates the release of the PDU session, thereby reducing the occurrence of paging the terminal due to the existence of the PDU session but the terminal is not located in the service area of the LADN. Signaling waste.

In a fourth optional implementation of the first aspect, the method further includes: the terminal receiving a first session modification command message sent by the SMF, where the first session modification command message includes an identifier of the PDU session and a first parameter, the first session modification command message A parameter is used to indicate that the PDU session is not available, and the identity of the PDU session is used to identify the PDU session. The PDU session unavailable includes one or a combination of the following: the user plane connection of the LADN session has been released; the UPF has been notified to discard the downlink data of the LADN session; the UPF has been notified to stop sending downlink data notifications related to the session to the SMF (downlink data notification, DDN), and the gate corresponding to the LADN session is set to off. The embodiment of the present application can realize that after the network side modifies or releases the PDU session, the terminal is notified, so that the terminal can synchronously modify or release the PDU session, thereby reducing the situation when the terminal is not in the service area of the LADN due to the existence of the PDU session. , the signaling waste caused by paging the terminal.

In a fifth optional implementation of the first aspect, the method further includes: the terminal marking the PDU session as unavailable. The embodiment of the present application can realize that by marking the PDU session, the terminal can count the number of times that the terminal continuously enters the registration area of the service area that does not include LADN, so as to set a rule. In the case of equal to the set number of times, the terminal modifies the PDU session, and when the set number of times is reached or exceeded, the terminal releases the PDU session, and the management granularity of the PDU session accessing the LADN is finer.

In a sixth optional implementation of the first aspect, the terminal determines that the availability state of the LADN changes according to the first message, including: when the first message includes the information of the LADN, and the terminal receives the When the information of the LADN is not included in the first RA before the first message, the terminal determines that the availability state of the LADN has changed; or, when the first message includes the information of the LADN and the second When the information of the LADN is not included in the RA, the terminal determines that the availability state of the LADN has changed; the second RA is the RA before the terminal enters the first RA.

In a seventh optional implementation of the first aspect, the method further includes: the terminal sends a second session modification request message to the SMF, where the second session modification request message includes a second indication, where the second indication is used to indicate the The information of the LADN is not included in the first RA. Through the embodiments of the present application, when the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session can be managed from a finer granularity, and the The network equipment is more reasonable for paging of the terminal, saving signaling and improving efficiency.

In an eighth optional implementation of the first aspect, the method further includes: the terminal receives a second session modification command message sent by the SMF, where the second session modification command message includes a second parameter, and the second parameter is used to indicate PDU session is available. The embodiment of the present application can realize the synchronization of the PDU session state between the network side and the terminal side, thereby reducing the possibility of data loss.

In a ninth optional implementation of the first aspect, the method further includes: the terminal marking the PDU session as available. The embodiment of the present application can realize that by marking the PDU session, the terminal can count the number of times that the terminal continuously enters the registration area of the service area that does not include LADN, so as to set a rule. In the case of equal to the set number of times, the terminal modifies the PDU session, and when the set number of times is reached or exceeded, the terminal releases the PDU session, and the management granularity of the PDU session accessing the LADN is finer.

According to the embodiment of the present application, for a LADN session, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing the number of network devices searching for the LADN access PDU session due to the arrival of downlink data. Signaling waste caused by calling the terminal. The PDU session can also be managed based on the current registration area and the service area of the LADN with finer granularity.

In a second aspect, a method for session management is provided. The SMF has a PDU session in which the terminal accesses the LADN, and the method includes: the SMF receives a session modification request message sent by the terminal, where the session modification request message includes an indication, and the indication is used to indicate that the registration area includes or does not include the LADN information ; The SMF modifies the PDU session according to the instruction, and the information of the LADN may be the available information of the LADN. The embodiment of the present application can realize that the PDU session is managed based on the current registration area and the service area of the LADN, and the granularity is relatively fine.

In a first optional implementation of the second aspect, when the indication is used to indicate that the RA does not include LADN information, the SMF modifies the PDU session according to the indication, including: the SMF sends a first session modification command message to the terminal , the first session modification command message includes an identifier of the PDU session and a first parameter, where the first parameter is used to indicate that the PDU session is unavailable. The embodiment of the present application can realize that the PDU session is managed based on the current registration area and the service area of the LADN, and the granularity is relatively fine.

In a second optional implementation of the second aspect, the SMF modifies the PDU session according to the instruction, including one or more of the following: the SMF marks the PDU session as unavailable; the SMF notifies the user plane function entity UPF to discard the The downlink data corresponding to the PDU session; the SMF notifies the UPF to stop sending the downlink data to the SMF to notify the DDN.

In a third optional implementation of the second aspect, when the indication is used to indicate that the RA does not include LADN information, the SMF modifies the PDU session according to the indication, including: the SMF sends a second session modification to the terminal The command message, the second session modification command message includes an identifier of the PDU session and a second parameter, where the second parameter is used to indicate that the PDU session is available. Through the embodiments of the present application, when the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session can be managed from a finer granularity, and the The network equipment is more reasonable for paging of the terminal, saving signaling and improving efficiency.

It can be understood that the SMF modifies the PDU session according to the instruction, and the SMF modifies the PDU session according to the received identifier of the PDU session and the instruction.

In a third aspect, a method for service subscription is provided. The SMF has a PDU session in which the terminal accesses the LADN, and the method includes: the SMF subscribes to the AMF for a notification service, where the notification service is used to notify the SMF when a preset event occurs, wherein the available state of the LADN changes. The embodiment of the present application can realize the change notification of the service area of the RA including the LADN to which the AMF subscribes the terminal to be moved by the SMF to the AMF. When the conditions are met, the AMF notifies the SMF. More granularity for PDU session management.

In a first optional implementation of the third aspect, the SMF subscribes the notification service to the AMF, including: the SMF sends the data network name of the LADN and a preset event to the AMF to subscribe the notification service to the AMF. The embodiment of the present application can realize the change notification of the service area of the RA including the LADN to which the SMF moves to the AMF subscription terminal. More granularity for PDU session management.

In a second optional implementation of the third aspect, the change in the available state of the LADN includes at least one of the following: the first registration area does not include the information of the LADN, and the second registration area includes the LADN The information of the LADN is changed from the information including the LADN in the first registration area to the information not including the LADN; the information of the LADN is included in the first registration area, and the information of the LADN is not included in the second registration area; Or, the first registration area is changed from information not including the LADN to information including the LADN; wherein the first registration area is the current registration area of the terminal, and the second registration area is the The terminal enters the registration area before the first registration area, and the information of the LADN may be the available information of the LADN.

In a third optional implementation of the third aspect, the SMF receives notification information sent by the AMF, where the notification information is used to notify that the registration area of the terminal includes or does not include the information of the LADN. The SMF modifies the PDU session according to the notification information. The AMF notifies the RA that the terminal moves to, including the change notification of the service area of the LADN, and the SMF initiates the release or modification of the LADN session, thereby reducing the information caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN. to waste.

In a fourth optional implementation of the third aspect, the SMF modifies the PDU session according to the notification information, including: when the notification information is used to notify that the registration area of the terminal does not include the information of the LADN , the SMF performs one or more of the following: notifying the user plane functional entity UPF to discard the downlink data corresponding to the PDU session; notifying the UPF to stop sending the downlink data corresponding to the PDU session to the SMF and notifying the DDN; or, When the notification information is used to notify that the registration area of the terminal includes the information of the LADN, the SMF performs one or more of the following: notifying the UPF to send downlink data corresponding to the PDU session; notifying all The UPF notifies the DDN of the downlink data corresponding to the PDU session. The embodiment of the present application can realize that the SMF determines whether to initiate the release or modification of the LADN session according to the support of the LADN in the registration area, and the management granularity is fine, which reduces the network equipment because the PDU session accessing the LADN has downlink data arriving However, the signaling waste caused by paging the terminal makes it unnecessary to page the terminal and saves signaling.

It can be achieved through the embodiments of the present application that the AMF notifies the SMF of the change notification of the service area of the RA including the LADN to which the terminal moves, and the SMF initiates the release or modification of the LADN session, thereby reducing network equipment because the PDU session accessing the LADN has The signaling waste caused by paging the terminal when downlink data arrives. Alternatively, the SMF can discard the downlink data without modifying the PDU session, so that the terminal does not need to be paged and signaling is saved.

In a fourth aspect, a service subscription method is provided. The AMF has a PDU session in which the terminal accesses the LADN. The method includes: the AMF receives a subscription notification service request sent by the SMF, and the notification service is used for the AMF to notify the SMF when a preset event occurs, wherein the preset The event is that the availability state of the LADN changes, wherein the information of the LADN may be the availability information of the LADN. Through the embodiment of the present application, the SMF can realize the change notification of the service area of the RA including the LADN to which the AMF subscribes the terminal to move. When the conditions are met, the AMF notifies the SMF.

In a first optional implementation of the fourth aspect, the AMF receives a subscription notification service request sent by the SMF, including:

The AMF receives the data network name DNN and preset events of the LADN sent by the SMF to accept the SMF subscription notification service.

In a second optional implementation of the fourth aspect, the change in the available state of the LADN includes at least one of the following: the first registration area does not include information about the LADN, the second registration area includes information about the LADN, and the first registration area includes information about the LADN. The area is changed from the information including the LADN to the information not including the LADN; the first registration area includes the information of the LADN, the second registration area does not include the information of the LADN; the first registration area is changed from not including the information of the LADN is the information including the LADN; wherein the first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the first registration area.

In a third optional implementation of the fourth aspect, after the AMF receives the subscription notification service request sent by the SMF, the method further includes: the AMF sends notification information to the SMF, where the notification information is used to notify that the registration area of the terminal includes or Information on the LADN is not included. The notification information may specifically include the LADN DNN and an indication, and the indication is used to indicate that the registration area does not include the LADN information

It can be realized by the embodiments of the present application that the SMF can realize that the downlink data can be discarded when the PDU session is not modified, so that the terminal does not need to be paged, and signaling is saved.

In a fifth aspect, a session management method is provided. The SMF has a PDU session accessing the LADN, and the method includes: the SMF receives a downlink data notification corresponding to the PDU session sent by the UPF; the SMF invokes a first service provided by the AMF, and the first service is used for the The SMF requests the AMF to send a message or information, such as N2 SMinformation, to the access node AN. The SMF receives an indication parameter sent by the AMF, where the indication parameter is used to indicate that the current registration area does not include the information of the LADN; the SMF modifies the PDU session according to the indication parameter. It can be realized by the embodiments of the present application that the SMF can realize that the downlink data can be discarded when the PDU session is not modified, so that the terminal does not need to be paged, and signaling is saved.

In a sixth aspect, a session management method is provided. The SMF has a PDU session accessing the LADN, and the method includes: the AMF receives a first service request invoked by the SMF, where the first service request is used by the SMF to request the AMF to send a message or information to the access node AN; When the registration area of the terminal does not include the service area of the LADN, the AMF sends an indication parameter to the SMF, where the indication parameter is used to indicate that the registration area does not include the information of the LADN. The indication parameter may specifically include the LADN DNN and an indication, where the indication is used to indicate that the registration area does not include the LADN information. It can be realized by the embodiments of the present application that the SMF can realize that the downlink data can be discarded when the PDU session is not modified, so that the terminal does not need to be paged, and signaling is saved.

In a seventh aspect, a terminal is provided, the terminal having the function of implementing the above-mentioned first aspect and the terminal behavior in the optional implementation thereof. The functions can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. Through the embodiments of the present application, for a PDU session accessing LADN, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing network equipment because the PDU session accessing LADN has downlink data Signaling waste caused by arriving and paging the terminal. The PDU session can also be managed based on the current registration area and the service area of the LADN with finer granularity. It solves the problem that when the terminal is outside the service area of the LADN, the terminal initiates the release of the PDU session, thereby reducing the signaling waste caused by paging the terminal when the terminal is not in the service area of the LADN due to the existence of the PDU session. It is also possible to notify the terminal after the PDU session is modified or released on the network side, so that the terminal can modify or release the PDU session synchronously, thereby reducing the problem of paging the terminal due to the existence of the PDU session but the terminal is not in the service area of the LADN. Signaling waste. By marking the PDU session, the terminal can count the number of times that the terminal continuously enters the registration area of the service area that does not include LADN, so as to set rules. The terminal modifies the PDU session, and when the set number of times is reached or exceeded, the terminal releases the PDU session, and the management granularity of the PDU session accessing the LADN is finer. When the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session is managed from a finer granularity and the paging of the terminal by the network device is improved. Reasonable, saving signaling and improving efficiency.

In an eighth aspect, an SMF entity is provided, and the SMF entity has the function of implementing the second aspect and the SMF entity behavior in the optional implementation thereof. The functions can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. Through the embodiment of the present application, the PDU session is managed based on the current registration area and the service area of the LADN, and the granularity is relatively fine. When the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session is managed from a finer granularity and the paging of the terminal by the network device is improved. Reasonable, saving signaling and improving efficiency.

In a ninth aspect, an SMF entity is provided, and the SMF entity has the function of implementing the third aspect and the SMF entity behavior in the optional implementation thereof or the fifth aspect. The functions can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. Through the embodiment of this application, the AMF notifies the SMF about the change notification of the RA to which the terminal moves, including the service area of the LADN, and the SMF initiates the release or modification of the LADN session, thereby reducing network equipment because the PDU session accessing the LADN has downlink data Signaling waste caused by arriving and paging the terminal. The SMF can subscribe to the AMF to notify the change of the service area of the RA including the LADN to which the terminal moves. When the conditions are met, the AMF notifies the SMF. Alternatively, the SMF can discard the downlink data without modifying the PDU session, so that the terminal does not need to be paged and signaling is saved.

In a tenth aspect, an AMF entity is provided, and the AMF entity has the function of implementing the fourth aspect and the AMF entity behavior in the optional implementation or the sixth aspect. The functions can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. Through the embodiment of this application, the AMF notifies the SMF about the change notification of the RA to which the terminal moves, including the service area of the LADN, and the SMF initiates the release or modification of the LADN session, thereby reducing network equipment because the PDU session accessing the LADN has downlink data Signaling waste caused by arriving and paging the terminal. The SMF can subscribe to the AMF to notify the change of the service area of the RA including the LADN to which the terminal moves. When the conditions are met, the AMF notifies the SMF. Alternatively, the SMF can discard the downlink data without modifying the PDU session, so that the terminal does not need to be paged and signaling is saved.

In an eleventh aspect, a computer-readable storage medium is provided, and a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the above-mentioned first aspect, second aspect, third aspect, and first aspect are realized. The method of any one or more of the fourth, fifth and sixth aspects.

A twelfth aspect provides a computer program product comprising instructions that, when executed on a computer, cause the computer to perform the first, second, third, fourth, fifth, and The method of any one or more of the sixth aspects.

The embodiments of the present application can realize that, for a LADN session, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing network equipment because the LADN access PDU session has downlink data arriving And the signaling waste caused by paging the terminal. The PDU session can also be managed based on the current registration area and the service area of the LADN with finer granularity. It solves the problem that when the terminal is outside the service area of the LADN, the terminal initiates the release of the PDU session, thereby reducing the signaling waste caused by paging the terminal when the terminal is not in the service area of the LADN due to the existence of the PDU session.

Description of drawings

Figure 1 is a schematic diagram of a 5G communication network structure;

FIG. 2 is a schematic diagram of a service area of a LADN.

3 is a schematic diagram of signaling interaction of a method for session management provided by an embodiment of the present application;

4 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application;

5 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application;

FIG. 6 provides an example of an embodiment of the present application;

7 is a schematic diagram of signaling interaction of a service subscription method provided by an embodiment of the present application;

FIG. 8 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application;

FIG. 10 provides another example of the embodiment of the present application;

FIG. 11 is a schematic structural diagram of a terminal according to an embodiment of the present application;

FIG. 12 is a schematic structural diagram of an SMF provided by an embodiment of the present application;

FIG. 13 is a schematic structural diagram of another SMF provided by an embodiment of the present application;

14 is a schematic structural diagram of an AMF provided by an embodiment of the present application;

FIG. 15 is a schematic structural diagram of another SMF provided by an embodiment of the present application;

16 is a schematic structural diagram of another AMF provided by an embodiment of the present application;

FIG. 17 is a schematic structural diagram of another terminal provided by an embodiment of the present application;

FIG. 18 is a schematic structural diagram of another SMF provided by an embodiment of the present application;

FIG. 19 is a schematic structural diagram of another SMF provided by an embodiment of the present application;

20 is a schematic structural diagram of another AMF provided by an embodiment of the present application;

FIG. 21 is a schematic structural diagram of another SMF provided by an embodiment of the present application;

FIG. 22 is a schematic structural diagram of another AMF provided by an embodiment of the present application.

Detailed ways

The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

The embodiments of the present application provide a method and device for session management, which are applied to a 5G communication network.

In this embodiment of the present application, a terminal may also be referred to as user equipment, which may be a device that provides voice and/or data connectivity to a user, a handheld device with a wireless connection function, or a device connected to a wireless Other processing equipment for the modem. A wireless terminal may communicate with one or more core networks via a Radio Access Network (RAN), and the wireless terminal may be a mobile terminal such as a mobile phone (or "cellular" phone) and a computer with mobile terminal equipment Mobile devices, which may be portable, pocket-sized, hand-held, computer-embedded, or vehicle-mounted, for example, exchange language and/or data with the wireless access network. For example, personal communication service (PCS) phones, cordless phones, session initiated protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs) ) and other equipment. A wireless terminal may also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile, remote station, access point, A remote terminal (remote terminal), an access terminal (access terminal), a user terminal (user terminal), a user agent (useragent), a user device (user device), or a terminal equipment (terminal equipment), which are not limited in the embodiments of this application . Divided according to service types, the terminals involved in the embodiments of the present invention may be terminal devices that have higher requirements for speed and mobility, such as mobile phones, multimedia devices, etc., or terminals of the Internet of Things, or Internet of Vehicles. terminal.

FIG. 1 is a schematic structural diagram of a 5G communication network according to an embodiment of the present application.

As shown in Figure 1, authentication service function entity (authentication server function, AUSF), AMF, SMF, unified data management entity (unified data management, UDM), application function entity (application function, AF), policy control function entity ( The policy control function, PCF) and the UPF may be one or more servers in the core network of the 5G communication network. The terminal can realize network interconnection by accessing the communication network. For example, a PDU session can be established for data transmission with the UPF by accessing the communication network, and the PDU session can be managed by the SMF.

The function of each module in the 5G communication network is briefly introduced below.

AUSF is mainly used for authentication.

The AMF has functions such as terminal mobility management, registration management, connection management, legal interception, support for transmitting session management (session management, SM) information between the terminal and the SMF, access authentication and access authorization. The AMF can determine information such as TA, RA, and LADN of the terminal.

SMF has functions such as session management and roaming. Among them, session management functions, such as session establishment, modification and release, include tunnel maintenance for UPF and access network (access network, AN) nodes (nodes). Roaming functions may include billing data collection, signaling to support authentication/authorization with an external data network (DN). For example, the SMF can be used to manage the PDU session accessing the LADN, including modifying or releasing the PDU session accessing the LADN, receiving the DDN corresponding to the PDU session accessing the LADN, and so on.

UPF has functions such as packet routing and lawful interception. The UPF can route and legally monitor the data packets corresponding to the PDU session accessing the LADN.

UDM has functions such as authentication certificate processing, user identification processing, access authorization, registration and mobility management, subscription management, and SMS management.

The AF can interact with the 3GPP core network.

PCF can support policy frameworks as well as policy rules.

The specific interface between the various entities may refer to the 3GPP standard. It should be known that the 5G communication network structure shown in FIG. 1 is only an example, and the 5G communication network structure used in the embodiment of the present invention may include more or less network devices.

The applicant of the present application found through analysis that there is a certain relationship between LADN and RA in a 5G network, and the tracking area (TA) in RA may support LADN in whole or in part, or TA in RA may not support all LADN. When all or part of the TAs in the RA support LADN, that is, when the LADN Service Area and the Registration Area have an intersection, it is considered that the RA includes the LADN service area. When all the TAs in the RA do not support the LADN, that is, when the LADNServcie Area and the RA have no intersection, it is considered that the RA does not include the service area of the LADN.

It can be understood that the TA supporting LADN means that when the terminal is within the coverage of the TA, a PDU session to access the LADN can be established through the base station under the TA and data transmission can be performed on the LADN PDU session. The TA does not support LADN means that when the terminal is within the coverage of the TA, it cannot establish a PDU session accessing the LADN, and for the established LADN PDU session, the corresponding user plane connection cannot be activated for data transmission.

For example, as shown in FIG. 2 , FIG. 2 is a schematic diagram of a service area of a LADN. TA1-TA16 constitute a total of four RAs (RA1-RA4), of which TA1-TA5 support LADN. At this time, if all the TAs in RA1 support LADN, it is considered that the RA1 includes the service area of LADN; if only TA5 in RA2 supports LADN, it is considered that the RA1 includes the service area of LADN; all TAs in RA3 and RA4 do not support LADN. If LADN is supported, it is considered that the RA3 and RA4 do not include the service area of LADN.

The embodiments of the present application will be further introduced below with reference to the accompanying drawings.

FIG. 3 is a schematic diagram of signaling interaction of a method for session management provided by an embodiment of the present application. The terminal has a PDU session accessing the LADN.

Wherein, the terminal has a PDU session accessing the LADN, which may mean that the terminal saves the context of the PDU session accessing the LADN, where the context of the PDU session may include one or more of the following: the identifier of the PDU session; the SSC of the PDU session Mode; type of PDU session (such as IP type), Ethernet (ethernet) type, unstructured (unstructured) type, etc.; DNN corresponding to PDU session; network slice information corresponding to PDU session, such as S-NSSAI, network slice identifier ( NSI), etc.; the QFI of the PDU session, the QoS parameters corresponding to the QoS flow (such as 5QI), GFBR, MFBR, Session-AMBR, the radio bearer information corresponding to the PDU session, such as DRB, can also refer to the PDU that the UE has established to access the LADN session, the terminal can transmit uplink and downlink data through the PDU session. Specifically, the PDU session accessing the LAND means that the DNN attribute corresponding to the PDU session is LADNDNN.

As shown in Figure 3, the method specifically includes:

S310, the terminal receives the first message sent by the AMF. The AMF registered by the terminal will send the information of the LADN in the registration area where the terminal is located to the terminal through the first message. LADN information includes LADN DNN and LADN Service Area. Of course, the LADN information sent to the terminal is a set of LADN information corresponding to the LADN subscribed by the terminal. If the terminal subscribes to multiple LADNs, the LADN information corresponding to the multiple LADNs is sent to the terminal. Wherein, when the registration area RA where the terminal is located supports LADN information, the first message may carry LADN information, for example, the LADN information may be LADN availability information (LADN availability info). For example, the first message may be a registration accept message (Registrationaccept), and the registration accept message includes the information of the LADN; or, the first message may be a UE configuration update command message (UE configuration update command), and the terminal configuration update command message includes the information of the LADN. information and more. The terminal performs the registration process, and the AMF sends a registration acceptance message to the terminal.

When the registration area where the terminal is located does not support the LADN information, the first message may not carry the LADN information.

In an example of the LADN information, the LADN information includes the LADN data network name (LADN DNN) and the LADN service area (LADN service area). The LADN service area may refer to the TA set of the LADN.

Wherein, the 5G network may include multiple LADNs, and the multiple LADNs are not necessarily all available to the terminal. The LADN information received by the terminal includes the LADN DNN of the LADN that the terminal can access, and the corresponding LADN service area.

Specifically, the AMF stores the service area of the LADN available to the terminal, and the AMF can determine whether the current RA of the terminal includes the information of the LADN according to the current RA of the terminal and the service area of the LADN available to the terminal, that is, the current RA of the terminal and the service area of the LADN available to the terminal. Whether the service areas of the available LADNs overlap. When the current RA of the terminal includes the information of the LADN, that is, when the current RA of the terminal overlaps the service area of the LADN available to the terminal, the first message may carry the information of the LADN, and the information of the LADN indicates the LADN ( LADN DNN) and the service area of the LADN; when the current RA of the terminal does not include the information of the LADN, that is, when the current RA of the terminal does not overlap with the service area of the LADN available to the terminal, the information of the LADN may not be carried in the first message .

As an example, as shown in FIG. 2 , TA1-TA5 belong to the service area of LADN available to the terminal. If the current RA of the terminal is RA1, since RA1 includes TA1-TA4, the first message can carry LADN information. If the current RA of the terminal is RA3, since RA3 does not overlap with the service area of the LADN available to the terminal, the information of the LADN may not be carried in the first message. If the current RA of the terminal is RA2, since RA2 includes TA5, the first message may carry LADN information.

S320, the terminal determines that the first message does not include the information of the LADN.

After receiving the first message, the terminal may determine that the state of the LADN in the registration area changes according to the first message, thereby triggering modification or release of the PDU session accessing the LADN.

Specifically, when the first message received by the terminal does not include the LADN information, the terminal determines that the first RA does not include the LADN information. Further, the terminal determines that before receiving the first message When the information of the LADN is included in the first RA, that is, the terminal currently saves the information of the LADN, the terminal determines that the available state of the LADN in the RA has changed, thereby triggering modification or release of the access LADN. PDU session, the first RA is the current RA of the terminal.

In another scenario, when the first message received by the terminal does not include the LADN information, the terminal determines that the first RA does not include the LADN information, and further, the terminal determines that the second RA includes the LADN information. When the information of the LADN is obtained, that is, the terminal currently saves the information of the LADN, the terminal determines that the availability state of the LADN in the RA has changed. The first RA is the current RA of the terminal, and the second RA is the RA before the terminal enters the first RA.

In another embodiment, the terminal may determine whether the preset condition is met according to the first message, and if so, release the PDU session accessing the LADN. If not reached, modify the PDU session accessing the LADN.

For example, the preset condition may be the number of times that the terminal is continuously in the RA that does not support LADN. That is, the number of times that the current RA of the terminal does not continuously include the information of the LADN. For example, when the terminal is in an RA that does not support LADN for the first time, the PDU session accessing the LADN may be marked as unavailable. Next, when the terminal is in an RA that does not support LADN for the second time in a row, the terminal determines that the PDU session for accessing the LADN has been marked as unavailable, and releases the PDU session for accessing the LADN. Among them, unavailable may include a pending state.

For modifying the PDU session accessing the LADN, as shown in FIG. 3, it may specifically include S330-S360:

S330, the terminal sends a first session modification request message (PDU session Modificationrequest) to the SMF. The first session modification request message includes a first indication, where the first indication may be used to indicate that the current RA does not include LADN information (no LADN available info indication in current RA). The LADN information includes at least one of LADN DNN and LADN Service Area.

The terminal also needs to send the PDU session ID to the SMF, and the PDU session ID may be included in the first session modification request message, or may be included in the NAS message sent by the terminal to the AMF, and the AMF sends the PDU session ID to the SMF, The PDU session ID identifies the PDU session in which the terminal accesses the LADN.

S340, the SMF modifies the PDU session accessing the LADN according to the first session modification request message.

The SMF modifies the PDU session accessing the LADN according to the first session modification request message, including one or more of the following:

The SMF instructs the UPF to set the gate corresponding to the PDU session accessing the LADN to be closed, for example, the SMF can send a gate close command (GATE OFF) to the PDU;

SMF informs UPF to stop sending DDNs related to PDU sessions accessing LADN;

The SMF informs the UPF to discard the downlink data corresponding to the PDU session accessing the LADN;

The SMF marks the PDU session accessing the LADN as unavailable or suspended. Among them, the unavailable or suspended state includes one or more of the following:

The user plane connection of the PDU session does not exist;

SMF cannot trigger a user plane connection that activates a PDU session;

The SMF cannot accept the user plane connection request to activate the PDU session requested by the terminal.

In addition, after receiving the first session modification request message, the SMF may determine whether the state of the PDU session corresponding to the first session modification request message is available, for example, the PDU session corresponding to the first session modification request message is unavailable Or in the suspended state, it means that the PDU session is unavailable before receiving the first session modification request message, and at this time, the PDU session can be directly released, that is, the context of the PDU session is deleted. If the PDU session corresponding to the first session modification request message is available, it means that the PDU session is available before receiving the first session modification request message. At this time, after receiving the first session modification request message, the PDU session is available The session is marked as unavailable or suspended. The available states of the PDU session include one or more of the following:

The user plane connection of the PDU session exists;

SMF can trigger a user plane connection that activates a PDU session;

The SMF can accept the user plane connection request to activate the PDU session requested by the terminal;

The SMF can send messages about the PDU session to other network elements.

S350, the SMF sends a first session modification command message (PDU session modificationcommand) to the terminal. The first session modification command message includes an identifier of the PDU session and a first parameter, where the first parameter may be used to indicate that the PDU session is unavailable or suspended.

Wherein, after marking the PDU session as unavailable or suspended, the SMF may further instruct the terminal to mark the PDU session as unavailable or suspended.

S360, the terminal marks the PDU session as unavailable or suspended.

The terminal marks the PDU session accessing the LADN as unavailable or suspended.

In another implementation manner, the terminal may also save a record that the first indication has been sent to the SMF. Wherein, for the PDU session, if there is a record that the terminal has sent the first indication to the SMF, it may indicate that the PDU session is marked as unavailable.

Among them, S350 and S360 are optional steps. For example, the process of marking the PDU session as unavailable by the terminal may also be performed locally by the terminal. In this case, the terminal may perform the process before receiving the first session modification command message, or the SMF does not need to send the first session modification command message.

Through S360, the terminal may also implement statistics on the number of times that the terminal is continuously in the RA that does not support LADN. Further, a rule can be set so that the terminal modifies the PDU session when the registration area that continuously enters the service area that does not include the LADN is less than or equal to the set number of times, and when it reaches or exceeds the set number of times, the terminal releases the PDU session, the management granularity of the PDU session accessing the LADN is finer.

In this way, after the network side modifies or releases the PDU session, the terminal is notified, so that the terminal can synchronously modify or release the PDU session, thereby reducing the paging process when the terminal is not in the service area of the LADN due to the existence of the PDU session. Signaling waste caused by the terminal. .

In the case that the PDU session accessing the LADN is marked as unavailable, when the terminal determines to re-enter the RA supporting the LADN, the terminal may further mark the PDU session accessing the LADN as available. FIG. 4 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application. With reference to Fig. 4, it can specifically include S410-S460:

S410, the terminal receives the second message sent by the AMF.

The AMF also determines whether the current RA of the terminal includes the information of the LADN according to the current RA of the terminal and the service area of the LADN available to the terminal. When the current RA of the terminal includes the information of the LADN, the second message may carry the information of the LADN, and the information of the LADN indicates the LADN and the service area of the LADN included in the current RA; when the current RA of the terminal does not include the information of the LADN, the first The LADN information may not be carried in the second message. The second message may be a registration acceptance message or a terminal configuration update command message. For example, the information of the LADN may be the available information of the LADN.

As an example, as shown in FIG. 2 , TA1-TA5 belong to the service area of LADN available to the terminal. If the current RA of the terminal is RA1, since RA1 includes TA1-TA4, the second message can carry LADN information. If the current RA of the terminal is RA3, since RA3 does not overlap with the service area of the LADN available to the terminal, the second message may not carry the information of the LADN. If the current RA of the terminal is RA2, since RA2 includes TA5, the second message may carry LADN information.

S420, the terminal determines that the second message includes the information of the LADN.

After receiving the second message, the terminal may determine that the availability state of the LADN changes according to the change in the availability state of the LADN carried in the second message. This triggers the modification of the PDU session accessing the LADN.

Specifically, when the first message received by the terminal includes the LADN information, the terminal determines that the first RA includes the LADN information. Further, before the terminal receives the second message, the first RA includes the LADN information. When the information of the LADN is not included, that is, the terminal currently does not have the information of the LADN, the terminal determines that the availability state of the LADN has changed; or

When the second information includes the information of the LADN and the second RA does not include the information of the LADN, that is, the terminal does not currently have the information of the LADN, the terminal determines that the availability state of the LADN has changed;

The first RA is the current registration area of the terminal, and the second RA is the RA before the terminal enters the first RA.

S430, the terminal sends a second session modification request message (PDU session Modificationrequest) to the SMF. The second session modification request message includes a second indication, and the second indication may be used to indicate that the current RA includes LADN information (no LADN available info indication in current RA).

The terminal also needs to send the identifier of the PDU session to the SMF. The identifier of the PDU session may be included in the second session modification request message, or may be included in the NAS message sent by the terminal to the AMF, which is sent by the AMF to the SMF. The ID identifies the PDU session in which the terminal accesses the LADN.

S440, the SMF modifies the PDU session accessing the LADN according to the second session modification request message.

The SMF modifies the PDU session accessing the LADN according to the second session modification request message, including one or more of the following:

The SMF instructs the UPF to set the gate corresponding to the PDU session accessing the LADN to on, for example, the SMF can send a gate open command (GATE ON) to the PDU;

The SMF informs the UPF to send the DDN associated with the PDU session accessing the LADN;

The SMF notifies the UPF to send the downlink data corresponding to the PDU session accessing the LADN;

The SMF marks the PDU session to the LADN as available.

In addition, after receiving the second session modification request message, the SMF may determine whether the state of the PDU session corresponding to the second session modification request message is an available state, for example, the PDU session corresponding to the second session modification request message is unavailable, It means that the PDU session is unavailable before the second session modification request message is received, and at this time, the PDU session can be marked as available. If the PDU session corresponding to the second session modification request message is available, it means that the PDU session is available before the second session modification request message is received, and at this time, no modification is required.

S450, the SMF sends a second session modification command message (PDU session modificationcommand) to the terminal. The second session modification command message includes an identifier of the PDU session and a second parameter, where the second parameter is used to indicate that the PDU session is available.

Wherein, after marking the PDU session as available, the SMF may further instruct the terminal to mark the PDU session as available.

S460, the terminal marks the PDU session as available.

The terminal marks the PDU session accessing the LADN as available.

Among them, S450 and S460 are optional steps. For example, the process of marking the PDU session as available by the terminal may also be performed locally by the terminal. In this case, before receiving the second session modification command message, it may be performed after determining that the second message includes the LADN information, or the SMF does not need to send The second session modifies the command message.

Therefore, when the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session can be managed from a finer granularity, and the network device can be used for The paging of the terminal is more reasonable, signaling is saved, and efficiency is improved.

FIG. 5 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application. As shown in FIG. 5 , for releasing the established LADN-related PDU session, it may specifically include S510-S520:

S510, the terminal sends a session release message to the SMF. The session release message may include a PDU session ID indicating a PDU session in which the terminal accesses the LADN.

S520, the SMF releases the PDU session accessing the LADN according to the session release message.

According to the embodiment of the present application, for a LADN session, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing the number of network devices searching for the LADN access PDU session due to the arrival of downlink data. Signaling waste caused by calling the terminal. The PDU session can also be managed based on the current registration area and the service area of the LADN with finer granularity.

FIG. 6 provides an example of this embodiment of the present application. The terminal has a PDU session accessing the LADN. As shown in Figure 6, the method includes:

S601, the terminal performs a registration procedure (Mobility Registration procedure), and receives a registration acceptance message sent by the AMF.

S602, when the registration acceptance message received by the terminal does not include the information of the LADN, the terminal determines that the available state of the LADN has changed, thereby triggering the modification process of the LADN PDU session. For example, the information of the LADN may be the available information of the LADN.

Specifically, determining that the available state of the LADN has changed by the terminal is the same as the method in step S320. The registration acceptance message in this process is equivalent to the first message in S320.

S603, the terminal sends a PDU session modification request message (PDU session Modification request) to the AMF. The PDU session modification request message includes no LADN available info indication (no LADN available info indication), the indication information having no LADN availability information is used to indicate that the current RA does not include the LADN service area.

S604, the AMF sends a PDU session modification request message to the SMF through a request for invoking the SMF service.

S605, the SMF determines whether the PDU session accessing the LADN is in a suspended state.

If yes, execute S612 directly to release the PDU session; if not, execute S606-S611.

S606, the SMF marks the state of the PDU session accessing the LADN as a suspended state according to the PDU session modification request message.

S607, the SMF sends a response for invoking the SMF service to the AMF, where the response for invoking the SMF service includes a PDU session modification command message. The PDU session modification command message includes a session suspension parameter, and the parameter is used to instruct the terminal to mark the PDU session as a suspended state.

S608, the AMF sends a PDU session modification command message to the terminal.

After the PDU session is modified or released on the network side, the terminal can be notified, so that the terminal can synchronously modify or release the PDU session, thereby reducing the information caused by paging the terminal when the terminal is not in the service area of the LADN due to the existence of the PDU session. to waste.

S609, the terminal marks the PDU session accessing the LADN as a suspended state.

Or, in another implementation manner, the terminal may save a record of the indication information that the information without the LADN has been sent to the SMF. After the terminal re-enters the RA including the LADN service area, it initiates the PDU session modification process again to notify the SMF that the terminal re-enters the RA including the LADN service area.

By marking the PDU session, the terminal can count the number of times that the terminal continuously enters the registration area of the service area that does not include LADN, so as to set rules. The terminal modifies the PDU session, and when the set number of times is reached or exceeded, the terminal releases the PDU session, and the management granularity of the PDU session accessing the LADN is finer.

S610, the SMF sends a session modification request message to the UPF. The session modification request message may be sent through the N4 interface.

The session modification request message carries an indication that the gate control is set to off (GATE OFF), or informs the UPF to stop sending Downlink Data Notification (DNN) related to the PDU session accessing the LADN, and discard the corresponding downlink data.

S611, the UPF sends a session modification response to the SMF. The UPF may set the gate control of the data flow (flow) corresponding to the PDU session to a closed state, or stop sending the DDN related to the PDU session accessing the LADN, and discard the corresponding data.

When the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN is re-enabled for data transmission, so that the PDU session is managed from a finer granularity and the paging of the terminal by the network device is improved. Reasonable, saving signaling and improving efficiency.

According to the embodiment of the present application, for a LADN session, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing the number of network devices searching for the LADN access PDU session due to the arrival of downlink data. Signaling waste caused by calling the terminal. The PDU session can also be managed based on the current registration area and the service area of the LADN with finer granularity.

FIG. 7 is a schematic diagram of signaling interaction of a service subscription method provided by an embodiment of the present application. Wherein, the terminal has a PDU session accessing the LADN, as shown in Figure 7, the method specifically includes:

S710, the SMF subscribes the notification service to the AMF. For example, the SMF sends a subscription notification service request to the AMF, that is, the SMF invokes the subscription notification service provided by the AMF to implement the subscription notification service from the SMF to the AMF. The notification service is used for the AMF to notify the SMF when a preset event occurs, wherein the preset event is a change in the availability state of the LADN, and the change in the availability state of the LADN may be a change in the availability state of the LADN within the registration area.

When subscribing the notification service to the AMF, the SMF may send the data network name (LADNDNN) of the LADN and a preset event to the AMF to subscribe the notification service to the AMF. Of course, the SMF can also send the filter about the preset event to the AMF, so that the AMF can determine the occurrence of the preset event through the filter. In addition, the SMF can also send other parameters that can identify the occurrence of the preset event to the AMF. The present invention No specific restrictions are imposed.

The preset event is a change in the available state of the LADN. Specifically, it may refer to the transition of the registration area between including the LADN information and excluding the LADN information, including one or more of the following situations:

The terminal enters the second RA that does not include the information of the LADN from the first RA that includes the information of the LADN;

The terminal enters the second RA that includes the information of the LADN from the first RA that does not include the information of the LADN;

The terminal does not replace the RA, but the LADN available to the terminal is changed, so that the first RA of the terminal changes from the information including the LADN to the information not including the LADN;

The terminal does not replace the RA, but the LADN available to the terminal is changed, so that the first RA of the terminal changes from information that does not include the LADN to information that includes the LADN.

The first RA is the current RA of the terminal, and the second RA is the RA before the terminal enters the first RA. The information of the LADN may be the available information of the LADN.

For example, as shown in FIG. 2, TA1-TA5 belong to the service area of the LADN available to the terminal, when the current registration area of the terminal is moved from RA1 (or RA2) to RA3, or from RA2 to RA4, that is, the terminal is moved by The RA that includes the information of the LADN moves to the RA that does not include the information of the LADN. At this time, it is considered that the registration area entered by the terminal changes between the information including and not including the LADN, and vice versa.

For another example, as shown in FIG. 2 , TA1-TA5 belong to the service area of the LADN available to the terminal. When the network side cancels the LADN service from TA1-TA5, if the current registration area of the terminal is RA1, and the RA of the terminal changes from information including LADN to information that does not include LADN, it is considered that the registration area entered by the terminal includes and does not include LADN. Changes between information including LADN. When the network side sets TA10 to support LADN, and TA10 belongs to the service area of LADN available to the terminal, if the current registration area of the terminal is RA3, the RA of the terminal changes from information that does not include LADN to information that includes LADN. The registration area entered by the terminal is considered to vary between including and excluding the information of the LADN.

S720, the AMF determines that the availability state of the LADN has changed.

The AMF determines whether the current RA of the terminal includes the LADN information according to the change of the RA of the terminal and the change of the service area of the LADN available to the terminal, and judges whether the information of the LADN has changed in the registration area entered by the terminal, or whether the information of the LADN has changed in the same registration area. In the registration area, whether there is a change between the information that includes the LADN and the information that does not include the LADN, that is, whether the availability of the LADN changes.

S730, the AMF sends notification information to the SMF, where the notification information is used to notify the occurrence of a preset event subscribed by the SMF. The notification information may include the LADN DNN and/or an indication parameter, the LADN DNN is used to identify the LADN, and the indication parameter is used to indicate the occurrence of a preset event for SMF subscription, specifically, the RA of the terminal may include or not include the information of the LADN (LADN available/unavailable indication in current RA), or used to instruct the RA of the terminal to switch between the available information including the LADN and the information not including the LADN, or other parameters used to indicate that the preset event has changed, the present invention No specific restrictions are imposed.

Specifically, the AMF sends the SMF that the registration area of the terminal includes the LAND information, which means that the registration area of the terminal is converted from the information that does not include the LADN to the available information that includes the LADN. If it is sent to the SMF, the registration area of the terminal does not include the available information of the LADN, which means that the registration area of the terminal is converted from the information including the LADN to the information not including the LADN. Of course, the AMF can also send other parameters to the SMF to indicate that the registration area of the terminal is switched between including the LADN information and not including the LADN information.

For example, when the AMF determines that the terminal enters the first registration area that does not include the LADN information from the second registration area that includes the LADN information, when the terminal registers in the first registration area, the AMF sends a notification message to the SMF, and the notification message does not Include LADN information.

Or, when the AMF determines that the terminal enters the first registration area including the LADN information from the second registration area that does not include the LADN information, when the terminal registers in the first registration area, the AMF sends a notification message to the SMF, and the notification message includes LADN information.

Or, when the AMF determines that the registration area of the terminal is the first registration area, and the first registration area is reconfigured to not include the LADN information from the information including the LADN, the AMF sends a notification message to the SMF, and the notification message does not include the LADN information. information.

Or, when the AMF determines that the registration area of the terminal is the first registration area, and the first registration area is reconfigured to include the LADN information from the information that does not include the LADN, the AMF sends a notification message to the SMF, and the notification message includes the LADN information .

For another example, as shown in FIG. 2 , when the current registration area of the terminal moves from RA1 (or RA2) to RA3, or from RA2 to RA4, that is, the terminal moves from the RA that includes the LADN information to the one that does not include the LADN. RA of the information, at this time, the AMF sends the notification information that the current RA of the terminal does not include the information of the LADN to the SMF. When the current registration area of the terminal moves from RA3 to RA1 (or RA2), or from RA4 to RA2, that is, the terminal moves from the RA that does not include the information of the LADN to the RA that includes the information of the LADN. The SMF sends notification information that the current RA of the terminal includes the information of the LADN.

S740, the SMF modifies or releases the PDU session according to the notification information.

After the SMF receives the notification information and determines that the available state of the LADN has changed, it can modify or release the PDU session accessing the LADN.

Wherein, if the PDU session accessing the LADN is unavailable, after the SMF receives the notification information that the current RA of the terminal includes the LADN information, the SMF modifies the PDU session accessing the LADN to an available state. Further, the SMF may also perform one or more of the following steps: notify the UPF to set the gate corresponding to the PDU session accessing the LADN to on; notify the UPF to send the DDN related to the PDU session accessing the LADN; notify the UPF to send Downlink data related to PDU sessions accessing the LADN.

If the PDU session accessing the LADN is in the available state, after the SMF receives the notification information that the current RA of the terminal does not include the LADN information, it modifies the PDU session accessing the LADN to be unavailable. Further, the SMF may also perform the following one Item or more steps: informing the UPF to set the gate corresponding to the PDU session accessing the LADN to OFF; informing the UPF to stop sending DDNs related to the PDU session accessing the LADN; informing the UPF to discard the DDN related to the PDU session accessing the LADN; Downlink data.

In another possible implementation, after the SMF receives the notification information that the current RA of the terminal does not include the information of the LADN, it can also release the PDU session accessing the LADN. For example, if the PDU session accessing the LADN is in the available state, after the SMF receives the notification information that the current RA of the terminal does not include the information of the LADN, the SMF releases the PDU session accessing the LADN to the available state.

In another possible implementation, when the downlink data arrives, when the SMF obtains the registration information of the terminal, after the AMF sends the notification information that the current RA of the terminal does not include the information of the LADN to the SMF, the SMF may also perform the following One or more steps: informing the UPF to discard the downlink data; informing the UPF to set the gate corresponding to the PDU session accessing the LADN to off; informing the UPF to stop sending DDNs related to the PDU session accessing the LADN; The PDU session for LADN is modified to be unavailable. When the SMF does not modify the PDU session, the downlink data can be discarded, so that the terminal does not need to be paged and signaling is saved.

The embodiment of the present application can realize that the AMF notifies the SMF that when the RA to which the terminal moves is switched between the service area including the LADN and the service area not including the LADN, the SMF initiates the release or modification of the LADN session, thereby reducing the need for When the terminal is in an RA that does not support LADN, the network equipment wastes signaling due to the arrival of downlink data in the PDU session accessing the LADN and paging the terminal.

FIG. 8 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application. Wherein, the terminal has a PDU session accessing the LADN, as shown in Figure 8, the method specifically includes:

S810, the terminal receives the first message sent by the AMF in the first RA. Wherein, the first message includes or does not include LADN information (for example, the first message shown in combination with FIG. 8 may be the first message shown in combination with FIG. 3 or the second message shown in combination with FIG. 4 ), the first message RA is the current registration area of the terminal.

The first message may be a registration acceptance message or a terminal configuration update command message.

For example, when the AMF determines that the terminal enters the first registration area from the second registration area, if the first registration area includes the LADN information, the AMF sends a registration accept message to the terminal, and the registration accept message includes the LADN information. If the area does not include the information of the LADN, the AMF sends a registration acceptance message to the terminal, and the registration acceptance message does not include the information of the LADN.

It can be understood that the registration acceptance message does not include LADN information, which may specifically be no LADN information, or the LADN information is empty, or other indication information indicates no LADN information.

Or, when the AMF determines that the terminal enters the first registration area that does not include the LADN information from the second registration area including the LADN information, when the terminal registers in the first registration area, the AMF sends a registration accept message to the terminal, and the registration accepts The message does not include LADN information.

Or, when the AMF determines that the terminal enters the first registration area including the LADN information from the second registration area that does not include the LADN information, when the terminal registers in the first registration area, the AMF sends a registration acceptance message to the terminal, and the registration accepts The message includes the information of the LADN.

Or, when the AMF determines that the registration area of the terminal is the first registration area, and the first registration area is reconfigured to not include the LADN information from the information including the LADN, the AMF sends a terminal configuration update command message to the terminal, and the terminal configuration update The command message does not include LADN information.

Or, when the AMF determines that the registration area of the terminal is the first registration area, and the first registration area is reconfigured to include the LADN information from the information that does not include the LADN, the AMF sends a terminal configuration update command message to the terminal, and the terminal configuration update The command message includes the information of the LADN.

In this embodiment of the present application, the first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the current registration area.

For the information of the LADN, reference may be made to the relevant description in S310 in the embodiment shown in FIG. 3 , and details are not repeated here.

S820, the terminal determines that the availability state of the LADN has changed according to the first message.

The change in the available state of the LADN includes: the registration area changes from information including LADN to information not including LADN, or, the registration area changes from information not including LADN to information including LADN.

For example, when the first message does not include the LADN information, indicating that the current registration area does not include the LADN information and the second registration area includes the LADN information, the terminal determines that the availability state of the LADN has changed; or, when the first message includes the LADN information information, indicating that the current registration area includes the information of the LADN, and the terminal determines that the available state of the LADN changes when the second registration area does not include the information of the LADN.

The information that the second registration area includes or does not include the LADN may be determined according to the second message received by the terminal when the terminal is in the second registration area. The second message may or may not include the information of the LADN. The second message includes the LADN information, indicating that the second registration area includes the LADN information; the second message does not include the LADN information, indicating that the second registration area does not include the LADN information. The second message may be a registration acceptance message or a terminal configuration update command message. The second message received by the terminal in the second registration area may be recorded, or the information that the second registration area includes or does not include the LADN may be recorded. When the terminal receives the first message, it may be directly determined according to the record that the second registration area includes the LADN. Or do not include LADN information.

In addition, the second registration area includes or does not include the information of the LADN, and may also be determined according to the state of the PDU session in which the terminal accesses the LADN when the first message is received. For example, when the first message is received, the status of the PDU session of the terminal accessing the LADN is unavailable, indicating that the second registration area does not include the information of the LADN; when the first message is received, the status of the PDU session of the terminal accessing the LADN is unavailable. The state is the available state, indicating that the second registration area includes the information of the LADN.

For another example, when the first message does not include the information of the LADN, and the terminal includes the information of the LADN in the first registration area before receiving the first message, the terminal determines that the availability state of the LADN has changed; or, when the first message includes the information of the LADN; When the information of the LADN is not included before the terminal receives the first message, the terminal determines that the available state of the LAND in the registration area has changed.

The first registration area includes or does not include the information of the LADN before receiving the first message, which may be determined according to the third message received in the first registration area, or determined according to the state of the PDU session accessing the LADN. The third message includes or does not include the information of the LADN. The third message includes the LADN information, indicating that the first registration area includes the LADN information, and the third message does not include the LADN information, indicating that the first registration area does not include the LADN information. The third message may be a registration acceptance message or a terminal configuration update command message. The second message received by the terminal in the second registration area can be recorded, or the information that the first registration area includes or does not include the LADN can be recorded. When the terminal receives the first message, it can be directly determined according to the record that the first registration area is in the receiving area. The information of the LADN is included or not included before the first message.

In addition, before receiving the first message, the first registration area includes or does not include the information of the LADN, and may also be determined according to the state of the PDU session in which the terminal accesses the LADN when the first message is received. For example, when receiving the first message, the state of the PDU session of the terminal accessing the LADN is unavailable, indicating that the first registration area does not include the information of the LADN before receiving the first message; when receiving the first message, the terminal The status of the PDU session accessing the LADN is available, indicating that the first registration area includes the information of the LADN before the first message is received.

The state of the PDU session in which the terminal accesses the LADN is unavailable, please refer to the relevant description in the embodiments shown in combination with FIG. 3 , FIG. 4 and FIG. 6 .

The SMF can manage the PDU session based on the current registration area and the service area of the LADN with finer granularity. It solves the problem that when the terminal is outside the service area of the LADN, the terminal initiates the release of the PDU session, thereby reducing the signaling waste caused by paging the terminal when the terminal is not in the service area of the LADN due to the existence of the PDU session.

S830, modify or release the PDU session.

When the first message does not include the information of the LADN and the second registration area includes the information of the LADN, or, when the first message does not include the information of the LADN and the first registration area includes the information of the LADN before receiving the first message , modifying or releasing a PDU session includes one or more of the following (refer to S330-S360 in the embodiment shown in FIG. 3, S510-S520 in the embodiment shown in FIG. 5, and the embodiment shown in FIG. 6 Relevant descriptions of S603-S611 in the embodiments):

The terminal notifies the SMF to modify or release the PDU session;

The terminal marks the PDU session as unavailable;

SMF marks the PDU session as unavailable;

The SMF notifies the UPF to discard the downlink data corresponding to the PDU session;

The SMF notifies the UPF to stop sending downlink data to the SMF to notify the DDN.

When the first message includes the information of the LADN, and the second registration area does not include the information of the LADN; or, when the first message includes the information of the LADN, and the first registration area does not include the information of the LADN before receiving the first message ; Modifying or releasing a PDU session includes one or more of the following (refer to the relevant descriptions of S430-S460 in the embodiment shown in FIG. 4 ):

The terminal notifies the SMF to modify the PDU session;

The terminal marks the PDU session as available;

SMF marks the PDU session as available;

The SMF notifies the UPF to send the downlink data corresponding to the PDU session;

The SMF notifies the UPF to send the downlink data corresponding to the PDU session to notify the DDN.

After the PDU session is modified or released on the network side, the terminal can be notified, so that the terminal can synchronously modify or release the PDU session, thereby reducing the information caused by paging the terminal when the terminal is not in the service area of the LADN due to the existence of the PDU session. to waste. By marking the PDU session, the terminal can count the number of times that the terminal continuously enters the registration area of the service area that does not include LADN, so as to set rules. The terminal modifies the PDU session, and when the set number of times is reached or exceeded, the terminal releases the PDU session, and the management granularity of the PDU session accessing the LADN is finer.

In addition, when the terminal re-enters the RA of the service area including the LADN, the PDU session accessing the LADN can be re-enabled for data transmission, so that the PDU session can be managed from a finer granularity, and the network device can be used for the terminal. The paging is more reasonable, signaling is saved, and efficiency is improved.

The embodiments of the present application can realize that, for a LADN session, when a terminal enters a registration area that does not support LADN, the terminal modifies or releases the PDU session, thereby reducing the need for the network device because the terminal is in an RA that does not support LADN. In the PDU session accessing the LADN, there is a waste of signaling caused by the arrival of downlink data and the paging of the terminal. return

FIG. 9 is a schematic diagram of signaling interaction of another session management method provided by an embodiment of the present application. As shown in Figure 9, the method includes:

S910, the UPF sends the DDN to the SMF. The DNN is used to indicate that the downlink data corresponding to the PDU session accessing the LADN needs to be transmitted.

S920, the SMF invokes the first service provided by the AMF, where the first service is used by the SMF to request the AMF to send a message or information, such as N2 SM information, to the access node AN. The message or information sent by the SMF to the access node AN through the AMF is used to instruct the SMF to request the AMF to send the message or information to the AN.

S930, the AMF determines that the PDU session is a session corresponding to the LADN, and there is no available LADN service area in the current registration area of the terminal.

S940, the AMF sends an indication parameter to the SMF, where the indication parameter is used to indicate that the information of the LADN is not included in the current registration area, and the indication parameter may be the confirmation of the message in S920.

If the downlink data belongs to the PDU session accessing the LADN, the AMF judges that there is no service area of the LADN in the current RA, and sends an indication that the current registration area LADN is unavailable (LADN unavailable indication incurrent TA) to the SMF. The AMF saves the indication that the LADN unavailable indication in current TA has been sent to the SMF, and notifies the SMF after the terminal re-enters the RA of the service area including the LADN.

The AMF may store information indicating parameters that have been sent to the SMF. When the terminal re-enters the RA of the service area including the LADN, the SMF can be notified to re-enable the PDU session accessing the LADN for data transmission, so that the PDU session can be managed from a finer granularity and the network device can be used for the terminal. Paging is more reasonable, signaling is saved, and efficiency is improved.

S950, the SMF modifies the PDU session according to the indicated parameter.

The SMF modifies the PDU session based on the indicated parameters, including the SMF performing one or more of the following:

Notify the UPF to discard the downlink data corresponding to the PDU session;

Notify the UPF to stop sending the downlink data corresponding to the PDU session to the SMF and notify the DDN.

FIG. 10 provides another example of this embodiment of the present application. As shown in Figure 10, the method specifically includes the following steps:

S1001, the terminal sends a registration request message to the AMF.

When the terminal moves from one RA to another RA, the AMF may change. At this time, the terminal can register with the new AMF.

S1002, the AMF determines that the available state of the LADN of the terminal changes.

If, before S1001, the SMF subscribes the notification service to the AMF. The notification service is used for the AMF to notify the SMF when a preset event occurs, wherein the preset event is whether there is a change in the LADN information. At this time, S1002 can be executed. The SMF subscribes the notification service to the AMF may refer to the description in conjunction with the embodiment shown in FIG. 7 .

S1003, the AMF sends notification information to the SMF.

If the SMF subscribes the notification service to the AMF, the AMF needs to send notification information to the SMF when the AMF determines in S1002 that the available state of the LADN of the terminal changes.

After receiving the notification information, the SMF can return a response.

After receiving the notification information, the SMF can execute S1005b, and the SMF modifies or releases the PDU session accessing the LADN. Wherein, for the SMF to modify or release the PDU session accessing the LADN, reference may be made to the description in conjunction with the embodiment shown in FIG. 7 .

S1004, the AMF sends a registration acceptance message to the terminal.

If the registration area of the terminal includes the information of the LADN, the registration reception message of the AMF to the terminal may include the information of the LADN, otherwise, it is not included. Wherein, the AMF sends a registration acceptance message to the terminal, and reference may be made to the description in the embodiments shown in FIG. 3 to FIG. 6 and FIG. 8 .

When the terminal determines, according to the registration acceptance message received in S1004, whether there is a change in the LADN information in the registration area, S1005a is executed, and the terminal modifies or releases the PDU session accessing the LADN. For the terminal to modify or release the PDU session accessing the LADN, reference may be made to the description in conjunction with the embodiments shown in FIG. 3 to FIG. 6 and FIG. 8 .

FIG. 11 is a schematic structural diagram of a terminal according to an embodiment of the present application. As shown in FIG. 11 , the terminal includes a receiving unit 1101 , a determining unit 1102 , a modifying unit 1103 , and may also include a sending unit 1104 . Wherein, the terminal has a protocol data unit PDU session accessing the local area data network LADN, specifically,

A receiving unit 1101, configured to receive, in a first registration area RA, a first message sent by an access and mobility management function entity AMF, where the first message includes or does not include the information of the LADN; wherein the first RA is the current registration area of the terminal;

a determining unit 1102, configured to determine that the availability state of the LADN has changed according to the first message;

A modification unit 1103, configured to modify the PDU session; or, a release unit, configured to release the PDU session.

Optionally, the determining unit 1102 is further configured to:

When the first message does not include the information of the LADN, and the information of the LADN is included in the first RA before the terminal receives the first message, determining that the available state of the LADN has changed; or

When the first message does not include the information of the LADN and the second RA includes the information of the LADN, determining that the availability state of the LADN has changed;

The second RA is the RA before the terminal enters the first RA.

Optionally, the sending unit 1104 is configured to send a first session modification request message to the session management function entity SMF, where the first session modification request message includes a first indication, and the first indication is used to indicate the first session modification request message. An RA does not include the information of the LADN; or, a session release request message is sent to the SMF.

Optionally, the receiving unit 1101 is further configured to receive a first session modification command message sent by the SMF, where the first session modification command message includes the identifier of the PDU session and the first parameter, the identifier of the PDU session For identifying the PDU session, the first parameter is used to indicate that the PDU session is unavailable.

Optionally, the modifying unit 1103 is further configured to: the terminal marks the PDU session as unavailable.

Optionally, the determining unit 1102 is further configured to: when the first message includes the information of the LADN, and the first RA does not include the information of the LADN before the terminal receives the first message , determining that the available state of the LADN has changed; or, when the first message includes the information of the LADN and the second RA does not include the information of the LADN, determining that the available state of the LADN has changed; The second RA is the RA before the terminal enters the first RA.

Optionally, the sending unit 1101 is further configured to send a second session modification request message to the SMF, where the second session modification request message includes a second indication, and the second indication is used to indicate that the LADN is included in the first RA Information.

Optionally, the receiving unit 1104 is further configured to:

A second session modification command message sent by the SMF is received, where the second session modification command message includes a second parameter, and the second parameter is used to indicate that a PDU session is available.

Optionally, the modifying unit 1103 is further configured to mark the PDU session as available.

The terminal can be used as the terminal of the session management method described in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 , and execute the steps performed by the terminal in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 12 is a schematic structural diagram of an SMF provided by an embodiment of the present application. As shown in FIG. 12 , the SMF includes a receiving unit 1201 , a modifying unit 1202 , and may also include a sending unit 1203 . The SMF has a protocol data unit PDU session accessing the local area data network LADN, and the SMF includes:

A receiving unit 1201, configured to receive a session modification request message sent by a terminal, where the session modification request message includes an indication, and the indication is used to indicate that the registration area includes or does not include the information of the LADN;

A modification unit 1202, configured to modify the PDU session according to the instruction.

Optionally, it further includes that the sending unit 1203 is configured to send a first session modification command message to the terminal when the indication is information indicating that the RA of the terminal does not include the LADN, the first session modification command The message includes an identification of the PDU session and a first parameter, where the first parameter is used to indicate that the PDU session is unavailable.

Optionally, the modifying unit 1202 is further configured to mark the PDU session as unavailable; notify the user plane function entity UPF to discard downlink data corresponding to the PDU session; notify the UPF to stop sending downlink data notifications to the SMF DDN.

Optionally, the sending unit 1203 is further configured to, when the indication is information indicating that the RA of the terminal does not include the LADN, send a second session modification command message to the terminal, the second session modification command message The identifier of the PDU session and a second parameter are included, and the second parameter is used to indicate that the PDU session is available.

Optionally, the modifying unit 1202 is further configured to mark the PDU session as available; notify the UPF to send downlink data corresponding to the PDU session; and notify the UPF to send the downlink data corresponding to the PDU session to notify the DDN.

The SMF can be used as the SMF of the session management method described in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 , and performs the steps performed by the SMF in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 13 is a schematic structural diagram of another SMF provided by an embodiment of the present application. As shown in FIG. 13 , the SMF includes a subscribing unit 1301 , and may further include a receiving unit 1302 and a modifying unit 1303 . The SMF has a protocol data unit PDU session in which the terminal accesses the local area data network LADN, specifically,

Subscribing unit 1301, configured to subscribe a notification service to the access and mobility management function entity AMF, where the notification service is used to notify the SMF of the AMF when a preset event occurs, wherein the preset event is an LADN Availability status changes.

Optionally, the subscription unit 1301 is further configured to:

Sending the data network name DNN of the LADN and the preset event to the AMF to subscribe the notification service to the AMF.

Optionally, the available state of the LADN changes, including at least one of the following:

The information of the LADN is not included in the first registration area, and the information of the LADN is included in the second registration area;

The first registration area is changed from information including the LADN to information not including the LADN;

The information of the LADN is included in the first registration area, and the information of the LADN is not included in the second registration area; or,

The first registration area is changed from the information not including the LADN to the information including the LADN;

The first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the first registration area.

Optionally, also include:

The receiving unit 1302 is configured to receive notification information sent by the AMF, where the notification information is used to notify that the registration area of the terminal includes or does not include the information of the LADN.

Optionally, also include:

The modifying unit 1303 is configured to modify the PDU session according to the notification information.

Optionally, the modifying unit 1303 is further configured to:

When the notification information is used to notify that the registration area of the terminal does not include the information of the LADN, notify the user plane function entity UPF to discard the downlink data corresponding to the PDU session; notify the UPF to stop sending the PDU to the SMF The downlink data corresponding to the session is notified to DDN;

or,

When the notification information is used to notify that the registration area of the terminal includes the information of the LADN, notify the UPF to send the downlink data corresponding to the PDU session; notify the UPF to send the downlink data notification corresponding to the PDU session DDN.

The SMF can be used as the SMF of the service subscription method described in FIG. 7 and FIG. 10 , and performs the steps performed by the SMF in FIG. 7 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 14 is a schematic structural diagram of an AMF provided by an embodiment of the present application. As shown in FIG. 14 , the AMF includes a subscribing unit 1401 and may also include a receiving unit 1402 . The session management function entity SMF exists in the protocol data unit PDU session of the terminal accessing the local area data network LADN, including:

The subscription unit 1401 is configured to receive the SMF subscription notification service, where the notification service is used for the AMF to notify the SMF when a preset event occurs, wherein the preset event is a change in the availability state of the LADN.

Optionally, the subscribing unit 1402 is further configured to:

The receiving SMF sends the data network name DNN of the LADN and the preset event, so as to accept the subscription of the notification service by the SMF.

Optionally, the available state of the LADN changes, including at least one of the following:

The information of the LADN is not included in the first registration area, and the information of the LADN is included in the second registration area;

The first registration area is changed from information including the LADN to information not including the LADN;

The information of the LADN is included in the first registration area, and the information of the LADN is not included in the second registration area;

The first registration area is changed from the information not including the LADN to the information including the LADN;

The first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the first registration area.

Optionally, also include:

The sending unit 1402 is configured to send notification information to the SMF, where the notification information is used to notify that the registration area of the terminal includes or does not include the information of the LADN.

The AMF can be used as the AMF of the service subscription method described in FIG. 7 and FIG. 10 , and executes the steps performed by the SMF in FIG. 7 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 15 is a schematic structural diagram of another SMF provided by an embodiment of the present application. As shown in Figure 15, the SMF has a PDU session accessing the LADN, and the SMF includes:

A receiving unit 1501, configured to receive a downlink data notification corresponding to the PDU session sent by the user plane function entity UPF;

The sending unit 1502 is configured to invoke a first service provided by an access and mobility management entity AMF, where the first service is used by the SMF to send a message to the access node AN through the AMF. ;

The receiving unit 1501 is further configured to receive an indication parameter sent by the AMF, where the indication parameter is used to indicate that the current registration area does not include the information of the LADN;

A modification unit 1503, configured to modify the PDU session according to the indication parameter.

Optionally, the modifying unit 1503 is further configured to:

Notifying the user plane function entity UPF to discard the downlink data corresponding to the PDU session;

Notify the UPF to stop sending the downlink data corresponding to the PDU session to the SMF and notify the DDN.

The SMF can be used as the SMF of the session management method described in FIG. 9 , and executes the steps performed by the SMF in FIG. 9 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 16 is a schematic structural diagram of another AMF provided by an embodiment of the present application. As shown in Figure 16, the SMF has a protocol data unit PDU session accessing the local area data network LADN, and the AMF includes:

a receiving unit 1601, configured to receive a first service invoked by the SMF, where the first service is used by the SMF to send a message to an access node AN through the AMF;

The sending unit 1602 is configured to send an indication parameter to the SMF when the registration area of the terminal does not include the service area of the LADN, where the indication parameter is used to indicate that the registration area does not include the information of the LADN.

Optionally, also include:

A saving unit, configured to save the information that the indication parameter has been sent to the SMF.

The AMF can be used as the AMF of the session management method described in FIG. 9 , and executes the steps performed by the AMF in FIG. 9 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 17 is a schematic structural diagram of another terminal provided by an embodiment of the present application. As shown in FIG. 17 , the terminal includes a transceiver 1701, a processor 1702 and a memory 1703. The transceiver 1701 is used for communicating with AMF, UPF or SMF; the memory 1703 is used for storing programs; the processor 1702 is used for The program stored in the memory is executed to execute the steps performed by the terminal in the foregoing FIG. 3 to FIG. 6 and FIG. 8 . The terminal has a PDU session accessing the LADN, specifically,

A transceiver 1701, configured to receive a first message sent by an access and mobility management function entity AMF in a first registration area RA, where the first message includes or does not include the information of the LADN; wherein the first RA is the current registration area of the terminal;

A processor 1702, configured to determine, according to the first message, that the available state of the LADN has changed;

The processor 1702 is configured to modify the PDU session; or, configured to release the PDU session.

Optionally, the processor 1702 is further configured to:

When the first message does not include the information of the LADN, and the information of the LADN is included in the first RA before the terminal receives the first message, determining that the available state of the LADN has changed; or

When the first message does not include the information of the LADN and the second RA includes the information of the LADN, determining that the availability state of the LADN has changed;

The second RA is the RA before the terminal enters the first RA.

Optionally, the transceiver 1701 is configured to send a first session modification request message to the session management function entity SMF, where the first session modification request message includes a first indication, and the first indication is used to indicate the first RA The information of the LADN is not included; or, a session release request message is sent to the SMF.

Optionally, the transceiver 1701 is further configured to receive a first session modification command message sent by the SMF, where the first session modification command message includes the identifier of the PDU session and the first parameter, the identifier of the PDU session For identifying the PDU session, the first parameter is used to indicate that the PDU session is unavailable.

Optionally, the processor 1702 is further configured for the terminal to mark the PDU session as unavailable.

Optionally, the processor 1702 is further configured to: when the first message includes the information of the LADN, and the first RA does not include the information of the LADN before the terminal receives the first message , determining that the available state of the LADN has changed; or, when the first message includes the information of the LADN and the second RA does not include the information of the LADN, determining that the available state of the LADN has changed;

The second RA is the RA before the terminal enters the first RA.

Optionally, the transceiver 1701 is further configured to send a second session modification request message to the SMF, where the second session modification request message includes a second indication, and the second indication is used to indicate that the registration area of the terminal includes the information of the LADN .

Optionally, the transceiver 1701 is also used for:

A second session modification command message sent by the SMF is received, where the second session modification command message includes a second parameter, and the second parameter is used to indicate that a PDU session is available.

Optionally, the processor 1702 is further configured to mark the PDU session as available.

The terminal can be used as the terminal of the session management method described in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 , and execute the steps performed by the terminal in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 18 is a schematic structural diagram of another SMF provided by an embodiment of the present application. As shown in FIG. 18 , the SMF includes a transceiver 1801, a processor 1802 and a memory 1803. The transceiver 1801 is used for communicating with AMF, UPF or a terminal; the memory 1803 is used for storing programs; the processor 1802 is used for The program stored in the memory is executed to perform the steps performed by the SMF in the aforementioned FIGS. 3-6 , 8 and 10 . The SMF has a PDU session accessing the LADN, specifically:

A transceiver 1801, configured to receive a session modification request message sent by a terminal, where the session modification request message includes an indication, and the indication is used to indicate that the registration area includes or does not include the information of the LADN;

The processor 1802 is configured to modify the PDU session according to the instruction.

Optionally, it further includes that the transceiver 1801 is configured to send a first session modification command message to the terminal when the indication is information indicating that the RA of the terminal does not include the LADN, the first session modification command The message includes an identification of the PDU session and a first parameter, where the first parameter is used to indicate that the PDU session is unavailable.

Optionally, the processor 1802 is further configured to mark the PDU session as unavailable; notify the user plane function entity UPF to discard downlink data corresponding to the PDU session; notify the UPF to stop sending downlink data notifications to the SMF DDN.

Optionally, the transceiver 1801 is further configured to, when the indication is information indicating that the RA of the terminal does not include the LADN, send a second session modification command message to the terminal, the second session modification command message The identifier of the PDU session and a second parameter are included, and the second parameter is used to indicate that the PDU session is available.

Optionally, the processor 1802 is further configured to mark the PDU session as available; notify the UPF to send downlink data corresponding to the PDU session; and notify the UPF to send the downlink data corresponding to the PDU session to notify the DDN.

The SMF can be used as the SMF of the session management method described in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 , and performs the steps performed by the SMF in FIG. 3 to FIG. 6 , FIG. 8 and FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 19 is a schematic structural diagram of another SMF provided by an embodiment of the present application. The SMF includes a transceiver 1901, a processor 1902 and a memory 1903. The transceiver 1901 is used to communicate with AMF, UPF or a terminal; the memory 1903 is used to store programs; the processor 1902 is used to execute the program stored in the memory. The program to perform the steps performed by the SMF in the aforementioned Figures 7 and 10. The SMF has a PDU session accessing the LADN, specifically:

The processor 1902 is configured to subscribe a notification service to the access and mobility management function entity AMF, where the notification service is used to notify the SMF of the AMF when a preset event occurs, wherein the preset event is an LADN Availability status changes.

Optionally, the processor 1902 is further configured to:

Sending the data network name DNN of the LADN and the preset event to the AMF to subscribe the notification service to the AMF.

Optionally, the available state of the LADN changes, including at least one of the following:

The information of the LADN is not included in the first registration area, and the information of the LADN is included in the second registration area;

The first registration area is changed from information including the LADN to information not including the LADN;

The information of the LADN is included in the first registration area, and the information of the LADN is not included in the second registration area; or,

The first registration area is changed from the information not including the LADN to the information including the LADN;

The first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the first registration area.

Optionally, also include:

The transceiver 1901 is configured to receive notification information sent by the AMF, where the notification information is used to notify that the registration area of the terminal includes or does not include the information of the LADN.

Optionally, also include:

The processor 1902 is configured to modify the PDU session according to the notification information.

Optionally, the processor 1902 is further configured to:

When the notification information is used to notify that the registration area of the terminal does not include the information of the LADN, notify the user plane function entity UPF to discard the downlink data corresponding to the PDU session; notify the UPF to stop sending the PDU to the SMF The downlink data corresponding to the session is notified to DDN;

or,

When the notification information is used to notify that the registration area of the terminal includes the information of the LADN, notify the UPF to send the downlink data corresponding to the PDU session; notify the UPF to send the downlink data notification corresponding to the PDU session DDN.

The SMF can be used as the SMF of the service subscription method described in FIG. 7 or FIG. 10 , and executes the steps performed by the SMF in FIG. 7 or FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 20 is a schematic structural diagram of another AMF provided by an embodiment of the present application. The AMF includes a transceiver 2001, a processor 2002 and a memory 2003. The transceiver 2001 is used to communicate with the SMF or the terminal; the memory 2003 is used to store programs; the processor 2002 is used to execute the program to perform the steps performed by the AMF in the aforementioned FIG. 7 or FIG. 10 . The SMF has a PDU session accessing the LADN, specifically:

The processor 2002 is configured to receive the SMF subscription notification service, where the notification service is configured to notify the SMF by the AMF when a preset event occurs, where the preset event is a change in the availability state of the LADN.

Optionally, the processor 2002 is further configured to:

The receiving SMF sends the data network name DNN of the LADN and the preset event, so as to accept the subscription of the notification service by the SMF.

Optionally, the available state of the LADN changes, including at least one of the following:

The information of the LADN is not included in the first registration area, and the information of the LADN is included in the second registration area;

The first registration area is changed from information including the LADN to information not including the LADN;

The information of the LADN is included in the first registration area, and the information of the LADN is not included in the second registration area;

The first registration area is changed from the information not including the LADN to the information including the LADN;

The first registration area is the current registration area of the terminal, and the second registration area is the registration area before the terminal enters the first registration area.

Optionally, also include:

The transceiver 2001 is configured to send notification information to the SMF, where the notification information is used to notify that the registration area of the terminal includes or does not include the information of the LADN.

The AMF can be used as the AMF of the service subscription method described in FIG. 7 or FIG. 10 , and executes the steps performed by the SMF in FIG. 7 or FIG. 10 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 21 is a schematic structural diagram of another SMF provided by an embodiment of the present application. As shown in FIG. 21, the SMF includes a transceiver 2101, a processor 2102 and a memory 2103. The transceiver 2101 is used to communicate with AMF, UPF or a terminal; the memory 2103 is used for storing programs; the processor 2102 is used for The program stored in the memory is executed to perform the aforementioned steps performed by the SMF in FIG. 9 . The SMF has a PDU session accessing the LADN, and the SMF includes:

A transceiver 2101, configured to receive a downlink data notification corresponding to the PDU session sent by the user plane function entity UPF;

The transceiver 2101 is configured to invoke a first service provided by an access and mobility management entity AMF, where the first service is used by the SMF to send a message to the access node AN through the AMF. ;

The transceiver 2101 receives an indication parameter sent by the AMF, where the indication parameter is used to indicate that the current registration area does not include the information of the LADN;

The processor 2102 is configured to modify the PDU session according to the indication parameter.

Optionally, the processor 2102 is further configured to notify the user plane functional entity UPF to discard the downlink data corresponding to the PDU session; and notify the UPF to stop sending the downlink data corresponding to the PDU session to the SMF to notify the DDN.

The SMF can be used as the SMF of the session management method described in FIG. 9 , and executes the steps performed by the SMF in FIG. 9 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

FIG. 22 is a schematic structural diagram of another AMF provided by an embodiment of the present application. As shown in FIG. 22, the AMF includes a transceiver 2201, a processor 2202 and a memory 2203. The transceiver 2201 is used to communicate with the SMF or the terminal; the memory 2203 is used to store programs; the processor 2202 is used to execute all The program stored in the memory is used to perform the steps performed by the SMF in the aforementioned FIG. 9 . The SMF has a PDU session accessing the LADN, and the AMF includes:

A transceiver 2201, configured to receive a first service invoked by the SMF, where the first service is used by the SMF to send a message to an access node AN through the AMF;

The transceiver 2201 is configured to send an indication parameter to the SMF when the service area of the LADN is not included in the registration area of the terminal, where the indication parameter is used to indicate that the registration area does not include the information of the LADN.

Optionally, the method further includes a processor 2202, configured to save the information that the indication parameter has been sent to the SMF.

The AMF can be used as the AMF of the session management method described in FIG. 9 , and executes the steps performed by the AMF in FIG. 9 . This reduces the data loss caused by the network modifying or releasing the PDU session when the terminal is in an idle state, and also reduces the signaling waste caused by the network device paging the terminal due to the arrival of downlink data in the PDU session accessing the LADN.

The embodiments of the present application provide a computer program product containing instructions, when the instructions are run on a computer, the methods/steps in the above-mentioned FIG. 3 to FIG. 10 are executed.

Embodiments of the present application provide a computer-readable storage medium for storing instructions, and when the instructions are executed on a computer, the methods/steps in the foregoing FIG. 3 to FIG. 10 are performed.

The embodiments of the present application provide a communication system. The system includes any one or more of the apparatuses of the embodiments described above in connection with FIGS. 3 to 10 .

The above embodiments of the present invention may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable medium to another computer-readable medium, for example, the computer instructions may be transmitted over a wire from a website site, computer, server or data center. (eg coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (eg infrared, wireless, microwave, etc.) means to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, solid state drives), and the like.

The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited to this. Substitutions should be covered within the protection scope of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (74)

1. A method for managing session, wherein a Protocol Data Unit (PDU) session accessing a Local Area Data Network (LADN) exists in a terminal, comprising:

the terminal receives a first message sent by an access and mobility management function (AMF) entity in a first Registration Area (RA), wherein the first message comprises or does not comprise the information of the LADN; wherein the first RA is a current registration area of the terminal;

the terminal determines that the available state of the LADN changes according to the first message;

and the terminal modifies or releases the PDU session.

2. The method of claim 1, wherein the terminal determines from the first message that the availability of the LADN has changed, comprising:

when the first message does not include information of the LADN and includes information of the LADN in the first RA before the terminal receives the first message, the terminal determines that an available state of the LADN changes; or,

when the first message does not comprise the information of the LADN and the second RA comprises the information of the LADN, the terminal determines that the available state of the LADN changes;

the second RA is an RA before the terminal enters the first RA.

3. The method of claim 2, wherein the terminal modifies the PDU session, comprising:

the terminal sends a first session modification request message to a Session Management Function (SMF), wherein the first session modification request message comprises a first indication, and the first indication is used for indicating that information of a LADN is not included in the first RA; or,

the terminal releases the PDU session, including: and the terminal sends a session release request message to the SMF.

4. The method of claim 3, further comprising:

and the terminal receives a first session modification command message sent by the SMF, wherein the first session modification command message comprises an identifier of the PDU session and a first parameter, the identifier of the PDU session is used for identifying the PDU session, and the first parameter is used for indicating that the PDU session is unavailable.

5. The method according to any of claims 2-4, wherein the terminal modifying the PDU session comprises:

the terminal marks the PDU session as unavailable.

6. The method of claim 1,

the terminal determines that the available state of the LADN changes according to the first message, and the method comprises the following steps:

when the first message includes information of the LADN and the information of the LADN is not included in the first RA before the terminal receives the first message, the terminal determines that the availability status of the LADN changes; or,

when the first message comprises the information of the LADN and the information of the LADN is not included in the second RA, the terminal determines that the available state of the LADN changes;

the second RA is an RA before the terminal enters the first RA.

7. The method of claim 6, wherein the terminal modifies the PDU session, comprising:

and the terminal sends a second session modification request message to the SMF, wherein the second session modification request message comprises a second indication, and the second indication is used for indicating that the information of the LADN is not included in the first RA.

8. The method of claim 7, further comprising:

and the terminal receives a second session modification command message sent by the SMF, wherein the second session modification command message comprises a second parameter, and the second parameter is used for indicating that the PDU session is available.

9. The method according to any of claims 6-8, wherein the terminal modifying the PDU session comprises:

the terminal marks the PDU session as available.

10. A method for managing session, wherein a Protocol Data Unit (PDU) session accessing a Local Area Data Network (LADN) exists in a terminal, comprising:

the terminal receives a first session modification command message sent by the SMF, wherein the first session modification command message comprises an identifier of the PDU session and a first parameter, the identifier of the PDU session is used for identifying the PDU session, and the first parameter is used for indicating that the PDU session is unavailable;

and the terminal modifies the PDU session according to the first session modification command message.

11. The method of claim 10, wherein the terminal modifying the PDU session according to the first session modification command message comprises:

the terminal marks the PDU session as unavailable.

12. The method of claim 10, further comprising:

the terminal receives a second session modification command message sent by the SMF, wherein the second session modification command message comprises a second parameter, and the second parameter is used for indicating that the PDU session is available;

and the terminal modifies the PDU session according to the second session modification command message.

13. The method of claim 12, wherein the terminal modifying the PDU session according to the second session modification command message comprises:

the terminal marks the PDU session as available.

14. A session management method is characterized in that a Session Management Function (SMF) has a Protocol Data Unit (PDU) session accessing a Local Area Data Network (LADN), and the method comprises the following steps:

a session management function entity (SMF) receives a session modification request message sent by a terminal, wherein the session modification request message comprises an indication, and the indication is used for indicating that a Registration Area (RA) comprises or does not comprise information of a Location Area (LADN);

when the indication is used for indicating that the RA comprises LADN information, the SMF sends a first session modification command message to the terminal, wherein the first session modification command message comprises an identification of the PDU session and a first parameter, the identification of the PDU session is used for identifying the PDU session, and the first parameter is used for indicating that the PDU session is unavailable.

15. The method of claim 14, wherein the SMF modifies the PDU session based on the indication, including one or more of:

the SMF marks the PDU session as unavailable;

the SMF informs a user plane functional entity UPF to discard the downlink data corresponding to the PDU session; or,

and the SMF informs the UPF to stop sending the downlink data notification DDN to the SMF.

16. The method of claim 14, wherein before the SMF sends the first session modification command message to the terminal, the method further comprises:

the SMF receives a session modification request message sent by the terminal, wherein the session modification request message comprises an indication, and the indication is used for indicating that a registration area RA does not comprise LADN information.

17. The method of claim 16, wherein when the indication indicates that the RA does not include a LADN, the method further comprises:

and the SMF sends a second session modification command message to the terminal, wherein the second session modification command message comprises an identifier of the PDU session and a second parameter, the identifier of the PDU session is used for identifying the PDU session, and the second parameter is used for indicating that the PDU session is available.

18. The method of claim 17, wherein the SMF modifies the PDU session based on the indication, including one or more of:

the SMF marks the PDU session as available;

the SMF informs a UPF to send downlink data corresponding to the PDU session; or,

and the SMF informs the UPF to send a downlink data notification DDN corresponding to the PDU session.

19. The method of claim 18, wherein before the SMF sends the first session modification command message to the terminal, the method comprises:

the SMF subscribes a notification service to an access and mobile management function (AMF), wherein the notification service is used for notifying the SMF by the AMF when a preset event occurs, and the preset event is that the available state of the LADN changes.

20. The method of claim 19, the SMF subscribing to the notification service from the AMF, comprising:

and the SMF sends the data network name DNN of the LADN and the preset event to the AMF.

21. The method of claim 19 or 20, wherein the availability of the LADN changes, including at least one of:

the first registration area does not comprise the information of the LADN, and the second registration area comprises the information of the LADN;

changing from information including the LADN to information not including the LADN within a first registration area;

the first registration area comprises the information of the LADN, and the second registration area does not comprise the information of the LADN; or,

changing from not including the LADN to including the LADN information within a first registration area;

wherein the first registration area is a current registration area of the terminal, and the second registration area is a registration area before the terminal enters the first registration area.

22. The method of claim 19 or 20, after the SMF subscribes to the notification service from the AMF, further comprising:

and the SMF receives notification information sent by the AMF, wherein the notification information is used for notifying that the information of the LADN is included or not included in the current registration area of the terminal.

23. The method of claim 22, wherein after the SMF receives the notification message, further comprising:

and the SMF modifies the PDU session according to the notification information.

24. The method of claim 23, wherein the SMF modifies the PDU session based on the notification information, comprising:

when the notification information is used for notifying that the current registration area of the terminal does not include the information of the LADN, the SMF performs one or more of the following:

informing a user plane functional entity UPF to discard downlink data corresponding to the PDU session;

and informing the UPF to stop sending the downlink data notification DDN corresponding to the PDU session to the SMF.

25. The method of claim 23, wherein the SMF modifies the PDU session based on the notification information, comprising:

when the notification information is used for notifying that the current registration area of the terminal includes the information of the LADN, the SMF performs one or more of the following:

informing the UPF to send downlink data corresponding to the PDU session;

and informing the UPF to send a downlink data notification DDN corresponding to the PDU session.

26. The method of claim 14, further comprising:

the SMF receives a downlink data notification corresponding to the PDU session sent by a user plane functional entity UPF;

the SMF calls a first service provided by AN access and mobile management entity (AMF), wherein the first service is used for the SMF to send a message to AN Access Node (AN) through the AMF;

the SMF receives an indication parameter sent by the AMF, wherein the indication parameter is used for indicating that the information of the LADN is not included in the current registration area;

and the SMF modifies the PDU session according to the indication parameter.

27. The method of claim 26, wherein the SMF modifying the PDU session based on the indication parameter comprises the SMF performing one or more of:

informing a user plane functional entity UPF to discard downlink data corresponding to the PDU session;

and informing the UPF to stop sending the downlink data notification DDN corresponding to the PDU session to the SMF.

28. A session management method is characterized in that a Protocol Data Unit (PDU) session of an access and mobile management function (AMF) presence terminal accessing a Local Area Data Network (LADN) comprises the following steps:

and the AMF sends a first message to a terminal, wherein the first message comprises or does not comprise the information of the LADN, so that the terminal determines that the available state of the LADN changes according to the first message and modifies or releases the PDU session, the terminal is located in a first registration area RA, and the first RA is the current registration area of the terminal.

29. The method of claim 28, further comprising:

the method comprises the steps that an AMF receives a subscription notification service request sent by an SMF, wherein the notification service request is used for notifying the SMF when a preset event occurs, and the preset event is that the available state of a LADN changes.

30. The method of claim 29, wherein the AMF receiving the subscription notification service request sent by the SMF comprises:

and the AMF receives the data network name DNN of the LADN and the preset event sent by the SMF.

31. The method of claim 29 or 30, wherein the availability of the LADN changes, including at least one of:

the first registration area does not comprise the information of the LADN, and the second registration area comprises the information of the LADN;

changing from information including the LADN to information not including the LADN within a first registration area;

the first registration area comprises the information of the LADN, and the second registration area does not comprise the information of the LADN;

changing from not including the LADN to including the LADN information within a first registration area;

wherein the first registration area is a current registration area of the terminal, and the second registration area is a registration area before the terminal enters the first registration area.

32. The method according to claim 29 or 30, wherein after the AMF receives the subscription notification service request sent by the SMF, the method further comprises:

and the AMF sends notification information to the SMF, wherein the notification information is used for notifying that the current registration area of the terminal comprises or does not comprise the information of the LADN.

33. The method of claim 29, wherein the method comprises:

the AMF receives a first service request called by a Session Management Function (SMF), wherein the first service request is used for the SMF to request the AMF to send a message to AN Access Node (AN); wherein, the first service request includes an identifier of the PDU session;

and when the registration area of the terminal does not comprise the service area of the LADN, the AMF sends an indication parameter to the SMF, wherein the indication parameter is used for indicating that the registration area of the terminal does not comprise the information of the LADN.

34. The method of claim 33, wherein after sending the indication parameter to the SMF, the AMF further comprises:

the AMF stores the information that the indication parameter has been sent to the SMF.

35. A terminal, wherein the terminal has a protocol data unit, PDU, session to access a local area data network, LADN, the terminal comprising:

a receiving unit, configured to receive, in a first registration area RA, a first message sent by an access and mobility management function entity AMF, where the first message may or may not include the information of the LADN; wherein the first RA is a current registration area of the terminal;

a determining unit, configured to determine that an available state of the LADN changes according to a first message;

a modification unit for modifying the PDU session; or, a release unit, configured to release the PDU session.

36. The terminal according to claim 35, wherein the determining unit is further configured to,

determining that an available state of the LADN changes when the first message does not include information of the LADN and the information of the LADN is included in the first RA before the terminal receives the first message; or,

determining that an available state of the LADN changes when the first message does not include information of the LADN and information of the LADN is included in a second RA; the second RA is an RA before the terminal enters the first RA.

37. The terminal of claim 36, further comprising: a sending unit, configured to send a first session modification request message to a session management function entity, SMF, where the first session modification request message includes a first indication, and the first indication is used to indicate that the information of the LADN is not included in the first RA; alternatively, a session release request message is sent to the SMF.

38. The terminal of claim 37, wherein the receiving unit is further configured to receive a first session modification command message sent by the SMF, and wherein the first session modification command message comprises an identifier of the PDU session and a first parameter, and wherein the identifier of the PDU session is used for identifying the PDU session, and wherein the first parameter is used for indicating that the PDU session is unavailable.

39. The terminal according to any of claims 36-38, wherein said modifying unit is further configured to mark said PDU session as unavailable by said terminal.

40. The terminal of claim 35, wherein the determining unit is further configured to determine that the availability of the LADN changes when the first message includes information of the LADN and the information of the LADN is not included in the first RA before the terminal receives the first message; or,

determining that an available state of the LADN changes when the first message includes information of the LADN and information of the LADN is not included in a second RA; the second RA is an RA before the terminal enters the first RA.

41. The terminal of claim 40, further comprising: a sending unit, configured to send a second session modification request message to the SMF, where the second session modification request message includes a second indication, and the second indication is used to indicate that the first RA includes the information of the LADN.

42. The terminal of claim 41, wherein the receiving unit is further configured to,

and receiving a second session modification command message sent by the SMF, wherein the second session modification command message comprises a second parameter, and the second parameter is used for indicating that the PDU session is available.

43. The terminal according to any of claims 40-42, wherein said modifying unit is further adapted to mark said PDU session as available.

44. A terminal, wherein the terminal has a protocol data unit, PDU, session to access a local area data network, LADN, the terminal comprising:

a receiving unit, configured to receive a first session modification command message sent by an SMF, where the first session modification command message includes an identifier of the PDU session and a first parameter, the identifier of the PDU session is used to identify the PDU session, and the first parameter is used to indicate that the PDU session is unavailable;

and the modifying unit is used for modifying the PDU conversation according to the first conversation modifying command message.

45. The terminal of claim 44, wherein the modifying unit is further configured to mark the PDU session as unavailable.

46. The terminal of claim 44, wherein the receiving unit is further configured to receive a second session modification command message sent by the SMF, and wherein the second session modification command message includes a second parameter, and wherein the second parameter is used to indicate that a PDU session is available;

the modifying unit is further configured to modify the PDU session according to the second session modification command message.

47. The terminal of claim 46, wherein the modifying unit is further configured to mark the PDU session as available.

48. A session management function, SMF, wherein the SMF has a PDU session for accessing a local area data network, LADN, the SMF comprising:

a receiving unit, configured to receive a session modification request message sent by a terminal, where the session modification request message includes an indication that indicates that a registration area RA includes or does not include the information of the LADN;

and a sending unit, configured to send a first session modification command message to the terminal when the indication is used to indicate that the RA includes the information of the LADN, where the first session modification command message includes an identifier of the PDU session and a first parameter, the identifier of the PDU session is used to identify the PDU session, and the first parameter is used to indicate that the PDU session is unavailable.

49. The SMF of claim 48, further comprising:

a modification unit for marking the PDU session as unavailable;

informing a user plane functional entity UPF to discard downlink data corresponding to the PDU session; or,

and informing the UPF to stop sending downlink data notification DDN to the SMF.

50. The SMF of claim 48, further comprising:

a receiving unit, configured to receive a session modification request message sent by the terminal, where the session modification request message includes an indication, and the indication is used to indicate that a registration area RA does not include the information of the LADN.

51. The SMF of claim 50, wherein the sending unit is further configured to, when the indication is information indicating that the RA of the terminal does not include a LADN,

and sending a second session modification command message to the terminal, wherein the second session modification command message comprises the identification of the PDU session and a second parameter, and the second parameter is used for indicating that the PDU session is available.

52. The SMF of claim 51, further comprising:

a modification unit for marking the PDU session as available;

informing the UPF to send downlink data corresponding to the PDU session; or,

and informing the UPF to send a downlink data notification DDN corresponding to the PDU session.

53. The SMF of claim 48, further comprising:

the system comprises a subscription unit and a mobile management function (AMF) unit, wherein the subscription unit is used for subscribing a notification service to an AMF (access and mobile management function) entity, and the notification service is used for notifying the SMF when a preset event occurs, wherein the preset event is that the available state of the LADN changes.

54. The SMF of claim 53, the subscription unit further to,

and sending the data network name DNN of the LADN and the preset event to the AMF.

55. The SMF of claim 53 or 54, wherein the availability of the LADN changes, including at least one of:

the first registration area does not comprise the information of the LADN, and the second registration area comprises the information of the LADN;

changing from information including the LADN to information not including the LADN within a first registration area;

the first registration area comprises the information of the LADN, and the second registration area does not comprise the information of the LADN; or,

changing from not including the LADN to including the LADN information within a first registration area;

wherein the first registration area is a current registration area of the terminal, and the second registration area is a registration area before the terminal enters the first registration area.

56. The SMF according to claim 53 or 54, wherein the receiving unit is further configured to receive notification information sent by the AMF, and the notification information is used to notify that the information of the LADN is included or excluded in the current registration area of the terminal.

57. The SMF of claim 56, further comprising: and the modifying unit is used for modifying the PDU session according to the notification information.

58. The SMF according to claim 57, wherein the modifying unit is further configured to perform one or more of the following when the notification information is used to notify that the current registration area of the terminal does not include the information of the LADN: informing a user plane functional entity UPF to discard downlink data corresponding to the PDU session; and informing the UPF to stop sending the downlink data notification DDN corresponding to the PDU session to the SMF.

59. The SMF according to claim 57, wherein the modifying unit is further configured to perform, when the notification information is used to notify that the current registration area of the terminal includes the information of the LADN, one or more of: informing the UPF to send downlink data corresponding to the PDU session; and informing the UPF to send a downlink data notification DDN corresponding to the PDU session.

60. The SMF according to claim 48, wherein the receiving unit is further configured to receive a downlink data notification corresponding to the PDU session sent by a user plane function entity (UPF);

the sending unit is further configured to invoke a first service provided by AN access and mobility management entity (AMF), where the first service is used for the SMF to send a message to AN Access Node (AN) through the AMF;

the receiving unit is further configured to receive an indication parameter sent by the AMF, where the indication parameter is used to indicate that the information of the LADN is not included in the current registration area;

and the modifying unit is used for modifying the PDU session according to the indication parameter.

61. The SMF of claim 60, wherein the modification unit is further configured to,

informing a user plane functional entity UPF to discard downlink data corresponding to the PDU session;

and informing the UPF to stop sending the downlink data notification DDN corresponding to the PDU session to the SMF.

62. An access and mobility management function (AMF), wherein a Session Management Function (SMF) exists a Protocol Data Unit (PDU) session of a terminal accessing a Local Area Data Network (LADN), and the AMF comprises:

a sending unit, configured to send a first message to a terminal, where the first message includes or does not include information of the LADN, so that the terminal determines, according to the first message, that an available state of the LADN changes, and modifies or releases the PDU session, where the terminal is located in a first registration area RA, and the first RA is a current registration area of the terminal.

63. The AMF of claim 62, further comprising:

and the subscription unit is used for receiving a subscription notification service request message sent by the SMF, and the notification service is used for notifying the SMF by the AMF when a preset event occurs, wherein the preset event is that the available state of the LADN changes.

64. The AMF of claim 63, wherein the subscription unit is further configured to receive a Data Network Name (DNN) of the LADN and the predetermined event sent by the SMF.

65. The AMF of claim 63 or 64, wherein the availability of the LADN changes, including at least one of:

the first registration area does not comprise the information of the LADN, and the second registration area comprises the information of the LADN;

changing from information including the LADN to information not including the LADN within a first registration area;

the first registration area comprises the information of the LADN, and the second registration area does not comprise the information of the LADN;

changing from not including the LADN to including the LADN information within a first registration area;

wherein the first registration area is a current registration area of the terminal, and the second registration area is a registration area before the terminal enters the first registration area.

66. The AMF of claim 63 or 64, wherein the sending unit is further configured to send notification information to the SMF, the notification information being used for notifying that the registration area of the terminal includes or does not include the LADN.

67. The AMF of claim 62, further comprising:

a receiving unit, configured to receive a first service invoked by a session management function entity, SMF, where the first service is used for the SMF to send a message to AN access node, AN, through the AMF;

the sending unit is further configured to send an indication parameter to the SMF when the registration area of the terminal does not include a service area of the LADN, where the indication parameter is used to indicate that the registration area does not include the information of the LADN.

68. The AMF of claim 67, further comprising:

and the storage unit is used for storing the information of the indication parameters sent to the SMF.

69. A Session Management Function (SMF) is characterized by comprising a transceiver, a processor and a memory, wherein the transceiver is used for communicating with an access and mobile management function (AMF), a User Plane Function (UPF) or a terminal; the memory is used for storing programs; the processor is configured to execute the program stored in the memory to perform the method of any of claims 14-27.

70. An access and mobility management function (AMF), comprising a transceiver, a processor and a memory, wherein the transceiver is configured to communicate with a Session Management Function (SMF) or a terminal; the memory is used for storing programs; the processor is configured to execute the program stored in the memory to perform the method of any of claims 28-34.

71. A terminal, comprising a transceiver, a processor and a memory, the transceiver being configured to communicate with an access and mobility management function, AMF, or a session management function, SMF; the memory is used for storing programs; the processor is configured to execute the program stored in the memory to perform the method of any of claims 1-9 or 10-13.

72. A computer readable storage medium comprising computer readable instructions which, when read and executed by a computer, cause the computer to perform the method of any of claims 1-34.

73. A communication system, comprising: a terminal according to any of claims 35-43 and a session management function, SMF, according to any of claims 48-61; or a terminal according to any of claims 44-47 and a session management function, SMF, according to any of claims 48-61.

74. A communication system, comprising: a session management function entity, SMF, according to any of claims 48-61 and an access and mobility management function entity, AMF, according to any of claims 62-68.

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