Patent Publication Number: US-2021168902-A1

Title: User Group Session Management Method and Apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/CN2019/100497 filed on Aug. 14, 2019, which claims priority to Chinese Patent Application No. 201810924641.4, filed on Aug. 14, 2018. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     Embodiments of this application relate to the field of mobile communications technologies, and in particular, to a user group establishment method and an apparatus. 
     BACKGROUND 
     At present, an IP service provided by a traditional 3rd generation partnership project (3GPP) uses a server-client mode, and implements mutual communication between clients by using agent forwarding of a server. For example, for a WeChat application, a user A sends a WeChat message to a user B by using a 3rd generation partnership project (3GPP) network; the 3GPP network first sends an IP data packet (including the WeChat message) of the user A to a WeChat application server outside the 3GPP network; and the WeChat application server determines that the WeChat message is sent to the user B, and then sends the IP data packet to the user B by using the 3GPP network again, to implement mutual communication between the user A and the user B. 
     With development of communications technologies, a virtual local area network service (virtual LAN service) needs to be supported in a 5th generation (5G) network. That is, the 3GPP network needs to provide a plurality of types of transmission services for terminals in a set. For example, the services include an internet protocol (IP) service, an Ethernet-based service, or a service based on another non-IP technology, to ensure mutual communication between the terminals in the set. That is, by using the virtual LAN service, the 3GPP network implements mutual communication between the user A and the user B, for example, functions such as file sharing between PCs and online neighbor discovery, without needing deployment and participation of an external application server. A current problem is: how to establish and manage a virtual LAN service session for UE, and implement routing of mutual communication between UEs within a 3GPP network, without depending on deployment and participation of an external application server. 
     SUMMARY 
     Embodiments of this application provide a user group session management method and an apparatus, to manage a user group session. 
     According to a first aspect, an embodiment of this application provides a user group establishment method. The method includes: receiving, by a session management network element, a first message sent by a mobility management network element, where the first message carries an identifier of a first terminal and an identifier of a user group, and the first message is used to request to establish, for the first terminal, a user group session corresponding to the identifier of the user group; generating, by the session management network element based on the identifier of the user group, a routing forwarding policy for the first terminal; and sending, by the session management network element, a second message to a user plane network element, where the second message is used to instruct the user plane network element to establish a first session for the first terminal, and the second message carries the routing forwarding policy. 
     In the foregoing technical solution, the session management network element instructs the user plane network element to establish the first session for the first terminal and generate the routing forwarding policy for the first terminal. This can implement routing of communication between terminals of the user group within a 3GPP network, without depending on deployment and participation of an external application server. 
     With reference to the first aspect, in some implementations of the first aspect, the first message is a PDU session establishment request message. 
     With reference to the first aspect, in some implementations of the first aspect, the generating, by the session management network element based on the identifier of the user group, a routing forwarding policy for the first terminal includes: obtaining, by the session management network element based on the identifier of the user group, a second terminal list of the user group from local information, where the second terminal list includes one or more second terminals, and the second terminal is a group member of the user group; and generating, by the session management network element based on the second terminal list, the routing forwarding policy for the first terminal. 
     With reference to the first aspect, in some implementations of the first aspect, the generating, by the session management network element based on the identifier of the user group, a routing forwarding policy for the first terminal includes: sending, by the session management network element, a third message to a user group management network element, where the third message carries the identifier of the user group, used to request group member information of the user group; receiving, by the session management network element, the second terminal list returned by the user group management network element, where the second terminal list includes one or more second terminals, and the second terminal is a group member of the user group; and generating, by the session management network element based on the second terminal list, the routing forwarding policy for the first terminal. 
     With reference to the first aspect, in some implementations of the first aspect, the generating, by the session management network element based on the second terminal list, the routing forwarding policy for the first terminal includes: obtaining, by the session management network element based on the second terminal list, a second session corresponding to the second terminal, and generating the routing forwarding policy, where the routing forwarding policy is used to instruct the user plane network element to send, to the second terminal by using the second session, data that is from the first terminal and that is received from the first session, and/or send, to the first terminal by using the first session, data that is from the second terminal and that is received from the second session. 
     With reference to the first aspect, in some implementations of the first aspect, the first message further carries user group verification information of the first terminal, used to verify the first terminal, so that the third message sent by the session management network element to the user group management network element further carries the user group verification information of the first terminal; and the method further includes: receiving, by the session management network element, indication information from the user group management network element, where the indication information is used to indicate that the first terminal is an authorized user of the user group. 
     According to a second aspect, a user group session management method is provided. The method includes: receiving, by a user group management network element, a third message from a session management network element, where the third message carries an identifier of a user group, used to request group member information of the user group; obtaining, by the user group management network element, the second terminal list based on the identifier of the user group, where the second terminal list includes one or more second terminals, and the second terminal is a group member of the user group; and sending the second terminal list to the session management network element for managing a user group session. 
     With reference to the second aspect, in some implementations of the second aspect, the third message further carries user group verification information of a first terminal; and the method further includes: determining, by the user group management network element based on the user group verification information of the first terminal, that the first terminal is an authorized user of the user group; and sending indication information to the session management network element, where the indication information is used to indicate that the first terminal is the authorized user of the user group. 
     According to a third aspect, a communications device is provided. The communications device is configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect. Specifically, the device includes the units configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect. 
     According to a fourth aspect, another communications device is provided. The communications device is configured to perform the method according to any one of the second aspect or the possible implementations of the second aspect. Specifically, the device includes the units configured to perform the method according to any one of the second aspect or the possible implementations of the second aspect. 
     According to a fifth aspect, a communications device is provided. The device includes a transceiver and a processor. The transceiver communicates with the processor by using an internal connection path. The processor is configured to control a receiver to receive a signal and control a transmitter to send a signal. Optionally, the communications device further includes a memory. The transceiver, the memory, and the processor communicate with each other by using an internal connection path, the memory is configured to store an instruction, and the processor is configured to execute the instruction stored in the memory, to control the receiver to receive a signal and control the transmitter to send a signal, so that the device performs the method according to any one of the first aspect or the possible implementations of the first aspect. 
     According to a sixth aspect, a communications device is provided. The device includes a transceiver and a processor. The transceiver communicates with the processor by using an internal connection path. The processor is configured to control a receiver to receive a signal and control a transmitter to send a signal. Optionally, the communications device further includes a memory. The transceiver, the memory, and the processor communicate with each other by using an internal connection path, the memory is configured to store an instruction, and the processor is configured to execute the instruction stored in the memory, to control the receiver to receive a signal and control the transmitter to send a signal, so that the device performs the method according to any one of the first aspect or the possible implementations of the first aspect. 
     According to a seventh aspect, an embodiment of this application provides a communications system. The communications system includes one or more of a session management network element and a user group management network element. 
     The session management network element is configured to perform the method according to any one of the first aspect or the possible designs of the first aspect, or the method performed by a transmission agent in the solutions provided in the embodiments of this application. The user group management network element is configured to perform the method according to any one of the second aspect, a service instance that can be used to perform the second aspect, or the possible implementations of the second aspect; the method according to any one of the third aspect or the possible implementations of the third aspect; or the method performed by the service instance in the solutions provided in the embodiments of this application. 
     In a possible implementation, the system further includes another device that interacts with any device in the session management network element and the user group management network element in the solution provided in this embodiment of this application, for example, a mobility management network element and/or a user plane network element. 
     According to an eighth aspect, a computer program product is provided. The computer program product includes computer program code, where when the computer program code is run by a computer, the computer is enabled to perform the method according to any possible implementation of any one of the foregoing aspects. 
     According to a ninth aspect, a computer-readable medium is provided and is used to store a computer program. The computer program includes an instruction used to perform the method according to any possible implementation of any one of the foregoing aspects. 
     According to a tenth aspect, a communications chip is provided. The communications chip stores an instruction, and when the instruction is run on a computer device, the communications chip is enabled to perform the method according to any possible implementation of any one of the foregoing aspects. 
     In addition, for technical effects brought by any implementation according to the second aspect to the tenth aspect, refer to technical effects brought by different implementations according to the first aspect. Details are not described herein again. 
     These aspects or other aspects in the embodiments of this application are clearer and more comprehensible in descriptions of the following embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of a possible network architecture according to an embodiment of this application; 
         FIG. 2  is a schematic diagram of another possible network architecture according to an embodiment of this application; 
         FIG. 3  is a flowchart of a user group establishment method according to an embodiment of this application; 
         FIG. 4  is a flowchart of another user group establishment method according to an embodiment of this application; 
         FIG. 5  is a schematic diagram of an apparatus according to an embodiment of this application; 
         FIG. 6  is a schematic diagram of another apparatus according to an embodiment of this application; 
         FIG. 7  is a schematic diagram of another apparatus according to an embodiment of this application; and 
         FIG. 8  is a schematic diagram of another apparatus according to an embodiment of this application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following further describes in detail the embodiments of this application with reference to accompanying drawings. 
     A specific operation method in method embodiments may also be applied to an apparatus embodiment or a system embodiment. In the descriptions of the embodiments of this application, “at least one” means one or more, and “a plurality of” means two or more. The term “and/or” is used to describe an association relationship between associated objects, and indicates that three relationships may exist. For example, “A and/or B” may indicate the following three cases: Only A exists, only B exists, and both A and B exist, where A and B may be singular or plural. The character “/” generally indicates an “or” relationship between the associated objects. “At least one of the following” or a similar expression thereof indicates any combination of the following, including any combination of one or more of the following. For example, at least one of a, b, or c may indicate a, b, c, “a and b”, “a and c”, “b and c”, or “a, b, and c”, where a, b, and c may be singular or plural. 
     A communication method provided in the embodiments of this application may be applied to a plurality of system architectures. A network architecture and a service scenario described in the embodiments of this application are intended to describe the technical solutions in the embodiments of this application more clearly, and do not constitute a limitation to the technical solutions provided in the embodiments of this application. A person of ordinary skill in the art may know that: With evolution of the network architecture and emergence of new service scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems. 
       FIG. 1  is a schematic diagram of a possible network architecture to which an embodiment of this application is applicable. The network architecture may include devices such as a terminal device, an access network device, a mobility management network element, a session management network element, a network storage network element, a data management network element, a policy control network element, a user group management network element, and a user plane network element. 
     The terminal device is a device having a wireless transmission/reception function, and may be deployed on the land, such as an indoor device, an outdoor device, a handheld device, or a vehicle-mounted device; may be deployed on the water (for example, in a steamship); or may be deployed in the air (for example, on an airplane, on a balloon, or on a satellite). The terminal device may be a mobile phone, a tablet computer, a computer having wireless transmission and reception functions, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, or the like. 
     The access network (RAN) device is a device that provides a wireless communication function for a terminal. For example, the access network device includes but is not limited to: a next generation NodeB (gNB), an evolved NodeB (eNB), a radio network controller (RNC), a NodeB (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved nodeB, or a home node B, HNB), a baseband unit (BBU), a transmission reception point (TRP), a transmission point (TP), a mobile switching center, and the like in 5G. 
     The mobility management network element is mainly used for mobility management, for example, user location update, a user registration network, and user handover, in a mobile network. In a 5G communications system, the mobility management network element may be an access and mobility management function (AMF) network element, Namf is a service-based interface provided by an AMF, and the AMF may communicate with another network function by using the Namf. In future communication such as 6G communication, the mobility management network element may still be an AMF network element. Alternatively, the mobility management network element may have another name. This is not limited in this embodiment of this application. 
     The session management network element is mainly used for session management, for example, session establishment, modification, or release, in a mobile network. A specific function is, for example, allocating an internet protocol (IP) address to a user, or selecting a user plane network element that provides a packet forwarding function. In a 5G system, the session management network element may be a session management function (SMF) network element, Nsmf is a service-based interface provided by an SMF, and the SMF may communicate with another network function by using the Nsmf. In the future communication such as 6G communication, the session management network element may still be an SMF network element. Alternatively, the session management network element may have another name. This is not limited in this embodiment of this application. 
     The network storage network element is configured to store a network function entity and description information of a service provided by the network function entity, support service discovery, network element entity discovery, and the like. In 5G communication, the network storage network element may be a network repository function (NRF) network element, Nnrf is a service-based interface provided by an NRF, and the NRF may communicate with another network function by using the Nnrf. In the future communication such as the 6G communication, the network repository network element may still be an NRF network element. Alternatively, the network repository network element may have another name. This is not limited in this embodiment of this application. 
     The data management network element is configured to process a user identifier, access authentication, registration, mobility management, or the like. In the 5G communication, the data management network element may be a unified data management (UDM) network element. Nudm is a service-based interface provided by a UDM, and the UDM may communicate with another network function by using Nudm. In the future communication such as the 6G communication, the data management network element may still be a UDM network element. Alternatively, the data management network element may have another name. This is not limited in this embodiment of this application. 
     The policy control network element is configured to guide a unified policy framework of network behavior, and provide policy rule information, and the like for a control plane function network element (such as an AMF or an SMF). In the 5G communication, the policy control network element may be a policy control function (PCF) network element. Npcf is a service-based interface provided by a PCF, and the PCF may communicate with another network function by using Npcf. In the future communication such as the 6G communication, the policy control network element may still be an PCF network element. Alternatively, the policy control network element may have another name. This is not limited in this embodiment of this application. 
     The user group management network element may be configured to establish and manage a user group including a plurality of terminals, for example, allocate an identifier of the user group, establish an association between the identifier of the user group and an identifier of the terminal, and obtain user group authentication information. For example, the user group management network element may be a LAN service management function (LSMF), a group management function (GMF), or a unified data management function. This is not limited in the present invention. It should be noted that the user group management function network element may be an independent network element, or may be a function module of an existing network element, including but not limited to a function template of an existing AMF network element, a function template of a policy control function (PCF) network element or a function template of an SMF network element. 
     The user plane network element is mainly configured to forward a user data packet according to a routing rule of the session management network element. In the 5G communications system, the user plane network element may be a user plane function (UPF) network element. In the future communication such as the 6G communication, the user plane network element may still be a UPF network element. Alternatively, the user plane network element may have another name. This is not limited in this embodiment of this application. 
       FIG. 2  is a schematic diagram of a specific possible network architecture to which an embodiment of this application is applicable. A 5G communications system is used as an example and includes a terminal, a RAN, an AMF, an SMF, an NRF, a UPF, and an LSMF. An N1 interface in  FIG. 2  is a reference point between UE and the AMF; an N2 interface is a reference point between the RAN and the AMF and is configured to send a non-access stratum (NAS) message, a next generation application protocol (NGAP) message, and the like; an N3 interface is a reference point between the RAN and the UPF and is configured to transmit user plane data and the like; an N4 interface is a reference point between the SMF and the UPF and is configured to transmit information such as identification information of a tunnel connected to the N3 interface, data buffering indication information, and a downlink data notification message; and an N6 interface is a reference point between the UPF and a DN and is configured to transmit user plane data and the like. 
     It may be understood that the foregoing functions may be network elements in a hardware device, software functions that are run on dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform). 
     Based on  FIG. 1  or  FIG. 2 , the following specifically describes the user group session management method provided in the embodiments of this application. 
     It should be noted that the embodiments of this application are not limited to the system architecture shown in  FIG. 1  and  FIG. 2 , and may be further applied to another future communications system, for example, a sixth generation (6G) communications system architecture. In addition, in the embodiments of this application, names of the foregoing used network elements may be changed while functions of the network elements may remain the same in a future communications system. 
     For ease of description, in subsequent embodiments of the embodiments of this application, the LSMF network element, the AMF network element, the UPF network element, the SMF network element are respectively referred to as the LSMF, the AMF, the UPF, and the SMF for short. It may be understood that, all LSMFs described subsequently in the embodiments of this application may be replaced with user group management network elements, all AMFs may be replaced with mobility management network elements, all UPFs may be replaced with user plane network elements, and all SMFs may be replaced with session management network elements. 
     Based on the network architecture in  FIG. 1 ,  FIG. 3  shows a user group session management method according to an embodiment of this application. The method includes the following steps. 
     Step  301 . A session management network element receives a first message sent by a mobility management network element, where the first message carries an identifier of a first terminal and an identifier of a user group, and the first message is used to request to establish, for the first terminal, a user group session corresponding to the identifier of the user group. 
     The identifier of the user group may be any information that can be used to identify the user group. For example, the identifier of the user group may be a 5G LAN group ID, or a virtual network ID, or a virtual DNN, or other identification information that can be used to represent a group including a group of UEs. 
     Specifically, the first message may be a PDU session establishment request message. The first message may further include a NAS message. 
     In a possible implementation, the identifier of the first terminal may be located in the PDU session establishment request message, and the identifier of the user group may be located in the NAS message. For example, the PDU session establishment request message (the identifier of the first terminal, the NAS message (the identifier of the user group, . . . ) . . . ). 
     In another possible implementation, both the identifier of the first terminal and the identifier of the user group may be located in the PDU session establishment request message. For example, the PDU session establishment request message (the identifier of the first terminal, the identifier of the user group, the NAS message ( . . . ), . . . ). 
     In still another possible implementation, both the identifier of the first terminal and the identifier of the user group may be located in the NAS message. For example, the PDU session establishment request message (the NAS message (the identifier of the first terminal, the identifier of the user group, . . . ), . . . ). 
     Step  302 . The session management network element generates, based on the identifier of the user group, a routing forwarding policy for the first terminal. 
     The routing forwarding policy is used to instruct the user plane network element how to forward a user plane packet. The routing forwarding policy corresponds to the identifier of the user group, that is, a user plane packet of a terminal belonging to the user group needs to be forwarded based on the routing forwarding policy. 
     That the session management network element generates, based on the identifier of the user group, a routing forwarding policy for the first terminal may be specifically implemented in any one of the following manners. 
     Manner 1. The session management network element obtains, based on the identifier of the user group, a second terminal list of the user group from local information, and the session management network element generates, based on the second terminal list, the routing forwarding policy for the first terminal. 
     Manner 2. The session management network element sends a third message to a user group management network element (as shown in step  304 ), where the third message carries an identifier of a user group, used to request group member information of the user group; the session management network element receives the second terminal list returned by the user group management network element (as shown in step  305 ); and the session management network element generates, based on the second terminal list, the routing forwarding policy for the first terminal. 
     That the session management network element generates, based on the second terminal list, a routing forwarding policy for the first terminal includes: obtaining, based on the second terminal list, a second session corresponding to a second terminal (where there are a plurality of second terminals, there are a plurality of corresponding second sessions), and associating the second session with a first session, where the routing forwarding policy is a local exchange policy indicating that the user plane network element sends, to the second terminal by using the second session, data that is from the first terminal and that is received from the first session, and/or send, to the first terminal by using the first session, data that is from the second terminal and that is received from the second session. 
     Step  303 . The session management network element sends a second message to the user plane network element, where the second message is used to instruct the user plane network element to establish the first session for the first terminal, and the second message carries the routing forwarding policy. 
     Step  304 . The user plane network element establishes, based on the second message, the first session for the first terminal; and sends, based on the routing forwarding policy to the second terminal by using the second session, the data that is from the first terminal and that is received from the first session, or sends, based on the routing forwarding policy to the first terminal by using the first session, the data that is from the second terminal and that is received from the second session. 
     Optionally, the first message in step  301  may further include user group verification information of the first terminal, for example, a security certificate, used by the LSMF to verify the first terminal and determine whether the first terminal is an authorized user of the user group. In step  304  in Manner 2 in step  302 , the third message may further carry the user group verification information. In step  305 , the session management network element receives indication information from the user group management network element, and the indication information is used to indicate that the first terminal is the authorized user of the user group. 
     In the foregoing technical solution, the session management network element instructs the user plane network element to establish the first session for the first terminal and generate the routing forwarding policy for the first terminal. This can implement routing of communication information between terminals of the user group within a 3GPP network, without depending on deployment and participation of an external application server. 
     With reference to a specific embodiment in  FIG. 4 , the following describes in detail the communication method in the foregoing Embodiment 3 by using an example. 
       FIG. 4  is a schematic diagram of another communication method according to an embodiment of this application. When a terminal device registers with a network, that a network side provides, for the terminal device, a user plane connection security context required when the terminal device accesses a UCF includes the following steps. 
     Step  401 . UE sends a NAS message to an AMF, where the message includes a UE ID and a LAN service session establishment request. Optionally, the LAN service session establishment request includes an identifier of a user group. 
     The identifier of the user group may be, for example, a 5G LAN group ID, or a virtual network ID, or a virtual DNN, or other identification information that can be used to represent a group including a group of UEs. 
     Step  402 . The AMF sends a PDU session establishment request message to an SMF, where the PDU session establishment request message includes the UE ID and the identifier of the user group. The PDU session establishment request message includes the foregoing LAN service session establishment request. The AMF may query, by using the UE ID, the user group to which the UE belongs from a user group management network element, and obtain the identifier of the user group. A correspondence between the UE ID and the user group is stored in the user group management network element. 
     Step  403 . The SMF receives the PDU session establishment request message sent by the AMF, and obtains the UE ID and the identifier of the user group. Optionally, the SMF may obtain the identifier of the user group from the LAN service session establishment request, and obtain the UE ID from the PDU session establishment request message. 
     Step  404 . The SMF sends an LAN ID to an LSMF (the SMF determines, based on the LAN service session establishment request or the LAN ID, that the UE initiates LAN session establishment, and the SMF determines that the SMF needs to communicate with the LSMF). Optionally, the message further includes the UE ID and LAN verification information, used by the LSMF to verify the group to which the UE belongs. 
     Step  405 . The LSMF determines a UE member list based on the LAN ID. Optionally, before determining the UE member list, the LSMF determines, based on the UE ID and the LAN verification information, whether the UE is an authorized user of the user group indicated by the LAN ID. 
     Step  406 . The LSMF returns the UE member list to the SMF. 
     Step  407 . The SMF generates a UE session routing forwarding policy based on the UE member list. The routing forwarding policy is used to instruct a UPF how to forward a user plane packet. The routing forwarding policy corresponds to the identifier of the user group, that is, only the user plane packet of the UE belonging to the user group is forwarded based on the routing forwarding policy. 
     A specific process is as follows: The SMF obtains, based on a second terminal list, a second session corresponding to a second terminal, and the SMF generates the routing forwarding policy, where the routing forwarding policy instructs the UPF to send, to second UE by using a second PDU session, data received from a first PDU session. 
     Step  408 . The SMF sends the routing forwarding policy to the UPF. The UPF performs subsequent packet forwarding for the UE based on the routing forwarding policy. 
     The foregoing mainly describes the solutions provided in the embodiments of this application from perspectives of interaction between network elements. It may be understood that, the network elements include corresponding hardware structures and/or software modules for performing the foregoing functions. A person skilled in the art should easily be aware that, in combination with the examples described in the embodiments disclosed in this specification, units, algorithms, and steps may be implemented by hardware or a combination of hardware and computer software in this application. Whether a function is performed by hardware or hardware driven by computer software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the embodiments of this application. 
     When an integrated unit is used,  FIG. 5  is a possible example block diagram of an apparatus  500  according to an embodiment of this application. The apparatus  500  may exist in a form of software, may be a session management network element, or may be a chip in the session management network element. The apparatus  500  includes a processing unit  502  and a communications unit  503 . The communications unit  503  may include a receiving unit and a sending unit. The processing unit  502  is configured to control and manage behavior of the apparatus  500 . The communications unit  503  is configured to support the apparatus  500  in communicating with another network entity (for example, a mobility management network element, a user plane network element, or a user group management network element). The apparatus  500  may further include a storage unit  501 , configured to store program code and data of the apparatus  500 . 
     The processing unit  502  may be a processor or a controller, such as a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or another programmable logic device, a transistor logic device, a hardware component, or a combination thereof. The processor may implement or execute various example logical blocks, modules, and circuits described with reference to content disclosed in the embodiments of this application. The processor may be a combination for implementing a computing function, for example, a combination of one or more microprocessors, or a combination of the DSP and a microprocessor. The communications unit  503  may be a communications interface, a transceiver, a transceiver circuit, or the like. The communications interface is a general term. During specific implementation, the communications interface may include a plurality of interfaces. For example, the communications interface may include an interface between a session management network element and a mobility management network element, an interface between user plane network elements, an interface between user group management network elements, and/or another interface. The storage unit  501  may be a memory. 
     The processing unit  502  may support the apparatus  500  in performing the actions of the session management network element in the foregoing method examples. For example, the processing unit  502  may support the apparatus  500  in performing step  302  in  FIG. 3 , step  403  and step  407  in  FIG. 4 , and the like. The communications unit  503  may support communication between the apparatus  500  and another device. For example, the communications unit  503  may support the apparatus  500  in performing step  301 , step  303 , step  304 , and step  305  in  FIG. 3 , and the like. 
     When the processing unit  502  is a processor, the communications unit  503  is a communications interface, and the storage unit  501  is a memory, the apparatus  500  in this embodiment of this application may be a session management network element  600  shown in  FIG. 6 . 
     As shown in  FIG. 6 , the session management network element  600  includes a processor  602  and a communications interface  603 . Optionally, the session management network element  600  may further include a memory  601 . Optionally, the session management network element  600  may further include a bus  604 . The communications interface  603 , the processor  602 , and the memory  601  may be connected to each other by using the bus  604 . The bus  604  may be a PCI bus, an EISA bus, or the like. The bus  604  may be classified into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is used to represent the bus in  FIG. 6 , but this does not mean that there is only one bus or only one type of bus. 
     When an integrated unit is used,  FIG. 7  is a possible example block diagram of an apparatus  700  according to an embodiment of this application. The apparatus  700  may exist in a form of software, may be a user group management network element, or may be a chip in the user group management network element. The apparatus  700  includes a processing unit  702  and a communications unit  703 . The communications unit  703  may include a receiving unit and a sending unit. The processing unit  702  is configured to control and manage behavior of the apparatus  700 . The communications unit  703  is configured to support the apparatus  700  in communicating with another network entity (for example, a session management network element). The apparatus  700  may further include a storage unit  701 , configured to store program code and data of the apparatus  700 . 
     The processing unit  702  may be a processor or a controller, such as a CPU, a general-purpose processor, a DSP, an ASIC, an FPGA, or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor may implement or execute various example logical blocks, modules, and circuits described with reference to content disclosed in the embodiments of this application. The processor may be a combination for implementing a computing function, for example, a combination of one or more microprocessors, or a combination of the DSP and a microprocessor. The communications unit  703  may be a communications interface, a transceiver, a transceiver circuit, or the like. The communications interface is a general term. During specific implementation, the communications interface may include a plurality of interfaces. For example, the communications interface may include an interface between a user group management network element and a session management network element, and/or another interface. The storage unit  701  may be a memory. 
     The processing unit  702  may support the apparatus  700  in performing the actions of the user group management network element in the foregoing method examples. For example, the processing unit  702  may support the apparatus  700  in performing step  405  in  FIG. 4 , and the like. The communications unit  703  may support communication between the apparatus  700  and an AMF, a UCF or a UDM. For example, the communications unit  703  may support the apparatus  700  in performing step  304  and step  305  in  FIG. 3 , step  404  and step  406  in  FIG. 4 , and the like. 
     When the processing unit  702  is a processor, the communications unit  703  is a communications interface, and the storage unit  701  is a memory, the apparatus  700  in this embodiment of this application may be a user group management network element  800  shown in  FIG. 8 . 
     As shown in  FIG. 8 , the user group management network element  800  includes a processor  802 , a communications interface  803 , and a memory  801 . Optionally, the user group management network element  800  may further include a bus  804 . The communications interface  803 , the processor  802 , and the memory  801  may be connected to each other by using the bus  804 . The bus  804  may be a PCI bus, an EISA bus, or the like. The bus  804  may be classified into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is used to represent the bus in  FIG. 8 , but this does not mean that there is only one bus or only one type of bus. 
     All or some of the foregoing embodiments may be implemented by using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, the embodiments may be implemented completely or partially in a form of a computer program product. The computer program product includes one or more computer program instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of this application are all or partially generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or another programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or may be transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer-readable storage medium may be any usable medium accessible by a computer, or a data storage device, such as a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a DVD), a semiconductor medium (for example, a solid-state drive (SSD)), or the like. 
     The various illustrative logical units and circuits described in the embodiments of this application may implement or operate the described functions by using a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logical apparatus, a discrete gate or a transistor logic, a discrete hardware component, or a design of any combination thereof. The general-purpose processor may be a microprocessor. Optionally, the general-purpose processor may also be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented by a combination of computing apparatuses, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors with a digital signal processor core, or any other similar configuration. 
     Steps of the methods or algorithms described in the embodiments of this application may be directly embedded into hardware, a software unit executed by a processor, or a combination thereof. The software unit may be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable magnetic disk, a CD-ROM, or a storage medium of any other form in the art. For example, the storage medium may connect to a processor, so that the processor may read information from the storage medium and write information to the storage medium. Optionally, the storage medium may further be integrated into a processor. The processor and the storage medium may be arranged in an ASIC, and the ASIC may be arranged in a terminal device. Optionally, the processor and the storage medium may also be arranged in different components of the terminal device. 
     These computer program instructions may also be loaded onto a computer or another programmable data processing device, so that a series of operations and steps are performed on the computer or the another programmable device, thereby generating computer-implemented processing. Therefore, the instructions executed on the computer or the another programmable device provide steps for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams. 
     Although the present invention is described with reference to the embodiments, in a process of implementing the present invention that claims protection, a person skilled in the art may understand and implement another variation of the disclosed embodiments by viewing the accompanying drawings, disclosed content, and the appended claims. In the claims, “comprising” does not exclude another component or another step, and “a” or “one” does not exclude a meaning of plurality. A single processor or another unit may implement several functions enumerated in the claims. Some measures are recorded in dependent claims that are different from each other, but this does not mean that these measures cannot be combined to produce a better effect. 
     A person skilled in the art should understand that the embodiments of this application may be provided as a method, an apparatus (device), a computer-readable storage medium, or a computer program product. Therefore, the embodiments of this application may use a form of hardware only embodiments, software only embodiments, or embodiments with a combination of software and hardware. They are collectively referred to as “modules” or “systems”. 
     A person skilled in the art may further understand that various illustrative logical blocks (illustrative logic block) and steps (step) that are listed in the embodiments of this application may be implemented by using electronic hardware, computer software, or a combination thereof. Whether the functions are implemented by using hardware or software depends on particular applications and a design requirement of the entire system. A person skilled in the art may use various methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the embodiments of this application. 
     Although the present invention is described with reference to specific features and the embodiments thereof, clearly, various modifications and combinations may be made to them without departing from the scope of the present invention. Correspondingly, the specification and accompanying drawings are merely example descriptions of the present invention defined by the appended claims, and are considered as any of or all modifications, variations, combinations or equivalents that cover the scope of the present invention. Clearly, a person skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. The present invention is intended to cover these modifications and variations provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.