Abstract: Embodiments of the present disclosure provide a method, an apparatus, and a system for changing an association relationship between an MCPTT user and an MCPTT group. A method for changing an association relationship between an MCPTT user and an MCPTT group is performed by a first network element device, including: receiving an association change request sent by first UE, where the association change request includes request information, the request information is used to indicate that a first MCPTT user requests to change an association relationship between a second MCPTT user and a first MCPTT group, and the first MCPTT user is an MCPTT user using the first UE; and setting the association relationship between the second MCPTT user and the first MCPTT group according to the association change request.

Abstract: An address obtaining method includes obtaining, by a third network device, an identifier of a first application from a terminal device. The identifier of the first application indicates a request for obtaining an address of an instance of the first application. The address obtaining method further includes sending, by the third network device, a first message to a first network device, wherein the first message comprises the identifier of the first application, and the first message is useable to request the address of the instance of the first application. The address obtaining method further includes receiving, by the third network device, the address of the instance of the first application from the first network device, and sending the address of the instance of the first application to the terminal device.

Abstract: A communication method and an apparatus are provided. The method includes: A common application programming interface framework core function (CCF) network element first sends reference information of an application to a first network element. Therefore, the first network element determines network slice information corresponding to the application; and then the first network element sends the determined network slice information to the CCF network element. In this way, the CCF network element may determine the network slice information corresponding to the application, so that when an API invoker network element searches for an API, the CCF network element can accurately find, based on an API inquiry parameter, the API from a network slice corresponding to the network slice information.

Abstract: Embodiments of this application relate to the communications field, and describe an alias management method and device. One example method includes receiving, by a mission critical service server, a first call request message from a first client determining, by the mission critical service server based on the identity of the calling user, that the calling user has an alias call right receiving, by the mission critical service server from a functional alias management entity, activating user information corresponding to the identity of the alias requested to be called; calling, by the mission critical service server, a user in the activating user information based on the activating user information corresponding to the identity of the alias requested to be called; and sending, by the mission critical service server, a first call response message to the first client.

Abstract: A multicast communication method and a communication apparatus provide for transmission of data of a multicast service using a PDU session established by a terminal device to improve network element utilization. An AF network element sends first multicast service indication information to a session management network element indicating a first multicast service. The session management network element sends, based on the first multicast service indication information, multicast service information to an access network device that serves a terminal device. The access network device establishes an association relationship between the terminal device and the first multicast service based on the multicast service information, so that the access network device can send, when receiving data of the first multicast service, the data of the first multicast service to the terminal device using a PDU session.

Abstract: A media downlink transmission control method and a related device, the method including receiving a remote media reception message sent by an authorized terminal, where the remote media reception message includes a target user identifier, determining a first target media stream based on the remote media reception message, and sending the first target media stream to a destination terminal corresponding to the target user identifier.

Abstract: The present disclosure relates to mobile edge computing (MEC) information obtaining methods and apparatus. One example method performed by a first network element includes receiving target reference information from a second network element, and sending, to the second network element, information about a MEC platform corresponding to the target reference information. The target reference information comprises target capability information.

Abstract: A handover method and a communication apparatus are provided. The method includes: A target access network device obtains a first message and information used for transmitting multicast data, where the first message is used for requesting to establish a resource for handing over a terminal device to the target access network device. The target access network device sends a second message, where the second message indicates the established resource on the target access network device; receives a first packet from a user plane network element, where the first packet corresponds to the information used for transmitting the multicast data; and sends the first packet to the terminal device. In this way, the terminal device is handed over from a source access network device to the target access network device when the terminal device receives the multicast data.

Abstract: An application programming interface (API) method includes determining, by a first common API core function (CCF) entity, a to-be-shared API, and sharing, by the first CCF entity, information about the to-be-shared API with a target CCF entity of the to-be-shared API.

Abstract: A communication method and an apparatus are provided. The method includes: A common application programming interface framework core function (CCF) network element first sends reference information of an application to a first network element. Therefore, the first network element determines network slice information corresponding to the application; and then the first network element sends the determined network slice information to the CCF network element. In this way, the CCF network element may determine the network slice information corresponding to the application, so that when an API invoker network element searches for an API, the CCF network element can accurately find, based on an API inquiry parameter, the API from a network slice corresponding to the network slice information.

Abstract: This application provides a method and an apparatus for invoking an application programming interface (API), to determine a target exposing function network element used to invoke an API. The method includes: A first network element obtains routing information of an API, where the routing information is used to indicate a route for invoking the API, and the API is provided by a first exposing function network element and a second exposing function network element; the first network element obtains invocation parameter information of the API, where the invocation parameter information is used to handle the API; and the first network element determines a target exposing function network element in the first exposing function network element and the second exposing function network element based on the routing information and the invocation parameter information.

Abstract: This application discloses a communications system, a communication method, and an apparatus thereof. The system includes: a multicast session management network element, an access and mobility management network element and a user plane function network element. The multicast session management network element sends a first multicast session request carrying a multicast session context to the access and mobility management network element to request to establish a multicast session based on the multicast session context; and sends a second multicast session request to the user plane function network element, where the second multicast session request carries user plane forwarding-related information indicating a user plane forwarding rule of the multicast session. The access and mobility management network element sends the first multicast session request to an access network node.

Abstract: The present disclosure relates to network slicing, in particular, in 5G networks systems. The disclosure is concerned with network slice enablement for (vertical) applications. Thus, an entity for inter-operation between a network system and at least one application is provided. The entity provides a request to the network system, for selection and/or adjustment of a network slice instance (NSI) providing one or more services to the at least one application. The request comprises a set of requirements for the at least one application and/or the one or more services. The set of requirements comprises a required configuration or adaption of at least one NSI related parameter. The entity further receives a response to the request from the network system. The response indicates a decision of the network system regarding the selection and/or adjustment of the NSI.

Abstract: Embodiments of this application relate to the communications field, and describe an alias management method and device. One example method includes the following operations: a functional alias management entity receives a management request message sent by a first client, where the management request message includes an identity of a user and information about an alias requested to be managed; and the functional alias management entity sends a management response message to the first client when the user has an alias management right, where the management response message includes the identity of the user, and information about an alias that is successfully managed.

Abstract: This application discloses a communications system, a communication method, and an apparatus thereof. The system includes: a multicast session management network element, an access and mobility management network element and a user plane function network element. The multicast session management network element sends a first multicast session request carrying a multicast session context to the access and mobility management network element to request to establish a multicast session based on the multicast session context; and sends a second multicast session request to the user plane function network element, where the second multicast session request carries user plane forwarding-related information indicating a user plane forwarding rule of the multicast session. The access and mobility management network element sends the first multicast session request to an access network node.

Abstract: A data transmission method and apparatus, a system, and a storage medium are provided. In the method, a user plane function network element performs transmission through an established unicast user plane connection, and when sending data of a first service to an access network device, the user plane function network element can be configured to send only the data that is of the first service and that is carried in one data flow to improve use efficiency of resources on a core network side. Then, the access network device can send, in a multicast manner through an established unicast channel, the received data of the first service to a group of terminals corresponding to the data of the first service, and does not need to additionally establish a multicast channel and switch to the multicast channel, thereby further reducing data transmission delay.

Abstract: This application provides an unmanned aerial vehicle authentication method and an apparatus. The method includes: sending, by a communications device after determining that a type of a terminal is a UAV, authentication information of the terminal to an authentication server, so that the authentication server can perform authentication on the terminal based on the authentication information of the terminal, and therefore, the authentication server completes authentication on the terminal. In addition, the unmanned aerial vehicle is allowed to fly only after authentication on the terminal succeeds. Therefore, flight security of the unmanned aerial vehicle can be improved.

Abstract: This application discloses an authorization revocation method and an apparatus, and relates to the communications field. An example method includes: receiving, by a first entity, an authorization revocation request message from a second entity, wherein the authorization revocation request message carries an identifier of an application programming interface (API) invocation entity; and sending, by the first entity, an authorization revocation response message to the second entity based on the authorization revocation request message, wherein the authorization revocation response message indicates that authorization revocation succeeds or fails.

Abstract: This specification provides a session establishment method and device. The method includes: sending, by an SMF entity, a PDU session establishment request message to a terminal, where the PDU session establishment request message is used to request to establish a PDU session; and receiving, by the SMF entity, a PDU session establishment response message from the terminal. A method for actively initiating a PDU session establishment procedure on a network side is provided.

Abstract: Embodiments of this application disclose an information obtaining method that may be applied to the multi-access edge computing MEC field, for example, a vehicle to everything scenario of MCE or an internet of things scenario of the MEC. The method in the embodiments of this application includes: A first server receives information about a first instance of an application and information about a second instance of the application from a second server and a third server respectively, and then the first server stores the information about the first instance and the information about the second instance. In this way, the first server can centrally maintain information about different instances of the application, so that another device can directly obtain the information about the application instances from the first server.