A communication method and apparatus

Abstract

The application relates to the technical field of communication. A communication method and device are provided to provide a multicast service for a terminal device. An SMF receives a first message from a terminal, including a multicast address. The SMF sends a second message to an NRF, the second message being used for querying an SMF for establishing a multicast session for a multicast service corresponding to the multicast address. The first SMF receives a third message from the NRF, the third message being used for indicating that the SMF for establishing the multicast session for the multicast service corresponding to the multicast address is not queried. The first SMF sends a fourth message to the terminal, the fourth message being used for indicating that the terminal is rejected to join the multicast session corresponding to the multicast address. The multicast session establishment scenario and the multicast session configuration scenario are distinguished through the second message, and authorization verification can be performed on the multicast service. When the condition is not met, the NRF does not allocate an SMF to the first SMF for establishing the multicast session, thereby reasonably providing the multicast service for the terminal device.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of communication, and particularly relate to a communication method and apparatus. BACKGROUND

[0002] With the rapid development of global networks, the communication traffic is rapidly rising. Video on demand, video phone, video conference and other audio and video services, Internet of Vehicles, Internet of Things and other services have the characteristics of large data volume, strong time delay sensitivity and long duration compared with general services. Based on these service requirements, multicast / broadcast service (MBS) is proposed, and MBS has become one of the key technologies of network evolution.

[0003] In the multicast service, how to reasonably provide multicast service for terminal devices is a technical problem to be solved. SUMMARY

[0004] Embodiments of the present application provide a communication method and apparatus to provide a way for terminal devices to provide multicast service.

[0005] In a first aspect, a communication method is provided. The execution subject of the method can be a first session management function (SMF) network element, or a component applied in the first SMF network element, such as a chip, a processor, etc. Hereinafter, the execution subject is taken as the first SMF network element for example. First, the first session management function SMF network element receives a first message from a terminal device, the first message including a multicast address, the first message being used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address. Then, the first SMF network element sends a second message to a network repository function (NRF) network element, the second message including the multicast address, the second message being used to query an SMF for establishing a multicast session for a multicast service corresponding to the multicast address. Then, the first SMF network element receives a third message from the NRF, the third message being used to indicate that no SMF for establishing a multicast session for the multicast service corresponding to the multicast address is queried. Next, the first SMF network element sends a fourth message to the terminal device, the fourth message being used to indicate that the terminal device is rejected to join the multicast session corresponding to the multicast address.

[0006] The second message distinguishes the multicast session establishment scenario from the multicast session configuration scenario, so that the NRF network element knows that the SMF to be queried in the current scenario is used for establishing a multicast session, instead of being used for configuring a multicast session. In addition, in the prior art, when there is no SMF currently serving the multicast service corresponding to the multicast address, the NRF network element selects an MB-SMF according to slice information and the like, and feeds back the MB-SMF to the first SMF for establishing a multicast session. In the present application, the SMF network element can perform authorization verification on the multicast service, and when the authorization verification fails, sends indication information of rejection of joining to the terminal device, so as to avoid waste of resources of the terminal device. In addition, in the authorization verification process, the SMF network element queries the NRF network element for a suitable SMF, and determines whether the authorization verification passes according to the query result. If the NRF network element does not allocate an SMF to the first SMF network element for establishing a multicast session, the authorization verification fails. The non-allocation of the SMF can avoid waste of resources and illegal attacks. Thus, the terminal device is reasonably provided with multicast service.

[0007] In a possible implementation, the second message further includes a first indication, the first indication being used for indicating establishment of a multicast session. Through improvement on the existing message, a new indication information is added in the existing message to indicate the scenario of establishment of a multicast session, and the generality is stronger.

[0008] In a possible implementation, the third message includes a second indication, the second indication being used for indicating query failure, and / or an empty SMF list. Through improvement on the existing message, a new indication information is added in the existing message to indicate the scenario of establishment of a multicast session, and the generality is stronger. When the third message includes the empty SMF list, the format of the existing message can be used, and the generality is stronger.

[0009] In a second aspect, a communication method is provided. The execution subject of the method can be a first SMF network element or a component applied in the first SMF network element, such as a chip, a processor, etc. Hereinafter, the execution subject is taken as the first SMF network element for example. First, the first session management function (SMF) network element receives a first message from a terminal device, the first message including a multicast address, and the first message being used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address. Then, the first SMF network element sends a second message to a network registration function (NRF) network element, the second message including the multicast address, and the second message being used to query an SMF for establishing a multicast session for a multicast service corresponding to the multicast address. Further, the first SMF network element receives a third message from the NRF, the third message including a second SMF, and the second SMF supporting the establishment of the multicast session for the multicast service corresponding to the multicast address. Next, the first SMF network element sends a fourth message to the terminal device, and the fourth message being used to indicate that the terminal device is accepted to join the multicast session corresponding to the multicast address.

[0010] The multicast session establishment scenario and the multicast session configuration scenario are distinguished by the second message, so that the NRF network element knows that the SMF to be queried in the current scenario is for establishing a multicast session, instead of for configuring a multicast session. In the multicast session establishment scenario, the SMF network element can perform authorization verification on the multicast service, and send indication information of acceptance to join to the terminal device when the authorization verification is passed. In addition, in the authorization verification process, the SMF network element queries a suitable SMF from the NRF network element, and determines whether the authorization verification is passed according to the query result. If the NRF network element allocates an SMF to the first SMF network element for establishing a multicast session, the authorization verification is passed, so that the terminal device is reasonably provided with multicast service.

[0011] In a possible implementation, the second message further includes a first indication, and the first indication is used to indicate the establishment of a multicast session. By improving the existing message, a new indication information is added to the existing message to indicate the scenario of establishing a multicast session, and the generality is stronger.

[0012] In a third aspect, a communication method is provided. An execution subject of the method can be a network repository function (NRF) network element or a component (e.g., a chip, a processor, etc.) applied in the NRF network element. Hereinafter, the execution subject is taken as an example of the NRF network element. First, the NRF network element receives a second message from a first SMF network element, where the second message includes a multicast address and is used to query an SMF for establishing a multicast session for a multicast service corresponding to the multicast address. Then, the NRF sends a third message to the first SMF network element, where the third message is used to indicate that no SMF is found for establishing the multicast session for the multicast service corresponding to the multicast address.

[0013] The multicast session establishment scenario and the multicast session configuration scenario are distinguished by the second message, so that the NRF network element knows that the SMF to be queried in the current scenario is for establishing a multicast session, rather than for configuring a multicast session. In addition, in the prior art, when there is no SMF currently serving the multicast service corresponding to the multicast address, the NRF selects an MB-SMF according to slice information, etc., and feeds back the MB-SMF to the first SMF for establishing a multicast session. In the present application, the SMF network element can perform authorization verification on the multicast service, and when the authorization verification fails, sends indication information of rejection to join to the terminal device, so as to avoid waste of resources of the terminal device. In addition, in the authorization verification process, the SMF network element queries the NRF network element for a suitable SMF, and determines whether the authorization verification passes according to the query result. If the NRF network element does not assign an SMF to the first SMF network element for establishing a multicast session, the authorization verification fails. Assigning no SMF can avoid waste of resources and illegal attacks. Thus, multicast service is reasonably provided for the terminal device.

[0014] In a possible implementation, the second message further includes a first indication, where the first indication is used to indicate establishment of a multicast session. By improving the existing message, a new indication information is added to the existing message to indicate the scenario of establishment of a multicast session, which is more versatile.

[0015] In a possible implementation, the third message includes a second indication and / or an empty SMF list, where the second indication is used to indicate query failure. By improving the existing message, a new indication information is added to the existing message to indicate the scenario of establishment of a multicast session, which is more versatile. When the third message includes the empty SMF list, the format of the existing message can be used, which is more versatile.

[0016] In a possible implementation, the NRF sends a third message to the first SMF network element, including: in a case where allowed multicast addresses of SMFs supporting establishment of a multicast session for multicast service do not include the multicast address, the NRF sends the third message to the first SMF network element; or, in a case where there is no SMF currently serving multicast service corresponding to the multicast address and allowed multicast addresses of SMFs supporting establishment of a multicast session for multicast service do not include the multicast address, the NRF sends the third message to the first SMF network element; or, in a case where allowed multicast addresses of an operator do not include the multicast address, the NRF sends the third message to the first SMF network element.

[0017] In a possible implementation, the NRF network element receives allowed multicast addresses of SMFs supporting establishment of a multicast session for multicast service, where the allowed multicast addresses do not include the multicast address.

[0018] In a possible implementation, the NRF network element receives allowed multicast addresses of an operator, where the allowed multicast addresses of the operator do not include the multicast address.

[0019] In a possible implementation, the NRF network element locally queries whether the multicast address belongs to allowed multicast addresses of an operator; or, the NRF queries, to a unified data storage (UDR) network element, whether the multicast address belongs to allowed multicast addresses of an operator.

[0020] In a fourth aspect, a communication method is provided. An execution subject of the method can be a network registration function (NRF) network element or a component (such as a chip, a processor, or the like) applied to the NRF network element. Hereinafter, the execution subject is taken as an example of the NRF network element. First, the NRF network element receives a second message from a first SMF network element, where the second message includes a multicast address and is used to query an SMF supporting establishment of a multicast session for multicast service corresponding to the multicast address. Then, the NRF network element sends a third message to the first SMF network element, where the third message includes a second SMF supporting establishment of a multicast session for multicast service corresponding to the multicast address.

[0021] The second message distinguishes the multicast session establishment scenario from the multicast session configuration scenario, so that the NRF network element knows that the SMF to be queried in the current scenario is used for establishing a multicast session, instead of being used for configuring a multicast session. The SMF network element can perform authorization verification on the multicast service, and send indication information of accepting joining to the terminal device when the authorization verification is passed. In addition, in the authorization verification process, the SMF network element queries the NRF network element for a suitable SMF, and determines whether the authorization verification is passed according to the query result. If the NRF network element allocates the SMF to the first SMF network element to establish a multicast session, the authorization verification is passed, so that the terminal device is reasonably provided with multicast service.

[0022] In a possible implementation, the second message further includes a first indication, and the first indication is used to indicate establishment of a multicast session. By improving the existing message, a new indication information is added to the existing message to indicate the scenario of establishing a multicast session, and the generality is stronger.

[0023] In a possible implementation, the second SMF is an SMF currently serving a multicast session corresponding to the multicast address; or the multicast address allowed by the second SMF includes the multicast address.

[0024] In a possible implementation, the NRF network element receives the multicast address allowed by the second SMF, and the multicast address allowed by the second SMF includes the multicast address.

[0025] In a possible implementation, when there is no SMF currently serving a multicast service corresponding to the multicast address, and the multicast address belongs to the multicast address allowed by the operator, the NRF network element is configured to establish an SMF for a multicast session corresponding to the multicast address.

[0026] In a possible implementation, the NRF network element receives the multicast address allowed by the operator, and the multicast address allowed by the operator includes the multicast address.

[0027] In a possible implementation, the NRF network element locally queries whether the multicast address belongs to the multicast address allowed by the operator; or the NRF queries a unified data storage (UDR) network element whether the multicast address belongs to the multicast address allowed by the operator.

[0028] In a fifth aspect, a communication apparatus is provided, which has the functions of the above first aspect and any possible implementation of the first aspect, or the functions of the above second aspect and any possible implementation of the second aspect, or the functions of the above third aspect and any possible implementation of the third aspect, or the functions of the above fourth aspect and any possible implementation of the fourth aspect. These functions can be implemented through hardware, or by executing corresponding software through hardware. The hardware or software includes one or more functional modules corresponding to the above functions.

[0029] In a sixth aspect, a communication apparatus is provided, which includes a processor, and optionally, a memory; the processor and the memory are coupled; the memory is configured to store computer programs or instructions; and the processor is configured to execute part or all of the computer programs or instructions in the memory, so as to realize the functions of the first SMF network element in the method of the above first aspect and any possible implementation of the first aspect, or the functions of the first SMF network element in the method of the above second aspect and any possible implementation of the second aspect, or the functions of the NRF network element in the method of the above third aspect and any possible implementation of the third aspect, or the functions of the NRF network element in the method of the above fourth aspect and any possible implementation of the fourth aspect.

[0030] In a possible implementation, the apparatus can further include a transceiver, configured to send signals processed by the processor, or receive signals input to the processor. The transceiver can perform the sending actions or receiving actions performed by the first SMF network element in the first aspect and any possible implementation of the first aspect, or the sending actions or receiving actions performed by the first SMF network element in the second aspect and any possible implementation of the second aspect, or the sending actions or receiving actions performed by the NRF network element in the third aspect and any possible implementation of the third aspect, or the sending actions or receiving actions performed by the NRF network element in the fourth aspect and any possible implementation of the fourth aspect.

[0031] In a seventh aspect, the present application provides a chip system, comprising one or more processors (also referred to as processing circuitry), which are electrically coupled with a memory (also referred to as storage medium); the memory can or can not be located in the chip system; the memory is configured to store computer programs or instructions; the processor is configured to execute part or all of the computer programs or instructions in the memory, and when the part or all of the computer programs or instructions are executed, to implement the functions of the first SMF network element in the method of the first aspect and any possible implementation of the first aspect, or to implement the functions of the first SMF network element in the method of the second aspect and any possible implementation of the second aspect, or to implement the functions of the NRF network element in the method of the third aspect and any possible implementation of the third aspect, or to implement the functions of the NRF network element in the method of the fourth aspect and any possible implementation of the fourth aspect.

[0032] In a possible implementation, the chip system can further comprise an input / output interface (also referred to as a communication interface), configured to output signals processed by the processor, or receive input signals to the processor. The input / output interface can perform the sending actions or receiving actions performed by the first SMF network element in the first aspect and any possible implementation of the first aspect; or perform the sending actions or receiving actions performed by the first SMF network element in the second aspect and any possible implementation of the second aspect; or perform the sending actions or receiving actions performed by the NRF network element in the third aspect and any possible implementation of the third aspect; or perform the sending actions or receiving actions performed by the NRF network element in the fourth aspect and any possible implementation of the fourth aspect. Specifically, the output interface performs the sending actions, and the input interface performs the receiving actions.

[0033] In a possible implementation, the chip system can be composed of a chip, or can comprise a chip and other discrete devices.

[0034] In an eighth aspect, a computer readable storage medium is provided for storing a computer program, the computer program comprising instructions for implementing the functions in the first aspect and any possible implementation of the first aspect, or for implementing the functions in the second aspect and any possible implementation of the second aspect.

[0035] Alternatively, a computer readable storage medium for storing a computer program, the computer program, when executed by a computer, causing the computer to perform the method executed by the first SMF network element in the first aspect and any possible implementation of the first aspect, or perform the method executed by the first SMF network element in the second aspect and any possible implementation of the second aspect, or perform the method executed by the NRF network element in the third aspect and any possible implementation of the third aspect, or perform the method executed by the NRF network element in the fourth aspect and any possible implementation of the fourth aspect.

[0036] In a ninth aspect, a computer program product is provided, the computer program product comprising: computer program code which, when run on a computer, causes the computer to perform the method executed by the first SMF network element in the first aspect and any possible implementation of the first aspect, or perform the method executed by the first SMF network element in the second aspect and any possible implementation of the second aspect, or perform the method executed by the NRF network element in the third aspect and any possible implementation of the third aspect, or perform the method executed by the NRF network element in the fourth aspect and any possible implementation of the fourth aspect.

[0037] In a tenth aspect, a communication system is provided, the communication system comprising a first SMF network element performing the method in the first aspect and any possible implementation of the first aspect, and a NRF network element performing the method in the third aspect and any possible implementation of the third aspect. Alternatively, the communication system comprises a first SMF network element performing the method in the second aspect and any possible implementation of the second aspect, and a NRF network element performing the method in the fourth aspect and any possible implementation of the fourth aspect.

[0038] The technical effects of the fifth aspect to the tenth aspect can refer to the description in the first aspect to the fourth aspect, and the repeated parts will not be described again. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1a A communication system architecture diagram provided in an embodiment of the present application;

[0040] Figure 1b A communication system architecture diagram provided in an embodiment of the present application;

[0041] Figure 1c A communication system architecture diagram provided in an embodiment of the present application;

[0042] Figure 2 A multicast session establishment process flowchart provided in an embodiment of the present application;

[0043] Figure 3 A communication process flowchart provided in an embodiment of the present application;

[0044] Figure 4 A communication process flow chart provided for the implementation of the present application;

[0045] Figure 5 A communication process flow chart provided for the implementation of the present application;

[0046] Figure 6 A communication transpose structure diagram provided for the implementation of the present application;

[0047] Figure 7 A communication transpose structure diagram provided for the implementation of the present application. DETAILED DESCRIPTION

[0048] In order to facilitate the understanding of the technical solutions of the embodiments of the present application, the system architecture of the method provided by the embodiments of the present application will be briefly described below. It can be understood that the system architecture described in the embodiments of the present application is to more clearly illustrate the technical solutions of the embodiments of the present application, and does not constitute a limitation on the technical solutions provided by the embodiments of the present application.

[0049] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as satellite communication systems, traditional mobile communication systems. Among them, the satellite communication system can be integrated with the traditional mobile communication system (i.e. ground communication system). The communication system, for example: wireless local area network (wireless local area network, WLAN) communication system, wireless fidelity (wireless fidelity, WiFi) system, long term evolution (long term evolution, LTE) system, LTE frequency division duplex (frequency division duplex, FDD) system, LTE time division duplex (time division duplex, TDD), 5th generation (5th generation, 5G) system or new radio (new radio, NR), 6th generation (6th generation, 6G) system, and other future communication systems, etc., also support a variety of wireless technology integrated communication system, for example, it can also be applied to unmanned aerial vehicle, satellite communication system, high altitude platform (high altitude platform station, HAPS) communication, etc. Non-terrestrial network (non-terrestrial network, NTN) integrated ground mobile communication network system.

[0050] As an example, only the fifth generation communication system is taken as an example to describe the application scenario of the embodiments of the present application and the method of the embodiments of the present application.

[0051] The present application takes the 5G communication system as an example for illustration.

[0052] For example, Figure 1a is a schematic diagram of a 5G communication system architecture that can be applicable to the present application. Specifically, Figure 1a is a schematic diagram of a 5G network architecture based on a service-oriented architecture.

[0053] For example, Figure 1b is another schematic diagram of a 5G communication system architecture that can be applicable to the present application. Specifically, Figure 1b is a schematic diagram of a 5G architecture based on point-to-point. Figure 1a The main difference between Figure 1b is that the interface between each network element in Figure 1a is a service-oriented interface, Figure 1b the interface between each network element in

[0054] Figure 1a and Figure 1b The 5G network architecture shown in the figure can include a terminal device part, an access network part, and a core network part. Optionally, it also includes a data network (data network, DN) and an application function (application function, AF) network element part. The terminal accesses the core network through the access network, and the core network communicates with the DN or the AF. The functions of some network elements are briefly introduced below.

[0055] The terminal device (terminal device) can also be called user equipment (user equipment, UE), which is a device with wireless transceiver function. It can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.). The terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (virtual reality, VR) terminal, an augmented reality (augmented reality, AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc.

[0056] The (R)AN device in the present application is a device that provides wireless communication functions for terminal devices, and is also referred to as an access network device. The RAN device in the present application includes, but is not limited to, a next generation base station (g nodeB, gNB) in 5G, an evolved node B (eNB), a radio network controller (RNC), a node B (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 transmitting and receiving point (TRP), a transmitting point (TP), a mobile switching center, and the like. In systems using different wireless access technologies, the names of devices with base station functions may be different, for example, in a 5th generation (5G) system, it is referred to as a RAN or gNB (5G NodeB); in an LTE system, it is referred to as an evolved node B (eNB or eNodeB); in a 3rd generation (3G) system, it is referred to as a node B (Node B), and the like.

[0057] The data network DN can deploy various services and provide data and / or voice services for terminal devices. For example, the DN is a private network of a certain intelligent factory, sensors installed in the workshop of the intelligent factory can be terminal devices, and the DN deploys sensors and a control server, and the control server can provide services for the sensors. The sensors can communicate with the control server, obtain instructions from the control server, and transmit collected sensor data to the control server according to the instructions, and the like. For another example, the DN is an internal office network of a certain company, and the mobile phones or computers of employees of the company can be terminal devices, and the mobile phones or computers of the employees can access information and data resources on the internal office network of the company.

[0058] The application network element mainly supports interaction with the 3rd generation partnership project (3GPP) core network to provide services, such as affecting data routing decisions, policy control functions, or providing some services of third parties to the network side. In the 5G communication system, the application network element can be an application function (AF) network element. In future communication systems, the application network element can still be an AF network element, or can also have other names, which are not limited in the present application.

[0059] The core network part can include one or more of the following network elements:

[0060] The access management network element is a control plane network element provided by the operator network, responsible for access control and mobility management of terminal devices accessing the operator network, such as including mobile state management, allocation of user temporary identity, authentication and user functions. In the 5G communication system, the access management network element can be an access and mobility management function (AMF) network element. In future communication systems, the access management network element can still be an AMF network element, or can also have other names, which are not limited in the present application.

[0061] The session management network element is mainly responsible for session management in the mobile network, such as session establishment, modification, and release. Specific functions such as allocating IP addresses for users and selecting user plane network elements that provide message forwarding functions. In the 5G communication system, the session management network element can be a session management function (SMF) network element. In future communication systems, the session management network element can still be an SMF network element, or can also have other names, which are not limited in the present application.

[0062] The user plane network element is responsible for the forwarding and receiving of user data in the terminal device. It can receive user data from the data network and transmit it to the terminal device through the access network device; the user plane network element can also receive user data from the terminal device through the access network device and forward it to the data network. The transmission resources and scheduling functions provided by the user plane network element for the terminal device are managed and controlled by the SMF network element. In the 5G communication system, the user plane network element can be a user plane function (UPF) network element. In future communication systems, the user plane network element can still be a UPF network element, or can also have other names, which are not limited in the present application.

[0063] Data management network element, which is used to generate authentication credentials, user identity processing (such as storing and managing user permanent identity, etc.), access control and subscription data management, etc. In the 5G communication system, the data management network element can be a unified data management (UDM) network element. In the future communication system, the unified data management can still be a UDM network element, or can also have other names, which are not limited in the present application.

[0064] Policy control network element, which mainly supports providing a unified policy framework to control network behavior, providing policy rules to control layer network functions, and being responsible for obtaining user subscription information related to policy decision. In the 4G communication system, the policy control network element can be a policy and charging rules function (PCRF) network element. In the 5G communication system, the policy control network element can be a policy control function (PCF) network element. In the future communication system, the policy control network element can still be a PCF network element, or can also have other names, which are not limited in the present application.

[0065] Network storage network element, which can be used to provide network element discovery function, and provide network element information corresponding to network element type based on the request of other network elements. The NRF also provides network element management services, such as network element registration, update, deregistration, and network element state subscription and push, etc. In the 5G communication system, the network storage network element can be a network repository function (NRF) network element. In the future communication system, the network storage network element can still be a NRF network element, or can also have other names, which are not limited in the present application.

[0066] Network exposure function network element, which can be used to provide services and capabilities provided by 3GPP network function devices to the outside safely. In the 5G communication system, the network exposure function network element can be a network exposure function (NEF) network element. In the future communication system, the network exposure function network element can still be a NEF network element, or can also have other names, which are not limited in the present application.

[0067] Network slice selection network element, which can be used to select a suitable network slice for the service of the terminal. In the 5G communication system, the network slice selection network element can be a network slice selection function (NSSF) network element. In the future communication system, the network exposure function network element can still be a NSSF network element, or can also have other names, which are not limited in the present application.

[0068] The network data analytics network element can collect data from various network functions (NFs), such as a policy control network element, a session management network element, a user plane network element, an access management network element, and an application function network element (through a network capability exposure function network element), and perform analysis and prediction. In the 5G communication system, the network data analytics network element can be a network data analytics function (NWDAF). In future communication systems, the network exposure function network element can still be the NWDAF network element, or can also have other names, which are not limited in the present application.

[0069] The unified data storage network element is responsible for storing structured data information, including subscription information, policy information, and network data or service data with a standard format definition. In the 5G communication system, the unified data storage network element can be a unified data repository (UDR). In future communication systems, the network exposure function network element can still be the UDR network element, or can also have other names, which are not limited in the present application.

[0070] It can be understood that the above network elements or functions can be network elements in a hardware device, or software functions running on a dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform). In one possible implementation, the above network elements or functions can be implemented by one device, or can be implemented by multiple devices together, or can be a functional module in one device, and the embodiments of the present application do not make specific limitations. In addition, in the following, in order to facilitate description, the "network element" can be omitted. For example, the SMF network element of the present application has the same meaning as the SMF, and only the network element is omitted for the convenience of description, and the rest are similar.

[0071] As shown in Figure 1c , a multicast / broadcast service MBS system architecture diagram under the fifth generation mobile communication system is provided, compared with the system architecture of Figure 1a , the main differences include:

[0072] A new network element, MB-SMF, MB-UPF and multicast / broadcast service function (MBSF), is added. Among them, the MB-SMF is used for multicast session configuration, the MB-UPF is used for multicast data transmission, and the MBSF is used for multicast / broadcast service MBS requirement configuration between the AF and the MB-SMF. Among them, the MB-UPF is configured by the MB-SMF, connected with the AF / AS (which may include a content provider) through an N6 connection, obtains multicast data, and is connected with the NG-RAN through an N3 connection to send downlink multicast data to the RAN. The MBSF mainly initiates a multicast session establishment / management requirement to the MB-SMF according to the multicast service requirement of the AF / AS, and performs related configuration.

[0073] To facilitate understanding of the embodiments of the present application, the application scenarios of the present application are introduced as follows. The network architecture and service scenarios described in the embodiments of the present application are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. It can be known by those skilled in the art that, with the emergence of new service scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0074] In the multicast service, the MBS session configuration procedure and the MBS session establishment procedure are included.

[0075] In an example, the MBS session configuration procedure can be initiated by an application function (AF) network element. For example, the AF sends a temporary mobile group identity (TMGI) allocation request to a core network network element (for example, a network exposure function (NEF) network element or a multicast / broadcast service function (MBSF) network element), and the TMGI is used to identify an MBS session. Then, the core network network element (for example, the NEF / MBSF) performs authorization verification on the AF, and only opens the MBS session configuration permission to the AF that passes the authorization verification.

[0076] In another example, the MBS session configuration procedure can be initiated by the MB-SMF. This scenario is usually to support multicast service without AF, or to support multicast service that AF does not initiate the MBS session configuration procedure. In this scenario, the operator can pre-configure some default quality of service (QoS) information and the like for the multicast service. When the unicast SMF detects the request of the UE to join the multicast service, the unicast SMF sends an information query request to the MB-SMF, and then the MB-SMF initiates the MBS session configuration procedure.

[0077] The present application mainly focuses on the MBS session establishment procedure, and does not introduce the MBS session configuration procedure in detail.

[0078] As shown in Figure 2 , a communication process schematic diagram is introduced.

[0079] Step 201: The UE sends a request message for joining the MBS session to the unicast SMF, and the message contains the MBS session ID.

[0080] For example, the MBS session ID is a multicast address (such as an IP multicast address), indicating that the UE requests to join the multicast session corresponding to the multicast address.

[0081] For example, the UE sends the request message for joining the MBS session to the unicast SMF through the established unicast session in the form of a protocol data unit (PDU) session modification request message through N1 message, and the request message contains the MBS session ID.

[0082] Step 202: UE authorization is performed.

[0083] For example, the unicast SMF sends an authorization request for the UE to a unified data management (UDM) network element, verifies the subscription information of the UE, and determines whether the UE can use the multicast service. When it is determined that the UE can use the multicast service, the subsequent steps are executed.

[0084] Step 203: If the unicast SMF queries that there is no context information of the MBS session locally, it means that the unicast SMF has not established an association with the MBS session, and then the unicast SMF queries the MB-SMF corresponding to the MBS session from the NRF. It is also understood that the MB-SMF serving the MBS session is queried from the NRF.

[0085] Step 204: The NRF feeds back the MB-SMF to the unicast SMF.

[0086] For example, if the NRF queries an MB-SMF currently serving the MBS session, the MB-SMF currently serving the MBS session can be fed back to the unicast SMF. If the NRF does not query an MB-SMF currently serving the MBS session, one or more MB-SMFs are selected according to slice information and the like, and fed back to the unicast SMF.

[0087] Here, the "feedback MB-SMF" can be to feed back entity information of the MB-SMF based on registration information of the MB-SMF. The entity information can be part of the registration information.

[0088] Step 205: The unicast SMF initiates an information query request to the MB-SMF to query related information of the MBS session, and the query request includes the MBS session ID.

[0089] The related information is, for example, quality of service (QoS) information corresponding to the MBS session.

[0090] After receiving the information query request, the MB-SMF can query whether there is context information of the MBS session locally. If there is no context information of the MBS session locally, it means that the multicast address has not been configured for the multicast session, and the MB-SMF can initiate an MBS session configuration procedure.

[0091] Step 206: The MB-SMF feeds back the related information of the MBS session, for example, QoS information, to the unicast SMF.

[0092] The MBS session establishment procedure can be performed next, for example, the following procedures are performed:

[0093] The unicast SMF feeds back context information corresponding to the MBS session to the RAN through the AMF, and determines to add the UE to the multicast session.

[0094] The RAN initiates an MBS session establishment procedure to establish a downlink data path from a content provider to the RAN according to whether the RAN can already receive downlink data of the multicast session.

[0095] The RAN notifies the UE of the success of joining the group and allocates transmission resources on the RAN side.

[0096] The RAN reports the execution of the UE joining the multicast group to the unicast SMF, and the unicast SMF records and adjusts context information related to the UE.

[0097] In Figure 2In the example, only the authorization verification of whether the UE can use the multicast service (for example, step 202) is performed, and no authorization verification is performed for the multicast service (which can also be understood as the multicast address requested by the terminal device). This will cause the following problems: if the multicast address requested by the UE to join is not within a reasonable range (for example, the range allowed by the operator), the MB-SMF will still perform a session configuration process for the multicast service, and the network elements involved in the session configuration process, such as the MB-SMF, the MB-UPF, and the UE, will all reserve resources for the multicast service. However, since the multicast address is illegal, the operator cannot provide multicast services for the multicast address, resulting in context occupation and resource waste. If an illegal UE uses this mechanism to perform a DDoS attack, it may cause normal multicast services to be unable to be used.

[0098] Based on this, the present application proposes various schemes to perform authorization verification on the multicast service to avoid resource waste or illegal attacks.

[0099] As shown in Figure 3 , a communication method flowchart is provided, including the following steps:

[0100] It should be noted that the first SMF network element is a unicast SMF network element, and the second SMF network element is an MB-SMF network element. The SMF that establishes a multicast session for a multicast address corresponding multicast service can also be an MB-SMF. The SMF that supports establishing a multicast session for a multicast service can also be an MB-SMF.

[0101] Step 301: The terminal device sends a first message to the first SMF network element, and correspondingly, the first SMF network element receives the first message from the terminal device.

[0102] The first message includes a multicast address, and the first message is used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address.

[0103] Step 302: The first SMF network element sends a second message to a network registration function (NRF) network element, and correspondingly, the network registration function (NRF) network element receives the second message from the first SMF network element.

[0104] The second message includes the multicast address, and the second message is used to query an SMF that establishes a multicast session for a multicast service corresponding to the multicast address.

[0105] It should be noted that in the prior art, when querying the SMF corresponding to the multicast service of the multicast address (for example, querying the MB-SMF in step 203), the session establishment scenario or the session configuration scenario is not distinguished, but in the present application, the second message is different from the existing query message, and the second message of the present application can distinguish the multicast session establishment scenario and the multicast session configuration scenario, so that the NRF network element can perform different actions corresponding to different scenarios. In Figure 3 In the scheme, the NRF can distinguish through the second message that the SMF to be queried in the current scenario is used to establish a multicast session, not to configure a multicast session.

[0106] The second message can be a new message or an improvement on the existing message.

[0107] In an optional example, the second message can further include a first indication indicating the establishment of a multicast session. By improving the existing message and adding a new indication information in the existing message to indicate the establishment of a multicast session scenario, the generality is stronger.

[0108] For the NRF network element, it can query the SMF for establishing a multicast session for the multicast service corresponding to the multicast address, and then step 303b and step 304b can be performed after step 302. It can also not query the SMF for establishing a multicast session for the multicast service corresponding to the multicast address, and then step 303a and step 304a can be performed after step 302. The following is divided into embodiment 1 and embodiment 2 for introduction.

[0109] Embodiment 1: No SMF is queried for establishing a multicast session for the multicast service corresponding to the multicast address.

[0110] Step 303a: The NRF network element sends a third message to the first SMF network element, and correspondingly, the first SMF network element receives the third message from the NRF network element.

[0111] The third message is used to indicate that no SMF is queried for establishing a multicast session for the multicast service corresponding to the multicast address.

[0112] In an optional example, the third message includes a second indication indicating query failure. The second indication can occupy one bit, for example, 0 represents query failure and 1 represents query success. By indicating through the indication information, the occupied bit can be saved, and resources can be saved.

[0113] In an alternative example, the third message includes: an empty SMF list. The empty SMF list can be an empty list with a table header form. When the third message includes an empty SMF list, the third message can be in the format of an existing message, which is more general.

[0114] In an alternative example, the third message includes: a second indication and an empty SMF list. The SMF that is not queried to establish the multicast session for the multicast service corresponding to the multicast address is indicated by the second indication and / or the empty SMF list.

[0115] In an alternative example, the SMF that is not queried to establish the multicast session for the multicast service corresponding to the multicast address is indicated by the message name of the third message.

[0116] The NRF network element can indicate to the first SMF network element that the SMF that is not queried to establish the multicast session for the multicast service corresponding to the multicast address in the following cases:

[0117] Case la: when the allowed multicast address of the SMF that supports establishing the multicast session for the multicast service does not include the multicast address.

[0118] Case 2a: when there is no SMF currently serving the multicast service corresponding to the multicast address, and the allowed multicast address of the SMF that supports establishing the multicast session for the multicast service does not include the multicast address.

[0119] It should be noted that for any multicast address, if the SMF that serves the multicast service corresponding to the multicast address is selected based on the condition that the allowed multicast address of the SMF must include the multicast address, then the SMF that currently serves the multicast service corresponding to the multicast address must be one of the SMFs whose allowed multicast address includes the multicast address.

[0120] If the SMF that serves the multicast service corresponding to any multicast address is selected based on the condition that the allowed multicast address of the SMF includes the multicast address, or other conditions (e.g., based on slice selection, AF selection), then the SMF that currently serves the multicast service corresponding to the multicast address can or can not be one of the SMFs whose allowed multicast address includes the multicast address.

[0121] Based on this, if the SMF currently serving the multicast service corresponding to the multicast address is any of the SMFs allowing multicast addresses including the multicast address, as long as the multicast session establishment-enabled SMF does not allow the multicast address, it can be determined that there is no SMF currently serving the multicast service corresponding to the multicast address, and it can be unnecessary to repeatedly determine whether there is an SMF currently serving the multicast service corresponding to the multicast address.

[0122] If the SMF currently serving the multicast service corresponding to the multicast address can or can not be any of the SMFs allowing multicast addresses including the multicast address, it can be determined whether there is an SMF currently serving the multicast service corresponding to the multicast address first. When there is no SMF currently serving the multicast service corresponding to the multicast address, it is determined whether the multicast session establishment-enabled SMF allows the multicast address.

[0123] In addition, the SMF establishing the multicast session for the multicast service can report its allowed multicast address to the NRF network element, and correspondingly, the NRF network element can receive the allowed multicast address of the SMF enabling the establishment of the multicast session for the multicast service. In this way, the NRF network element can determine whether the multicast address requested by the terminal device is included in the allowed multicast address of the SMF enabling the establishment of the multicast session for the multicast service, and when the multicast address requested by the terminal device is not included in the allowed multicast address, the terminal device can be rejected to join the multicast session corresponding to the multicast address.

[0124] The allowed multicast address in the SMF can be configured by the operator to the SMF.

[0125] Case 3a: the case where the operator's allowed multicast address does not include the multicast address.

[0126] The NRF can query whether the multicast address requested by the terminal device is included in the operator's allowed multicast address.

[0127] For example, the operator can configure the operator's allowed multicast address in the NRF, for example, the NRF network element receives the operator's allowed multicast address. In this way, the NRF network element can locally query whether the multicast address belongs to the operator's allowed multicast address. In this case 3a, the operator's allowed multicast address does not include the multicast address requested by the terminal device.

[0128] For another example, the operator can configure allowed multicast addresses in a unified data storage (UDR), and the NRF queries the UDR network element to determine whether the multicast address requested by the terminal device belongs to the allowed multicast addresses of the operator. In this case 3a, the allowed multicast addresses of the operator do not include the multicast address requested by the terminal device.

[0129] An optional example can further limit case 3a, there is no SMF currently serving the multicast service corresponding to the multicast address, and the allowed multicast addresses of the operator do not include the multicast address. The NRF network element indicates to the first SMF network element that no SMF is found for establishing a multicast session for the multicast service corresponding to the multicast address.

[0130] Step 304a: The first SMF network element sends a fourth message to the terminal device, and the fourth message is used to indicate that the terminal device is rejected to join the multicast session corresponding to the multicast address.

[0131] In the prior art, when there is no SMF currently serving the multicast service corresponding to the multicast address, the NRF selects an MB-SMF according to slice information and the like, and feeds back the first SMF for establishing / configuring a multicast session. In this embodiment 1, the NRF can distinguish, through the second message, that the SMF to be queried in the current scenario is for establishing a multicast session, rather than for configuring a multicast session. In the scenario of establishing a multicast session, the SMF network element can perform authorization verification on the multicast service, and when the authorization verification fails, sends indication information of rejection to join to the terminal device, so as to avoid resource waste of the terminal device. In addition, in the authorization verification process, the SMF network element queries the NRF network element for a suitable SMF, and determines whether the authorization verification passes according to the query result. If the NRF network element does not allocate an SMF to the first SMF network element for establishing a multicast session, the authorization verification fails. Not allocating an SMF can avoid resource waste and illegal attacks.

[0132] Embodiment 2: Querying an SMF for establishing a multicast session for the multicast service corresponding to the multicast address.

[0133] Step 303b: The NRF network element sends a third message to the first SMF network element, and correspondingly, the first SMF network element receives the third message from the NRF network element.

[0134] The third message includes a second SMF, and the second SMF supports establishing a multicast session for the multicast service corresponding to the multicast address.

[0135] The NRF network element can indicate the second SMF to the first SMF network element in the following cases:

[0136] Case 1b: a case where there exists an SMF currently serving the multicast session corresponding to the multicast address.

[0137] In the case where there exists an SMF currently serving the multicast address, the SMF currently serving the multicast address is determined as the second SMF. Then, the second SMF is the SMF currently serving the multicast session corresponding to the multicast address.

[0138] An optional example can further limit case 1b, there exists an SMF currently serving the multicast session corresponding to the multicast address, and the allowed multicast address of the operator includes the multicast address, the NRF network element indicates the second SMF to the first SMF network element.

[0139] Case 2b: a case where the allowed multicast address of the SMF supporting establishing a multicast session for the multicast service includes the multicast address.

[0140] The NRF network element can first determine whether there exists an SMF currently serving the multicast session corresponding to the multicast address. When there does not exist an SMF currently serving the multicast session corresponding to the multicast address, it is then determined whether the allowed multicast address of the SMF supporting establishing a multicast session for the multicast service includes the multicast address. If the allowed multicast address of a certain SMF supporting establishing a multicast session for the multicast service includes the multicast address requested by the terminal device, the SMF can be determined as the second SMF. That is, in the case where there does not exist an SMF currently serving the multicast address, the SMF whose allowed multicast address includes the multicast address can be determined as the second SMF, and then the allowed multicast address of the second SMF includes the multicast address.

[0141] In addition, the SMF (including the second SMF) supporting establishing a multicast session for the multicast service can report its allowed multicast address to the NRF network element, and correspondingly, the NRF network element can receive the allowed multicast address of the SMF (including the second SMF) supporting establishing a multicast session for the multicast service. In this way, the NRF network element can determine whether the multicast address requested by the terminal device is included in the allowed multicast address of the SMF (including the second SMF) supporting establishing a multicast session for the multicast service, and when the multicast address requested by the terminal device is included in the allowed multicast address, the SMF whose allowed multicast address includes the multicast address can be informed to the first SMF.

[0142] The allowed multicast address in the SMF can be configured to the SMF by an operator.

[0143] Case 3b: in the case that there is no SMF currently serving the multicast service corresponding to the multicast address, and the multicast address belongs to the multicast address allowed by the operator, the NRF network element establishes a multicast session configuration SMF for the multicast service corresponding to the multicast address. Further, a third message is sent to the first SMF network element, and the third message includes the second SMF.

[0144] An optional example, the NRF network element can first determine whether there is an SMF currently serving the multicast service corresponding to the multicast address. When there is an SMF currently serving the multicast service corresponding to the multicast address, the SMF currently serving the multicast address can be determined as the second SMF. Corresponding to case 1b.

[0145] When there is no SMF currently serving the multicast service corresponding to the multicast address, it can be further queried whether the multicast address requested by the terminal device belongs to the multicast address allowed by the operator. If the multicast address belongs to the multicast address allowed by the operator, the NRF network element establishes a multicast session configuration SMF for the multicast service corresponding to the multicast address.

[0146] An optional example, the NRF network element can first query whether the multicast address requested by the terminal device belongs to the multicast address allowed by the operator. If not, it corresponds to the case 3a described above; if yes, it can be further determined whether there is an SMF currently serving the multicast service corresponding to the multicast address.

[0147] For example, the operator can configure the multicast address allowed in the NRF, for example, the NRF network element receives the multicast address allowed by the operator. In this way, the NRF network element can locally query whether the multicast address belongs to the multicast address allowed by the operator. In this case 3b, the multicast address allowed by the operator includes the multicast address requested by the terminal device.

[0148] For another example, the operator can configure the multicast address allowed in the unified data storage UDR, and then the NRF queries the unified data storage UDR network element whether the multicast address belongs to the multicast address allowed by the operator. In this case 3b, the multicast address allowed by the operator includes the multicast address requested by the terminal device.

[0149] Step 304b: the first SMF network element sends a fourth message to the terminal device, and the fourth message is used to indicate that the terminal device is accepted to join the multicast session corresponding to the multicast address.

[0150] In the prior art, when there is no SMF currently serving the multicast service corresponding to the multicast address, the NRF selects an MB-SMF according to slice information and the like, and feeds back the MB-SMF to the first SMF for establishing / configuring a multicast session. In this embodiment 2, the NRF can distinguish, through the second message, that the SMF to be queried in the current scenario is for establishing a multicast session, rather than for configuring a multicast session. In the scenario of establishing a multicast session, the SMF network element can perform authorization verification on the multicast service, and send indication information of accepting joining to the terminal device when the authorization verification is passed. In addition, in the authorization verification process, the SMF network element queries the NRF network element for a suitable SMF, and determines whether the authorization verification is passed according to the query result. If the NRF network element allocates an SMF to the first SMF network element for establishing a multicast session, the authorization verification is passed, thereby realizing reasonable multicast service provision for the terminal device.

[0151] As shown in Figure 4 , a communication mode flowchart is introduced. In this example, an SMF supporting establishment of a multicast session for a multicast service reports to the NRF, and the multicast address allowed by the SMF can be applicable to the cases of 1a, 2a, 1b, 2b and the like introduced above.

[0152] Step 400: An SMF supporting establishment of a multicast session for a multicast service (for the convenience of understanding, the SMF supporting establishment of a multicast session for a multicast service is referred to as MB-SMF hereinafter) reports to the NRF, and the multicast address allowed by the MB-SMF. Correspondingly, the NRF network element receives the multicast address allowed by the MB-SMF.

[0153] The MB-SMF can report the multicast address allowed by the MB-SMF when creating a network function profile (NF profile create), or can report the multicast address allowed by the MB-SMF when updating a network function profile (NF profile update). For example, the MB-SMF includes the multicast address allowed by the MB-SMF in the NF profile when creating or updating the NF profile of the MB-SMF to the NRF.

[0154] The multicast address allowed can be pre-configured by an operator to the MB-SMF, and the MB-SMF can serve a multicast service corresponding to a pre-configured multicast address.

[0155] The multicast address allowed can be one, or can be multiple, or can be a range of allowed multicast addresses, and the multicast address allowed can be reported to the NRF in the form of a list.

[0156] For example, the multicast address is an IP multicast address.

[0157] Step 401: The terminal device sends a first message to a first SMF network element, and correspondingly, the first SMF network element receives the first message from the terminal device.

[0158] The first message includes a multicast address, and the first message is used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address.

[0159] The first message can be a request, for example, an MBS session join request.

[0160] For example, when the UE detects that the application layer sends an internet group management protocol (IGMP) Join message of a multicast address, the UE sends an MBS session join request to the first SMF, and the request includes the multicast address.

[0161] For example, the UE sends an MBS session join request to the first SMF through an established unicast session in the form of a PDU session modification request message through an N1 message.

[0162] Optionally, the UE can be verified (UE authorization). For example, the first SMF sends an authorization request for the UE to a unified data management (UDM) network element, verifies the subscription information of the UE, and determines whether the UE can use multicast services. When it is determined that the UE can use multicast services, subsequent steps are performed. This step can also not be performed.

[0163] Step 402: The first SMF network element sends a second message to a network registration function (NRF) network element, and correspondingly, the network registration function (NRF) network element receives the second message from the first SMF network element.

[0164] The second message includes the multicast address, and the second message is used to query an SMF that establishes a multicast session for a multicast service corresponding to the multicast address.

[0165] It should be noted that here, the SMF that establishes a multicast session for a multicast service corresponding to the multicast address is queried, rather than the SMF that configures a multicast session for a multicast service corresponding to the multicast address.

[0166] The first SMF can first query whether there is context information corresponding to the multicast address locally, and if there is no context information corresponding to the multicast address locally, it indicates that the first SMF has not established an association with the multicast address. The first SMF can use the multicast address to query the NRF for an SMF that establishes a multicast session for the multicast service corresponding to the multicast address.

[0167] The second message can be a request, for example, a network function discovery request (Nnrf NF Discovery request) of a service interface.

[0168] The second message can be a new message or an improvement on an existing message. For example, the existing network function discovery request (NF Discovery request) is improved, for example, a session establishment indication (session Establishment indication) is added in the existing network function discovery request (NF Discovery request), that is, the first indication introduced above, which is used to indicate the establishment of a multicast session.

[0169] Step 403: The NRF network element sends a third message to the first SMF network element, and correspondingly, the first SMF network element receives the third message from the NRF network element.

[0170] The third message is used to indicate that the SMF that establishes a multicast session for the multicast service corresponding to the multicast address is not queried. Alternatively, the third message includes a second SMF (MB-SMF instance), and the second SMF supports establishing a multicast session for the multicast service corresponding to the multicast address.

[0171] It can also be understood that the NRF performs a MS-SMF profile query for an unconfigured MBS session.

[0172] The NRF can query the profile of the MB-SMF, and the profile records the allowed multicast addresses of each MB-SMF.

[0173] If the SMF currently serving the multicast service corresponding to the multicast address is not found, the multicast address can also be queried in the multicast address allowed by the MB-SMF. If the multicast address is not included in the multicast address allowed by the MB-SMF (it can also be understood that there is no MB-SMF allowed to serve the multicast service corresponding to the multicast address), the NRF no longer allocates the MB-SMF for the multicast service corresponding to the multicast address, and the NRF can feed back to the first SMF that no SMF is found to establish a multicast session for the multicast service corresponding to the multicast address. The SMF not found to establish a multicast session for the multicast service corresponding to the multicast address may, for example, be a failed query or an empty MB-SMF list.

[0174] If the SMF currently serving the multicast service corresponding to the multicast address is found, the NRF can feed back to the first SMF the related information of the SMF currently serving the multicast service corresponding to the multicast address. If the multicast address is queried in the multicast address allowed by the MB-SMF, the NRF can feed back to the first SMF the SMF whose multicast address allowed includes the multicast address (it can also be understood as the MB-SMF allowed to serve the multicast service corresponding to the multicast address). When the multicast address is queried in the multicast address allowed by multiple MB-SMFs, one MB-SMF or multiple MB-SMFs can be fed back to the first SMF, for example, the entity list of the MB-SMF is sent to the SMF.

[0175] The third message can be a response, for example, a network function discovery response (Nnrf NF Discovery response) of a service interface.

[0176] It should be noted that if the second message queries the SMF configured to establish a multicast session for the multicast service corresponding to the multicast address. The application does not limit the processing process of the NRF.

[0177] Next, the first SMF performs corresponding actions according to the third message fed back by the NRF.

[0178] Step 404a: If the second SMF is included in the third message, the first SMF authorizes the join request corresponding to the multicast address (accepts the UE to join) when it is determined that the NRF finds the SMF that can establish a multicast session for the multicast service corresponding to the multicast address.

[0179] Optionally, when the third message includes multiple second SMFs, the first SMF can also select the MB-SMF.

[0180] Step 404b: If the third message indicates that no SMF is found to establish the multicast session for the multicast address, the join request corresponding to the multicast address is rejected, and the first SMF can send indication information to the UE or the access network device to reject the terminal device to join the multicast session corresponding to the multicast address.

[0181] Step 405: The first SMF sends an information query request to the second SMF, and the second SMF receives the information query request from the first SMF. The information query request is used to query the related information of the multicast session corresponding to the multicast address, such as Qos information. The multicast address is included in the information query request.

[0182] The information query request may be, for example, Nmbsmf information request, where N represents the service interface Nnrf and mbsmf represents MB-SMF.

[0183] Step 406: The second SMF queries whether there is context information of the multicast address locally. If there is no context information of the multicast address locally, it indicates that the multicast address has not been configured for the multicast session, and the second SMF can decide to initiate the configuration of the multicast session.

[0184] Step 407: The second SMF initiates the MBS session configuration procedure to configure the multicast session corresponding to the multicast address.

[0185] Step 408: After the multicast session configuration is completed, the second SMF feeds back an information query response to the first SMF.

[0186] The information query response may be, for example, Nmbsmf information response.

[0187] The information query response may include Qos information.

[0188] Step 409: Multicast session establishment procedure.

[0189] In Figure 4In the example, when the MB-SMF registers or updates to the NRF, the MB-SMF informs the NRF of the allowed multicast address range. In addition, the second message can distinguish between a multicast session establishment scenario and a multicast session configuration scenario. When the second message is used to establish a multicast session, the NRF queries the MB-SMF entity, and preferentially queries the MB-SMF currently serving the multicast service corresponding to the multicast address. If there is no MB-SMF currently serving the multicast service corresponding to the multicast address, the MB-SMF is queried again for the multicast address (i.e., the MB-SMF allowed to serve the multicast service corresponding to the multicast address is queried again), and if none of them can be queried, an unqueried indication is returned to the first SMF. Compared with the prior art, when the second message is used to establish a multicast session, the unqueried message can be fed back, and a new MB-SMF is no longer allocated, so that for illegal requests, the unqueried indication can be used for identification. When other query requests for establishing a multicast session, such as AF / NEF / MBSF, are queried, according to the existing normal logic, when the MB-SMF cannot be queried, a new MB-SMF is allocated according to other information such as slices and DNNs.

[0190] As shown in Figure 5 , a communication method flowchart is provided. In this example, the operator configures the allowed multicast address to the NRF, which can be applicable to the 3a, 3b, etc. introduced above.

[0191] Step 500a: The operator sends the allowed multicast address of the operator to the NRF, and these allowed multicast addresses can support the configuration process of the multicast session triggered by the UE Join.

[0192] Step 500b: The operator sends the allowed multicast address of the operator to the UDR, and these allowed multicast addresses can support the configuration process of the multicast session triggered by the UE Join.

[0193] Step 501: The terminal device sends a first message to the first SMF network element, and correspondingly, the first SMF network element receives the first message from the terminal device.

[0194] The first message includes a multicast address, and the first message is used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address.

[0195] Step 501 is the same as step 401, and will not be repeated.

[0196] Step 502: The first SMF network element sends a second message to the network registration function NRF network element, and correspondingly, the network registration function NRF network element receives the second message from the first SMF network element.

[0197] The second message includes the multicast address, and the second message is used to query the SMF for establishing a multicast session for a multicast service corresponding to the multicast address.

[0198] Step 502 is the same as step 402, and will not be repeated.

[0199] Step 503a: The NRF network element locally queries whether the multicast address belongs to the multicast address allowed by the operator.

[0200] Step 503b: The NRF network element queries the UDR network element whether the multicast address belongs to the multicast address allowed by the operator.

[0201] Steps 503a and 503b can be selected to be executed, or both can be executed.

[0202] For example, after receiving the second message, the NRF network element can query the UDR whether the multicast address belongs to the multicast address allowed by the operator. Alternatively, after receiving the second message, the NRF network element can first query whether there is an SMF currently serving the multicast service corresponding to the multicast address, and if no SMF currently serving the multicast service corresponding to the multicast address is queried, the NRF queries the UDR whether the multicast address belongs to the multicast address allowed by the operator.

[0203] Step 504: The NRF network element sends a third message to the first SMF network element, and correspondingly, the first SMF network element receives the third message from the NRF network element.

[0204] The third message is used to indicate that no SMF for establishing a multicast session for the multicast service corresponding to the multicast address is queried. Alternatively, the third message includes a second SMF (MB-SMF instance) that supports establishing a multicast session for the multicast service corresponding to the multicast address. If the multicast address does not belong to the multicast address allowed by the operator, the NRF does not allocate the MB-SMF for the multicast service corresponding to the multicast address, and the NRF can feed back to the first SMF that no SMF for establishing a multicast session for the multicast service corresponding to the multicast address is queried. No SMF for establishing a multicast session for the multicast service corresponding to the multicast address is queried, for example, the query fails or the MB-SMF list is empty.

[0205] If the SMF currently serving the multicast service corresponding to the multicast address is queried, the NRF can feed back to the first SMF the related information of the SMF currently serving the multicast service corresponding to the multicast address.

[0206] If the multicast address belongs to the multicast address allowed by the operator, the NRF network element establishes a multicast session configuration SMF for the multicast service corresponding to the multicast address. Further, a third message is sent to the first SMF network element, and the third message includes the second SMF.

[0207] The third message can be a response, for example, a network function discovery response (Nnrf NF Discovery response) of a service interface.

[0208] It should be noted that if the second message queries the SMF for configuring the multicast session for the multicast service corresponding to the multicast address. The application does not limit the processing process of the NRF.

[0209] Next, the first SMF performs corresponding actions according to the third message fed back by the NRF.

[0210] The steps 505a and 505b described below are the same as the steps 404a and 404b, and the steps 506-510 are the same as the steps 405-409.

[0211] Step 505a: If the second SMF is included in the third message, the first SMF authorizes the join request corresponding to the multicast address (accepts the UE to join) if the NRF queries the SMF that can establish the multicast session for the multicast service corresponding to the multicast address.

[0212] Optionally, when the third message includes multiple second SMFs, the first SMF can also select the MB-SMF.

[0213] Step 505b: If the third message indicates that no SMF is queried for establishing the multicast session for the multicast service corresponding to the multicast address, the join request corresponding to the multicast address is rejected, and the first SMF can subsequently send indication information rejecting the terminal device to join the multicast session corresponding to the multicast address to the UE or the access network device.

[0214] Step 506: The first SMF sends an information query request to the second SMF, and correspondingly, the second SMF receives the information query request from the first SMF. The information query request is used to query the related information for establishing the multicast session corresponding to the multicast address, for example, Qos information. The multicast address is included in the information query request.

[0215] The information query request can be, for example, Nmbsmf information request, wherein N represents the service interface Nnrf mbsmf represents the MB-SMF.

[0216] Step 507: The second SMF queries whether there is context information for the multicast address locally. If there is no context information for the multicast address locally, it means that the multicast address has not been configured for a multicast session, and then it can be decided to initiate a configuration multicast session (decide to ConfigurationMBS Session).

[0217] Step 508: The second SMF initiates the MBS Session Configuration process to configure the multicast session corresponding to the multicast address.

[0218] Step 509: After the multicast session configuration is completed, the second SMF sends a response to the first SMF regarding the information query.

[0219] The information query response could be, for example, an Nmbsmf information response.

[0220] The query response may include QoS information.

[0221] Step 510: Multicast session establishment procedure.

[0222] exist Figure 5 In the example, the operator configures the range of multicast addresses allowed by the operator to the NRF or UDR. Additionally, the second message can distinguish between multicast session establishment scenarios and multicast session configuration scenarios. When the second message is used to establish a multicast session, if the NRF queries the MB-SMF entity and there is no MB-SMF currently serving the multicast service corresponding to that multicast address, and that multicast address is not within the operator's allowed multicast addresses, it replies to the first SMF with a "not found" indication. Compared to existing technologies, when the second message is used to establish a multicast session, it can return a "not found" message and not allocate a new MB-SMF. This allows for the identification of illegal requests through the "not found" indication. For other query requests used to establish multicast sessions, such as queries for AF / NEF / MBSF, according to existing normal logic, if no available MB-SMF is found, a new MB-SMF is allocated based on other information such as slices and DNN.

[0223] The methods of the embodiments of this application have been introduced above. The apparatus of the embodiments of this application will be described below. The methods and apparatus are based on the same technical concept. Since the principles of solving the problem by the methods and apparatus are similar, the implementation of the apparatus and methods can refer to each other, and the repeated parts will not be described again.

[0224] The embodiments of the present application can divide the device into functional modules according to the above method examples. For example, each function can be divided into a functional module, two or more functions can be integrated into one module, the module can be realized in the form of hardware or software function module. It should be noted that the division of the modules in the embodiments of the present application is illustrative, and is only a logical function division. When implemented, another division mode can be used.

[0225] Based on the same technical concept as the above method, referring to Figure 6 , a communication device 600 structure diagram is provided, which can include a processing module 610, and optionally, a receiving module 620a, a sending module 620b, and a storage module 630. The processing module 610 can be connected to the storage module 630, the receiving module 620a, and the sending module 620b, respectively, and the storage module 630 can also be connected to the receiving module 620a and the sending module 620b.

[0226] In an example, the receiving module 620a and the sending module 620b described above can also be integrated together, defined as a transceiver module.

[0227] In an example, the device 600 can be a first SMF network element, or a chip or functional unit applied to the first SMF network element. The device 600 has any function of the first SMF network element in the above method, for example, the device 600 can perform each step executed by the first SMF network element in the methods described above Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 .

[0228] The receiving module 620a can perform the receiving actions performed by the first SMF network element in the method embodiments described above.

[0229] The sending module 620b can perform the sending actions performed by the first SMF network element in the method embodiments described above.

[0230] The processing module 610 can perform other actions in addition to the sending actions and the receiving actions performed by the first SMF network element in the method embodiments described above.

[0231] In an example, the receiving module 620a is configured to receive a first message from a terminal device, the first message including a multicast address, the first message being used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address.

[0232] The sending module 620b is configured to send a second message to a network registration function (NRF) network element, where the second message includes the multicast address, and the second message is used to query an SMF that establishes a multicast session for a multicast service corresponding to the multicast address.

[0233] The receiving module 620a is further configured to receive a third message from the NRF, where the third message is used to indicate that no SMF that establishes a multicast session for a multicast service corresponding to the multicast address is queried.

[0234] The sending module 620b is further configured to send a fourth message to the terminal device, where the fourth message is used to indicate that the terminal device is rejected to join the multicast session corresponding to the multicast address.

[0235] In an example, the receiving module 620a is configured to receive a first message from a terminal device, where the first message includes a multicast address, and the first message is used to indicate that the terminal device requests to join a multicast session corresponding to the multicast address.

[0236] The sending module 620b is configured to send a second message to a network registration function (NRF) network element, where the second message includes the multicast address, and the second message is used to query an SMF that establishes a multicast session for a multicast service corresponding to the multicast address.

[0237] The receiving module 620a is configured to receive a third message from the NRF, where the third message includes a second SMF that supports establishing a multicast session for a multicast service corresponding to the multicast address.

[0238] The sending module 620b is configured to send a fourth message to the terminal device, where the fourth message is used to indicate that the terminal device is accepted to join the multicast session corresponding to the multicast address.

[0239] The processing module 610 is configured to generate the second message, generate the fourth message, and the like.

[0240] In an example, the storage module 630 can store computer-executed instructions of a method executed by a first SMF network element, so that the processing module 610 and the receiving module 620a and the sending module 620b execute the method executed by the first SMF network element in the above example.

[0241] In an example, the storage module can include one or more memories, and the memory can be a device for storing programs or data in one or more devices or circuits. The storage module can be a register, a cache, or a RAM, and the storage module can be integrated with the processing module. The storage module can be a ROM or other type of static storage device that can store static information and instructions, and the storage module can be independent of the processing module.

[0242] The transceiver module can be an input or output interface, a pin, or a circuit, etc.

[0243] In an example, the apparatus 600 can be an NRF network element, or a chip or functional unit applied in the NRF network element. The apparatus 600 has any function of the NRF network element in the above method, for example, the apparatus 600 can perform each step executed by the NRF network element in the method of the above Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 .

[0244] The receiving module 620a can perform the receiving action performed by the NRF network element in the above method embodiment.

[0245] The sending module 620b can perform the sending action performed by the NRF network element in the above method embodiment.

[0246] The processing module 610 can perform other actions in addition to the sending action and the receiving action performed by the NRF network element in the above method embodiment.

[0247] In an example, the receiving module 620a is configured to receive a second message from a first SMF network element, the second message including a multicast address, the second message being used to query an SMF for establishing a multicast session for a multicast service corresponding to the multicast address;

[0248] The sending module 620b is configured to send a third message to the first SMF network element, the third message being used to indicate that no SMF is queried for establishing a multicast session for a multicast service corresponding to the multicast address. Alternatively, the third message includes a second SMF, and the second SMF supports establishing a multicast session for a multicast service corresponding to the multicast address.

[0249] The processing module 610 is configured to locally query whether the multicast address belongs to a multicast address allowed by an operator.

[0250] The processing module 610 is configured to query a unified data storage (UDR) network element whether the multicast address belongs to a multicast address allowed by an operator.

[0251] In an example, the storage module 630 can store computer execution instructions of the method executed by the NRF network element, so that the processing module 610 and the receiving module 620a and the sending module 620b perform the method executed by the NRF network element in the above example.

[0252] The storage module can include one or more memories, which can be devices in one or more apparatuses or circuits for storing programs or data. The storage module can be a register, a cache, a RAM, or the like, and can be integrated with the processing module. The storage module can be a ROM or other type of static storage device that can store static information and instructions, and can be independent of the processing module.

[0253] The transceiver module can be an input or output interface, a pin, or a circuit, or the like.

[0254] As a possible product form, the apparatus can be implemented by a general bus architecture.

[0255] As shown in Figure 7 , a schematic block diagram of a communication apparatus 700 is provided.

[0256] The apparatus 700 can include a processor 710, and optionally a transceiver 720 and a memory 730. The transceiver 720 can be used to receive programs or instructions and transmit them to the processor 710, or the transceiver 720 can be used for the apparatus 700 to communicate with other communication devices, such as interaction control signaling and / or service data, etc. The transceiver 720 can be a code and / or data read-write transceiver, or the transceiver 720 can be a signal transmission transceiver between the processor and the transceiver. The processor 710 and the memory 730 are electrically coupled.

[0257] In an example, the apparatus 700 can be a first SMF network element, or a chip applied in the first SMF network element. It should be understood that the apparatus has any function of the first SMF network element in the above method, for example, the apparatus 700 can perform each step executed by the first SMF network element in the above method of Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 . For example, the memory 730 is configured to store a computer program, and the processor 710 is configured to invoke the computer program or instructions stored in the memory 730 to execute the method performed by the first SMF network element in the above example, or execute the method performed by the first SMF network element in the above example through the transceiver 720.

[0258] In an example, the apparatus 700 can be a NRF network element, or a chip applied in the NRF network element. It should be understood that the apparatus has any function of the NRF network element in the above method, for example, the apparatus 700 can perform each step executed by the NRF network element in the above method of Figure 2 、 Figure 3 、 Figure 4 、 Figure 5the method executed by the NRF network element in the examples. For example, the memory 730 is configured to store the computer program; the processor 710 is configured to invoke the computer program or instructions stored in the memory 730 to execute the method executed by the NRF network element in the examples above, or execute the method executed by the NRF network element in the examples above through the transceiver 720.

[0259] Figure 6 The processing module 610 in the apparatus can be implemented by the processor 710.

[0260] Figure 6 The receiving module 620a and the sending module 620b in the apparatus can be implemented by the transceiver 720. Alternatively, the transceiver 720 is divided into a receiver and a transmitter, the receiver performs the functions of the receiving module, and the transmitter performs the functions of the sending module.

[0261] Figure 6 The storage module 630 in the apparatus can be implemented by the memory 730.

[0262] As a possible product form, the apparatus can be implemented by a general-purpose processor (the general-purpose processor can also be referred to as a chip or a chip system).

[0263] In a possible implementation, the general-purpose processor implementing the apparatus applied to the first SMF network element or the apparatus of the NRF network element includes: a processing circuit (the processing circuit can also be referred to as a processor); and optionally, further includes: an input output interface in communication with the processing circuit, and a storage medium (the storage medium can also be referred to as a memory), the storage medium being configured to store instructions executed by the processing circuit to execute the method executed by the first SMF network element or the NRF network element in the examples above.

[0264] Figure 6 The processing module 610 in the apparatus can be implemented by the processing circuit.

[0265] Figure 6 The receiving module 620a and the sending module 620b in the apparatus can be implemented by the input output interface. Alternatively, the input output interface is divided into an input interface and an output interface, the input interface performs the functions of the receiving module, and the output interface performs the functions of the sending module.

[0266] Figure 6 The storage module 630 in the apparatus can be implemented by the storage medium.

[0267] As a possible product form, the apparatus of the embodiments of the present application can also be implemented using one or more FPGAs (field programmable gate arrays), PLDs (programmable logic devices), controllers, state machines, gate logic, discrete hardware components, any other suitable circuitry, or any combination of circuitry capable of performing the various functions described throughout this application.

[0268] The embodiments of the present application also provide a computer readable storage medium storing a computer program, which, when executed by a computer, can cause the computer to perform the above-mentioned communication method. In other words, the computer program includes instructions for implementing the above-mentioned communication method.

[0269] The embodiments of the present application also provide a computer program product, comprising: computer program code, which, when executed on a computer, causes the computer to perform the above-mentioned communication method.

[0270] The embodiments of the present application also provide a communication system, comprising: a first SMF network element and a NRF network element performing the above-mentioned communication method.

[0271] In addition, the processor mentioned in the embodiments of the present application can be a central processing unit (CPU), a baseband processor, a baseband processor and a CPU which can be integrated together or separated, and can also be a network processor (NP) or a combination of a CPU and an NP. The processor can further include a hardware chip or other general-purpose processors. The hardware chip can be an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL) and other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. or any combination thereof. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0272] The memory mentioned in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM) or a flash memory. The volatile memory can be a random access memory (Random Access Memory, RAM) used as an external cache. By way of example but not limitation, many forms of RAM can be used, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DR RAM). It should be noted that the memory described in the present application is intended to include but not limited to these and any other suitable types of memory.

[0273] The transceiver mentioned in the embodiments of the present application can include a separate transmitter and / or a separate receiver, or can be a transmitter and a receiver integrated together. The transceiver can work under the indication of the corresponding processor. Alternatively, the transmitter can correspond to the transmitter in the physical device, and the receiver can correspond to the receiver in the physical device.

[0274] Those skilled in the art can realize that, in combination with the method steps and units described in the embodiments disclosed herein, the methods and units can be realized in electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the steps and components of the embodiments have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0275] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely illustrative. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electric, mechanical or other forms.

[0276] The units described as separated components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments of the present application.

[0277] In addition, each functional unit in the embodiments of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be implemented in the form of hardware, or in the form of software functional units.

[0278] When the integrated unit is implemented in the form of software functional units and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such an understanding, the technical solutions of the present application essentially, or the part that makes a contribution to the prior art, or all or a part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and various other media that can store program codes.

[0279] The "and / or" in the present application describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the associated objects before and after it are in an "or" relationship. The plurality of the present application refers to two or more. In addition, it should be understood that in the description of the present application, "first", "second", and the like are used only to distinguish the description purpose, and cannot be understood as indicating or implying relative importance, nor can it be understood as indicating or implying order.

[0280] Although the preferred embodiments of the present application have been described, those skilled in the art who understand the basic creative concept can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0281] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A communication method, characterized in that, include: The first session management function (SMF) network element receives a first message from a terminal device. The first message includes a multicast address and is used to instruct the terminal device to request to join the multicast session corresponding to the multicast address. The first SMF network element sends a second message to the network registration function NRF network element. The second message includes the multicast address and is used to query the SMF that has established a multicast session for the multicast service corresponding to the multicast address. The first SMF network element receives a third message from the NRF network element. The third message indicates that no SMF was found to establish a multicast session for the multicast service corresponding to the multicast address. The third message includes an empty SMF list. The first SMF network element sends a fourth message to the terminal device, the fourth message being used to indicate that the terminal device is refused entry into the multicast session corresponding to the multicast address.

2. The method as described in claim 1, characterized in that, The second message also includes: a first instruction, which is used to instruct the establishment of a multicast session.

3. A communication method, characterized in that, include: The network registration function (NRF) network element receives a second message from the first SMF network element. The second message includes a multicast address and is used to query the SMF that has established a multicast session for the multicast service corresponding to the multicast address. The NRF network element sends a third message to the first SMF network element. The third message is used to indicate that no SMF has been found to establish a multicast session for the multicast service corresponding to the multicast address. The third message includes an empty SMF list.

4. The method as described in claim 3, characterized in that, The second message also includes: a first instruction, which is used to instruct the establishment of a multicast session.

5. The method as described in claim 3 or 4, characterized in that, The NRF network element sends a third message to the first SMF network element, including: If the allowed multicast addresses of the SMF supporting the establishment of multicast sessions for multicast services do not include the multicast address, the NRF network element sends a third message to the first SMF network element; or... If there is no SMF currently serving the multicast service corresponding to the multicast address, and the allowed multicast addresses of the SMF that supports establishing multicast sessions for multicast services do not include the multicast address, the NRF network element sends a third message to the first SMF network element. If the multicast address is not included in the operator's allowed multicast addresses, the NRF network element sends a third message to the first SMF network element.

6. The method as described in claim 5, characterized in that, The method further includes: The NRF network element receives an allowed multicast address of the SMF that supports establishing multicast sessions for multicast services, wherein the allowed multicast address does not include the multicast address.

7. The method as described in claim 5, characterized in that, The method further includes: The NRF network element receives the operator's allowed multicast address, wherein the operator's allowed multicast address does not include the multicast address.

8. A communication device, characterized in that, include: A functional module that implements the method as described in any one of claims 1-7.

9. A communication device, characterized in that, Including processor and memory; The memory is used to store computer programs or instructions; The processor is configured to execute some or all of the computer programs or instructions in the memory, and when the some or all of the computer programs or instructions are executed, to implement the method as described in any one of claims 1-7.

10. A chip system, characterized in that, The chip system includes: a processing circuit; the processing circuit is coupled to a storage medium; The processing circuit is configured to execute part or all of the computer program or instructions in the storage medium, and when the part or all of the computer program or instructions are executed, to implement the method as described in any one of claims 1-7.

11. A computer-readable storage medium, characterized in that, Used to store computer programs, which, when executed by a computer, are implemented as described in any one of claims 1-7.

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