CN110012437A

CN110012437A - A kind of sending method of multicast message, apparatus and system

Info

Publication number: CN110012437A
Application number: CN201810012362.0A
Authority: CN
Inventors: 李汉成
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-01-05
Filing date: 2018-01-05
Publication date: 2019-07-12
Anticipated expiration: 2038-01-05
Also published as: CN110012437B

Abstract

The application provides a kind of sending method of multicast message, apparatus and system.This method comprises: when first user's veil member cannot use the mode of Multicast Tunnel to send multicast message, it can not use and multicast message is passed through to each session that mode of unicast is sent to terminal respectively, and it only needs through the single tunnel between first user's veil member and communication network element, multicast message is sent to communication network element, is continued with by communication network element.Be conducive to the load bottleneck for avoiding the processing capacity of first user's veil member from becoming whole network, so as to realize the load balancing of network；Simultaneously as first user's veil member does not need copy packet to each session, to be conducive to mitigate the bandwidth consumption of copy packet bring.

Description

Method, device and system for sending multicast message

Technical Field

The present application relates to the field of mobile communications technologies, and in particular, to a method, an apparatus, and a system for sending a multicast packet.

Background

Multicast (multicast), also known as multicasting. Compared with unicast (unicast) for one-to-one communication and broadcast (broadcast) for one-to-all communication, multicast can efficiently solve the point-to-multipoint transmission and distribution problem. In multicast mode, data may be sent to a group of users along a particular path, with at most one copy of the same multicast data on each link. Compared with unicast, the information is transmitted by using a multicast mode, the load of the network is not obviously increased by the increase of users, and the load of the server and the equipment is reduced. A user who does not need this message cannot receive the message. Compared with broadcasting, the multicast data is only transmitted to the place with the receiver, thereby reducing redundant flow, saving network bandwidth and reducing network load.

In a 5th Generation (5G) communication system, a user plane network element of a core network may receive a multicast packet of a user, encapsulate the multicast packet in a multicast tunnel, and send the multicast packet as a multicast tunnel packet.

However, in practical applications, because there may be a situation that part of the network does not support multicast, the user plane network element cannot send a multicast packet in a multicast manner. Under the condition, the message can only be sent in a unicast mode at present, that is, the message is copied into each session of the terminal and sent to the terminal as a unicast message.

The main problems of the above method are: the deployment position of the user plane network element may be higher, that is, there are more network hierarchies between the user plane network element and the terminal, and there are more terminals gathered at the user plane network element, so that when the user plane network element sends a message in a unicast manner, the amount of the message that the user plane network element needs to copy is larger, the load is heavier, and further, the processing capability of the user plane network element will be referred to as a load bottleneck of the entire network, and the bandwidth consumption of the network will be increased.

Disclosure of Invention

The application provides a method, a device and a system for sending a multicast message, which are used for realizing load balance of a network and reducing bandwidth consumption caused by message duplication of a user plane network element.

In a first aspect, the present application provides a method for sending a multicast packet. The method may be performed by a user plane network element, e.g. by a first user plane network element. The method comprises the following steps: firstly, a first user plane network element receives a multicast message; then, the first user plane network element sends the multicast message to the communication network element through the first unicast tunnel. The first unicast tunnel is a tunnel between the first user plane network element and the communication network element and used for sending the multicast message.

According to the method, after receiving the multicast message, the first user plane network element can send the multicast message through the first unicast tunnel between the first user plane network element and the communication network element, so that even if the first user plane network element cannot send the multicast message through the multicast tunnel at present, the first unicast tunnel can be used for sending the multicast message to the communication network element, and then the communication network element selects to send the multicast message to the terminal in a multicast or unicast mode. The method realizes that when the first user plane network element can not send the multicast message in the multicast tunnel mode, the multicast message does not need to be sent to each session of the terminal in a unicast mode, and only the multicast message needs to be sent to the communication network element and is continuously processed by the communication network element. Therefore, the method is favorable for preventing the processing capacity of the first user plane network element from becoming the load bottleneck of the whole network, thereby realizing the load balance of the network; meanwhile, the first user plane network element does not need to copy the message to each session, so that the bandwidth consumption caused by message copying is favorably reduced.

Optionally, the communication network element may be a user plane network element (for example, referred to as a second user plane network element), or may also be an access gateway device, or may also be a wireless access device.

When the communication network element is a second user plane network element, if the second user plane network element can send the multicast message in the multicast tunnel mode, after receiving the multicast message sent by the first user plane network element, the second user plane network element can select to send the multicast message through the multicast tunnel, or alternatively, the second user plane network element can select to use a unicast mode to copy the multicast message to a session registered in a terminal of the second user plane network element, and then the multicast message is respectively sent to the terminal in the unicast mode.

Here, if the second user plane network element sends the multicast packet in the multicast tunnel mode, the following beneficial effects are provided: because the first user plane network element can not send the multicast message in the multicast tunnel mode, but can send the multicast message to the second user plane network element in the first unicast tunnel, and the second user plane network element can send the multicast message in the multicast tunnel mode, when only part of networks in the network support multicast, the multicast message can be sent to the user plane network element which can send the message in the multicast mode, the function of fully utilizing the user plane network element which can send the message in the multicast mode is realized, and the performance of the whole network is improved.

Here, if the second user plane network element sends the received multicast packet in a unicast manner, the following beneficial effects are provided: because the hierarchy between the second user plane network element and the terminal is less than the hierarchy between the first user plane network element and the terminal, the multicast message that the second user plane network element needs to copy is less than the first user plane network element, and therefore, even if the second user plane network element sends the received multicast message in a unicast manner, the occupied bandwidth resource is relatively less, thereby realizing load balance of the network and reducing bandwidth consumption caused by copying the message.

When the communication network element is an access gateway device, the received multicast packet may be copied to each session of the terminal in a unicast manner and sent to the terminal. Or, when the access gateway device itself supports the multicast capability, the received multicast message can be directly sent to the terminal by adopting the multicast mode, so that the multicast capability of the access gateway device can be fully utilized, and the performance of the whole network can be improved.

When the communication network element is a wireless access device, the received multicast packet may be broadcast to the terminal in a broadcast manner. Or, when the wireless access device supports the multicast capability, the received multicast message can be directly sent to the terminal by adopting the multicast mode, so that the multicast capability of the wireless access device can be fully utilized, and the performance of the whole network can be improved.

In a possible implementation manner, when a first unicast tunnel between a first user plane network element and a communication network element needs to be created, the first user plane network element may receive multicast group information and information of the first unicast tunnel from a session management network element, where the multicast group information is used to indicate a multicast packet sent in the first unicast tunnel. The information of the first unicast tunnel comprises identification information of the first unicast tunnel; alternatively, the information of the first unicast tunnel may further include address information of the communication network element and identification information of the first unicast tunnel.

In the foregoing implementation manner, when the communication network element has no multicast source, if the session management network element determines that the first user plane network element is the multicast source of the communication network element, the session management network element sends the multicast group information and the information of the first unicast tunnel to the first user plane network element, so that the first user plane network element can subsequently send the multicast packet identified by the multicast group information to the communication network element through the first unicast tunnel. That is, the first user plane network element may serve as a multicast source of the communication network element, and send a multicast packet to the communication network element.

In a possible implementation manner, if the first user plane network element does not have a multicast source, the first user plane network element may receive indication information from the session management network element, where the indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information. Optionally, the indication information may include a multicast join message, where the multicast join message includes the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information. Therefore, the first user plane network element may request to join the multicast group corresponding to the multicast group information through the received multicast join message, for example, may send a multicast join message to the multicast platform to request to join the multicast group corresponding to the multicast group information in the multicast platform.

In another possible implementation manner, if the first user plane network element determines that there is no multicast source corresponding to the multicast group information, a report message is sent to the session management network element, where the report message includes the multicast group information, and the report message is used to notify that the first user plane network element lacks a multicast source. That is, in this implementation, the user plane network element actively reports no multicast source to the session management network element, so that the subsequent session management network element may instruct the first user plane network element to request to join the multicast group corresponding to the multicast group information by sending the multicast join message.

In any of the foregoing implementation manners, the multicast packet received by the first user plane network element includes, but is not limited to, the following implementation manners:

in the first mode, the first user plane network element receives a multicast message from the multicast platform.

In the second mode, the first user plane network element receives the multicast message from the third user plane network element through a second unicast tunnel, wherein the second unicast tunnel is a tunnel between the third user plane network element and the first user plane network element and used for sending the multicast message.

In a third mode, the first user plane network element receives the multicast packet from the third party device through a third unicast tunnel, where the third unicast tunnel is a tunnel between the third party device and the first user plane network element and used for sending the multicast packet.

In the fourth mode, the first user plane network element receives the multicast message from the fourth user plane network element through the multicast tunnel.

It should be noted that in any of the foregoing embodiments, in an implementation manner, one or more first unicast tunnels are provided between the first UPF and the communication network element, and each first unicast tunnel corresponds to one type of multicast group information, so that multicast packets corresponding to different multicast group information are sent to the communication network element by using different first unicast tunnels respectively.

In another implementation manner, a first unicast tunnel may also be established only between the first UPF and the communication network element, and the first unicast tunnel may be used to send different multicast packets corresponding to different multicast group information, that is, the first UPF sends different multicast packets corresponding to different multicast group information to the communication network element through the same first unicast tunnel.

In a second aspect, the present application provides a method for sending a multicast packet. The method may be performed by a communication network element, which may be a user plane network element, for example referred to as a second user plane network element, an access gateway device, or a wireless access device. The method comprises the following steps: firstly, a communication network element receives a multicast message from a first user plane network element through a unicast tunnel, wherein the unicast tunnel is a tunnel used for sending the multicast message between the first user plane network element and the communication network element. Then, the communication network element sends the multicast message.

According to the method, the communication network element can receive the multicast message through the first unicast tunnel between the first user plane network element and the communication network element, so that even if the first user plane network element cannot send the multicast message through the multicast tunnel at present, the first unicast tunnel can be used for sending the multicast message to the communication network element, and then the communication network element selects to continue to send the multicast message to the terminal in a multicast or unicast mode. The method realizes that when the first user plane network element can not send the multicast message in the multicast tunnel mode, the multicast message does not need to be sent to each session of the terminal in a unicast mode, and only the multicast message needs to be sent to the communication network element and is continuously processed by the communication network element. Therefore, the method is favorable for preventing the processing capacity of the first user plane network element from becoming the load bottleneck of the whole network, thereby realizing the load balance of the network; meanwhile, the first user plane network element does not need to copy the message to each session, so that the bandwidth consumption caused by message copying is favorably reduced.

In a possible implementation manner, when a unicast tunnel between the first user plane network element and the communication network element needs to be created, the communication network element may receive indication information from the session management network element, where the indication information is used to indicate that the unicast tunnel is created.

For example, if the session management network element generates information of a unicast tunnel, the indication information further includes the information of the unicast tunnel. The information of the unicast tunnel includes identification information of the unicast tunnel, or the information of the unicast tunnel includes identification information of the unicast tunnel and address information of the communication network element.

For another example, if the communication network element generates information of a unicast tunnel, the communication network element further sends the generated information of the unicast tunnel to the session management network element.

In a possible implementation manner, if the communication network element determines that there is no multicast source, a report message is sent to the session management network element, where the report message includes multicast group information, the multicast group information is used to indicate a multicast packet sent in the unicast tunnel, and the report message is used to notify that the communication network element lacks a multicast source.

In another possible implementation manner, if the communication network element determines that there is no multicast source, a report message is sent to the session management network element, where the report message includes multicast group information and information of the unicast tunnel generated by the communication network element, the multicast group information is used to indicate a multicast packet sent in the unicast tunnel, and the report message is used to notify that the communication network element lacks a multicast source. In the implementation mode, when no multicast source is reported, the information of the unicast tunnel generated by the communication network element is simultaneously sent to the session management network element, so that the signaling overhead can be reduced, the establishment speed of the unicast tunnel can be increased, and the network performance can be further improved.

In a third aspect, the present application provides a method for sending a multicast packet. The method may be performed by a session managing network element, which may be referred to as a first session managing network element, for example. The method comprises the following steps: first, a first session management network element obtains multicast group information and information of a unicast tunnel, where the unicast tunnel is a tunnel used for a first user plane network element to send a multicast packet to a communication network element, and the multicast group information is used to indicate the multicast packet sent in the unicast tunnel. Then, the first session management network element sends the multicast group information and the unicast tunnel information to the first user plane network element. The communication network element may be a second user plane network element, or may also be an access gateway device, or may also be a wireless access device.

The method can be used for establishing a unicast tunnel between the first user plane network element and the communication network element, that is, the session management network element sends the multicast group information and the unicast tunnel information to the first user plane network element, so that the first user plane network element records the received information, and subsequently, if a multicast message corresponding to the multicast group information arrives, the multicast message can be sent to the communication network element through the unicast tunnel. The multicast message is sent through the unicast tunnel, so that when the first user plane network element cannot send the multicast message through the multicast mode, the multicast message can be sent to the communication network element through the unicast tunnel, and the communication network element sends the multicast message to the terminal again, so that the first user plane network element is prevented from sending the multicast message through the unicast mode, and bandwidth consumption caused by message copying of the first user plane network element can be reduced. Meanwhile, the multicast message is sent to a plurality of communication network elements, and the multicast message is multicast or unicast to the terminal by the plurality of communication network elements respectively, so that load balancing can be realized.

In one possible implementation manner, the first session management network element may obtain the multicast group information and the information of the unicast tunnel by one or more of the following manners:

in the first mode, the first session management network element obtains the multicast group information and the unicast tunnel information from the second session management network element.

Further, the second session management network element may obtain the multicast group information and the unicast tunnel information from the communication network element at the same time, or may obtain the unicast tunnel information from the local, where the multicast group information is derived from the communication network element, that is, the multicast group information is obtained from the communication network element.

In the second mode, the first session management network element acquires the multicast group information and the unicast tunnel information from the communication network element.

In the third mode, the first session management network element locally obtains the information of the unicast tunnel, and the multicast group information originates from the communication network element.

In a possible implementation manner, the first session management network element receives a first report message from the first user plane network element, where the first report message includes multicast group information, and the first report message is used to notify that the first user plane network element lacks a multicast source. Then, the first session management network element sends first indication information to the first user plane network element, where the first indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information. Optionally, the first indication information includes a multicast join message, where the multicast join message includes multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

In a possible implementation manner, the first session management network element receives a second report message from the communication network element, where the second report message includes multicast group information, and the second report message is used to notify that the communication network element lacks a multicast source. Optionally, the second report message further includes information of the unicast tunnel.

In a possible implementation manner, the first session management network element sends second indication information to the communication network element, where the second indication information is used for indicating that a unicast tunnel is created. Optionally, the second indication information comprises information of a unicast tunnel. The information of the unicast tunnel includes identification information of the unicast tunnel, or the information of the unicast tunnel includes identification information of the unicast tunnel and address information of the communication network element.

In a possible implementation, the first session managing network element further receives information of the unicast tunnel from the communication network element, if the information of the unicast tunnel is generated by the communication network element.

In a fourth aspect, the present application provides an apparatus, which may be a user plane network element or a chip. The apparatus has the function of implementing the embodiments of the first aspect described above. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a fifth aspect, the present application provides an apparatus comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the apparatus is running, the processor executes the computer executable instructions stored in the memory, so as to enable the apparatus to perform the multicast packet sending method according to any one of the above first aspects. It should be noted that the memory may be integrated into the processor or may be independent from the processor.

In another implementation manner, the present application further provides an apparatus, which includes a processor, where the processor is configured to couple with a memory, read an instruction in the memory, and execute the multicast packet sending method according to the instruction.

In a sixth aspect, the present application provides an apparatus, which may be a communication network element or a chip, where the communication network element may specifically be an access gateway device, or a wireless access device, or a user plane network element. The apparatus has the function of implementing the embodiments of the second aspect described above. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a seventh aspect, the present application provides an apparatus comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the apparatus is running, the processor executes the computer executable instructions stored in the memory, so as to enable the apparatus to perform the multicast packet sending method according to any one of the above second aspects. It should be noted that the memory may be integrated into the processor or may be independent from the processor.

In another implementation manner, the present application further provides an apparatus, which includes a processor, where the processor is configured to couple with a memory, read an instruction in the memory, and execute the multicast packet sending method according to the instruction in the second aspect.

In an eighth aspect, the present application provides an apparatus, which may be a session management device or a chip. The apparatus has a function of realizing the embodiments of the third aspect described above. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a ninth aspect, the present application provides an apparatus comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the apparatus is operating, the processor executes the computer executable instructions stored in the memory, so as to enable the apparatus to perform the multicast packet sending method according to any one of the third aspects. It should be noted that the memory may be integrated into the processor or may be independent from the processor.

In another implementation manner, the present application further provides an apparatus, which includes a processor, where the processor is configured to couple with a memory, read an instruction in the memory, and execute the multicast packet sending method according to the instruction in the third aspect.

In a tenth aspect, the present application provides a system comprising the apparatus of the above eighth or ninth aspect, and the apparatus of the fourth or fifth aspect.

In an eleventh aspect, the present application also provides a computer-readable storage medium having stored therein instructions, which, when run on a computer, cause the computer to perform the method of the above aspects.

In a twelfth aspect, the present application also provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the above aspects.

In a thirteenth aspect, the present application further provides a chip system, where the chip system includes a processor, configured to support a user plane network element to implement the multicast packet sending method according to the first aspect or any one of the first aspects. In one possible design, the system-on-chip further includes a memory. The memory is used for storing program instructions and data necessary for the user plane network element. The chip system may be formed by a chip, and may also include a chip and other discrete devices, which is not specifically limited in this embodiment of the present application.

In a fourteenth aspect, the present application further provides a chip system, where the chip system includes a processor, and is configured to support a communication network element to implement the multicast packet sending method according to any one of the second aspect and the second aspect. In one possible design, the system-on-chip further includes a memory. The memory is used for storing program instructions and data necessary for the communication network element. The chip system may be formed by a chip, and may also include a chip and other discrete devices, which is not specifically limited in this embodiment of the present application.

In a fifteenth aspect, the present application further provides a chip system, where the chip system includes a processor, configured to support a session management network element to implement the multicast packet sending method according to any one of the third aspect and the fourth aspect. In one possible design, the system-on-chip further includes a memory. The memory is used for storing program instructions and data necessary for the session management network element. The chip system may be formed by a chip, and may also include a chip and other discrete devices, which is not specifically limited in this embodiment of the present application.

In addition, for technical effects brought by any one of the design manners of the fourth aspect to the fifteenth aspect, reference may be made to technical effects brought by different implementation manners of the first aspect to the third aspect, and details are not described here.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

FIG. 1 is a schematic diagram of a possible network architecture provided herein;

FIG. 2 is a schematic diagram of a network architecture suitable for use in the present application;

fig. 3 is a schematic diagram of a method for sending a multicast packet according to an embodiment of the present application;

fig. 4(a) is a schematic diagram of another multicast packet sending method according to an embodiment of the present application;

fig. 4(b) is a schematic diagram of another multicast packet sending method according to the embodiment of the present application;

fig. 4(c) is a schematic diagram of another multicast packet sending method according to the embodiment of the present application;

fig. 4(d) is a schematic diagram of another multicast packet sending method according to the embodiment of the present application;

FIG. 5 is a schematic view of an apparatus provided herein;

FIG. 6 is a schematic view of yet another apparatus provided herein;

FIG. 7 is a schematic view of yet another apparatus provided herein;

fig. 8 is a schematic view of yet another apparatus provided herein.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clear, the present application will be further described in detail with reference to the accompanying drawings. The particular methods of operation in the method embodiments may also be applied to apparatus embodiments or system embodiments. In the description of the present application, the term "plurality" means two or more unless otherwise specified.

The network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not form a limitation on the technical solution provided in the embodiment of the present application, and as a person of ordinary skill in the art knows that along with the evolution of the network architecture and the appearance of a new service scenario, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems.

Fig. 1 is a schematic diagram of a possible network architecture to which the present application is applicable. The network architecture includes the following systems: the system comprises a user plane network element and a communication network element, a user plane network element and a session management network element, a user plane network element and a communication network element.

It should be noted that, in order to be distinguished from other user plane network elements appearing later in the embodiment of the present application, such as a second user plane network element, a third user plane network element, a fourth user plane network element, and the like, the user plane network element in the system architecture shown in fig. 1 may also be referred to as a first user plane network element. The unified description is made here, and the description is not repeated.

The session management network element is mainly used for session management in the mobile network, such as session establishment, modification and release. The specific functions include allocating an Internet Protocol (IP) address to a user, selecting a user plane functional network element providing a message forwarding function, and the like. In 5G, the session management network element may be a Session Management Function (SMF) network element, and certainly, in future communication, for example, in a 6th generation (6G), the session management network element may still be an SMF network element or have another name, which is not limited in this application.

The user plane network element is mainly responsible for processing user messages, such as forwarding, charging and the like. In 5G, the network slice selection network element may be a User Plane Function (UPF) network element, and certainly, in future communication, for example, in 6G, the user plane network element may still be a UPF network element or have another name, which is not limited in this application.

The communication network element is a generic term, and in a specific embodiment, the communication network element may be a user plane network element, which is subsequently referred to as a second user plane network element in this application embodiment. The function of the second user plane network element is the same as that of the user plane network element, which can refer to the foregoing description and is not described herein again.

The communication network element may also be an access gateway device. The access gateway device is an access point in the fixed network that accesses the fixed network to the core network, and the access gateway device may communicate with a network element of the core network control plane, such as a mobility management network element (e.g., an access and mobility management function (AMF) network element), through the N2 interface. As a specific implementation manner, the access gateway device may be, for example, an Access Gateway Function (AGF) network element in the fixed network.

The communication network element may also be a radio access device. A radio access device is a device for accessing a terminal to a wireless network, and in 5G, the radio access device may also be referred to as a Radio Access Network (RAN) device. Wireless access devices include, but are not limited to: a base station (G node B, gNB), 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 (e.g., home node B or home node B), a BaseBand Unit (BBU), a transmission point (TRP), a Transmission Point (TP), a mobile switching center, etc., in 5G, and may further include a wireless fidelity (wifi) access point (access point, AP), etc.

The respective systems mentioned above are explained below separately. In order to distinguish from other user plane network elements described later, the user plane network element in fig. 1 is subsequently represented by using a first user plane network element, that is, the user plane network element shown in fig. 1, which may also be referred to as the first user plane network element in the embodiment of the present application, and is described here in a unified manner.

To a system of a first user plane network element and a communication network element. A first unicast tunnel for sending the multicast message is established between the first user plane network element and the communication network element.

The first user plane network element is used for receiving the multicast message; and sending the multicast message to a communication network element through a first unicast tunnel;

and the communication network element is used for receiving the multicast message sent by the first user plane network element and sending the received multicast message.

The communication network element may be a second user plane network element, an access gateway device, or a wireless access device.

To a system comprised of a first user plane network element and a session management network element. May be configured to establish the first unicast tunnel and determine a multicast source for the first user plane network element.

The session management network element is configured to acquire multicast group information and information of a first unicast tunnel, and send the multicast group information and the information of the first unicast tunnel to a first user plane network element, where the multicast group information is used to indicate a multicast packet in the first unicast tunnel;

and the first user plane network element is used for receiving the multicast group information and the first unicast tunnel information from the session management network element.

Therefore, the information of the first unicast tunnel and the multicast group information are recorded on the first user plane network element, and the association between the first unicast tunnel and the multicast group information is established, so that the establishment of the first unicast tunnel between the first user plane network element and the communication network element is realized.

Further, the session management network element is further configured to receive a first report message from the first user plane network element, where the first report message includes multicast group information, and the first report message is used to notify that the first user plane network element lacks a multicast source; the first indication information is used for indicating the first user plane network element to request to join a multicast group corresponding to the multicast group information;

the first user plane network element is further configured to receive the first indication information from the session management network element.

Therefore, the first user plane network element can be indicated to request to join the multicast group through the first report message and the first indication information, and a multicast source is generated for the first user plane network element.

The method is directed to a system consisting of a first user plane network element, a communication network element and a session management network element. The functions of the system formed by the first user plane network element and the communication network element and the functions of the system formed by the first user plane network element and the session management network element can be realized, and on the basis of the functions of the system, the method further comprises the following steps:

as an implementation manner, the session management network element receives a second report message from the communication network element, where the second report message includes multicast group information, and the second report message is used to notify that the communication network element lacks a multicast source.

The second report message may further include information of a unicast tunnel generated by the communication network element.

Further, the session management network element sends second indication information to the communication network element, where the second indication information is used to indicate that the unicast tunnel is created.

Optionally, the first user plane network element, or the communication network element or the session management network element shown in fig. 1 may be a single network element, or may be implemented by multiple network elements together, or may be used as a functional module in one network element, which is not specifically limited in this embodiment of the present application.

It is understood that the above functions may be either network elements in a hardware device, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform).

For convenience of description, the following description of the present application takes a session management network element as an SMF network element, a user plane network element as an UPF network element, a radio access device as RAN equipment, and an access gateway device as an AGF network element as an example. For convenience of description, the SMF network element, the UPF network element, and the AGF network element are respectively abbreviated as SMF, UPF, and AGF.

Fig. 2 is a schematic diagram of a network architecture to which the present application is applied. The network architecture is a specific application scenario of the network architecture shown in fig. 1.

Wherein, the first UPF in fig. 2 is the user plane network element in fig. 1.

The communication network element in fig. 2 (which may be a second UPF, RAN equipment, or AGF) is the communication network element in fig. 1. And the first UPF sends the multicast message through a first unicast tunnel between the first UPF and the communication network element.

When the first UPF and the second UPF are managed by the first SMF and the second SMF, respectively, the first SMF in fig. 2 is the session management network element in fig. 1.

When the first UPF and the second UPF are managed by the same SMF, as shown in fig. 2, and both the first UPF and the second UPF are managed by the SMF in fig. 2, the SMF in fig. 2 is the session management network element in fig. 1, and at this time, the first SMF and the second SMF are not present in fig. 2, and only the SMF needs to be reserved. Alternatively, it is understood that a first SMF managing a first UPF is the same SMF as a second SMF managing a second UPF, i.e., the SMF in fig. 2.

The following describes a method for sending a multicast packet according to the present application with reference to fig. 2. The first UPF shown in fig. 2 cannot send the received multicast packet to the communication network element in a multicast tunnel, so in this embodiment of the application, a first unicast tunnel is established between the first UPF and the communication network element, then the first UPF sends the received multicast packet to the communication network element through the established first unicast tunnel, and the communication network element further sends the received multicast packet to a terminal, where the terminal may be a mobile terminal in a mobile network or a fixed network terminal in a fixed network. Or, when the communication network element is the second UPF, the second UPF may send the received multicast packet to the RAN device or the AGF, and then the RAN device or the AGF further sends the multicast packet to the terminal.

As shown in fig. 3, a method for sending a multicast packet provided in this embodiment includes the following steps:

step 301, the first UPF receives a multicast packet.

Step 302, the first UPF sends a multicast packet to a communication network element.

And the first UPF sends the multicast message to the communication network element through a first unicast tunnel between the first UPF and the communication network element.

Step 303, the communication network element sends the multicast packet.

According to the method, after the first UPF receives the multicast message, if the first UPF does not have the multicast capability, or the first UPF has the multicast capability but the network between the first UPF and the communication network element does not support multicast transmission, the first UPF cannot send the multicast method to the communication network element in a multicast mode. In this scenario, if the solution of the background art is adopted, the first UPF directly uses a unicast manner to copy the multicast packet to each session (for example, a Protocol Data Unit (PDU) session of a terminal), and then unicast the multicast packet to the terminal through each session.

According to the method provided by the application, when the first UPF cannot send the multicast message by the multicast method, the first UPF can send the multicast message to the communication network element through a first unicast tunnel (the first unicast tunnel can be established currently or can be established previously) between the first UPF and the communication network element, and then the communication network element selects to use a multicast or unicast mode to continue to send the multicast message to the terminal. Therefore, the method is beneficial to avoiding the processing capacity of the first UPF from becoming the load bottleneck of the whole network, thereby realizing the load balance of the network; meanwhile, the first UPF does not need to copy the message to each session, so that the bandwidth consumption caused by message copying is reduced.

The following describes the multicast packet sending method shown in fig. 3 with reference to fig. 2.

In step 301, the first UPF receives the multicast packet, for example, including but not limited to the following methods:

in the first method, a first UPF receives a multicast message from a multicast platform.

That is, the first UPF may be an anchor (anchor) UPF, and receive the multicast packet from the multicast platform, where the multicast platform is a multicast source of the first UPF.

The multicast platform refers to a multicast source of a multicast message of a user. The multicast platform may be configured to send an original multicast packet, that is, the multicast platform may serve as a source of the multicast packet.

In the second method, the first UPF receives the multicast message from the third UPF through the second unicast tunnel.

And the second unicast tunnel is a tunnel between the third UPF and the first UPF and used for sending the multicast message.

At this time, the third UPF is the multicast source of the first UPF.

That is, after receiving the multicast packet, the third UPF sends the multicast packet to the first UPF through the second unicast tunnel. Here, the manner in which the third UPF sends the multicast packet to the first UPF is the same as the manner in which the first UPF sends the multicast packet to the communication network element, that is, the third UPF may not send the multicast packet to the first UPF by means of the multicast packet, so that a second unicast tunnel is established between the third UPF and the first UPF, and then the third UPF sends the multicast packet through the second unicast tunnel.

And in the third method, the first UPF receives the multicast message from the third-party equipment through the third unicast tunnel.

And the third unicast tunnel is a tunnel between the third-party equipment and the first UPF and used for sending the multicast message.

At this time, the third party device is the multicast source of the first UPF.

That is, after receiving the multicast packet, the third-party device sends the multicast packet to the first UPF through the third unicast tunnel. Here, the manner in which the third-party device sends the multicast packet to the first UPF is the same as the manner in which the first UPF sends the multicast packet to the communication network element, that is, the third-party device may not send the multicast packet to the first UPF in the manner of the multicast packet, so that a third unicast tunnel is established between the third-party device and the first UPF, and then the third-party device sends the multicast packet through the third unicast tunnel.

In this embodiment, the third-party device may be, for example, a device including a message copying function.

And the fourth method is that the first UPF receives the multicast message from the fourth UPF through the multicast tunnel.

In this case, the fourth UPF is the multicast source of the first UPF.

Because there is a multicast tunnel between the fourth UPF and the first UPF, and the fourth UPF can send the multicast message through the multicast tunnel, in the method, the fourth UPF can directly send the multicast message to the first UPF through the multicast tunnel in a multicast mode.

In this embodiment of the application, the first UPF may receive the multicast packet through the above four manners, but is not limited to the above four manners, and send the received multicast packet to the communication network element through the first unicast tunnel.

The following description is made for different cases where the communication network element is the second UPF, the RAN device, or the AGF, respectively.

Case one, the communication network element is the second UPF

As an implementation manner, after receiving a multicast packet sent by a first UPF through a first unicast tunnel, a second UPF may copy the multicast packet to a session of a terminal joining a multicast group, and then send the multicast packet to a terminal corresponding to each session in a unicast manner.

Here, if the second UPF sends the received multicast packet in a unicast manner, the following beneficial effects are provided: because the hierarchy between the second UPF and the terminal is less than the hierarchy between the first UPF and the terminal, the multicast message that the second UPF needs to copy is less than the first user plane network element, and therefore, even if the second UPF sends the received multicast message in a unicast manner, the occupied bandwidth resource is relatively less, thereby realizing load balance of the network and reducing bandwidth consumption caused by copying the message.

As another implementation manner, after receiving the multicast packet sent by the first UPF through the first unicast tunnel, the second UPF may encapsulate the multicast packet in the multicast tunnel, and send the multicast packet to other UPFs, wireless access devices, or access gateway devices in a multicast manner.

Here, if the second UPF sends the multicast packet in the multicast tunnel mode, the following beneficial effects are provided: the first UPF can not send the multicast message in the multicast tunnel mode, but can send the multicast message to the second UPF in the first unicast tunnel, and the second UPF can send the multicast message in the multicast tunnel mode. Therefore, when only part of the network supports multicast, the multicast message can be sent to the user plane network element capable of sending the message in the multicast mode, namely the second UPF, so that the function of fully utilizing the user plane network element capable of sending the message in the multicast mode is realized, and the performance of the whole network is improved.

Case two, the communication network element is RAN equipment

After receiving the multicast packet sent by the first UPF through the first unicast tunnel, the RAN device may broadcast the received multicast packet to the terminal in a broadcast manner. Or, when the RAN device itself supports the multicast capability, the received multicast packet may be directly sent to the terminal in a multicast manner, so that the multicast capability of the access gateway device may be fully utilized, which is beneficial to improving the performance of the whole network.

Case three, the communication network element is an AGF

When the communication network element is an AGF, the received multicast packet may be copied to each session of the terminal in a unicast manner and sent to the terminal. Or, when the AGF itself supports the multicast capability, the AGF can directly send the received multicast message to the terminal by using the multicast mode, so that the multicast capability of the AGF can be fully utilized, and the performance of the whole network can be improved.

In addition, referring to fig. 2, the second UPF may receive the multicast packet not only through the first unicast tunnel from the first UPF, but also through a multicast tunnel with another UPF.

The following describes a method for establishing the first unicast tunnel in the above embodiment with reference to the drawings. In the embodiment of the present application, the method can be divided into two scenarios. In a first scenario, the first UPF and the second UPF are managed by different SMFs, for example, referring to fig. 2, the first UPF is managed by a first SMF and the second UPF is managed by a second SMF. In a second scenario, the first UPF and the second UPF are managed by the same SMF, e.g., referring to fig. 2, both the first UPF and the second UPF are managed by the SMF of fig. 2, i.e., there is no first SMF and second SMF of fig. 2.

A method for establishing a first unicast tunnel in the embodiment of the present application is described below by taking an example in which a first UPF and a second UPF are managed by a first SMF and a second SMF, respectively.

As shown in fig. 4(a), a schematic diagram of a method for establishing a unicast tunnel is provided in the present application. Wherein, the communication network element is a second UPF. Before executing the method shown in fig. 4(a), the terminal sends a multicast join packet in the process of creating a session (e.g., a PDU session), where the multicast join packet includes multicast group information, and the multicast join packet is used to request to join a multicast group, and the multicast join packet is forwarded to the second UPF via the RAN device or the AGF.

In one implementation, the second UPF sends the received multicast join packet to the second SMF, and then the second SMF parses the received multicast join packet to obtain the multicast group information, and the second SMF may further obtain session information (for example, including a session identifier) of the terminal. And the second SMF sends the acquired multicast group information and session information to a second UPF, and then the second UPF adds the session information into a multicast replication list, wherein the multicast replication list at least comprises the association between the multicast group information and the session information.

The multicast group information may include a multicast network protocol (IP), and optionally, in a scenario of an internet group management protocol (internet protocol version 3, IGMPv3), the multicast group information may further include a multicast source IP.

The multicast group information may be used to identify multicast packets, i.e. one multicast group information may be used to identify one multicast packet. As shown in table 1, an example of a multicast replication list.

Multicast group information	Session information
		Multicast group information 1	Session information 1
Multicast group information 3	Session information 2
		Multicast group information 2	Session information 3

Table 1 multicast replication list

For example, (multicast group information 2, session information 3) in table 1 is newly added information. Subsequently, if there is a multicast packet indicated by the multicast group information 2 that reaches the second UPF, the second UPF may copy the multicast packet to the session indicated by the session information 3, and then send the multicast packet to the terminal, that is, the second UPF may send the multicast packet to the terminal in a unicast manner.

Of course, in another implementation manner, the second UPF may also directly acquire the multicast group information and the session information from the multicast join packet, for example, (multicast group information 2, session information 3) is acquired, and then the multicast group information and the session information are added to the multicast replication list. That is, when the second UPF has the capability of acquiring the multicast group information and the session information, the second SMF does not need to analyze the multicast join packet.

As another alternative implementation, if the second UPF supports multicast mode to send the packet, the above process may be replaced by a multicast tunnel creation process. For example, if the multicast tunnel is a tunnel between the second UPF and the RAN device, after the creation of the multicast tunnel is completed, the multicast replication list shown in table 2 may be obtained.

For example, as shown in table 2, if the newly created multicast tunnel is a tunnel between the second UPF and the RAN device 3, (multicast group information 2, tunnel 3, and forwarding port 4) is added to the multicast replication list, where the forwarding port 4 is a port on the second UPF that receives the multicast join packet from the RAN device 3.

Multicast group information	Multicast tunnel	Forwarding port list
			Multicast group information 1	Tunnel 1	Forwarding port 1, forwarding port 2
Multicast group information 3	Tunnel 2	Forwarding port 3
			Multicast group information 2	Tunnel 3	Forwarding port 4

Table 2 multicast replication list

As another alternative implementation, if the second UPF supports multicast mode to send the packet, the above process may be replaced by a multicast tunnel creation process. For example, if the multicast tunnel is a tunnel between the second UPF and the AGF, the multicast replication list shown in table 3 may be obtained after the multicast tunnel creation is completed.

For example, as shown in table 3, if the newly created multicast tunnel is a tunnel between the second UPF and the AGF3, (multicast group information 2, tunnel 3, and forwarding port 4) is added to the multicast replication list, where the forwarding port 4 is a port on the second UPF that receives the multicast join packet from the AGF 3.

Table 3 multicast replication list

After the above steps are completed, the method shown in fig. 4(a) of the embodiment of the present application may be performed next, which specifically includes the following steps:

step 401, the second SMF sends the indication information to the second UPF, and accordingly, the second UPF receives the indication information sent by the second SMF. Wherein the indication information is used for indicating the creation of the unicast tunnel.

Note that the indication information of step 401 may also be referred to as second indication information, so as to be distinguished from the first indication information mentioned in the subsequent step.

As an implementation manner, before step 401, after receiving a multicast join packet from a terminal forwarded by RAN equipment or an AGF, the second UPF further determines whether there is a multicast source of the multicast packet indicated by the multicast group information, and if the second UPF determines that there is no multicast source of the multicast packet indicated by the multicast group information, or it is understood that the second UPF determines that there is no multicast source corresponding to the multicast group information, the second UPF sends a report message (in this application, the report message is also referred to as a second report message) to the second SMF, where the report message includes the multicast group information, and the report message is used to notify the second SMF: the second UPF lacks a multicast source. In the method, when the second UPF determines that no multicast source exists, the second UPF actively reports the multicast source to the second SMF: the second UPF has no multicast source corresponding to the multicast group information. Further, after receiving the report message, the second SMF performs step 401, that is, sends an indication message to the second UPF to indicate the second UPF to create a unicast tunnel, where the unicast tunnel is also referred to as a first unicast tunnel, that is, the first unicast tunnel shown in fig. 1 or fig. 2.

As another implementation manner, before step 401, after receiving a multicast join packet from a terminal forwarded by the RAN device or the AGF, the second UPF sends the multicast join packet to the second SMF, where the second SMF determines whether the second UPF has a multicast source of the multicast packet indicated by the multicast group information, and if the second SMF determines that the second UPF does not have a multicast source of the multicast packet indicated by the multicast group information, or it is understood that the second SMF determines that the second UPF does not have a multicast source corresponding to the multicast group information, the second SMF further performs step 401, that is, sends indication information to the second UPF to indicate the second UPF to create a unicast tunnel, where the unicast tunnel is also referred to as a first unicast tunnel, that is, the first unicast tunnel shown in fig. 1 or fig. 2.

Optionally, the method for the second SMF to determine whether the second UPF has a multicast source includes, but is not limited to, the following:

in the first method, the second SMF queries locally.

Since the second SMF manages all multicast traffic on the second UPF, the second SMF may query locally: whether the second UPF has a multicast source. If it is determined that there is no multicast source, step 401 is executed.

The second SMF sends the inquiry information to the second UPF, and the second UPF returns the response information

In the method, the second SMF sends a query message to the second UPF to request the second UPF to query whether the second UPF has a multicast source corresponding to the multicast group information, and then the second UPF sends a response message aiming at the query message to the second SMF, wherein the response message comprises a query result, and the query result is the multicast source corresponding to the multicast group information or the multicast source corresponding to the multicast group information. Thus, the second SMF may determine whether the second UPF has a multicast source corresponding to the multicast group information, and if it is determined that there is no multicast source, step 401 is executed.

And in the third method, the second SMF queries network elements of other Network Functions (NF).

For example, the second SMF queries a Unified Data Management (UDM) network element, or other network elements for managing multicast traffic. The concrete implementation steps are the same as the second method, except that the inquired object is replaced by a UDM network element or other network elements for managing the multicast service.

Through the above step 401, the second SMF sends the indication information to the second UPF, for indicating the second UPF to create the first unicast tunnel.

Optionally, if the information of the first unicast tunnel is generated by the second SMF, the information of the first unicast tunnel may be further included in the indication information, where the information of the first unicast tunnel may include identification information of the first unicast tunnel and address information of the second UPF, or the information of the first unicast tunnel may include identification information of the first unicast tunnel but does not include address information of the second UPF. For example, when the second UPF has only one address information, the address information of the second UPF may not be transmitted to the second UPF.

Optionally, if the information of the first unicast tunnel is generated by the second UPF, the step 401 further includes: and the second UPF sends the generated information of the first unicast tunnel to the second SMF. Optionally, the step of the second UPF sending the generated information of the first unicast tunnel to the second SMF may be combined with the step 402 described below as a step.

It should be noted that, in step 401, when the second SMF or the second UPF determines that the second UPF has no multicast source, the second SMF selects a multicast source (i.e., the first UPF in this application) for the second UPF, and the second SMF may determine that the currently selected multicast source cannot send a multicast packet in a multicast manner, so that step 401 may be executed, that is, the second SMF sends indication information to the second UPF, where the indication information is used to indicate that a first unicast tunnel is created, and the first unicast tunnel is used to send the multicast packet.

Step 402, the second UPF sends a response message to the second SMF, and the second SMF receives the response message from the second UPF.

This step 402 is an optional step. The response message is used to reply to: the second UPF succeeds or fails to create the unicast tunnel.

If the step 402 is executed and the second UPF generates the information of the first unicast tunnel, the response message may further include the information of the first unicast tunnel.

Alternatively, as another implementation manner, when the information of the first unicast tunnel is generated by the second UPF, this step 402 may also be directly replaced with: and the second UPF sends the generated information of the first unicast tunnel to the second SMF. I.e. the second UPF does not send a response message to the second SMF but only information of the generated first unicast tunnel.

In another implementation manner, if the second UPF determines that there is no multicast source of the multicast packet indicated by the multicast group information before step 401, and the second UPF sends a report message (the report message is also referred to as a second report message) to the second SMF, step 401-step 402 may be replaced by the following steps: the second UPF sends a report message (the report message is also referred to as a second report message) to the second SMF, where the report message includes multicast group information and information of the first unicast tunnel, and the report message is used to notify the second SMF: the second UPF lacks a multicast source. In the method, the second UPF reports no multicast source to the second SMF, and simultaneously sends the generated first unicast tunnel information to the second SMF, thereby reducing signaling overhead.

In step 403, the second SMF sends the multicast group information and the information of the first unicast tunnel to the first SMF, and the first SMF receives the multicast group information and the information of the first unicast tunnel from the second SMF.

Optionally, the second SMF first selects one SMF, for example, the selected SMF is the first SMF, and then sends the multicast group information and the information of the first unicast tunnel to the first SMF. As an implementation manner, the second SMF may send a session creation message to the first SMF, where the session creation message carries information of the multicast group and information of the first unicast tunnel.

As an implementation manner, the second SMF may select the first SMF according to the configuration information, for example, the selected first SMF is an anchor device for multicast management.

Optionally, the second SMF may select one UPF while selecting the first SMF, and send information of the selected UPF (for example, identification information of the UPF, and/or address information of the UPF) to the selected first SMF, for example, the selected first UPF is obtained. The way for the second SMF to select the UPF may be: and the second SMF selects a UPF according to the principles of topology, load and the like, for example, the selected first UPF needs to be reachable by the second UPF and the first UPF has a multicast source, or the selected first UPF has a multicast source reachable, or the selected first UPF is a multicast anchor point device and the first UPF is managed by the first SMF.

Of course, it is also possible that the second SMF selects a UPF from the first SMF after selecting the first SMF, for example, the selected UPF is the first UPF, and the way that the first SMF selects the UPF is similar to the way that the second SMF selects the UPF, which is described above with reference to the foregoing description.

As another implementation, the first SMF or the second SMF may also send a request message to the other device, for example, the request message includes multicast group information, and then the other device queries to obtain a UPF according to the multicast group information and returns the UPF to the first SMF or the second SMF. The other device may be, for example, a device for managing multicast information and UPF information, which is not limited in this application.

It should be noted that the UPF selected by the second SMF or the first SMF is a UPF serving as a multicast source of the second UPF, that is, a multicast packet corresponding to the multicast group information is subsequently sent to the second UPF by the selected UPF.

Step 404, the first SMF sends the multicast group information and the information of the first unicast tunnel to the first UPF, and the first UPF receives the multicast group information and the information of the first unicast tunnel from the first SMF.

As an implementation manner, the first SMF may send a session creation request to the first UPF, where the session creation request carries multicast group information and information of the first unicast tunnel.

After the first UPF receives the multicast group information and the information of the first unicast tunnel, it can know that: and sending the subsequent multicast message indicated by the multicast group information to the second UPF through the first unicast tunnel. Therefore, through the above steps 401 to 404 and other related steps, selecting a multicast source (i.e., a first UPF) for the second UPF is realized, and a first unicast tunnel from the first UPF to the second UPF is also established, and the first UPF records the association between the multicast group information and the first unicast tunnel, so as to realize sending the multicast packet corresponding to the multicast group information through the first unicast tunnel.

As an implementation, the first UPF may also maintain a multicast replication list. As shown in table 4, an example of a multicast replication list.

Multicast group information	Information of the first unicast tunnel
		Multicast group information 1	Unicast tunnel 1
Multicast group information 3	Unicast tunnel 2
		Multicast group information 2	Unicast tunnel 3

Table 4 multicast replication list

For example, if the multicast group information and the identification information of the first unicast tunnel received by the first UPF are (multicast group information 2, unicast tunnel 3), the first UPF adds the information to the multicast replication list. Subsequently, when the first UPF receives the multicast packet corresponding to the multicast group information 2, the first UPF sends the multicast packet to the second UPF through the first unicast tunnel identified by the unicast tunnel 3.

Optionally, after step 404 in the embodiment of the present application, the method further includes the following steps:

in step 405, the first SMF sends the indication information to the first UPF, and accordingly, the first UPF receives the indication information sent by the first SMF. Wherein the indication information is used for indicating the creation of the unicast tunnel.

Note that the indication information of step 405 may also be referred to as first indication information, so as to be used for distinguishing from the second indication information mentioned in the foregoing step.

As an implementation manner, before the step 405, the method further includes: the first UPF determines that there is no multicast source of the multicast packet indicated by the multicast group information, or it is understood that the first UPF determines that there is no multicast source corresponding to the multicast group information, and then the first UPF sends a report message (in this application, the report message is also referred to as a first report message) to the first SMF, where the report message includes the multicast group information, and the report message is used to notify the first SMF: the first UPF lacks a multicast source. In the method, when the first UPF determines that no multicast source exists, the first UPF actively reports to the first SMF: the first UPF has no multicast source corresponding to the multicast group information. Further, after receiving the report message, the first SMF performs step 405, that is, sends indication information (the indication information may also be referred to as first indication information) to the first UPF, where the indication information is used to indicate that the first UPF requests to join the multicast group corresponding to the multicast group information.

As another implementation manner, before the step 405, the method further includes: if the first SMF determines that the first UPF does not have the multicast source of the multicast packet indicated by the multicast group information, or it is understood that the first SMF determines that the first UPF does not have the multicast source corresponding to the multicast group information, the second SMF further performs step 405 described above, that is, sends indication information (the indication information may also be referred to as first indication information) to the first UPF, where the indication information is used to indicate that the first UPF requests to join the multicast group corresponding to the multicast group information. The method for the first SMF to determine whether the first UPF has a multicast source is the same as the method for the second SMF to determine whether the second UPF has a multicast source, and reference may be made to the foregoing description.

Optionally, the indication information sent by the first SMF to the first UPF further includes a multicast join message, where the multicast join message includes multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information. Or, if the indication information does not include the multicast join message, the multicast join message may be generated by the first UPF. Then, the first UPF sends a multicast join message to join the multicast group, for example, referring to fig. 2, if the first UPF is an anchor UPF, the first UPF may send the multicast join message to the multicast platform, and then the multicast platform joins the first UPF in the multicast group indicated by the multicast group information in the multicast platform. That is, the multicast platform is used as a multicast source of the first UPF, and subsequently, the multicast platform sends the multicast packet corresponding to the multicast group information to the first UPF.

As an implementation manner, if the first SMF determines that the first UPF has no multicast source, the above steps 404 and 405 may be combined into one step, that is, the first SMF sends the indication information to the first UPF, and also sends the multicast group information and the information of the first unicast tunnel.

At step 406, the first UPF sends a response message to the first SMF, and the first SMF receives the response message from the first UPF.

This step 406 is an optional step. The response message is used to reply to: whether the first UPF joined the multicast group was successful or failed.

In the above embodiment, the communication network element is taken as the second UPF, and the first UPF and the second UPF are managed by the first SMF and the second SMF, respectively. It should be noted that, if the first UPF and the second UPF are managed by the same SMF, for example, both are managed by the SMF in fig. 2, the step 403 may not need to be executed. In addition, the first SMF and the second SMF in the above steps may be replaced by SMFs, that is, the operations of the first SMF and the second SMF are performed by the same SMF.

If the operations of the first SMF and the second SMF are both performed by the same SMF, the SMF may also directly acquire the multicast group information and the unicast tunnel information from the second UPF. Or, the SMF first acquires the information of the unicast tunnel from the second UPF and stores the information in the local, and then acquires the multicast group information from the second UPF, so that the SMF may first acquire the information of the unicast tunnel from the local, and then acquire the multicast group information from the second UPF.

In other embodiments, if the communication network element is a RAN device or an AGF, the second UPF in the embodiment shown in fig. 4(a) is replaced by the RAN device or the AGF, and the first SMF and the second SMF are merged into one SMF, that is, only one SMF is provided, and the SMF manages the first UPF. Thus, the SMF may determine whether the RAN device or the AGF has a multicast source, and send indication information to the RAN device or the AGF when it is determined that there is no multicast source; or the RAN equipment or the AGF determines whether a multicast source exists or not, and sends a report message to the SMF when determining that no multicast source exists.

In one implementation, if the RAN device or the AGF determines whether there is a multicast source, when the RAN device or the AGF determines that there is no multicast source, a report message (the report message is also referred to as a second report message) is sent to the SMF, where the report message may include multicast group information and information of the first unicast tunnel, that is, information of the first unicast tunnel generated by the RAN device or the AGF. Of course, if the SMF generates the information of the first unicast tunnel, the report message does not include the information of the first unicast tunnel.

By the method, the first unicast tunnel between the first UPF and the communication network element can be established, and the first unicast tunnel is used for the first UPF to send the multicast message corresponding to the multicast group information. In the above embodiment, different multicast group information between the first UPF and the communication network element corresponds to one first unicast tunnel, that is, one or more first unicast tunnels exist between the first UPF and the communication network element, and each first unicast tunnel corresponds to one multicast group information, so that multicast packets corresponding to different multicast group information are sent to the communication network element by using different first unicast tunnels respectively.

In practical application, as another implementation manner, it may also be that only one first unicast tunnel is established between the first UPF and the communication network element, and the first unicast tunnel may be used to send different multicast packets corresponding to different multicast group information, that is, the first UPF sends different multicast packets corresponding to different multicast group information to the communication network element through the same first unicast tunnel. Therefore, in this embodiment, if the SMF (or the second SMF) determines that the communication network element has no multicast source and determines that the first unicast tunnel is already established between the first UPF and the communication network element, the SMF (or the second SMF) notifies the second UPF to add the multicast group information to the already established first unicast tunnel. And the SMF (or the first SMF) notifies the first UPF and adds the multicast group information into the established first unicast tunnel.

Therefore, the present invention further provides a method for sending a multicast packet, including:

a first user plane network element receives a multicast message;

and the first user plane network element sends the multicast message to a communication network element through the first unicast tunnel, wherein the first unicast tunnel is a tunnel used for sending the multicast message between the first user plane network element and the communication network element.

The first unicast tunnel may be used to send multicast packets corresponding to different multicast group information.

In practical application, as another implementation manner, in any embodiment, if the communication network element is the second UPF, after the second UPF receives the multicast packet sent by the first UPF through the first unicast tunnel, or after the second UPF receives the multicast packet sent by another UPF or multicast platform through another manner, for example, a multicast tunnel or a multicast manner, the second UPF may further send the received multicast packet to the RAN device or AGF through the following manner: the second UPF selects a session of the terminal (or called a session of the user) from the multicast copy list stored in the second UPF, wherein only one session is selected to send the multicast message for the sessions with the same destination address, wherein the destination address may be, for example, a tunnel destination IP or the like. The destination address may be an IP address of the RAN device or an IP address of the AGF. Therefore, after receiving and decapsulating a message in a certain session, the AGF or RAN device parses that the message is a multicast message, and broadcasts or multicasts the multicast message, or copies the multicast message to a user session recorded by the AGF or RAN device and then unicast-transmits the multicast message.

the second user plane network element receives the multicast message;

the second user plane network element selects a session of a user and sends the multicast message to RAN equipment or an AGF through the selected session of the user; the destination address of the session of the user is the IP address of the RAN device or the IP address of the AGF.

Optionally, the selecting, by the second user plane network element, a session of a user specifically includes: and the second user plane network element randomly selects a user session from partial or all user sessions, wherein the destination addresses of the partial or all user sessions are the IP addresses of the RAN equipment or the IP addresses of the AGFs.

RAN equipment or AGF receives a multicast message sent by a second user plane network element through a session of a user;

the RAN equipment or the AGF acquires the multicast message from the session of the user;

and the RAN equipment or the AGF sends the multicast message to a terminal corresponding to the session of the user.

Optionally, the sending, by the RAN device or the AGF, the multicast packet to a terminal corresponding to the session of the user specifically includes: and the RAN equipment or the AGF sends the multicast message to a terminal corresponding to the session of the user in a broadcasting, unicast or multicast mode.

It should be noted that, the report message (including the first report message and the second report message), the notification message, the response message, and the like in the foregoing embodiment are only a name, and the name does not limit the message itself. In the 5G network and other future networks, the report message (including the first report message and the second report message), the notification message, and the response message may also be other names, which is not specifically limited in this embodiment of the present application.

Therefore, the invention discloses a method for sending a multicast message, which comprises the following steps:

a first user plane network element receives a multicast message;

and the first user plane network element sends the multicast message to a communication network element through a first unicast tunnel, wherein the first unicast tunnel is a tunnel used for sending the multicast message between the first user plane network element and the communication network element.

In one possible implementation, the method further includes: and the first user plane network element receives multicast group information and the information of the first unicast tunnel from a session management network element, wherein the multicast group information is used for indicating the multicast message.

In one possible implementation, the method further includes: and the first user plane network element receives indication information from the session management network element, wherein the indication information is used for indicating that the first user plane network element requests to join a multicast group corresponding to the multicast group information.

Optionally, the indication information includes a multicast join message, the multicast join message includes the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

In one possible implementation, the method further includes: the first user plane network element determines that there is no multicast source corresponding to the multicast group information, and sends a report message to the session management network element, where the report message includes the multicast group information, and the report message is used to notify that the first user plane network element lacks a multicast source.

In a possible implementation manner, the communication network element in the method is a second user plane network element, or an access gateway device, or a wireless access device.

In a possible implementation manner, the receiving, by the first user plane network element, the multicast packet includes:

the first user plane network element receives the multicast message from a multicast platform; or,

the first user plane network element receives the multicast message from a third user plane network element through a second unicast tunnel, wherein the second unicast tunnel is a tunnel used for sending the multicast message between the third user plane network element and the first user plane network element; or,

the first user plane network element receives the multicast message from third-party equipment through a third unicast tunnel, wherein the third unicast tunnel is a tunnel used for sending the multicast message between the third-party equipment and the first user plane network element; or,

and the first user plane network element receives the multicast message from a fourth user plane network element through a multicast tunnel.

In the sending method of the multicast packet, for example, the operation of the first user plane network element may refer to the operation of the first UPF in fig. 4(a) and the above description, and details are not repeated here.

The invention also discloses a method for sending the multicast message, which comprises the following steps:

a communication network element receives a multicast message from a first user plane network element through a unicast tunnel, wherein the unicast tunnel is a tunnel used for sending the multicast message between the first user plane network element and the communication network element;

and the communication network element sends the multicast message.

In one possible implementation, the method further includes: and the communication network element receives indication information from a session management network element, wherein the indication information is used for indicating the establishment of the unicast tunnel. Optionally, the indication information includes information of the unicast tunnel.

In one possible implementation, the method further includes: and the communication network element sends the information of the unicast tunnel to the session management network element.

In one possible implementation, the method further includes: the communication network element determines that no multicast source exists, and sends a report message to the session management network element, wherein the report message includes multicast group information, the multicast group information is used for indicating the multicast message, the report message is used for notifying that the communication network element lacks a multicast source.

In another possible implementation manner, the method further includes: the communication network element determines that no multicast source exists, and sends a report message to the session management network element, where the report message includes multicast group information and information of the unicast tunnel, the multicast group information is used to indicate the multicast packet, the report message is used to notify that the communication network element lacks a multicast source.

In the sending method of the multicast packet, for example, the operation of the communication network element (which may be the second UPF, the AGF, or the RAN device) may refer to the operation of the second UPF in fig. 4(a) and the above description, and details are not repeated here.

a first session management network element acquires multicast group information and unicast tunnel information, wherein the unicast tunnel is a tunnel used for a first user plane network element to send a multicast message to a communication network element, and the multicast group information is used for indicating the multicast message;

and the first session management network element sends the multicast group information and the unicast tunnel information to the first user plane network element.

In a possible implementation manner, the acquiring, by the first session management network element, the multicast group information and the unicast tunnel information includes:

the first session management network element acquires the multicast group information and the unicast tunnel information from a second session management network element; or,

the first session management network element acquires the multicast group information and the unicast tunnel information from the communication network element; or,

and the first session management network element locally acquires the information of the unicast tunnel, and the multicast group information comes from the communication network element.

In one possible implementation, the method further includes:

the first session management network element receives a first report message from the first user plane network element, where the first report message includes the multicast group information, and the first report message is used to notify that the first user plane network element lacks a multicast source;

and the first session management network element sends first indication information to the first user plane network element, wherein the first indication information is used for indicating the first user plane network element to request to join a multicast group corresponding to the multicast group information.

In a possible implementation manner, optionally, the first indication information includes a multicast join message, where the multicast join message includes the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

In one possible implementation, the method further includes: and the first session management network element receives a second report message from a communication network element, wherein the second report message comprises the multicast group information, and the second report message is used for notifying that the communication network element lacks a multicast source. Optionally, the second report message further includes information of the unicast tunnel.

In one possible implementation, the method further includes: and the first session management network element sends second indication information to the communication network element, wherein the second indication information is used for indicating the establishment of the unicast tunnel. Optionally, the second indication information includes information of the unicast tunnel, and the information of the unicast tunnel includes address information of the communication network element and identification information of the unicast tunnel.

In one possible implementation, the method further includes: and the first session management network element receives the information of the unicast tunnel from the communication network element, wherein the information of the unicast tunnel comprises the address information of the communication network element and the identification information of the unicast tunnel.

In the above-mentioned method for sending a multicast packet, for example, the operation of the first session managing network element may refer to the operation of the SMF (or the first SMF) in fig. 4(a) and the above-mentioned description, which is not described herein again.

The above-mentioned scheme provided by the present application is mainly introduced from the perspective of interaction between network elements. It is to be understood that the above-described implementation of each network element includes, in order to implement the above-described functions, a corresponding hardware structure and/or software module for performing each function. Those of skill in the art will readily appreciate that the present invention can be implemented in hardware or a combination of hardware and computer software, with the exemplary elements and algorithm steps described in connection with the embodiments disclosed herein. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The above various schemes are described below with reference to specific implementations.

Referring to fig. 4(b), a schematic diagram of another multicast packet sending method according to an embodiment of the present application is shown. The scenario of this embodiment is: the terminal sends a multicast adding message in the created PDU session to request to add a multicast group, the multicast adding message reaches a second UPF through RAN equipment or AGF and is forwarded to a second SMF of the control plane by the second UPF, the second SMF issues an instruction for copying the multicast message to the user PDU session to the user plane, and then the user plane completes the forwarding of the multicast message. And reporting the information to the control plane by the user plane under the condition that the user plane has no multicast source. The specific steps are described below.

Step 1, the terminal creates a PDU session to the second UPF.

And 2, the terminal acquires the multicast list.

For example, the terminal obtains a multicast list from the multicast platform, where the multicast list includes information of one or more multicast groups, where the information of each multicast group may include, for example, a multicast address, and optionally, may further include a multicast source address. For example, in the case of internet group management protocol version three (IGMPv 3), a multicast source address is also included.

The information of the multicast group may also be referred to as multicast group information for short.

And step 3, the terminal sends the multicast adding message, and the multicast adding message is forwarded to the second UPF by the RAN equipment or the AGF.

The multicast adding message is sent through PDU session, and the multicast adding message includes multicast group information. Therefore, there is an association between the multicast group information and the PDU session.

And 4, the second UPF forwards the multicast adding message to the second SMF.

For example, as a specific implementation manner of this step, the second UPF may send an N4 interface message to the second SMF, where the N4 interface message includes a multicast join packet and PDU session information.

And 5, the second SMF sends a PDU session modification instruction to the second UPF.

The PDU session modification instruction is used to instruct to modify the PDU session created in step 1 above. The PDU session modification instruction includes information of a multicast group to which the user joins, and user session identification or session information.

It should be noted that the name of the PDU session modification command is not limited, and other names may be used instead.

Step 6a, the second UPF adds the user session to the multicast replication list.

The multicast replication list records the association between the multicast group information and the user session, and is used for subsequently replicating the multicast message of the user to the unicast tunnel of the session in the list.

It should be noted that a user session or a session of a user may also be referred to as a terminal session or a session of a terminal, and in this application, the user session or the session of a user is used interchangeably and actually has the same meaning.

Through the steps 1 to 6a, the user session is added to the multicast replication list at the second UPF, so that when the subsequent second UPF receives the multicast message, the corresponding session can be found by searching the multicast replication list, and the multicast message is sent to the corresponding terminal through the unicast tunnel of the session.

As an alternative, if the second UPF supports the multicast mode, the above steps 1 to 6a may be replaced by a creation step of a multicast tunnel. For details of implementation, reference may be made to the process of creating a multicast tunnel in the prior art, which is not described herein again.

And 6b, for the multicast group added by the user, the second UPF detects whether a multicast source exists.

If a multicast source exists, the multicast source may send a multicast packet to the second UPF in a multicast mode, or send the multicast packet in a unicast tunnel mode.

When the second UPF detects that there is no multicast source, the following steps are further performed.

And 7, the second UPF sends a PDU session modification response to the second SMF.

The PDU session modification response includes a report message, where the report message includes multicast group information, and the report message is used to notify a second SMF: the second UPF has no multicast source of the multicast message corresponding to the multicast group information.

It should be noted that the report message is not limited to be carried in the PDU session modification response and sent to the second SMF, and may also be sent to the second SMF separately.

And 8, the second SMF sends a session creation instruction to the second UPF.

The session creation instruction is used for indicating the creation of a unicast tunnel for receiving the multicast message.

The session creation instruction includes multicast group information.

Optionally, if the tunnel information is allocated by the second SMF, the session creation instruction further includes information of a unicast tunnel for receiving the multicast packet on the second UPF (where the information of the unicast tunnel is the information of the first unicast tunnel described above), where the information of the unicast tunnel includes address information of the second UPF and identification information of the allocated tunnel.

If the tunnel information is allocated by the second UPF, the session creation command does not include the information of the unicast tunnel.

And 9, the second UPF sends a session creation response to the second SMF.

Optionally, if the second UPF allocates the tunnel information, the session creation response further includes information of a unicast tunnel, where the information of the unicast tunnel includes address information of the second UPF and identification information of the allocated tunnel.

Since the second UPF and the first UPF may be managed by the same SMF or by different SMFs. Therefore, the following description is divided into two cases.

In case one, the first SMF manages a first UPF, the second SMF manages a second UPF, and the first SMF and the second SMF are different SMFs.

After the above steps 1 to 9, the following steps are also included:

and step 10, the second SMF selects the first SMF and sends a session creation message to the first SMF.

The session creation message includes multicast group information and information of a unicast tunnel of the second UPF.

For example, the second SMF may select one SMF based on the configuration information, the selected SMF being, for example, the first SMF. As an example, the first SMF may be an anchor device for multicast management.

A UPF is then selected by the first SMF, the selected UPF being, for example, the first UPF. As an example, the first SMF may select to obtain the first UPF according to the principles of topology, load, and the like, for example, the first UPF is reachable by the second UPF, and the first UPF has a multicast source or is reachable by the multicast source; or the first UPF is a multicast anchor device and the first UPF is managed by the first SMF.

As another example, the second SMF may select a UPF, and send information (such as address information, name, and the like) of the selected UPF (for example, the first UPF) to the first SMF, for example, the information is carried in the session creation message and sent to the first SMF. The way for selecting the UPF by the second SMF may refer to the way for selecting the UPF by the first SMF, and is not described in detail.

In step 10a, the first SMF receives a session creation message from the second SMF and sends a session creation request to the first UPF.

It should be noted that, if the session creation message received by the first SMF does not include the information of the first UPF, the first SMF further needs to select one UPF, for example, to select the first UPF, and the specific method may refer to the related description in step 10.

And the session creating request sent to the first UPF by the first SMF comprises multicast group information and information of a unicast tunnel of the second UPF.

And 11a, the first UPF adds the information of the unicast tunnel of the second UPF into the multicast replication list.

Through the steps 7-11 a, the selection of a multicast source for the second UPF is realized, namely the first UPF, the information of the unicast tunnel of the second UPF is sent to the first UPF, the first UPF adds the information of the unicast tunnel of the second UPF into the multicast replication list, and the information can be sent to the second UPF through the unicast tunnel when a subsequent multicast message needing to be sent to the second UPF arrives.

And 11b, the first UPF detects whether a multicast source corresponding to the multicast group information exists.

When the first UPF detects that there is no multicast source, the following steps are further performed.

And step 12, the first UPF sends a report message to the first SMF.

The report message is used to notify: the first UPF lacks a multicast source, and the report message comprises multicast group information.

And step 13, the first SMF sends indication information to the first UPF.

The indication information includes multicast group information, and the indication information is used for indicating that the first UPF requests to join a multicast group corresponding to the multicast group information.

As an implementation manner, the indication information may include a multicast join message, where the multicast join message includes multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

Step 13a, the first SMF sends a session creation response to the second SMF.

And step 14, the first UPF sends a multicast join message to the multicast platform.

The multicast joining message is used for requesting to join the multicast group corresponding to the multicast platform. And then the multicast platform adds the first UPF into the multicast group indicated by the multicast group information in the multicast platform. That is, the multicast platform is used as a multicast source of the first UPF, and subsequently, the multicast platform sends the multicast packet corresponding to the multicast group information to the first UPF.

If the indication information in step 13 does not include the multicast join message, the first UPF generates the multicast join message.

In case two, the same SMF (taking the second SMF as an example) manages the first UPF and the second UPF.

After the above steps 1 to 9, the following steps are also included:

step 10, the second SMF selects the first UPF and sends a session creation message.

In this step, the method for selecting the first UPF by the second SMF can refer to the related description of step 10 in case one. The session creation message sent here is the same as the session creation message of step 10a in case one, and reference may be made to the related description of step 10a in case one.

Step 11 a-step 11b, as in case one, step 11 a-step 11b above.

And step 12, the first UPF sends a report message to the second SMF.

And step 13, the second SMF sends indication information to the first UPF.

Step 14, like step 14 of case one above.

The embodiment shown in fig. 4(b) creates a unicast tunnel between the UPFs, sends a multicast packet to the subordinate UPF through the unicast tunnel, and then copies the multicast packet to the user PDU session by the subordinate UPF. The scheme ensures that part of UPF of the user plane of the core network can support the multicast service without the requirement that the whole network supports the multicast protocol and topology generation. Meanwhile, in the process that the UPF adds the user session and the unicast tunnel of the UPF into the multicast replication list, if no multicast source is detected locally, the information is reported to the SMF, and the SMF issues an instruction for creating the unicast tunnel or adding the unicast tunnel into the multicast group, so that the complexity of the control plane for managing the multicast group is reduced.

Referring to fig. 4(c), a schematic diagram of another multicast packet sending method according to an embodiment of the present application is shown. Compared with the embodiment shown in fig. 4(b), in this embodiment, the SMF detects whether the UPF has a multicast source, and issues an instruction to create a unicast tunnel or join a multicast group. The following description will take as an example only one SMF (e.g., a second SMF) that manages the first UPF and the second UPF.

Step 1 to step 4, similar to step 1 to step 4 of the embodiment shown in FIG. 4 (b).

And 5, the second SMF inquires whether the second UPF has a multicast source. The query manner may refer to the description in the embodiment shown in fig. 4(b), and is not described here again.

And 6, if the second SMF determines that no multicast source exists on the second UPF, the second SMF sends a session creation instruction to the second UPF.

The session creation message is the same as the session creation instruction in step 8 shown in fig. 4(b), and reference may be made to the foregoing description.

And 7, the second UPF sends a session creation response to the second SMF.

Optionally, if there is the information that the second UPF generates the unicast tunnel, the session creation response may include the information of the unicast tunnel.

And 8, the second SMF selects the first UPF and inquires whether a multicast source record sent to the first UPF exists.

The method for selecting the first UPF by the second SMF is the same as the method for selecting the first UPF by the second SMF in the second embodiment shown in fig. 4 (b).

The second SMF queries whether there is a multicast source record addressed to the first UPF, as in step 5 above.

And 9, if the second SMF queries that the first UPF has no multicast source record, the second SMF sends a session creation message to the first UPF.

The session creation message contains multicast group information and information of a unicast tunnel of the second UPF. Optionally, the method further includes indicating information for joining the multicast group.

And 9a, the first UPF adds the information of the unicast tunnel of the second UPF into the multicast replication list.

Step 10, the first UPF sends a multicast join message to the multicast platform under the condition that no multicast source exists.

This step is the same as step 14 in case two of the embodiment shown in fig. 4 (b).

Step 11, the first UPF sends a session creation response to the second SMF.

And step 12, the second SMF sends a PDU session modification instruction to the second UPF.

The PDU session modification instruction includes information of a multicast group to which the user joins and user session identification or session information.

Step 12a, the second UPF adds the user session to the multicast replication list.

And step 13, the second UPF sends a PDU session modification response to the second SMF.

It should be noted that the execution positions of step 12 to step 13 may be any time point after step 4.

The embodiment shown in fig. 4(C) is compared with the embodiment shown in fig. 4(b), where the control plane manages the multicast source, and the handling of the UPF is simplified, so that the handling of the UPF is more in accordance with the principle of C/U (control plane/user plane) separation.

Referring to fig. 4(d), a schematic diagram of another multicast packet sending method according to an embodiment of the present application is shown. The embodiment is applicable to a network element which supports multicast or broadcast between a user and a network, such as a UPF or an AGF in a fixed-mobile convergence network, or a RAN device, and the like, and the AGF in a fixed-mobile convergence scenario is taken as an example below, and a description is given by taking only one SMF (for example, a second SMF) as an example, where the second SMF manages a first UPF and a second UPF.

Step 1 to step 2, similar to step 1 to step 2 of the embodiment shown in FIG. 4 (b).

The terminal in the fixed network may be a Residential Gateway (RG) or the like.

And step 3, the terminal sends a multicast adding message to the AGF.

Step 4, the AGF is used as a multicast agent to process the multicast adding message and detect whether a multicast source exists locally or whether a user has added the same multicast group before.

And 5, under the condition that the AGF does not have a multicast source locally or under the condition that no user joins the same multicast group before, sending a report message or a multicast joining message to the second SMF.

In one implementation, the AGF first looks up the AMF and then sends a report message or a multicast join message through the N2 interface.

If the sent report message is a report message, the report message includes multicast group information, and the report message is used for indicating: AGF lacks the message of the multicast source. If the multicast adding message is sent, the multicast adding message comprises multicast group information, and the multicast adding message is used for requesting to add a multicast group corresponding to the multicast group information.

Alternatively, if the AGF allocates the information of the tunnel, the AGF also sends the information of the tunnel of the AGF to the AMF. The information of the tunnel includes address information of the AGF and identification information of the tunnel.

Then, the AMF selects an SMF (for example, selects a second SMF), and forwards the report message or the multicast join message to the second SMF. Optionally, information of the tunnel of the AGF is also sent to the second SMF.

And 6, the second SMF sends a session creation command to the AGF.

The session creation instruction includes multicast group information and information of a tunnel allocated to the AGF by the second SMF.

This step 6 is an optional step, and is executed when the second SMF does not receive the information of the tunnel of the AGF in step 5.

And 7, the AGF sends a session response message to the second SMF.

This step 7 is an optional step and is performed when step 6 is performed.

Or, in another implementation manner, the tunnel information of the AGF is allocated by the AGF and is sent to the second SMF through the session response message of step 7.

It should be noted that, in the above step 5 to step 7, instead, the AGF may initiate a session creation procedure, and in the procedure, the AGF allocates information of the tunnel of the AGF and sends the information to the second SMF.

Step 8-step 12, reference may be made to step 10-step 14 of case two of the embodiment of fig. 4 (b). And will not be described in detail herein.

In the embodiment of fig. 4(d), the first UPF may forward the multicast packet to the AGF through the unicast tunnel, so that the AGF receives the multicast packet unrelated to the user through the unicast tunnel, and when the first UPF cannot multicast the packet, the AGF of the lower network may implement multicast or broadcast.

Based on the same inventive concept, as shown in fig. 5, a schematic diagram of an apparatus provided by the present application, where the apparatus may be a user plane network element, a radio access device, an access gateway device, a session management network element, or a chip, and may perform the method of any of the foregoing embodiments.

The apparatus 500 includes at least one processor 501, communication lines 502, memory 503, and at least one communication interface 504.

The processor 501 may be a general-purpose Central Processing Unit (CPU), a microprocessor, an Application Specific Integrated Circuit (ASIC), or one or more ics for controlling the execution of programs in accordance with the present disclosure.

The communication link 502 may include a path for transmitting information between the aforementioned components.

The communication interface 504 may be any device, such as a transceiver, for communicating with other devices or communication networks, such as an ethernet, a Radio Access Network (RAN), a Wireless Local Area Network (WLAN), a wired access network, etc.

The memory 503 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be separate and coupled to the processor via a communication line 502. The memory may also be integral to the processor.

The memory 503 is used for storing computer-executable instructions for executing the present application, and is controlled by the processor 501 to execute. The processor 501 is configured to execute a computer execution instruction stored in the memory 503, so as to implement the multicast packet sending method provided in the following embodiments of the present application.

Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application program codes, which are not specifically limited in the embodiments of the present application.

In particular implementations, processor 501 may include one or more CPUs such as CPU0 and CPU1 in fig. 5 as an example.

In particular implementations, apparatus 500 may include multiple processors, such as processor 501 and processor 508 in FIG. 5, for example, as an example. Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

When the apparatus shown in fig. 5 is a chip, for example, a chip of a user plane network element, a chip of an access gateway device, a chip of a radio access device, or a chip of a session management network element, the chip includes a processor 501 (which may also include a processor 508), a communication line 502, a memory 503, and a communication interface 504. In particular, the communication interface 504 may be an input interface, a pin or a circuit, or the like. The memory 503 may be a register, cache, or the like. The processor 501 and the processor 508 may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of programs of the multicast message transmission method according to any of the above embodiments.

The present application may perform division of functional modules on the apparatus according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, the division of the modules in the present application is schematic, and is only a logical function division, and there may be another division manner in actual implementation. For example, in the case of dividing each functional module by corresponding functions, fig. 6 shows a schematic diagram of an apparatus, where the apparatus 600 may be the first user plane network element referred to in the foregoing embodiments, or a chip in the first user plane network element, and the apparatus 600 includes a receiving unit 601, a sending unit 602, and a processing unit 603.

The receiving unit 601 is configured to receive a multicast packet;

the sending unit 602 is configured to send the multicast packet to a communication network element through a first unicast tunnel, where the first unicast tunnel is a tunnel between a first user plane network element and the communication network element and used for sending the multicast packet.

In a possible implementation manner, the receiving unit 601 is further configured to receive multicast group information and information of the first unicast tunnel from a session management network element, where the multicast group information is used to indicate the multicast packet.

In a possible implementation manner, the receiving unit 601 is further configured to receive indication information from the session management network element, where the indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information. Optionally, the indication information includes a multicast join message, the multicast join message includes the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

In a possible implementation manner, the processing unit 603 is configured to determine that there is no multicast source corresponding to the multicast group information;

the sending unit 602 is further configured to send a report message to the session management network element, where the report message includes the multicast group information, and the report message is used to notify that the first user plane network element lacks a multicast source.

In a possible implementation manner, the communication network element is a second user plane network element; or the communication network element is an access gateway device; or the communication network element is a wireless access device.

In a possible implementation manner, the receiving unit 601 is specifically configured to:

receiving the multicast message from a multicast platform; or,

receiving the multicast message from a third user plane network element through a second unicast tunnel, wherein the second unicast tunnel is a tunnel used for sending the multicast message between the third user plane network element and the first user plane network element; or,

receiving the multicast message from a third-party device through a third unicast tunnel, wherein the third unicast tunnel is a tunnel used for sending the multicast message between the third-party device and the first user plane network element; or,

and receiving the multicast message from the fourth user plane network element through a multicast tunnel.

It should be understood that the apparatus may be used to implement the steps performed by the first user plane network element in the method according to the embodiment of the present invention, and the related features may refer to the foregoing description, which is not described herein again.

Specifically, the functions/implementation procedures of the receiving unit 601, the processing unit 603, and the sending unit 602 in fig. 6 can be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503. Alternatively, the functions/implementation procedures of the processing unit 603 in fig. 6 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the functions/implementation procedures of the receiving unit 601 and the transmitting unit 602 in fig. 6 may be implemented by the communication interface 504 in fig. 5.

Alternatively, when the apparatus 600 is a chip or a circuit, the functions/implementation processes of the receiving unit 601 and the sending unit 602 may also be implemented by pins or circuits. Alternatively, when the apparatus 600 is a chip, the memory 603 may be a storage unit in the chip, such as a register, a cache, and the like. Of course, when the apparatus 600 is a user plane network element, the memory 603 may be a storage unit located outside a chip in the user plane network element, which is not specifically limited in this embodiment of the present application.

The present application may perform division of functional modules on the apparatus according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, the division of the modules in the present application is schematic, and is only a logical function division, and there may be another division manner in actual implementation. For example, in the case of dividing each functional module according to the corresponding function, fig. 7 shows a schematic diagram of an apparatus, the apparatus 700 may be a communication network element referred to in the foregoing embodiments, and the communication network element may be a radio access device, an access gateway device, or a second user plane network element, or a chip in the communication network element, and the apparatus 700 includes a receiving unit 701, a sending unit 702, and a processing unit 703.

The receiving unit 701 is configured to receive a multicast packet from a first user plane network element through a unicast tunnel, where the unicast tunnel is a tunnel between the first user plane network element and a communication network element and used for sending the multicast packet;

the sending unit 702 is configured to send the multicast packet.

In a possible implementation manner, the receiving unit 701 is further configured to receive indication information from a session management network element, where the indication information is used to indicate that the unicast tunnel is created.

Optionally, the indication information includes information of the unicast tunnel.

In a possible implementation manner, the sending unit 702 is further configured to send the information of the unicast tunnel to the session management network element.

In a possible implementation manner, the processing unit 703 is configured to determine that there is no multicast source;

the sending unit 702 is further configured to send a report message to the session management network element, where the report message includes multicast group information, the multicast group information is used to indicate the multicast packet, and the report message is used to notify that the communication network element lacks a multicast source.

In another possible implementation manner, the processing unit 703 is configured to determine that there is no multicast source;

the sending unit 702 is further configured to send a report message to the session management network element, where the report message includes multicast group information and information of the unicast tunnel, the multicast group information is used to indicate the multicast packet, and the report message is used to notify that the communication network element lacks a multicast source.

It should be understood that the apparatus may be used to implement the steps performed by the communication network element in the method according to the embodiment of the present invention, and the related features may refer to the foregoing description, which is not described herein again.

Specifically, the functions/implementation procedures of the receiving unit 701, the processing unit 703 and the sending unit 702 in fig. 7 can be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503. Alternatively, the functions/implementation procedures of the processing unit 703 in fig. 7 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the functions/implementation procedures of the receiving unit 701 and the sending unit 702 in fig. 7 may be implemented by the communication interface 504 in fig. 5.

Alternatively, when the apparatus 700 is a chip or a circuit, the functions/implementation processes of the receiving unit 701 and the sending unit 702 may also be implemented by pins or circuits. Alternatively, when the apparatus 700 is a chip, the memory 703 may be a storage unit in the chip, such as a register, a cache, and the like. Of course, when the apparatus 700 is a communication network element, the memory 703 may be a storage unit located outside a chip in the communication network element, and this embodiment of the present application is not limited in this respect.

The present application may perform division of functional modules on the apparatus according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, the division of the modules in the present application is schematic, and is only a logical function division, and there may be another division manner in actual implementation. For example, in the case of dividing each functional module by corresponding functions, fig. 8 shows a schematic diagram of an apparatus, where the apparatus 800 may be a session management network element as referred to in the foregoing embodiments, or a chip in the session management network element, and the apparatus 800 includes a receiving unit 801, a sending unit 802, and a processing unit 803.

The processing unit 803 is configured to acquire multicast group information and information of a unicast tunnel, where the unicast tunnel is a tunnel used for a first user plane network element to send a multicast packet to a communication network element, and the multicast group information is used to indicate the multicast packet;

the sending unit 802 is configured to send the multicast group information and the unicast tunnel information to the first user plane network element.

In a possible implementation manner, the processing unit 803 is specifically configured to:

acquiring the multicast group information and the unicast tunnel information from a second session management network element; or,

acquiring the multicast group information and the unicast tunnel information from the communication network element; or,

and acquiring the information of the unicast tunnel from the local, wherein the multicast group information is originated from the communication network element.

In a possible implementation manner, the receiving unit 801 is configured to receive a first report message from the first user plane network element, where the first report message includes the multicast group information, and the first report message is used to notify that the first user plane network element lacks a multicast source;

the sending unit 802 is further configured to send first indication information to the first user plane network element, where the first indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information.

Optionally, the first indication information includes a multicast join message, where the multicast join message includes the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

In a possible implementation manner, the receiving unit 801 is configured to receive a second report message from a communication network element, where the second report message includes the multicast group information, and the second report message is used to notify that the communication network element lacks a multicast source. Optionally, the second report message further includes information of the unicast tunnel.

In a possible implementation manner, the sending unit 802 is further configured to send second indication information to the communication network element, where the second indication information is used to indicate that the unicast tunnel is created. Optionally, the second indication information includes information of the unicast tunnel, and the information of the unicast tunnel includes address information of the communication network element and identification information of the unicast tunnel.

In a possible implementation manner, the receiving unit 801 is further configured to receive information of the unicast tunnel from the communication network element, where the information of the unicast tunnel includes address information of the communication network element and identification information of the unicast tunnel.

It should be understood that the apparatus may be used to implement the steps performed by the session management network element in the method according to the embodiment of the present invention, and reference may be made to the above for related features, which are not described herein again.

Specifically, the functions/implementation procedures of the receiving unit 801, the processing unit 803, and the sending unit 802 in fig. 8 may be implemented by the processor 501 in fig. 5 calling a computer executing instructions stored in the memory 503. Alternatively, the function/implementation procedure of the processing unit 803 in fig. 8 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the function/implementation procedures of the receiving unit 801 and the transmitting unit 802 in fig. 8 may be implemented by the communication interface 504 in fig. 5.

Alternatively, when the apparatus 800 is a chip or a circuit, the functions/implementation processes of the receiving unit 801 and the sending unit 802 may also be implemented by pins or circuits. Alternatively, when the apparatus 800 is a chip, the memory 803 may be a storage unit in the chip, such as a register, a cache, and the like. Of course, when the apparatus 800 is a session management network element, the memory 803 may be a storage unit located outside a chip in the session management network element, which is not specifically limited in this embodiment of the present application.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The various illustrative logical units and circuits described in this application may be implemented or operated upon by design of a general purpose processor, a digital signal processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

The steps of a method or algorithm described in the embodiments herein may be embodied directly in hardware, in a software element executed by a processor, or in a combination of the two. The software cells may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. For example, a storage medium may be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC, which may be disposed in a terminal device. In the alternative, the processor and the storage medium may reside as discrete components in a terminal device.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While the invention has been described in conjunction with specific features and embodiments thereof, it will be evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the invention. Accordingly, the specification and figures are merely exemplary of the invention as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for sending multicast messages is characterized by comprising the following steps:

a first user plane network element receives a multicast message;

2. The method of claim 1, further comprising:

and the first user plane network element receives multicast group information and the information of the first unicast tunnel from a session management network element, wherein the multicast group information is used for indicating the multicast message.

3. The method of claim 2, further comprising:

and the first user plane network element receives indication information from the session management network element, wherein the indication information is used for indicating that the first user plane network element requests to join a multicast group corresponding to the multicast group information.

4. The method according to claim 3, wherein the indication information comprises a multicast join message, and the multicast join message comprises the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

5. The method according to any one of claims 2 to 4, further comprising:

the first user plane network element determines that there is no multicast source corresponding to the multicast group information, and sends a report message to the session management network element, where the report message includes the multicast group information, and the report message is used to notify that the first user plane network element lacks a multicast source.

6. A method for sending multicast messages is characterized by comprising the following steps:

and the communication network element sends the multicast message.

7. The method of claim 6, further comprising:

and the communication network element receives indication information from a session management network element, wherein the indication information is used for indicating the establishment of the unicast tunnel.

8. The method of claim 7, wherein the indication information comprises information of the unicast tunnel.

9. The method of claim 7, further comprising:

and the communication network element sends the information of the unicast tunnel to the session management network element.

10. The method according to any one of claims 7 to 9, further comprising:

the communication network element determines that no multicast source exists, and sends a report message to the session management network element, wherein the report message includes multicast group information, the multicast group information is used for indicating the multicast message, the report message is used for notifying that the communication network element lacks a multicast source.

11. The method of claim 6, further comprising:

the communication network element determines that no multicast source exists, and sends a report message to the session management network element, where the report message includes multicast group information and information of the unicast tunnel, the multicast group information is used to indicate the multicast packet, the report message is used to notify that the communication network element lacks a multicast source.

12. The method according to any of claims 6 to 11, wherein the communication network element is a second user plane network element; or

The communication network element is an access gateway device; or

The communication network element is a wireless access device.

13. A method for sending multicast messages is characterized by comprising the following steps:

14. The method of claim 13, wherein the acquiring, by the first session management network element, the multicast group information and the unicast tunnel information comprises:

15. The method according to claim 13 or 14, characterized in that the method further comprises:

16. The method according to claim 15, wherein the first indication information comprises a multicast join message, and the multicast join message comprises the multicast group information, and the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

17. The method according to any one of claims 13 to 16, further comprising:

and the first session management network element receives a second report message from a communication network element, wherein the second report message comprises the multicast group information, and the second report message is used for notifying that the communication network element lacks a multicast source.

18. The method of claim 17, further comprising:

and the first session management network element sends second indication information to the communication network element, wherein the second indication information is used for indicating the establishment of the unicast tunnel.

19. The method according to claim 17 or 18, wherein the communication network element is a second user plane network element; or

The communication network element is an access gateway device; or

The communication network element is a wireless access device.

20. An apparatus comprising a receiving unit and a transmitting unit;

the receiving unit is used for receiving the multicast message;

the sending unit is configured to send the multicast packet to a communication network element through a first unicast tunnel, where the first unicast tunnel is a tunnel between a first user plane network element and the communication network element and used for sending the multicast packet.

21. The apparatus of claim 20, wherein the receiving unit is further configured to receive multicast group information and information of the first unicast tunnel from a session management network element, where the multicast group information is used to indicate the multicast packet.

22. The apparatus of claim 21, wherein the receiving unit is further configured to receive indication information from the session management network element, where the indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information.

23. The apparatus of claim 22, wherein the indication information comprises a multicast join message, and wherein the multicast join message comprises the multicast group information, and wherein the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

24. The apparatus according to any of claims 21 to 23, wherein the apparatus further comprises a processing unit, configured to determine that there is no multicast source corresponding to the multicast group information;

the sending unit is further configured to send a report message to the session management network element, where the report message includes the multicast group information, and the report message is used to notify that the first user plane network element lacks a multicast source.

25. An apparatus comprising a receiving unit and a transmitting unit;

the receiving unit is configured to receive a multicast packet from a first user plane network element through a unicast tunnel, where the unicast tunnel is a tunnel between the first user plane network element and a communication network element and used for sending the multicast packet;

and the sending unit is used for sending the multicast message.

26. The apparatus of claim 25, wherein the receiving unit is further configured to receive indication information from a session management network element, where the indication information is used to indicate that the unicast tunnel is created.

27. The apparatus of claim 26, wherein the indication information comprises information of the unicast tunnel.

28. The apparatus of claim 26, wherein the sending unit is further configured to send the information of the unicast tunnel to the session management network element.

29. The apparatus according to any of the claims 26 to 28, wherein the apparatus further comprises a processing unit for determining that there is no multicast source;

the sending unit is further configured to send a report message to the session management network element, where the report message includes multicast group information, the multicast group information is used to indicate the multicast packet, and the report message is used to notify that the communication network element lacks a multicast source.

30. An apparatus, comprising a processing unit and a transmitting unit;

the processing unit is configured to acquire multicast group information and information of a unicast tunnel, where the unicast tunnel is a tunnel used for a first user plane network element to send a multicast packet to a communication network element, and the multicast group information is used to indicate the multicast packet;

the sending unit is configured to send the multicast group information and the unicast tunnel information to the first user plane network element.

31. The apparatus of claim 30, further comprising a receiving unit, configured to receive a first report message from the first user plane network element, where the first report message includes the multicast group information, and is used to notify that the first user plane network element lacks a multicast source;

the sending unit is further configured to send first indication information to the first user plane network element, where the first indication information is used to indicate that the first user plane network element requests to join a multicast group corresponding to the multicast group information.

32. The apparatus of claim 31, wherein the first indication information comprises a multicast join message, and wherein the multicast join message comprises the multicast group information, and wherein the multicast join message is used to request to join a multicast group corresponding to the multicast group information.

33. The apparatus according to any of claims 30 to 32, wherein the apparatus comprises a receiving unit, configured to receive a second report message from a communication network element, where the second report message includes the multicast group information, and the second report message is used to notify that the communication network element lacks a multicast source.

34. A system comprising a user plane function network element and a session management network element;

the session management network element is configured to acquire multicast group information and unicast tunnel information, and send the multicast group information and the unicast tunnel information to the user plane network element, where the unicast tunnel is a tunnel used for the user plane network element to send a multicast packet to a communication network element, and the multicast group information is used to indicate the multicast packet;

and the user plane network element is configured to receive the multicast group information and the unicast tunnel information from the session management network element.

35. The system of claim 34, wherein the session management element is further configured to receive a first report message from the user plane element, where the first report message includes the multicast group information, and the first report message is used to notify that the user plane element lacks a multicast source;

the session management network element is further configured to send first indication information to the user plane network element, where the first indication information is used to indicate that the user plane network element requests to join a multicast group corresponding to the multicast group information;

the user plane network element is further configured to receive the first indication information from the session management network element.