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

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

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