Communication method and apparatus

A communication method, comprising:

• receiving, by a target access device, a second message from an access controller, wherein the second message comprises a multicast service context of a terminal device;
• sending, by the target access device, a fourth message to the access controller, wherein the fourth message is used to respond to a message used to request hand over of the terminal device to the target access device;
• and
• after the target access device receives the second message:
• when the target access device determines, based on the multicast service context of the terminal device, that the target access device does not subscribe to a multicast service currently performed by the terminal device, sending, by the target access device, a third message to a multicast source device, wherein the third message is used to subscribe to the multicast service currently performed by the terminal device.

A communication method, comprising:

• receiving, by a terminal device, a sixth message from a source access device, wherein the sixth message comprises notification information of subscribing to a multicast service currently performed by the terminal device;
• and
• sending, by the terminal device and based on the sixth message, a seventh message to a target access device, wherein the seventh message is used to indicate that the target access device does not subscribe to the multicast service currently performed by the terminal device, or the seventh message is used to request that the target access device subscribes to the multicast service currently performed by the terminal device,
• wherein in response to receiving the seventh message, the target access device sends a nineteenth message to the multicast source device, wherein the nineteenth message indicates that the multicast source device adds the target access device to the multicast service currently performed by the terminal device.