One example method includes receiving, by a first node, a first message from a second node, wherein the first message is used to page a third node, instruct the third node to access a network, instruct the first node to provide a relay serving for the third node, instruct to set the third node to a low configuration mode, instruct to set the third node to a high configuration mode, or instruct to update system information. The first node can send a second message to a third node, where the second message is used to instruct the third node to access a network, instruct the third node to perform communication with a second node by using the first node, instruct to set the third node to a low configuration mode, instruct to set the third node to a high configuration mode, or instruct the third node to update system information.