A mobility management network element receives a node capability notification message from the access node, where the node capability notification message is used to indicate that the access node supports use of a user datagram protocol (UDP), to receive a paging message from the mobility management network element, the mobility management network element selects the UDP to send a first paging message to the access node such that a consumption degree of resources of the mobility management network element may be reduced, and occurrence of congestion on the mobility management network element may be avoided.