In a possible design, the terminal device may implement, alternatively by using hardware executing corresponding software, functions performed by the terminal device in the foregoing method. The hardware or software includes one or more modules corresponding to the foregoing functions. The modules may be software and/or hardware.

According to still yet another aspect, an embodiment of the present invention provides an access network device, including a processing unit and a transceiver unit. The processing unit is configured to control the access network device to establish a radio resource control RRC connection to a terminal device by using the transceiver unit, where the RRC connection is one of dual connections, and the dual connections further include a communication connection between the terminal device and a second access network device. The transceiver unit is configured to send first configuration information to the terminal device, where the first configuration information includes signaling radio bearer SRB configuration information of the second access network device and a trigger condition for using the SRB configuration information, and the SRB configuration information of the second access network device is used by the terminal device to establish an RRC connection to the second access network device when the trigger condition is met.

In a possible design, the access network device may implement, by using hardware, functions performed by the access network device in the foregoing method. A structure of the access network device may include a processor and a transceiver. The processor can implement functions of the processing unit. The transceiver can implement functions of the transceiver unit.