A method includes: obtaining, by a control plane device, quality of service (QoS) required by a data transmission service and information about data transmission capabilities of at least two user plane devices controlled by the control plane device; after determining that a data transmission service needs to be established between a terminal and a user plane device, selecting, from the at least two user plane devices, a user plane device whose data transmission capability satisfies the QoS required by the data transmission service; and establishing a bearer of the data transmission service on the selected user plane device.