A method executed by a control device in a software defined network is disclosed. According to the method, after establishing a control channel with a switching device, the control device obtains an identifier of the control channel. Then, the control device generates a flow entry, where the flow entry includes a match field and the identifier of the control channel. Further, the control device sends the flow entry to the switching device, where the flow entry is used to instruct the switching device to send, to the control device using the control channel represented by the identifier of the control channel, a data packet that matches the match field. Hence, classification of a new flow is completed on a switching device side.