One embodiment of the present invention provides a switch in a software-defined network. The switch includes at least one port, a flow management module, and forwarding circuitry. The port is capable of receiving a frame belonging to a software-defined data flow and a frame belonging to a regular data flow. The flow management module logically partitions the port for the frame belonging to the software-defined data flow from the frame belonging to the regular data flow. The forwarding circuitry forwards the frame belonging to the software-defined data flow based on a flow definition in a local flow table. The flow definition indicates how the software-defined data flow is processed in a software-defined network.