Which of the Following Statements Are True About OpenFlow Interface

Which of the following statements are true about OpenFlow interface information reporting? (Choose all that apply.)

A) After the OpenFlow channel is successfully established, the controller actively queries port information from FPs.
B) The controller sends Multipart Request messages to query port information.
C) FPs respond with a Multipart Reply message for batch delivery of port information.
D) When a port changes, the corresponding FP actively sends a Flow Mod message to report the port change information.