The OpenFlow specification provides a mechanism in the controller to inform the switch about the list of asynchronous events that the controller or controller channel is interested in. This is achieved by sending the Set Asynchronous Configuration message (OFPT_SET_ASYNC
) to the switch. The switch should maintain a per-controller asynchronous configuration in its database, which will be used as a filter before sending the asynchronous configuration message to the controller.
The message format that will be used by the controller to send the OFPT_SET_ASYNC
is defined in the Configuring the switch to send a list of asynchronous events the controller channel is interested in recipe of Chapter 2, Symmetric Messages and Asynchronous Messages (Part 2).