Efficient access control for trigger events in SDN

A software defined network (SDN) with access control to control access to network resources, the SDN comprising:

• a network device comprising a controller that is configured, upon receiving a trigger event from a data plane of the software defined network, to trigger one or more applications that are installed to run at a control plane of the software defined network atop the controller to react to the trigger event,
• wherein the controller is further configured, before triggering applications due to the trigger event, to apply a conflict resolution scheme configured to resolve conflicts among the applications, the conflict resolution scheme comprising:
• determining all flow spaces that are affected by the trigger event and selecting from these flow spaces a single selected flow space having assigned a priority that complies with a predetermined policy,
• determining, from the applications related to the selected flow space, a single master application according to predefined criteria, and
• triggering, in addition to the master application, only those applications whose reactions to the trigger event do not conflict with the master application, and
• wherein the flow spaces are objects on the control plane.