Cisco CCNA 200-301 Practice Question

In Software-Defined Networking (SDN) architectures, the northbound interface is used by network applications to communicate with the SDN controller. This allows applications to send instructions and policies to the controller, which then manages the network devices accordingly. The southbound interface is used by the SDN controller to communicate with the underlying network devices, not with applications. Eastbound and westbound interfaces refer to communication between controllers or systems at the same layer and are not involved in application-to-controller interactions.