Cisco CCNA (200-301)Automation and ProgrammabilityMedium
A network application developer needs to build a dashboard that queries a Cisco DNA Center controller for real-time device health data. Which type of API does the developer's application use to communicate with the controller?
- AEast-west API
- BOpenFlow API
- CSouthbound API
- DNorthbound API
Show answer & explanationAnswer & explanation
Correct answer: D. Northbound API
Northbound APIs (typically REST-based) allow external applications to communicate with the controller to retrieve data or issue commands. Southbound APIs (e.g., NETCONF, OpenFlow) connect the controller down to network devices.
Why the other options are wrong
- A. East-west APIs (or protocols) are used for controller-to-controller communication, not app-to-controller.
- B. OpenFlow is a southbound protocol used for controller-to-switch communication.
- C. Southbound APIs connect the controller to devices, not applications to the controller.
Northbound vs Southbound APIs
Northbound APIs let applications interact with an SDN controller (typically REST), while southbound APIs let the controller manage network devices (e.g., NETCONF, OpenFlow).
- Northbound = controller-to-application (up)
- Southbound = controller-to-device (down)
- REST/RESTCONF often used northbound; NETCONF/OpenFlow southbound
Memory trick: North goes up to apps, South goes down to switches.