ISC2 CISSP (Certified Information Systems Security Professional)Communication and Network SecurityHard
A network architect is designing a highly scalable and resilient data center network using Software-Defined Networking (SDN). The goal is to decouple the control plane from the data plane to enable centralized management and programmatic network configuration. Which SDN component logically separates the intelligence for forwarding decisions from the actual packet forwarding process?
- ANorthbound API
- BApplication Layer
- CSDN Controller
- DSDN Switch (Data Plane)
Show answer & explanationAnswer & explanation
Correct answer: C. SDN Controller
The SDN Controller is the centralized intelligence that logically separates the control plane from the data plane. It makes all the forwarding decisions and communicates them to the SDN switches (data plane) via southbound APIs, enabling programmatic control over the network.
Why the other options are wrong
- A. Northbound APIs are interfaces between the SDN Controller and applications, not the component that separates control and data planes.
- B. The Application Layer uses the network services provided by SDN but is not an SDN component responsible for control/data plane separation.
- D. The SDN switch (data plane) executes the forwarding instructions received from the controller; it does not make the decisions itself.
SDN Controller
The central component of a Software-Defined Network (SDN) that acts as the 'brain,' separating the control plane from the data plane, providing a centralized view and programmatic control of the network.
- Centralizes network intelligence.
- Communicates with data plane via Southbound APIs (e.g., OpenFlow).
- Provides Northbound APIs for applications.
Memory trick: Controller thinks, Switch acts.