200-901 Network Fundamentals Practice Question
In Software-Defined Networking (SDN), the control plane is separated from the data plane. Which of the following best describes the function of the southbound API?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Interface between the controller and network devices
Southbound API is used by the SDN controller to communicate with network devices (e.g., switches, routers) to enforce forwarding rules.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Interface between applications and the controller
Why it's wrong here
That is the northbound API.
- ✓
Interface between the controller and network devices
Why this is correct
Southbound API (e.g., OpenFlow) allows the controller to configure devices.
- ✗
Communication between two controllers
Why it's wrong here
East-west APIs are used for controller-to-controller communication.
- ✗
Interface between the control plane and management plane
Why it's wrong here
Not a standard SDN API definition.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-901 exam.