CCDE: Cisco Certified Design Expert (Practical) — Question 86

A business invests in SDN and develops its own SDN controller that, due to budget constraints, runs on a single controller. The controller actively places an exclusive lock on the configuration of the devices to ensure it is the only source of changes to the environment. What is the result if the controller fails?

Answer options

• A. Manual changes are only possible until the controller is restored
• B. All device configurations are in read-only mode until the controller is restored
• C. The control plane is unavailable until the controller is restored
• D. If a device fails, the configuration backup is unavailable

Correct answer: B

Explanation

If the SDN controller fails and has locked the configurations, all devices will remain in read-only mode until the controller is operational again, preventing any changes. Option A is incorrect because manual changes are not possible at all without the controller. Option C is misleading; while the control plane may be affected, the question specifically addresses device configurations. Option D is irrelevant since the question focuses on configuration access and not on backup availability.