Automation and Programmability for CCNA

Sample Practice Questions

1. Question 1

   What is the function of a controller in controller-based networking?
   1. A. It serves as the centralized management point of an SDN architecture
   2. B. It is a pair of core routers that maintain all routing decisions for a campus
   3. C. It centralizes the data plane for the network
   4. D. It is the card on a core router that maintains all routing decisions for a campus.
   Explanation

   The correct answer is: A. It serves as the centralized management point of an SDN architecture.

   In a controller-based (SDN) architecture, the controller is the centralised brain that programs the forwarding behaviour of every device in the fabric — pushing policies, computing paths, and exposing northbound APIs to applications. A is correct: it serves as the centralised management point of the SDN architecture. B is wrong because a pair of core routers is a redundancy design, not a controller. C is wrong because SDN deliberately separates control and data planes — the controller centralises the control plane, while the data plane stays distributed in the switches/routers. D is wrong because a line card on a router is hardware, not the SDN controller.

2. Question 2

   What is the role of disaggregation in controller-based networking?
   1. A. It divides the control-plane and data-plane functions.
   2. B. It streamlines traffic handling by assigning individual devices to perform either Layer 2 or Layer 3 functions
   3. C. It summarizes the routes between the core and distribution layers of the network topology
   4. D. It enables a network topology to quickly adjust from a ring network to a star network
   Explanation

   The correct answer is: A. It divides the control-plane and data-plane functions..

   Disaggregation in controller-based (SDN) networking is the architectural separation of the control plane from the data plane — the controller centralises the decision-making (routing, policy, topology) and pushes forwarding instructions down to a distributed data plane in the switches and routers, which simply execute them. A is correct. B is wrong because assigning specific devices to L2 or L3 functions is just hierarchical design (access vs. distribution), not disaggregation. C is wrong because route summarisation between layers is a routing-protocol/configuration topic, not the SDN concept of disaggregation. D is wrong because dynamically restructuring physical topology between ring and star is unrelated — disaggregation is about control of forwarding, not about rewiring the network.

3. Question 3

   Which SDN plane forwards user-generated traffic?
   1. A. Management plane
   2. B. Control plane
   3. C. Policy plane
   4. D. Data plane
   Explanation

   The correct answer is: D. Data plane.

   Software-Defined Networking separates network functions into three planes: management (monitoring and configuration), control (routing decisions, topology, path computation), and data (actual packet forwarding). End-user traffic is forwarded by the data plane — the hardware/ASIC layer that moves packets at line rate based on what the control plane has installed. D is correct. A (management) handles configuration and telemetry. B (control) makes forwarding decisions but doesn't move packets. C (policy) is not a standard SDN plane — sometimes confused with the application plane in the SDN architecture.

4. Question 4

   How do traditional campus device management and Cisco DNA Center device management differ in regards to deployment?
   1. A. Traditional campus device management allows a network to scale more quickly than with Cisco DNA Center device management.
   2. B. Cisco DNA Center device management can deploy a network more quickly than traditional campus device management.
   3. C. Cisco DNA Center device management can be implemented at a lower cost than most traditional campus device management options.
   4. D. Traditional campus device management schemes can typically deploy patches and updates more quickly than Cisco DNA Center device management.
   Explanation

   The correct answer is: B. Cisco DNA Center device management can deploy a network more quickly than traditional campus device management..

   Cisco DNA Center provides templates, design profiles, and zero-touch provisioning so a new device can be discovered, configured, and pushed into production with no per-box CLI work — most of the deployment is automated. Traditional management is device-by-device CLI: the engineer logs into each switch/router and applies its config manually, which scales linearly with site count. B captures the deployment-speed advantage. A inverts it. C ('lower cost than most options') is not necessarily true — DNA Center has appliance and license costs that can exceed simple CLI tools at small scale. D inverts the patching speed — DNA Center's automated software-image update against a group of devices is faster than manual TFTP/SCP rollouts.

5. Question 5

   Which purpose does a northbound API serve in a controller-based networking architecture?
   1. A. facilitates communication between the controller and the applications
   2. B. reports device errors to a controller
   3. C. generates statistics for network hardware and traffic
   4. D. communicates between the controller and the physical network hardware
   Explanation

   The correct answer is: A. facilitates communication between the controller and the applications.

   In a controller-based architecture, the northbound API is the path between the controller and the applications above it — orchestrators, monitoring, business logic. Apps call the controller (typically via REST/JSON) to read state or push intent; the controller then translates that into device-level changes via its southbound APIs. A captures that. B (reporting device errors) is northbound output but not what defines the API's purpose. C (statistics) is part of what apps consume but again not the defining purpose. D (controller ↔ network hardware) describes the southbound API — the opposite direction.

Other CCNA domains

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