SDN Framework Models: Augmented vs Hybrid
Short answer
B The solution uses the augmented SDN framework model, which allows off-box applications to interact with the routing table and forwarding engine.
Question
Key Takeaways
The key is recognizing that 'distributed' implies a centralized controller pushing updates, whereas 'augmented' involves an external application or process accessing the local RIB/FIB directly without a central SDN controller managing the entire state.
This question distinguishes between SDN framework models based on the degree of control plane integration. The correct model allows off-box processes to interact directly with the routing table and forwarding engine.
Common mistake: Candidates often choose 'Hybrid' because it sounds like a mix of traditional and SDN, but the specific capability of off-box interaction with the RIB points strictly to the Augmented model definition in Cisco's SDN architecture.
Expert Analysis
Why the Answer Is Correct
The Augmented SDN model is characterized by an external controller or application that interacts with the network devices' existing control plane (RIB) and data plane (FIB). This allows for enhanced capabilities without replacing the distributed routing protocols. The scenario describes exactly this: off-box processes interacting with the routing table as if they were a distributed process, which is the hallmark of the Augmented model.
Why the Other Options Are Wrong
Replace refers to a fully centralized SDN where the controller replaces the device's control plane entirely. Distributed is not a standard SDN framework classification in this context; rather, traditional networks are distributed. Hybrid typically implies a combination of centralized and distributed control planes coexisting in a more complex manner, but the specific mechanism of 'off-box interaction with RIB' aligns best with Augmented.
Community Comment Notes
Community consensus heavily favors option C (Hybrid), likely due to confusion about the term 'hybrid' meaning a mix of old and new. However, as noted by users discussing the definitions, the Augmented model specifically enables applications to react to network state via APIs to the RIB. One user correctly identified that Augmented allows a controller to apply policy, distinguishing it from Replace.
Official Reference
https://learningnetwork.cisco.com/s/question/0D53i00000KsuxaCAB/sdn-models-doubts
This link opens the official vendor documentation in a new tab.
Exam Strategy
Focus on the precise definitions of SDN frameworks: Replace (Centralized), Augmented (External/Off-box access to local state), and Overlay (Encapsulation). Memorize the specific interactions allowed in each model to avoid confusion between Augmented and Hybrid.
Frequently Asked Questions
What is the difference between Augmented and Hybrid SDN?
Community Votes
78% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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bdp123 👍 4 Answered Chttps://learningnetwork.cisco.com/s/question/0D53i00000KsuxaCAB/sdn-models-doubts
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Seawanderer 👍 3 Answered CIn a hybrid SDN framework, both traditional distributed routing processes and centralized SDN control coexist. This approach allows for off-box processes to interact with the routing table and potentially the forwarding engine, enabling applications to understand and react to the network state in near real-time. The hybrid model leverages the strengths of both SDN and traditional networking, providing flexibility and enhanced control over the network.
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anonymousch 👍 2 Answered BAugmented: A controller that can apply policy in network devices. e.g. PfR
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