200-301 Question 472
Select 2An organization is deploying a software-defined network (SDN) in their enterprise environment. The network architect explains that the SDN architecture will utilize an underlay, overlay, and fabric design to simplify network management and enable automation. Which of the following statements correctly describe these components in the SDN architecture?
- A
The underlay is responsible for providing the physical infrastructure, including routers, switches, and links.
- B
The overlay utilizes tunnels or encapsulation to create virtual networks independent of the physical infrastructure.
- C
The fabric refers to the centralized control plane that manages the entire SDN network.
- D
The underlay is a virtualized network that exists independently of the physical infrastructure.
- E
The overlay is responsible for physical path selection and direct communication between devices.
Show answer and explanation
Correct answers: A, B
Explanation
In SDN architecture, the underlay provides the physical foundation for the network, including devices like routers and switches. The overlay creates virtualized networks on top of the underlay, using technologies such as VXLAN for encapsulation. Together, the underlay and overlay form the fabric, which is managed by the SDN controller to enable automation and centralized management.
- A. Correct.
Correct: The underlay provides the physical infrastructure on which the SDN operates, such as routers, switches, and physical links.
- B. Correct.
Correct: The overlay in an SDN architecture uses tunneling or encapsulation (e.g., VXLAN) to create logical networks independent of the physical topology.
- C. Incorrect.
Incorrect: The fabric in SDN refers to the combination of underlay and overlay working together, not the centralized control plane itself.
- D. Incorrect.
Incorrect: The underlay is the physical network, not a virtualized network.
- E. Incorrect.
Incorrect: The overlay manages virtual network communication but does not handle physical path selection, which is the role of the underlay.