300-420 Question 186
Select 3An enterprise network is expanding to include multiple branch offices that require secure communication with the headquarters and between each other. The design team has decided to implement a DMVPN solution. Which of the following design considerations will ensure optimal performance and scalability of the DMVPN deployment?
- A
Use a single-tier hub-and-spoke topology with all branch communication routed through the hub.
- B
Implement Phase 3 DMVPN to enable direct spoke-to-spoke communication.
- C
Ensure proper QoS policies are applied to prioritize critical traffic over the DMVPN tunnels.
- D
Use dynamic routing protocols such as EIGRP or OSPF over the DMVPN tunnel for route propagation.
- E
Deploy static routes at each branch to ensure consistent traffic flow through the hub.
Show answer and explanation
Correct answers: B, C, D
Explanation
For optimal performance and scalability in a DMVPN deployment, it is essential to enable Phase 3 DMVPN to support direct spoke-to-spoke communication, apply appropriate QoS policies to prioritize critical traffic, and use dynamic routing protocols for efficient and scalable route propagation. Avoid relying solely on single-tier hub-and-spoke topologies or static routing, as they do not fully utilize DMVPN's capabilities and may limit network growth.
- A. Incorrect.
This option describes a single-tier hub-and-spoke topology, which may lead to suboptimal performance due to all traffic being routed through the hub. It does not leverage DMVPN's full capabilities, such as spoke-to-spoke communication.
- B. Correct.
Phase 3 DMVPN supports NHRP redirection and shortcut routing, which allows direct spoke-to-spoke communication without routing traffic through the hub, improving performance and scalability.
- C. Correct.
Applying QoS policies ensures that critical traffic, such as voice or video, is prioritized over less important traffic, which is crucial for maintaining performance in a DMVPN deployment.
- D. Correct.
Dynamic routing protocols like EIGRP or OSPF simplify route propagation and allow for scalability in larger DMVPN deployments, as they adapt to network changes without manual intervention.
- E. Incorrect.
Static routes limit flexibility and scalability, especially in a growing network. Dynamic routing should be used to ensure efficient and automated route updates.