300-420 Question 185
Single answerAn enterprise network is deploying a Dynamic Multipoint VPN (DMVPN) solution to interconnect multiple branch offices with the headquarters. The network engineer wants to ensure that spoke-to-spoke traffic does not need to pass through the hub router to optimize latency. Which DMVPN phase configuration should the engineer implement to achieve this?
- A
DMVPN Phase 1
- B
DMVPN Phase 2
- C
DMVPN Phase 3
- D
Static GRE Tunnels
Show answer and explanation
Correct answer: B
Explanation
DMVPN Phase 2 is the appropriate choice for optimizing spoke-to-spoke traffic in a DMVPN deployment. It allows spokes to dynamically establish direct GRE tunnels between each other using NHRP, bypassing the hub for data traffic. This reduces latency and enhances network performance, meeting the requirements of the scenario.
- A. Incorrect.
DMVPN Phase 1 only supports spoke-to-hub communication, meaning all traffic, including spoke-to-spoke, must pass through the hub. This does not meet the requirement for spoke-to-spoke traffic optimization.
- B. Correct.
DMVPN Phase 2 supports dynamic spoke-to-spoke communication using NHRP (Next Hop Resolution Protocol). It allows direct traffic flow between spokes without passing through the hub, making it the correct choice for this scenario.
- C. Incorrect.
DMVPN Phase 3 introduces enhancements like hierarchical routing and summarization, but spoke-to-spoke traffic still relies on the hub for route redirection before establishing direct tunnels. This does not fully optimize latency.
- D. Incorrect.
Static GRE Tunnels are a point-to-point solution and lack the dynamic nature of DMVPN. They would require manual configuration for every spoke-to-spoke connection, which is not scalable or efficient.