300-440 Question 195
Single answerA company has deployed a DMVPN hub-and-spoke topology to connect its branch offices. The network engineer notices that spoke-to-spoke traffic is being routed through the hub, causing unnecessary latency. What must the engineer configure to enable direct spoke-to-spoke communication in the DMVPN network?
- A
Enable NHRP shortcut and redirect on the hub router
- B
Configure static routes on each spoke router to bypass the hub
- C
Enable dynamic NAT on the spoke routers
- D
Configure OSPF as the routing protocol between the hub and spokes
Show answer and explanation
Correct answer: A
Explanation
In a DMVPN topology, spoke-to-spoke communication is achieved by enabling NHRP shortcut and redirect on the hub router. NHRP ensures that spokes can dynamically discover each other and establish direct GRE tunnels, bypassing the hub for data traffic. This reduces latency and improves network efficiency. Other options, such as static routes or NAT, do not provide the required functionality for spoke-to-spoke communication.
- A. Correct.
Correct. Enabling NHRP (Next Hop Resolution Protocol) shortcut and redirect on the hub router allows spokes to dynamically discover each other and establish direct tunnels for spoke-to-spoke traffic, bypassing the hub.
- B. Incorrect.
Incorrect. Static routes may allow specific traffic to bypass the hub, but this approach is not scalable or dynamic in a DMVPN environment. NHRP is designed to handle this scenario dynamically.
- C. Incorrect.
Incorrect. Dynamic NAT on the spoke routers is unrelated to enabling direct spoke-to-spoke communication in a DMVPN topology. NAT is primarily used for IP address translation, not routing optimization.
- D. Incorrect.
Incorrect. While OSPF can be used as a routing protocol in DMVPN, it does not enable direct spoke-to-spoke communication. NHRP is required for spoke-to-spoke tunnels.