300-410 Question 180
Single answerA network engineer is deploying a DMVPN Phase 2 topology and needs to ensure that spoke-to-spoke communication is established dynamically without requiring traffic to pass through the hub after the initial setup. How can NHRP be configured to achieve this functionality?
- A
Configure NHRP shortcut commands on the hub router to allow spoke-to-spoke communication.
- B
Configure NHRP shortcut commands on all spoke routers to dynamically resolve next-hop addresses for spoke-to-spoke traffic.
- C
Enable NHRP redirect on the hub router and NHRP shortcut on the spoke routers.
- D
Enable NHRP redirect on the spoke routers to dynamically redirect traffic to the correct destination.
Show answer and explanation
Correct answer: C
Explanation
In a DMVPN Phase 2 topology, NHRP redirect on the hub router informs spoke routers about direct spoke-to-spoke paths. Additionally, NHRP shortcut on the spokes enables them to dynamically resolve next-hop addresses and establish direct tunnels for communication. This configuration ensures optimal routing without unnecessarily routing traffic through the hub.
- A. Incorrect.
This is incorrect because NHRP shortcut commands are not required on the hub router in a DMVPN Phase 2 topology. The hub router facilitates initial communication and NHRP redirection, but shortcuts are configured on spoke routers.
- B. Incorrect.
This is incorrect because while NHRP shortcut commands are necessary, they must be configured only on the spoke routers, not all devices in the topology.
- C. Correct.
This is correct because in DMVPN Phase 2, NHRP redirect on the hub router notifies spokes about optimal paths, and NHRP shortcut on the spokes allows them to dynamically establish direct spoke-to-spoke tunnels.
- D. Incorrect.
This is incorrect because NHRP redirect is configured on the hub router, not on the spoke routers, in a DMVPN Phase 2 topology.