DMVPN CCIE-ENTERPRISE-INFRASTRUCTURE Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard · select all that apply

   A dual-hub DMVPN Phase 3 network is experiencing issues when one hub fails. Spokes are unable to reach networks that were only advertised by the failed hub. The engineer wants to ensure that all networks remain reachable when either hub fails. Which two actions will help achieve this? (Select all that apply.)

   • AUse BGP multipath to allow spokes to use both hubs simultaneously.
   • BConfigure both hubs to advertise the same set of networks via BGP.
   • CConfigure the hubs to use a virtual IP (VIP) for NHRP, so that spokes always use the same address.
   • DEnsure that the spokes have NHRP mappings to both hubs.
   • EConfigure the spokes with a static route to the failed hub's networks.
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2. 27expert · hard

   A DMVPN Phase 3 network has two hubs. Spokes are configured with 'ip nhrp shortcut' and hubs with 'ip nhrp redirect'. The network engineer notices that some spoke-to-spoke shortcuts are established, but others are not. The 'show dmvpn' output on a non-working spoke shows that it has a shortcut entry, but the entry is in 'incomplete' state. What is the most likely cause?

   • AThe destination spoke is behind a NAT device that is not configured to allow IPsec traffic.
   • BThe hub is not configured with 'ip nhrp redirect'.
   • CThe source spoke is missing the 'ip nhrp shortcut' command.
   • DThe destination spoke is not registered with the hub.
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4. 28expert · hard

   An engineer is troubleshooting a dual-hub DMVPN Phase 3 network. Spokes are able to establish spoke-to-spoke shortcuts, but after a hub fails, the shortcuts are not being re-established through the remaining hub. The engineer suspects that the spokes are still using the failed hub's NHRP server address. What is the best way to verify this?

   • ARun 'debug nhrp' on the spoke and look for resolution requests sent to the failed hub.
   • BRun 'show ip nhrp' on a spoke and check if the failed hub's address is still in the NHRP cache.
   • CRun 'show ip route' on the spoke and check if the route to the destination is via the failed hub.
   • DRun 'show dmvpn' on the remaining hub and check if the spoke has a shortcut entry.
   Reveal Solution Discussion Select an answer first
5. 29expert · hard

   A DMVPN Phase 3 network has two hubs. A spoke is unable to establish a direct tunnel to another spoke. The engineer has verified that NHRP registration is successful, the hubs have 'ip nhrp redirect', and the spokes have 'ip nhrp shortcut'. The 'show dmvpn' output on the source spoke shows a shortcut entry, but the entry is in 'incomplete' state. What is the most likely cause?

   • AThe destination spoke is not configured with 'ip nhrp shortcut'.
   • BThe hub is not configured with 'ip nhrp redirect'.
   • CThe destination spoke is behind a NAT device that is not configured to allow IPsec traffic.
   • DThe source spoke's tunnel interface is not using the same tunnel key as the destination.
   Reveal Solution Discussion Select an answer first
6. 30expert · hard

   A dual-hub DMVPN Phase 3 network is configured with BGP as the routing protocol. Spokes have two NHRP server mappings, one for each hub. When Hub1 fails, spokes are able to reach networks via Hub2, but they are not establishing new spoke-to-spoke shortcuts. The engineer suspects that the spokes are still trying to use Hub1 for NHRP resolution. What is the most likely cause?

   • AThe spokes have a static NHRP mapping for Hub1 that does not expire.
   • BThe spokes are missing the 'ip nhrp shortcut' command.
   • CThe BGP hold timer on the spokes is too long.
   • DThe remaining hub is not configured with 'ip nhrp redirect'.
   Reveal Solution Discussion Select an answer first