300-410 Infrastructure Services Practice Question
A network engineer is deploying a DMVPN Phase 3 hub-and-spoke topology. The hub router must dynamically learn spoke-to-spoke routes and allow direct spoke-to-spoke tunnels. Which technology should be implemented on the hub to achieve this?
⚠ Common exam trap
The trap here is assuming that any NHRP configuration (like authentication or static maps) enables Phase 3 behavior, when actually only redirect and shortcut do.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable NHRP redirect on the hub and NHRP shortcut on the spokes.
In DMVPN Phase 3, the hub uses NHRP redirect to inform spokes that a more optimal path exists directly to another spoke. Spokes then use NHRP shortcut to resolve the destination's NBMA address and establish a direct tunnel. This reduces hub transit and latency. The other options are valid DMVPN features but do not provide the dynamic spoke-to-spoke capability required.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure NHRP authentication and NHRP map entries on all routers.
Why it's wrong here
NHRP authentication and static map entries are used for security and static binding in DMVPN, but they do not provide dynamic spoke-to-spoke tunnel establishment. Without redirect and shortcut, spokes will continue to send all traffic through the hub, even if maps exist, because they lack the trigger to build direct tunnels.
- ✗
Implement IPsec tunnel protection with IKEv2 and enable QoS pre-classify.
Why it's wrong here
IPsec tunnel protection and QoS pre-classify are used for encryption and QoS in DMVPN, but they do not facilitate direct spoke-to-spoke communication. These features secure and prioritize traffic but do not provide the NHRP signaling needed for spokes to dynamically discover and build tunnels to each other.
- ✗
Use OSPF broadcast network type on all tunnel interfaces and enable split horizon.
Why it's wrong here
OSPF broadcast network type and split horizon affect routing protocol behavior and may impact route propagation, but they do not enable DMVPN Phase 3 direct spoke-to-spoke tunnels. The key mechanisms for Phase 3 are NHRP redirect and shortcut, which operate at the NHRP layer, not the routing protocol layer.
- ✓
Enable NHRP redirect on the hub and NHRP shortcut on the spokes.
Why this is correct
NHRP redirect on the hub and NHRP shortcut on the spokes enable Phase 3 DMVPN. The hub sends NHRP redirect messages to spokes when it receives traffic that could go directly between them, and spokes use NHRP shortcut to resolve the destination spoke's NBMA address and build a direct tunnel, reducing hub load and latency.
Visual reference
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Related to this question
Learn chapter
DMVPN and FlexVPN Technologies
Key term
DMVPN Phase 3
DMVPN Phase 3 is a Cisco networking technology that allows branch offices to connect directly to each other without always going through a central hub, but with smarter routing that lets the hub control the traffic paths more efficiently.
Key term
DMVPN Phase 2
DMVPN Phase 2 is an advanced Cisco routing technology that allows spoke routers to communicate directly with one another without sending traffic through a central hub, using dynamic routing protocols and multipoint GRE tunnels.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.