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300-410 Practice Question: Configures a DMVPN spoke with OSPF as the routing…
A network engineer configures a DMVPN spoke with OSPF as the routing protocol:
interface Tunnel0 ip address 10.0.0.2 255.255.255.0 ip nhrp network-id 100 ip nhrp nhs 10.0.0.1
tunnel source GigabitEthernet0/0 tunnel mode gre multipoint
ip nhrp map 10.0.0.1 192.168.1.1 ip nhrp map multicast 192.168.1.1
!
router ospf 1 network 10.0.0.0 0.0.0.255 area 0
!
What is a common issue with OSPF in this DMVPN Phase 2 configuration?
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
✓
OSPF will elect a DR/BDR on the hub, which can cause suboptimal routing and adjacency issues.
OSPF over DMVPN Phase 2 requires the hub to be configured as an OSPF point-to-multipoint network type to avoid issues with DR/BDR elections and to allow spoke-to-spoke adjacencies.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
OSPF will elect a DR/BDR on the hub, which can cause suboptimal routing and adjacency issues.
Why this is correct
By default, OSPF over a multipoint interface uses broadcast network type, leading to DR/BDR elections that may not work well with DMVPN.
- ✗
OSPF will not form adjacencies because of NHRP authentication.
Why it's wrong here
NHRP authentication does not affect OSPF adjacencies.
- ✗
OSPF will use point-to-point network type by default.
Why it's wrong here
Default is broadcast for multipoint GRE tunnels.
- ✗
OSPF will automatically adjust to the DMVPN environment.
Why it's wrong here
OSPF requires manual configuration (e.g., ip ospf network point-to-multipoint) to work optimally.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.