hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show ip route ospf
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks O 172.16.0.0/24 [110/100] via 172.16.0.2, 00:00:15, Tunnel0 O 172.16.0.0/24 [110/100] via 172.16.0.3, 00:00:10, Tunnel0
Based on this output, what is the problem?
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 is learning the same subnet from multiple spokes, indicating a misconfiguration.
The output shows OSPF routes for the same network 172.16.0.0/24 via two different next hops (172.16.0.2 and 172.16.0.3). This indicates that OSPF is seeing the same subnet from multiple spokes, which is incorrect because the tunnel network should be unique per spoke. This suggests a misconfiguration where the tunnel IP addresses are overlapping or OSPF is not properly filtering.
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 is learning the same subnet from multiple spokes, indicating a misconfiguration.
Why this is correct
Duplicate routes for the same network via different next hops is problematic.
- ✗
The OSPF cost is 100, which is high.
Why it's wrong here
Cost is not necessarily a problem; it's a metric.
- ✗
The routes are learned via EIGRP.
Why it's wrong here
The O prefix indicates OSPF.
- ✗
The tunnel interface is down.
Why it's wrong here
Routes are present and recent, so tunnel is up.
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
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Introduction to ENARSI Exam and Network Fundamentals
Key term
OSPF Special Area Types
OSPF special area types are configurations within an OSPF network that limit the type of routing information shared across an area to reduce routing table size and processing overhead.
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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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.