easyMultiple ChoiceObjective-mapped
350-401 Practice Question: Is troubleshooting an OSPF adjacency issue…
A network engineer is troubleshooting an OSPF adjacency issue between two routers connected via a serial link. The adjacency is stuck in the INIT state. The engineer has verified that the IP addresses are in the same subnet and that the link is up. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the distinction between INIT and other OSPF states, and the trap here is that candidates confuse a network type mismatch (which causes EXSTART issues) with a Hello interval mismatch (which causes INIT), or incorrectly assume that the OSPF process ID must match.
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
✓
The OSPF hello interval is mismatched between the two routers.
The INIT state in OSPF indicates that a router has received a Hello packet from its neighbor but the neighbor has not yet seen its own Router ID in the received Hello. A mismatched Hello interval causes the routers to send Hellos at different rates, so one router may not receive a Hello within the expected Dead interval, preventing the neighbor from seeing its Router ID in the received Hello and thus stalling the adjacency in INIT.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The OSPF router IDs are the same.
Why it's wrong here
Incorrect because duplicate router IDs would cause the adjacency to fail at a later state, not INIT.
- ✓
The OSPF hello interval is mismatched between the two routers.
Why this is correct
Correct because if the hello intervals are different, the routers will not agree on the hello timer, causing the adjacency to remain in INIT.
- ✗
The OSPF process ID is different.
Why it's wrong here
Incorrect because OSPF process ID is locally significant and does not affect adjacency formation.
- ✗
The OSPF network type is point-to-point on one router and point-to-multipoint on the other.
Why it's wrong here
Incorrect because network type mismatch typically causes issues in the 2WAY state, not INIT.
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
About these practice questions
This 350-401 question is part of Courseiva's 1,175-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.