This 350-401 practice question tests your understanding of vrf and path isolation. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
What is the default OSPF hello interval on an Ethernet link?
10 seconds
Correct. Default hello interval for Ethernet is 10 seconds.
30 seconds
Why wrong: Incorrect. 30 seconds is the default for NBMA networks.
40 seconds
Why wrong: Incorrect. 40 seconds is not a standard OSPF timer.
5 seconds
Why wrong: Incorrect. 5 seconds is used in some fast convergence designs but not default.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
10 seconds
The default OSPF hello interval on an Ethernet link is 10 seconds, as defined in RFC 2328. OSPF uses this interval to maintain neighbor adjacency and detect link failures; on broadcast multi-access networks like Ethernet, the default is 10 seconds, while on non-broadcast multi-access (NBMA) networks it is 30 seconds.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
10 seconds
Why this is correct
Correct. Default hello interval for Ethernet is 10 seconds.
Related concept
Read the scenario before looking for a memorised answer.
30 seconds
Why it's wrong here
Incorrect. 30 seconds is the default for NBMA networks.
40 seconds
Why it's wrong here
Incorrect. 40 seconds is not a standard OSPF timer.
5 seconds
Why it's wrong here
Incorrect. 5 seconds is used in some fast convergence designs but not default.
Common exam traps
Cisco often tests the distinction between OSPF network types, where candidates confuse the default hello interval for Ethernet (10 seconds) with that of NBMA (30 seconds) or point-to-point (10 seconds on Cisco, but 5 seconds on some other vendors).
Detailed technical explanation
OSPF hello intervals are tied to the network type configured under the OSPF interface; the dead interval is typically 4 times the hello interval (40 seconds for Ethernet). On broadcast networks, the 10-second hello ensures rapid neighbor discovery, while on NBMA networks the longer 30-second hello accommodates slower or non-broadcast media. In real-world scenarios, mismatched hello/dead intervals between OSPF neighbors prevent adjacency formation, a common misconfiguration when mixing network types.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
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FAQ
VRF and Path Isolation — This question tests VRF and Path Isolation — Read the scenario before looking for a memorised answer..
The correct answer is: 10 seconds — The default OSPF hello interval on an Ethernet link is 10 seconds, as defined in RFC 2328. OSPF uses this interval to maintain neighbor adjacency and detect link failures; on broadcast multi-access networks like Ethernet, the default is 10 seconds, while on non-broadcast multi-access (NBMA) networks it is 30 seconds.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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