Quick Answer
The answer is 10 seconds. On Ethernet links, which operate as broadcast or point-to-point network types in OSPF, the default hello interval is 10 seconds because these network types are designed for fast neighbor discovery and rapid convergence, requiring frequent hello packets to maintain adjacency. The ENCOR 350-401 exam tests this foundational OSPF timer knowledge, often presenting a scenario where a non-broadcast multi-access (NBMA) network like Frame Relay uses a 30-second default, making the Ethernet 10-second value a common trap for candidates who confuse network types. Remember that OSPF’s hello interval directly affects the dead interval, which is four times the hello interval by default—so on Ethernet, the dead interval is 40 seconds. A simple memory tip: Ethernet is fast, so hello every 10 seconds; think “Ethernet = 10, everything else slower is 30.”
This 350-401 practice question tests your understanding of mpls. 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 in Cisco IOS?
10 seconds
Correct. The default hello interval for Ethernet (broadcast) is 10 seconds.
30 seconds
Why wrong: Incorrect. 30 seconds is the default hello interval for non-broadcast multi-access (NBMA) networks.
40 seconds
Why wrong: Incorrect. 40 seconds is not a standard OSPF hello interval.
5 seconds
Why wrong: Incorrect. 5 seconds is not the default; it can be configured manually.
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
OSPF hello interval defaults to 10 seconds on broadcast and point-to-point networks (e.g., Ethernet).
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
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. The default hello interval for Ethernet (broadcast) is 10 seconds.
Related concept
OSPF neighbours must agree on key parameters.
30 seconds
Why it's wrong here
Incorrect. 30 seconds is the default hello interval for non-broadcast multi-access (NBMA) networks.
40 seconds
Why it's wrong here
Incorrect. 40 seconds is not a standard OSPF hello interval.
5 seconds
Why it's wrong here
Incorrect. 5 seconds is not the default; it can be configured manually.
Common exam traps
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Detailed technical explanation
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
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
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 350-401 OSPF questions on adjacency and route selection.
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FAQ
MPLS — This question tests MPLS — OSPF neighbours must agree on key parameters..
The correct answer is: 10 seconds — OSPF hello interval defaults to 10 seconds on broadcast and point-to-point networks (e.g., Ethernet).
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 350-401 OSPF questions on adjacency and route selection.
OSPF neighbours must agree on key parameters.
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Last reviewed: Jun 18, 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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