- A
Neighbor discovery uses Hello packets to establish and maintain adjacencies.
OSPF Hello packets are used for neighbor discovery, forming adjacencies, and maintaining neighbor relationships. They are sent periodically on all interfaces to detect and maintain connectivity with neighboring routers.
- B
DR/BDR election reduces the number of LSAs flooded in a broadcast multiaccess network.
Why wrong: This is incorrect because DR/BDR election is used to minimize the number of adjacencies and reduce LSA flooding, but the statement is accurate. However, the question asks for the concept that matches 'Neighbor discovery uses Hello packets', so this option is not the correct match for that concept.
- C
LSA flooding is the process by which OSPF routers exchange link-state information to build a common topology database.
Why wrong: This is incorrect because LSA flooding is a separate process from neighbor discovery. While Hello packets are used for neighbor discovery, LSA flooding occurs after adjacencies are formed to exchange topology information.
- D
The SPF algorithm is used to compute the shortest path to each destination based on the link-state database.
Why wrong: This is incorrect because the SPF algorithm is used for route computation, not for neighbor discovery. Hello packets are specifically used for neighbor discovery and maintenance.
CCNA IP Routing Practice Question
This 200-301 practice question tests your understanding of ip routing. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: oSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies.. 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.
Match each OSPF adjacency requirement or concept to its most accurate description.
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
Neighbor discovery uses Hello packets to establish and maintain adjacencies.
Hello/Dead timers must match between neighbors to form a stable OSPF adjacency; mismatched timers cause neighbor relationships to fail. Area must be identical on the shared OSPF segment because routers in different areas do not establish full adjacencies. Router ID uniquely identifies the router within the OSPF process, used for DR/BDR election and LSA origination. Passive interface suppresses hello packets, preventing neighbor formation on that link, while still allowing the connected network to be advertised via the router's LSA.
Key principle: OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor 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.
- ✓
Neighbor discovery uses Hello packets to establish and maintain adjacencies.
Why this is correct
OSPF Hello packets are used for neighbor discovery, forming adjacencies, and maintaining neighbor relationships. They are sent periodically on all interfaces to detect and maintain connectivity with neighboring routers.
Related concept
OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies.
- ✗
DR/BDR election reduces the number of LSAs flooded in a broadcast multiaccess network.
Why it's wrong here
This is incorrect because DR/BDR election is used to minimize the number of adjacencies and reduce LSA flooding, but the statement is accurate. However, the question asks for the concept that matches 'Neighbor discovery uses Hello packets', so this option is not the correct match for that concept.
- ✗
LSA flooding is the process by which OSPF routers exchange link-state information to build a common topology database.
Why it's wrong here
This is incorrect because LSA flooding is a separate process from neighbor discovery. While Hello packets are used for neighbor discovery, LSA flooding occurs after adjacencies are formed to exchange topology information.
- ✗
The SPF algorithm is used to compute the shortest path to each destination based on the link-state database.
Why it's wrong here
This is incorrect because the SPF algorithm is used for route computation, not for neighbor discovery. Hello packets are specifically used for neighbor discovery and maintenance.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Neighbor discovery uses Hello packets to establish and maintain adjacencies.Correct answer▾
Why this is correct
OSPF Hello packets are used for neighbor discovery, forming adjacencies, and maintaining neighbor relationships. They are sent periodically on all interfaces to detect and maintain connectivity with neighboring routers.
✗DR/BDR election reduces the number of LSAs flooded in a broadcast multiaccess network.Wrong answer — click to see why▾
Why this is wrong here
The statement is factually correct for DR/BDR, but it does not describe neighbor discovery using Hello packets.
Why candidates choose this
Candidates might confuse the purpose of Hello packets with DR/BDR election, as both are OSPF concepts.
✗LSA flooding is the process by which OSPF routers exchange link-state information to build a common topology database.Wrong answer — click to see why▾
Why this is wrong here
The statement describes LSA flooding, not neighbor discovery using Hello packets.
Why candidates choose this
Candidates may think that LSA flooding is part of neighbor discovery, but it is a subsequent step.
✗The SPF algorithm is used to compute the shortest path to each destination based on the link-state database.Wrong answer — click to see why▾
Why this is wrong here
The statement describes the SPF algorithm, which is unrelated to neighbor discovery using Hello packets.
Why candidates choose this
Candidates might associate OSPF with SPF and incorrectly think that SPF is involved in neighbor discovery.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Do not confuse the purpose of Hello packets with other OSPF mechanisms. Hello packets are for neighbor discovery and keepalives, not for exchanging routing information or computing routes.
Detailed technical explanation
How to think about this question
OSPF adjacency formation is a fundamental concept in Cisco routing that ensures routers can exchange routing information reliably. The process begins with routers sending Hello packets to discover neighbors on a shared network segment. For two routers to become OSPF neighbors, they must agree on several key parameters, including the hello interval, dead interval, area ID, and network type. These parameters ensure that routers have compatible settings and can maintain stable communication. The router ID uniquely identifies each router in the OSPF domain but does not need to match between neighbors. The decision process for establishing OSPF adjacency involves comparing the hello and dead timers first; if these timers do not match, routers will not recognize each other as neighbors. Next, routers verify that they are in the same OSPF area by matching the area ID on the interface. Network type compatibility is also checked because different network types (broadcast, point-to-point, NBMA) have different adjacency behaviors. Only after these parameters align will routers proceed to exchange database description packets and synchronize their link-state databases. A frequent exam trap is confusing the router ID with the OSPF process ID or assuming that mismatched timers or area IDs can still allow adjacency. In practice, mismatched hello or dead timers cause routers to ignore each other's Hello packets, preventing neighbor formation. Similarly, routers in different areas will not form adjacencies even if other parameters match. Understanding these nuances helps avoid mistakes and ensures correct interpretation of OSPF adjacency requirements on the CCNA exam.
KKey Concepts to Remember
- OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies.
- The OSPF area ID must be identical on both routers' interfaces to establish adjacency within the same OSPF area.
- OSPF router ID uniquely identifies each router but does not need to match between neighbors for adjacency formation.
- Network type compatibility (broadcast, point-to-point, NBMA) influences OSPF adjacency behavior and must be consistent between neighbors.
- Mismatched hello or dead timers cause routers to ignore each other's Hello packets, preventing neighbor relationships.
- OSPF adjacency formation proceeds only after routers verify matching timers, area IDs, and compatible network types.
- The OSPF process ID is a local router configuration and does not affect neighbor adjacency or router ID selection.
- Routers exchange database description packets only after successfully establishing neighbor adjacency through parameter matching.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Review oSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies., then practise related 200-301 questions on the same topic to reinforce the concept.
- →
IP Routing — study guide chapter
Learn the concepts, then practise the questions
- →
IP Routing practice questions
Targeted practice on this topic area only
- →
All 200-301 questions
1,819 questions across all exam domains
- →
CCNA 200-301 v2 study guide
Full concept coverage aligned to exam objectives
- →
200-301 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network Infrastructure and Connectivity practice questions
Practise 200-301 questions linked to Network Infrastructure and Connectivity.
Switching and Network Access practice questions
Practise 200-301 questions linked to Switching and Network Access.
IP Routing practice questions
Practise 200-301 questions linked to IP Routing.
Network Services and Security practice questions
Practise 200-301 questions linked to Network Services and Security.
AI and Network Operations practice questions
Practise 200-301 questions linked to AI and Network Operations.
CCNA subnetting practice questions
Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.
CCNA OSPF practice questions
Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.
CCNA VLAN practice questions
Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.
CCNA STP practice questions
Practise spanning tree, root bridge election, port roles and STP troubleshooting.
CCNA EtherChannel practice questions
Practise LACP, PAgP, port-channel behaviour and bundle requirements.
CCNA ACL practice questions
Practise standard and extended ACLs, permit/deny logic and traffic filtering.
CCNA NAT practice questions
Practise static NAT, dynamic NAT, PAT and inside/outside address translation.
Practice this exam
Start a free 200-301 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this 200-301 question test?
IP Routing — This question tests IP Routing — OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies..
What is the correct answer to this question?
The correct answer is: Neighbor discovery uses Hello packets to establish and maintain adjacencies. — Hello/Dead timers must match between neighbors to form a stable OSPF adjacency; mismatched timers cause neighbor relationships to fail. Area must be identical on the shared OSPF segment because routers in different areas do not establish full adjacencies. Router ID uniquely identifies the router within the OSPF process, used for DR/BDR election and LSA origination. Passive interface suppresses hello packets, preventing neighbor formation on that link, while still allowing the connected network to be advertised via the router's LSA.
What should I do if I get this 200-301 question wrong?
Review oSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
OSPF routers must match hello and dead timers exactly on shared interfaces to successfully form neighbor adjacencies.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: May 17, 2026
This 200-301 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 200-301 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.