Quick Answer
The answer is LSA propagation delay across the network, CPU processing power for SPF calculations, and the number of routers in the OSPF area. These three factors directly influence OSPF convergence time because after a topology change, OSPF relies on the rapid flooding of Link State Advertisements (LSAs) to all routers, followed by the Dijkstra algorithm to recompute the shortest path tree. A slower CPU or a large number of routers increases the time needed for SPF calculations, while propagation delay across WAN links can slow LSA delivery, delaying convergence. On the Cisco DevNet Associate 200-901 exam, this question tests your understanding of OSPF’s link-state behavior versus distance-vector protocols; a common trap is confusing convergence with hello timer intervals. Remember the mnemonic “L-C-R” for LSA delay, CPU, and Router count—the three pillars of OSPF convergence speed.
This 200-901 practice question tests your understanding of network fundamentals. 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.
Which THREE factors influence the convergence time of OSPF in a large enterprise network? (Choose three.)
CPU processing power for SPF calculations
SPF computation time affects convergence.
Hello and dead interval timers
Shorter timers speed failure detection.
Bidirectional Forwarding Detection (BFD) implementation
Why wrong: BFD is not part of OSPF itself.
DUAL algorithm processing time
Why wrong: DUAL is used by EIGRP, not OSPF.
LSA propagation delay across the network
Flooding LSAs takes time.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
CPU processing power for SPF calculations
CPU processing power for SPF calculations directly affects convergence time because OSPF must run the Dijkstra algorithm to compute the shortest path tree after a topology change. In large networks with many routers and LSAs, a slower CPU increases the time to complete SPF, delaying route convergence.
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.
CPU processing power for SPF calculations
Why this is correct
SPF computation time affects convergence.
Related concept
Read the scenario before looking for a memorised answer.
Hello and dead interval timers
Why this is correct
Shorter timers speed failure detection.
Related concept
Read the scenario before looking for a memorised answer.
Bidirectional Forwarding Detection (BFD) implementation
Why it's wrong here
BFD is not part of OSPF itself.
DUAL algorithm processing time
LSA propagation delay across the network
Why this is correct
Flooding LSAs takes time.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Cisco often tests the distinction between failure detection mechanisms (like BFD or Hello timers) and actual convergence processes (SPF calculation and LSA propagation), so candidates may mistakenly think BFD directly reduces convergence time rather than just detection time.
Detailed technical explanation
OSPF convergence time is the sum of failure detection time (influenced by Hello/Dead timers or BFD), LSA flooding delay, and SPF computation time. In large networks, LSA propagation delay can be significant due to serialization delay on slow links and processing delay at intermediate routers, especially when many LSAs are generated. The SPF calculation itself is O(N log N) where N is the number of routers, so CPU power becomes critical in topologies with hundreds of routers.
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
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network Fundamentals — study guide chapter
Learn the concepts, then practise the questions
Network Fundamentals practice questions
Targeted practice on this topic area only
All 200-901 questions
505 questions across all exam domains
Cisco DevNet Associate 200-901 study guide
Full concept coverage aligned to exam objectives
200-901 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 200-901 questions linked to Software Development and Design.
Practise 200-901 questions linked to Understanding and Using APIs.
Practise 200-901 questions linked to Cisco Platforms and Development.
Practise 200-901 questions linked to Application Deployment and Security.
Practise 200-901 questions linked to Infrastructure and Automation.
Practise 200-901 questions linked to Network Fundamentals.
Practise 200-901 questions linked to 200-901 fundamentals.
Practise 200-901 questions linked to 200-901 scenario.
Practise 200-901 questions linked to 200-901 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Network Fundamentals — This question tests Network Fundamentals — Read the scenario before looking for a memorised answer..
The correct answer is: CPU processing power for SPF calculations — CPU processing power for SPF calculations directly affects convergence time because OSPF must run the Dijkstra algorithm to compute the shortest path tree after a topology change. In large networks with many routers and LSAs, a slower CPU increases the time to complete SPF, delaying route convergence.
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.
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: Jun 11, 2026
This 200-901 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 200-901 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.