This N10-009 practice question tests your understanding of network implementation. 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.
A network engineer needs to connect two switches that are located 450 meters apart. Which combination of fiber optic transceiver and cable type would support the highest data rate over this distance?
Why wrong: 10GBASE-SR is a short-reach 10 Gbps transceiver for multimode fiber with a maximum distance of about 400 m, which is insufficient for 450 m.
B
1000BASE-LX with single-mode fiber
Why wrong: 1000BASE-LX supports 1 Gbps over single-mode fiber up to 5 km, but the question asks for the highest data rate, and 10 Gbps is available.
C
10GBASE-LR with single-mode fiber
10GBASE-LR is a 10 Gbps transceiver designed for single-mode fiber with a reach of up to 10 km, easily covering 450 m at full speed.
D
1000BASE-SX with multimode fiber
Why wrong: 1000BASE-SX is a 1 Gbps transceiver for multimode fiber with a reach of 220-550 m, which could cover the distance but at a lower speed than 10 Gbps.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
10GBASE-LR with single-mode fiber
10GBASE-LR (Long Reach) supports 10 Gbps over single-mode fiber (SMF) up to 10 km, easily covering the 450-meter distance. Single-mode fiber has a smaller core (9 µm) that minimizes modal dispersion, enabling higher data rates over longer distances compared to multimode fiber. This combination provides the highest data rate (10 Gbps) among the options for the given distance.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
10GBASE-SR with multimode fiber
Why it's wrong here
10GBASE-SR is a short-reach 10 Gbps transceiver for multimode fiber with a maximum distance of about 400 m, which is insufficient for 450 m.
✗
1000BASE-LX with single-mode fiber
Why it's wrong here
1000BASE-LX supports 1 Gbps over single-mode fiber up to 5 km, but the question asks for the highest data rate, and 10 Gbps is available.
✓
10GBASE-LR with single-mode fiber
Why this is correct
10GBASE-LR is a 10 Gbps transceiver designed for single-mode fiber with a reach of up to 10 km, easily covering 450 m at full speed.
Related concept
Read the scenario before looking for a memorised answer.
✗
1000BASE-SX with multimode fiber
Why it's wrong here
1000BASE-SX is a 1 Gbps transceiver for multimode fiber with a reach of 220-550 m, which could cover the distance but at a lower speed than 10 Gbps.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume 10GBASE-SR is sufficient for 450 meters, but the maximum distance for 10GBASE-SR over OM3 MMF is 300 meters, and over OM4 it is 400 meters—both fall short of 450 meters, making 10GBASE-LR the correct choice for the highest data rate.
Detailed technical explanation
How to think about this question
Single-mode fiber (SMF) uses a 9 µm core that supports only the fundamental mode, virtually eliminating modal dispersion and allowing higher bandwidth over long distances. 10GBASE-LR typically uses a 1310 nm laser, which has lower attenuation in SMF than the 850 nm VCSELs used in 10GBASE-SR. In real-world deployments, engineers often choose 10GBASE-LR even for shorter runs to future-proof the link for higher speeds like 25G or 100G, as the same SMF can support multiple wavelengths via WDM.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
Network Implementation — This question tests Network Implementation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 10GBASE-LR with single-mode fiber — 10GBASE-LR (Long Reach) supports 10 Gbps over single-mode fiber (SMF) up to 10 km, easily covering the 450-meter distance. Single-mode fiber has a smaller core (9 µm) that minimizes modal dispersion, enabling higher data rates over longer distances compared to multimode fiber. This combination provides the highest data rate (10 Gbps) among the options for the given distance.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
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 →
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.
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 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.