The correct choice is single-mode fiber with 10GBASE-LR transceivers, as this combination supports 10 Gbps over distances up to 10 kilometers, easily covering the 300-meter requirement. The technical reason lies in the physics of light propagation: single-mode fiber uses a narrow core and 1310 nm laser optics, which minimize modal dispersion and signal loss, allowing the 10 Gbps signal to travel far beyond the 300-meter limit without degradation. On the CompTIA Network+ N10-009 exam, this scenario tests your understanding of fiber-optic standards and distance limitations—a common trap is choosing multimode fiber with 10GBASE-SR, which only reaches about 300 meters at 10 Gbps, making it a borderline fail for this exact distance. To remember, think "Long Reach for Long Distance": the "LR" in 10GBASE-LR stands for long reach, and single-mode is always your go-to for anything over 300 meters.
N10-009 Network Implementation Practice Question
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 company is connecting two buildings that are 300 meters apart. The link must support 10 Gbps. Which combination of cable and transceiver should be used?
Why wrong: Cat6a supports 10GBASE-T, but the maximum distance is only 100 meters, insufficient for 300 meters.
B
Cat5e UTP with 1000BASE-T
Why wrong: Cat5e only supports up to 1 Gbps and is limited to 100 meters, not meeting the speed or distance requirements.
C
Single-mode fiber with 10GBASE-LR
10GBASE-LR over single-mode fiber supports 10 Gbps up to 10 km, fully satisfying the 300-meter distance.
D
Multimode fiber with 10GBASE-SR
Why wrong: 10GBASE-SR over multimode fiber can reach 300-400 meters with OM4 fiber, but single-mode fiber provides a more reliable and future-proof solution for this distance.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Single-mode fiber with 10GBASE-LR
Option C is correct because single-mode fiber (SMF) with 10GBASE-LR supports 10 Gbps over distances up to 10 km, easily covering the 300-meter requirement. 10GBASE-LR uses 1310 nm laser optics over single-mode fiber, providing low signal loss and high bandwidth for long-reach links.
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.
✗
Cat6a UTP with 10GBASE-T
Why it's wrong here
Cat6a supports 10GBASE-T, but the maximum distance is only 100 meters, insufficient for 300 meters.
✗
Cat5e UTP with 1000BASE-T
Why it's wrong here
Cat5e only supports up to 1 Gbps and is limited to 100 meters, not meeting the speed or distance requirements.
✓
Single-mode fiber with 10GBASE-LR
Why this is correct
10GBASE-LR over single-mode fiber supports 10 Gbps up to 10 km, fully satisfying the 300-meter distance.
Related concept
Read the scenario before looking for a memorised answer.
✗
Multimode fiber with 10GBASE-SR
Why it's wrong here
10GBASE-SR over multimode fiber can reach 300-400 meters with OM4 fiber, but single-mode fiber provides a more reliable and future-proof solution for this distance.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume Cat6a can handle 10 Gbps at any distance, forgetting the 100-meter limitation for twisted-pair copper, or they confuse 10GBASE-LR with 10GBASE-SR, which has a shorter reach on multimode fiber.
Detailed technical explanation
How to think about this question
10GBASE-LR (Long Reach) operates over single-mode fiber (OS1/OS2) using a 1310 nm laser, achieving distances up to 10 km with a typical power budget of 8.2 dB. The 300-meter link is well within the loss budget, but note that using multimode fiber (e.g., 10GBASE-SR) would be limited to 300–400 meters with OM3/OM4, which is borderline; single-mode is the safer choice for guaranteed performance and future scalability.
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: Single-mode fiber with 10GBASE-LR — Option C is correct because single-mode fiber (SMF) with 10GBASE-LR supports 10 Gbps over distances up to 10 km, easily covering the 300-meter requirement. 10GBASE-LR uses 1310 nm laser optics over single-mode fiber, providing low signal loss and high bandwidth for long-reach links.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network engineer needs to connect two devices that are 150 meters apart with a 10 Gbps link. Which cabling type is most suitable?
easy
A.Cat6a UTP
B.Cat7 STP
✓ C.Single-mode fiber
D.Multimode fiber
Why C: Single-mode fiber (SMF) is the correct choice because it supports 10 Gbps transmission over distances well beyond 150 meters, typically up to 10 km or more using 10GBASE-LR optics. In contrast, copper cabling like Cat6a or Cat7 is limited to 100 meters for 10GBASE-T, and multimode fiber (MMF) with 10GBASE-SR is limited to about 300-400 meters depending on the fiber grade (e.g., OM3/OM4), but SMF provides the most reliable and future-proof solution for this distance.
Last reviewed: Jun 11, 2026
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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.
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