N10-009 Network Implementation Practice Question
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?
⚠ Common exam trap
Many 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.
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
✓
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.
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 offers a high-speed 10 Gigabit Ethernet connection but is specifically designed for short-reach applications over multimode fiber. Its maximum effective distance is typically around 300 meters for OM3 fiber or 400 meters for OM4 fiber, depending on the fiber grade. Therefore, it falls short of the required 450-meter distance, making it an unsuitable option despite its high data rate.
When this WOULD be correct
A question asking for the highest data rate over a distance of 300 meters or less, where cost is a concern, would make 10GBASE-SR with multimode fiber the correct answer because it supports 10 Gbps at lower cost than single-mode solutions.
- ✗
1000BASE-LX with single-mode fiber
Why it's wrong here
1000BASE-LX provides Gigabit Ethernet (1 Gbps) connectivity over single-mode fiber, with an impressive reach of up to 5 kilometers. Although its distance capability is more than sufficient for 450 meters, its primary drawback is the limited 1 Gbps data rate. This makes it a less desirable choice when 10 Gbps solutions are available and preferred for higher throughput requirements over the same distance.
When this WOULD be correct
If the question specified a distance of 10 km or required the lowest cost solution for a 1 Gbps link over single-mode fiber, 1000BASE-LX would be correct.
- ✓
10GBASE-LR with single-mode fiber
Why this is correct
10GBASE-LR is the optimal choice because it provides a high-speed 10 Gigabit Ethernet connection over single-mode fiber. Its design allows for reaches up to 10 kilometers, far exceeding the required 450 meters while maintaining full data rate. Single-mode fiber is ideal for such distances, ensuring signal integrity and minimal attenuation, making it perfectly suited for connecting switches 450 meters apart.
- ✗
1000BASE-SX with multimode fiber
Why it's wrong here
1000BASE-SX utilizes multimode fiber to deliver Gigabit Ethernet (1 Gbps) over distances up to 550 meters, which technically covers the 450-meter requirement. However, it operates at a significantly lower data rate compared to 10 Gbps options available for similar distances. While functional for the distance, it does not meet the implied need for the highest available performance, making it a less efficient choice.
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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓10GBASE-LR with single-mode fiberCorrect answer▾
Why this is correct
10GBASE-LR is the optimal choice because it provides a high-speed 10 Gigabit Ethernet connection over single-mode fiber. Its design allows for reaches up to 10 kilometers, far exceeding the required 450 meters while maintaining full data rate. Single-mode fiber is ideal for such distances, ensuring signal integrity and minimal attenuation, making it perfectly suited for connecting switches 450 meters apart.
✗10GBASE-SR with multimode fiberWrong answer — click to see why▾
Why this is wrong here
10GBASE-SR over multimode fiber is limited to distances around 300-400 meters (depending on OM3/OM4), so it cannot reliably support 450 meters. Single-mode fiber with 10GBASE-LR is required for that distance at 10 Gbps.
★ When this WOULD be the correct answer
A question asking for the highest data rate over a distance of 300 meters or less, where cost is a concern, would make 10GBASE-SR with multimode fiber the correct answer because it supports 10 Gbps at lower cost than single-mode solutions.
Why candidates choose this
Candidates may assume that 10GBASE-SR supports 10 Gbps over any multimode fiber distance, overlooking the specific reach limitations of multimode fiber at high data rates.
✗1000BASE-LX with single-mode fiberWrong answer — click to see why▾
Why this is wrong here
1000BASE-LX supports only 1 Gbps, while the question asks for the highest data rate over 450 meters. 10GBASE-LR provides 10 Gbps, which is higher.
★ When this WOULD be the correct answer
If the question specified a distance of 10 km or required the lowest cost solution for a 1 Gbps link over single-mode fiber, 1000BASE-LX would be correct.
Why candidates choose this
Candidates may confuse LX with LR, thinking both are single-mode and high-speed, or overlook that LX is limited to 1 Gbps while LR supports 10 Gbps.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Physical Network Infrastructure
Key term
Single-mode fiber
Single-mode fiber is a type of optical fiber used in high-speed, long-distance networking that transmits a single light signal along a very thin core, minimizing signal loss and enabling data to travel many kilometers without repeaters.
Key term
Transceiver
A transceiver is a device that both transmits and receives signals, combining a transmitter and a receiver into a single unit for communication over a network medium.
About these practice questions
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.