The answer is 1000BASE-SX, the correct transceiver for this 350-meter fiber backbone upgrade. This standard supports distances up to 550 meters over multimode fiber (MMF) using an 850 nm wavelength, which comfortably covers the required link length while eliminating electromagnetic interference through fiber optic cabling. On the CompTIA Network+ N10-009 exam, this question tests your ability to match IEEE 802.3z Gigabit Ethernet standards to real-world distance and cable type scenarios, often contrasting 1000BASE-SX with 1000BASE-LX (which uses single-mode fiber for longer runs). A common trap is assuming any fiber transceiver works for all distances, but 1000BASE-SX is specifically designed for short-haul fiber links under 550 meters, making it ideal for campus or building backbone segments. Remember the mnemonic: “SX for Short, LX for Long”—SX uses a shorter wavelength (850 nm) and shorter reach, while LX uses a longer wavelength (1310 nm) for extended distances.
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 network administrator needs to upgrade the backbone link between two switches to fiber optic to eliminate electromagnetic interference. The distance between the switches is 350 meters. Which transceiver type should be used?
1000BASE-SX operates over multi-mode fiber and supports distances up to 220-550 meters, covering 350 meters.
B
1000BASE-LX
Why wrong: 1000BASE-LX can also work but is designed for longer distances (up to 10 km over single-mode). It is a valid but less cost-effective choice for 350 m.
C
1000BASE-CX
Why wrong: 1000BASE-CX uses copper twinaxial cable, limited to 25 meters, and does not avoid EMI.
D
1000BASE-T
Why wrong: 1000BASE-T uses Cat5e/Cat6 copper, which is susceptible to EMI and does not provide the required isolation.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
1000BASE-SX
1000BASE-SX (option A) is correct because it supports distances up to 550 meters over multimode fiber (MMF) at 850 nm wavelength, making it suitable for the 350-meter backbone link. It is designed to eliminate electromagnetic interference (EMI) by using fiber optic cabling, and the distance falls within its maximum reach for common multimode fiber types like OM2 or OM3.
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.
✓
1000BASE-SX
Why this is correct
1000BASE-SX operates over multi-mode fiber and supports distances up to 220-550 meters, covering 350 meters.
Related concept
Read the scenario before looking for a memorised answer.
✗
1000BASE-LX
Why it's wrong here
1000BASE-LX can also work but is designed for longer distances (up to 10 km over single-mode). It is a valid but less cost-effective choice for 350 m.
✗
1000BASE-CX
Why it's wrong here
1000BASE-CX uses copper twinaxial cable, limited to 25 meters, and does not avoid EMI.
✗
1000BASE-T
Why it's wrong here
1000BASE-T uses Cat5e/Cat6 copper, which is susceptible to EMI and does not provide the required isolation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distance limitations of fiber transceivers, and the trap here is that candidates might choose 1000BASE-LX because they assume 'longer distance is always better,' overlooking that 1000BASE-SX is the correct, cost-effective choice for the given 350-meter range over multimode fiber.
Detailed technical explanation
How to think about this question
1000BASE-SX operates at 850 nm wavelength over multimode fiber, using a vertical-cavity surface-emitting laser (VCSEL) that is cost-effective for short-range links. The actual maximum distance depends on the fiber type: 220 m on OM1 (62.5/125 µm), 275 m on OM2 (50/125 µm), and up to 550 m on OM3 (50/125 µm laser-optimized). For a 350-meter link, OM3 fiber is recommended to ensure reliable performance, as the signal attenuation and modal dispersion are within acceptable limits.
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: 1000BASE-SX — 1000BASE-SX (option A) is correct because it supports distances up to 550 meters over multimode fiber (MMF) at 850 nm wavelength, making it suitable for the 350-meter backbone link. It is designed to eliminate electromagnetic interference (EMI) by using fiber optic cabling, and the distance falls within its maximum reach for common multimode fiber types like OM2 or OM3.
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.