- A
SFP-10G-SR transceivers require single-mode fiber.
Why wrong: SFP-10G-SR transceivers are designed for short-reach applications and use multimode fiber (MMF), not single-mode fiber (SMF).
- B
SFP-10G-LR transceivers use 1310 nm wavelength and can reach up to 10 km over single-mode fiber.
SFP-10G-LR (Long Reach) operates at 1310 nm over SMF, supporting distances up to 10 km, as per IEEE standards.
- C
SFP-10G-LR transceivers can only be used with multimode fiber.
Why wrong: SFP-10G-LR transceivers are designed for long reach and require single-mode fiber to achieve 10 km distances.
- D
SFP-10G-SR transceivers typically use 850 nm wavelength over multimode fiber.
SFP-10G-SR (Short Reach) uses 850 nm wavelength over MMF, suitable for distances up to 300-400 meters depending on fiber type.
- E
SFP-10G-LR transceivers support distances up to 40 km over single-mode fiber.
Why wrong: SFP-10G-LR max distance is 10 km; SFP-10G-ER (Extended Reach) supports up to 40 km.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. 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 TWO statements about SFP transceivers and their associated cable types are correct?
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
SFP-10G-LR transceivers use 1310 nm wavelength and can reach up to 10 km over single-mode fiber.
Option B is correct because the SFP-10G-LR transceiver operates at a 1310 nm wavelength and is designed for single-mode fiber, supporting distances up to 10 km. This is a standard specification defined by IEEE 802.3ae for 10GBASE-LR, making it the accurate description of this transceiver's capabilities.
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.
- ✗
SFP-10G-SR transceivers require single-mode fiber.
Why it's wrong here
SFP-10G-SR transceivers are designed for short-reach applications and use multimode fiber (MMF), not single-mode fiber (SMF).
- ✓
SFP-10G-LR transceivers use 1310 nm wavelength and can reach up to 10 km over single-mode fiber.
Why this is correct
SFP-10G-LR (Long Reach) operates at 1310 nm over SMF, supporting distances up to 10 km, as per IEEE standards.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
SFP-10G-LR transceivers can only be used with multimode fiber.
Why it's wrong here
SFP-10G-LR transceivers are designed for long reach and require single-mode fiber to achieve 10 km distances.
- ✓
SFP-10G-SR transceivers typically use 850 nm wavelength over multimode fiber.
Why this is correct
SFP-10G-SR (Short Reach) uses 850 nm wavelength over MMF, suitable for distances up to 300-400 meters depending on fiber type.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
SFP-10G-LR transceivers support distances up to 40 km over single-mode fiber.
Why it's wrong here
SFP-10G-LR max distance is 10 km; SFP-10G-ER (Extended Reach) supports up to 40 km.
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 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓SFP-10G-LR transceivers use 1310 nm wavelength and can reach up to 10 km over single-mode fiber.Correct answer▾
Why this is correct
SFP-10G-LR (Long Reach) operates at 1310 nm over SMF, supporting distances up to 10 km, as per IEEE standards.
✗SFP-10G-SR transceivers require single-mode fiber.Wrong answer — click to see why▾
Why this is wrong here
SFP-10G-SR uses multimode fiber, not single-mode.
✗SFP-10G-LR transceivers can only be used with multimode fiber.Wrong answer — click to see why▾
Why this is wrong here
SFP-10G-LR requires single-mode fiber, not multimode.
✗SFP-10G-LR transceivers support distances up to 40 km over single-mode fiber.Wrong answer — click to see why▾
Why this is wrong here
SFP-10G-LR max is 10 km, not 40 km (ER is 40 km).
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the confusion between SR and LR transceivers, where candidates mistakenly associate LR with multimode fiber or incorrect distances, such as thinking LR supports 40 km instead of the correct 10 km.
Detailed technical explanation
How to think about this question
The SFP-10G-SR (short reach) uses 850 nm VCSEL lasers over OM3/OM4 multimode fiber, achieving up to 300 meters, while the SFP-10G-LR (long reach) uses 1310 nm Fabry-Perot or DFB lasers over single-mode fiber for 10 km. In real-world deployments, mixing transceivers with incorrect fiber types causes excessive attenuation or no link; for example, using an LR transceiver with multimode fiber can damage the receiver due to modal dispersion. The IEEE 802.3ae standard defines these physical medium dependent (PMD) sublayers, ensuring interoperability when matched correctly.
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 practitioner preparing for the 200-301 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this 200-301 question test?
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: SFP-10G-LR transceivers use 1310 nm wavelength and can reach up to 10 km over single-mode fiber. — Option B is correct because the SFP-10G-LR transceiver operates at a 1310 nm wavelength and is designed for single-mode fiber, supporting distances up to 10 km. This is a standard specification defined by IEEE 802.3ae for 10GBASE-LR, making it the accurate description of this transceiver's capabilities.
What should I do if I get this 200-301 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
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Last reviewed: Jun 25, 2026
This 200-301 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 200-301 exam.
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