N10-009 Network Implementation Practice Question
A network engineer needs to connect two devices that are 150 meters apart with a 10 Gbps link. Which cabling type is most suitable?
⚠ Common exam trap
A common mix-up: candidates assume multimode fiber is sufficient for any distance under 300 meters, but the exam emphasizes 'most suitable' based on scalability and performance, making single-mode fiber the better choice even for shorter runs when future-proofing is considered.
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
✓
Single-mode fiber
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.
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
Why it's wrong here
Cat6a UTP cable is specified by the IEEE 802.3an standard for 10GBASE-T to reliably transmit 10 Gbps data, but only up to a maximum distance of 100 meters. Beyond this limit, signal attenuation and alien crosstalk become too significant, leading to an unacceptable bit error rate and unreliable connectivity. Therefore, attempting to use Cat6a for a 150-meter link at 10 Gbps would result in connectivity issues or complete failure, as it exceeds its engineered performance envelope.
When this WOULD be correct
For a 10 Gbps link over a distance of up to 100 meters in a cost-sensitive environment with existing copper infrastructure, Cat6a UTP would be suitable.
- ✗
Cat7 STP
Why it's wrong here
While Cat7 STP cable offers enhanced shielding and supports higher frequencies than Cat6a, its maximum specified transmission distance for 10 Gbps (10GBASE-T) remains 100 meters according to TIA/EIA standards. The improved performance of Cat7 primarily addresses alien crosstalk and noise immunity, which can be beneficial in dense cabling environments, but it does not extend the fundamental distance limitations imposed by signal attenuation and timing requirements over copper for 10 Gbps. Consequently, 150 meters is beyond its reliable operating range for this speed.
When this WOULD be correct
A network engineer needs to connect two devices 50 meters apart with a 10 Gbps link in an environment with high electromagnetic interference (EMI). Cat7 STP provides shielding to reduce interference and supports the required speed and distance.
- ✓
Single-mode fiber
Why this is correct
Single-mode fiber is the correct choice because it is specifically engineered for transmitting light over very long distances with minimal signal loss and dispersion. Its extremely small core diameter (typically 9 microns) allows only a single path for light to travel, effectively eliminating modal dispersion which limits multimode fiber. This capability enables 10 Gbps speeds to extend for many kilometers, making it exceptionally well-suited and highly reliable for a 150-meter link while providing significant headroom for future speed upgrades.
- ✗
Multimode fiber
Why it's wrong here
Multimode fiber, specifically OM3 or OM4, can indeed support 10 Gbps over distances of 300 meters and 400 meters respectively, making it technically capable of handling a 150-meter link. However, it is generally not the preferred choice compared to single-mode fiber for this distance when considering long-term scalability and cost-effectiveness for higher speeds. Multimode fiber experiences modal dispersion, which can become a limiting factor for future upgrades to 40 Gbps or 100 Gbps over similar distances, whereas single-mode offers superior future-proofing.
When this WOULD be correct
A network engineer needs to connect two devices that are 80 meters apart with a 10 Gbps link within a data center. Multimode fiber (OM3 or OM4) is the most cost-effective choice for distances up to 300 meters at 10 Gbps, making it suitable for this scenario.
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.
✓Single-mode fiberCorrect answer▾
Why this is correct
Single-mode fiber is the correct choice because it is specifically engineered for transmitting light over very long distances with minimal signal loss and dispersion. Its extremely small core diameter (typically 9 microns) allows only a single path for light to travel, effectively eliminating modal dispersion which limits multimode fiber. This capability enables 10 Gbps speeds to extend for many kilometers, making it exceptionally well-suited and highly reliable for a 150-meter link while providing significant headroom for future speed upgrades.
✗Cat6a UTPWrong answer — click to see why▾
Why this is wrong here
Cat6a UTP is limited to distances of up to 100 meters for 10 Gbps, so it cannot support a 150-meter link.
★ When this WOULD be the correct answer
For a 10 Gbps link over a distance of up to 100 meters in a cost-sensitive environment with existing copper infrastructure, Cat6a UTP would be suitable.
Why candidates choose this
Candidates may think Cat6a supports 10 Gbps and overlook the distance limitation, or assume that higher-category copper can exceed standard distance specs.
✗Cat7 STPWrong answer — click to see why▾
Why this is wrong here
Cat7 STP is a copper cabling standard that supports up to 10 Gbps but only over distances up to 100 meters. The required 150 meters exceeds this limit, making it unsuitable.
★ When this WOULD be the correct answer
A network engineer needs to connect two devices 50 meters apart with a 10 Gbps link in an environment with high electromagnetic interference (EMI). Cat7 STP provides shielding to reduce interference and supports the required speed and distance.
Why candidates choose this
Candidates may think Cat7 STP supports 10 Gbps and assume it can handle longer distances due to its higher category number, overlooking the 100-meter distance limitation for copper cabling.
✗Multimode fiberWrong answer — click to see why▾
Why this is wrong here
Multimode fiber (MMF) typically supports 10 Gbps up to 300-400 meters with OM3/OM4, but 150 meters is well within its range. However, the question asks for the 'most suitable' cabling. Single-mode fiber (SMF) is more suitable for future-proofing and longer distances, and MMF is often used for shorter runs within data centers. But the key here is that MMF can actually work at 150m for 10 Gbps, so it's not strictly wrong. However, the exam likely expects SMF for any distance over 100m for 10 Gbps, as MMF's reach at 10 Gbps is limited to 300m with OM3, but SMF is more reliable and scalable. Actually, MMF can work, but SMF is better. The question's correct answer is SMF, so MMF is wrong because it's less suitable for this distance due to higher attenuation and modal dispersion compared to SMF, though it could technically work.
★ When this WOULD be the correct answer
A network engineer needs to connect two devices that are 80 meters apart with a 10 Gbps link within a data center. Multimode fiber (OM3 or OM4) is the most cost-effective choice for distances up to 300 meters at 10 Gbps, making it suitable for this scenario.
Why candidates choose this
Candidates may think multimode fiber is sufficient for 150 meters because it supports 10 Gbps up to 300 meters with OM3/OM4, overlooking that single-mode fiber is more appropriate for longer distances and future scalability.
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?”
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Related to this question
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Physical Network Infrastructure
Key term
Multimode fiber
A type of optical fiber that carries multiple light signals simultaneously over short to medium distances, commonly used in local area networks and data centers.
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.
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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.