N10-009 Network Troubleshooting Practice Question
A technician is troubleshooting intermittent wireless connectivity in a conference room. A site survey shows strong signal strength but many nearby access points are using channels that overlap with the channel used by the conference room AP. Which of the following is the most likely cause of the issue?
⚠ Common exam trap
The N10-009 exam often tests the distinction between co-channel interference (same channel) and adjacent-channel interference (overlapping channels), and the trap here is that candidates confuse 'overlapping channels' with 'same channel,' incorrectly selecting co-channel interference instead of adjacent-channel interference.
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
✓
Adjacent channel interference from access points on overlapping channels.
The site survey shows strong signal strength but many nearby access points are using channels that overlap with the channel used by the conference room AP. This directly indicates adjacent-channel interference (ACI), where overlapping channels (e.g., channels 1, 2, 3, 4, and 5 all overlap with channel 1 in the 2.4 GHz band) cause contention and retransmissions, degrading performance even with strong signal. ACI is the most likely cause because the overlapping channels create co-existence issues without being on the exact same channel.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Multipath interference from reflective surfaces.
Why it's wrong here
Multipath interference occurs when a wireless signal travels along multiple paths, reflecting off surfaces like walls, floors, or metal objects, causing delayed and out-of-phase versions of the signal to arrive at the receiver. This can lead to signal degradation, increased error rates, and reduced throughput, sometimes manifesting as dead zones or inconsistent performance. However, the problem statement specifically implicates issues related to "overlapping channels," making adjacent channel interference a more direct and probable cause than multipath effects in this particular scenario.
When this WOULD be correct
A technician reports intermittent connectivity in a room with metal shelves and glass walls, and a site survey shows strong signal strength but high packet loss. In this case, multipath interference from reflective surfaces would be the likely cause.
- ✗
Co-channel interference from access points on the same channel.
Why it's wrong here
Co-channel interference happens when multiple access points within range operate on the exact same non-overlapping channel (e.g., two APs both on channel 6). While this can reduce overall network throughput as APs must share airtime, it is often a planned strategy in large deployments to reuse channels efficiently, and typically results in degraded performance rather than complete intermittent connectivity. The problem description specifically points to "overlapping channels," which is distinct from using the identical channel.
When this WOULD be correct
In a scenario where a site survey shows multiple access points in the same area all configured on the exact same channel, and clients experience poor performance or disconnections, co-channel interference would be the correct answer.
- ✓
Adjacent channel interference from access points on overlapping channels.
Why this is correct
Adjacent channel interference occurs when wireless access points operate on channels that are close but not identical, causing their signal spectra to overlap significantly. This spectral overlap leads to increased noise levels and corrupted data packets for devices trying to communicate on those channels. Consequently, client devices experience reduced data rates, frequent retransmissions, and intermittent connectivity issues as they struggle to maintain a stable link. This is a common problem in dense environments where channel planning is not optimized, especially in the 2.4 GHz band.
- ✗
Signal attenuation due to distance from the AP.
Why it's wrong here
Signal attenuation refers to the weakening of a wireless signal's strength as it travels through space or encounters obstacles. While excessive distance from an access point is a primary cause of attenuation, leading to poor signal quality and dropped connections, the provided scenario indicates a site survey confirmed strong signal strength. Therefore, the intermittent connectivity is not attributable to the signal losing power over distance, as the signal level is adequate.
When this WOULD be correct
A technician reports weak or dropping Wi-Fi in a far corner of a large office. A site survey shows low RSSI near that area, and the AP is located at the opposite end. In this scenario, signal attenuation due to distance would be the likely cause.
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.
✓Adjacent channel interference from access points on overlapping channels.Correct answer▾
Why this is correct
Adjacent channel interference occurs when wireless access points operate on channels that are close but not identical, causing their signal spectra to overlap significantly. This spectral overlap leads to increased noise levels and corrupted data packets for devices trying to communicate on those channels. Consequently, client devices experience reduced data rates, frequent retransmissions, and intermittent connectivity issues as they struggle to maintain a stable link. This is a common problem in dense environments where channel planning is not optimized, especially in the 2.4 GHz band.
✗Multipath interference from reflective surfaces.Wrong answer — click to see why▾
Why this is wrong here
The question states that many nearby access points are using overlapping channels, which is adjacent channel interference, not multipath. Multipath interference is caused by signal reflections off surfaces, not channel overlap.
★ When this WOULD be the correct answer
A technician reports intermittent connectivity in a room with metal shelves and glass walls, and a site survey shows strong signal strength but high packet loss. In this case, multipath interference from reflective surfaces would be the likely cause.
Why candidates choose this
Candidates may confuse multipath interference with any signal degradation in a conference room, especially if they recall that reflective surfaces can cause issues, but they overlook the specific channel overlap mentioned in the question.
✗Co-channel interference from access points on the same channel.Wrong answer — click to see why▾
Why this is wrong here
The question specifies that many nearby access points are using channels that overlap with the conference room AP's channel, which is adjacent channel interference, not co-channel interference. Co-channel interference occurs when multiple APs use the same channel, not overlapping ones.
★ When this WOULD be the correct answer
In a scenario where a site survey shows multiple access points in the same area all configured on the exact same channel, and clients experience poor performance or disconnections, co-channel interference would be the correct answer.
Why candidates choose this
Candidates may confuse 'overlapping channels' with 'same channel' or assume that any interference from other APs is co-channel, not realizing that adjacent channel overlap is a distinct and more common issue in the 2.4 GHz band.
✗Signal attenuation due to distance from the AP.Wrong answer — click to see why▾
Why this is wrong here
The question states that signal strength is strong, so distance-related attenuation is not the issue. The problem is channel overlap, not signal weakness.
★ When this WOULD be the correct answer
A technician reports weak or dropping Wi-Fi in a far corner of a large office. A site survey shows low RSSI near that area, and the AP is located at the opposite end. In this scenario, signal attenuation due to distance would be the likely cause.
Why candidates choose this
Candidates may default to blaming distance or signal strength when connectivity is poor, without carefully reading that the site survey already confirmed strong signal strength.
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
Troubleshooting Methodology
Key term
RSSI
RSSI is a measurement of the power level in a received radio signal, used by wireless devices to gauge signal strength.
Key term
Received Signal Strength Indicator
Received Signal Strength Indicator (RSSI) is a measurement of how strong a wireless signal is when it reaches a receiving device, like a laptop connecting to Wi-Fi.
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JA
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.