hardMultiple Choice
CCNP Practice Question: Runs the following command on a Cisco WLC: WLC#…
A network engineer runs the following command on a Cisco WLC:
WLC# show ap stats ap-name AP-3
AP Statistics for AP-3 ---------------------- Channel Utilization: 75% Interference: 30% Noise Floor: -80 dBm Total Packets Received: 5000 Total Packets Sent: 4500 Total Errors: 1500
Based on this output, what can be concluded?
⚠ Common exam trap
Cisco often tests the misconception that a high noise floor (e.g., -80 dBm) is good, when in fact lower (more negative) values indicate less background noise and a cleaner RF environment.
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
✓
The high error rate suggests possible co-channel interference or signal issues.
The output shows a total error count of 1500 out of 5000 received packets, which is a 30% error rate. This high error rate, combined with 75% channel utilization and 30% interference, strongly indicates co-channel interference or signal degradation issues. In wireless networks, excessive errors often stem from overlapping channels, poor signal-to-noise ratio, or adjacent-cell interference, making option B the correct conclusion.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The AP is operating in a clean environment with low interference.
Why it's wrong here
The assertion of a clean environment is contradicted by the reported interference level of 30% and a noise floor of -80 dBm. In Wi-Fi, a noise floor around -80 dBm is elevated, implying a poor signal-to-noise ratio and likely external RF sources. Such conditions are far from clean and would degrade performance, so this option is incorrect.
- ✓
The high error rate suggests possible co-channel interference or signal issues.
Why this is correct
A 30% error rate is abnormally high for a healthy wireless link, indicating that frames are frequently corrupted or lost. This pattern is typically associated with co-channel interference from neighboring APs or signal issues such as excessive path loss, multipath, or hidden nodes. The high error rate is a key diagnostic sign, making this the most accurate conclusion.
- ✗
The channel utilization is low, indicating spare capacity.
Why it's wrong here
The claim of low channel utilization is false because 75% utilization is actually high, meaning the wireless medium is busy for three-quarters of the time. This leaves little spare capacity and often leads to contention and reduced throughput. High utilization, especially combined with high error rates, indicates a congested channel rather than available resources.
- ✗
The noise floor is excellent at -80 dBm.
Why it's wrong here
A noise floor of -80 dBm is not excellent; it is considered high and poor for Wi-Fi environments. Typical noise floors are between -95 and -100 dBm, so -80 dBm significantly raises the noise level relative to the signal, causing a lower SNR and increased frame errors. Thus, this value is a red flag, not a positive indicator.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.