CWS Case Analysis & Practical Application 2 — Questions and Answers
Question 1: A coffee shop deploys a single 2.4 GHz AP and customers report slow speeds during peak hours. What is the most likely root cause?
- Incorrect SSID configuration
- Co-channel interference from neighboring APs on the same channel (Correct answer)
- WPA2 encryption overhead
- DNS resolution delays
Correct answer: Co-channel interference from neighboring APs on the same channel
Co-channel interference occurs when multiple APs share the same channel in overlapping coverage areas, causing collisions and reduced throughput.
Question 2: A hospital needs wireless coverage with zero tolerance for packet loss in life-critical monitoring equipment. Which deployment approach is most appropriate?
- Single AP per floor with high transmit power
- Overlapping coverage with fast BSS transition (802.11r) enabled (Correct answer)
- Guest network isolation only
- Channel bonding on all APs
Correct answer: Overlapping coverage with fast BSS transition (802.11r) enabled
802.11r Fast BSS Transition minimizes roaming latency and packet loss, which is critical for real-time medical monitoring devices.
Question 3: During a site survey, you measure a -75 dBm signal at the far edge of a conference room. Users report frequent disconnections. What should you do?
- Increase AP transmit power to maximum
- Add an AP to improve coverage and raise the signal floor (Correct answer)
- Switch to 5 GHz only
- Disable lower data rates
Correct answer: Add an AP to improve coverage and raise the signal floor
Adding an AP to reduce cell size raises the signal level at the coverage edge, improving reliability and reducing disconnections.
Question 4: A warehouse deploys 802.11ac APs but forklifts with metal frames cause intermittent connectivity. What RF phenomenon is most responsible?
- Refraction
- Multipath interference caused by metal reflections (Correct answer)
- Free-space path loss
- Doppler shift
Correct answer: Multipath interference caused by metal reflections
Metal surfaces reflect RF signals, creating multiple signal paths that arrive at the receiver at different times, causing multipath interference.
Question 5: A school wants to filter student internet access without purchasing additional hardware. Which feature on a business-grade AP achieves this?
- RADIUS server integration
- Integrated URL/content filtering or DNS-based filtering on the controller (Correct answer)
- WPA3 Enterprise mode
- MU-MIMO beamforming
Correct answer: Integrated URL/content filtering or DNS-based filtering on the controller
Many enterprise AP controllers include built-in content filtering or integrate with DNS filtering services to control internet access by client group.
Question 6: A client complains that their 5 GHz-capable laptop always associates to the 2.4 GHz band. Which setting on the AP would resolve this?
- Disabling WMM on 2.4 GHz
- Enabling band steering to prefer 5 GHz for capable clients (Correct answer)
- Reducing 2.4 GHz beacon interval
- Enabling U-APSD on 5 GHz
Correct answer: Enabling band steering to prefer 5 GHz for capable clients
Band steering nudges dual-band capable clients toward the less congested 5 GHz band by delaying or suppressing 2.4 GHz probe responses.
Question 7: A retail store experiences checkout system failures every Friday afternoon. A spectrum analyzer shows a strong non-802.11 signal around 2.45 GHz at those times. What is the likely cause?
- Customer smartphones causing interference
- A microwave oven operating during lunch prep nearby (Correct answer)
- Channel overlap from neighboring store APs
- Bluetooth headsets from staff
Correct answer: A microwave oven operating during lunch prep nearby
Microwave ovens emit broadband interference centered near 2.45 GHz, which can severely disrupt 2.4 GHz Wi-Fi during cooking operations.
CWS Case Analysis & Practical Application 2
A coffee shop deploys a single 2.4 GHz AP and customers report slow speeds during peak hours.
What is the most likely root cause?