CWNA Case Studies & Practical Application 2 — Questions and Answers
Question 1: A hospital deploys Wi-Fi for patient monitoring devices that require uninterrupted connectivity. During a site survey, you notice heavy co-channel interference on 2.4 GHz. What is the BEST remediation strategy?
- Increase transmit power on all APs to overcome interference
- Migrate patient monitoring devices to 5 GHz and use non-overlapping channels (Correct answer)
- Switch to a mesh topology using 2.4 GHz backhaul only
- Reduce AP density and rely on fewer high-power access points
Correct answer: Migrate patient monitoring devices to 5 GHz and use non-overlapping channels
Migrating to 5 GHz eliminates 2.4 GHz co-channel interference and provides more non-overlapping channels for critical medical devices.
Question 2: A retail store experiences poor Wi-Fi performance near the stockroom. A spectrum analysis shows a 2.4 GHz signal bursting every 30 seconds. What is the MOST likely source?
- A neighboring store's AP on the same channel
- A Bluetooth headset used by warehouse staff
- A microwave oven operating in the stockroom (Correct answer)
- A 2.4 GHz cordless phone on the loading dock
Correct answer: A microwave oven operating in the stockroom
Microwave ovens emit pulsed 2.4 GHz interference that bursts cyclically, typically matching the duty cycle of the magnetron during heating.
Question 3: An enterprise deploys 802.11ax APs in a high-density conference center. Users report inconsistent speeds. Which 802.11ax feature should be verified to be enabled to address this scenario?
- Beamforming with MU-MIMO only in the downlink direction
- OFDMA for efficient multi-user channel access (Correct answer)
- WEP encryption to reduce processing overhead
- Channel bonding to 160 MHz for all clients
Correct answer: OFDMA for efficient multi-user channel access
OFDMA allows 802.11ax APs to serve multiple clients simultaneously by dividing channels into resource units, ideal for high-density environments.
Question 4: A university IT team notices roaming issues between buildings when students move between APs. Authentication delays cause VoIP calls to drop. Which technology BEST resolves this?
- Increasing beacon intervals on all APs
- Implementing 802.11r Fast BSS Transition (Correct answer)
- Disabling PMF to speed up re-association
- Switching all APs to WPA-Personal for faster handoff
Correct answer: Implementing 802.11r Fast BSS Transition
802.11r (Fast BSS Transition) pre-establishes security keys between APs, dramatically reducing roaming authentication delays.
Question 5: During a post-installation validation of a warehouse WLAN, throughput tests show only 50% of expected performance. The APs use 5 GHz with 40 MHz channels. What should you check FIRST?
- Whether DFS channels are in use and radar events are occurring (Correct answer)
- Whether the DHCP server has sufficient IP addresses
- Whether WPA3 is causing processing overhead
- Whether beacon frames are using too high a data rate
Correct answer: Whether DFS channels are in use and radar events are occurring
DFS channels require radar detection and can trigger channel changes or reduce usable bandwidth, significantly impacting throughput in warehouses near airports or radar installations.
Question 6: A financial firm needs to ensure that no unauthorized APs are connected to their wired network. Which WLAN security feature addresses this requirement MOST directly?
- Rogue AP detection with wired-side correlation (Correct answer)
- Guest SSID isolation
- Band steering configuration
- 802.11w Management Frame Protection
Correct answer: Rogue AP detection with wired-side correlation
Rogue AP detection with wired-side correlation identifies unauthorized APs by matching their MAC addresses against the switch's ARP/CAM table.
Question 7: A school deploys a WLAN for 1:1 Chromebook use. Teachers report that throughput drops significantly when all 30 students open video streams simultaneously. The AP supports 802.11ac Wave 2. What is the MOST effective configuration change?
- Enable MU-MIMO to serve multiple clients simultaneously in the downlink (Correct answer)
- Disable 2.4 GHz radios and force all clients to 5 GHz
- Reduce the DTIM interval to 1 for all SSIDs
- Increase the fragmentation threshold to reduce overhead
Correct answer: Enable MU-MIMO to serve multiple clients simultaneously in the downlink
MU-MIMO allows 802.11ac Wave 2 APs to transmit to multiple clients at the same time in the downlink, improving aggregate throughput in high-density classrooms.
CWNA Case Studies & Practical Application 2
A hospital deploys Wi-Fi for patient monitoring devices that require uninterrupted connectivity.
During a site survey, you notice heavy co-channel interference on 2.4 GHz.
What is the BEST remediation strategy?