220-1101 Question 235
Single answerChannel configurationsA small office reports that laptops connected to a dual-band 802.11ac wireless router can see the SSID and connect successfully, but users experience frequent disconnects and low throughput during business hours. A technician uses a Wi-Fi analyzer and finds that several nearby networks are overlapping on the same 2.4 GHz channels, while the 5 GHz band is lightly used. Which action should the technician take FIRST to improve wireless performance for these users?
- A
Change the 2.4 GHz radio to channel 6 or 11 after checking which non-overlapping channel has the least interference
- B
Enable WPS so laptops can reconnect faster when signal quality drops
- C
Increase the 2.4 GHz channel width to 40 MHz to provide more bandwidth
- D
Move all client devices to a hidden SSID to reduce channel contention
Show answer and explanation
Correct answer: A
Explanation
This question tests practical wireless troubleshooting related to channel configurations. In a congested 2.4 GHz environment, nearby WLANs commonly interfere with one another when they use overlapping channels. A technician should first evaluate the least busy non-overlapping channel and reconfigure the access point accordingly. For 2.4 GHz, channels 1, 6, and 11 are the commonly recommended non-overlapping choices in many regions. Increasing channel width to 40 MHz on 2.4 GHz is generally discouraged in dense deployments because it increases overlap. Features like WPS or hiding the SSID do not address RF congestion. This aligns with common WLAN vendor guidance and wireless best practices used in enterprise and SMB environments.
- A. Correct.
Correct. In the 2.4 GHz band, the standard best practice is to use non-overlapping channels such as 1, 6, or 11 in many regulatory domains. If channel overlap and co-channel interference are causing disconnects and poor throughput, selecting the least congested non-overlapping channel is an appropriate first step. This directly addresses the channel configuration problem identified by the Wi-Fi analyzer.
- B. Incorrect.
Incorrect. WPS is a convenience feature for onboarding devices, not a performance or channel-management solution. It does not reduce interference, improve throughput, or stabilize a congested WLAN. It may also introduce security concerns depending on the implementation.
- C. Incorrect.
Incorrect. Using 40 MHz channel width on 2.4 GHz often makes interference worse because it consumes more of the already limited spectrum. In congested environments, 20 MHz channels are typically preferred on 2.4 GHz to minimize overlap and improve coexistence with neighboring networks.
- D. Incorrect.
Incorrect. Hiding the SSID does not reduce RF interference or channel contention. The access point still transmits beacons and uses the same channel. This is a common misconception: SSID visibility is unrelated to congestion or channel overlap.