220-1101 Question 82
Single answerFrequenciesA technician is troubleshooting poor Wi-Fi performance in a small office. Users on an older 2.4 GHz wireless network report slow speeds and frequent disconnects, especially during lunch when nearby offices are busy. A site survey shows many neighboring wireless networks overlapping on the same part of the spectrum. Which action is the BEST way to reduce interference while keeping all current devices connected?
- A
Change the wireless router to channel 6, using a 20 MHz channel width on the 2.4 GHz band
- B
Change the wireless router to a 40 MHz channel width on the 2.4 GHz band to increase throughput
- C
Move all users to a 5 GHz-only SSID and disable 2.4 GHz completely
- D
Lower the encryption level from WPA2 to WEP so clients can reconnect faster
Show answer and explanation
Correct answer: A
Explanation
This question tests practical understanding of wireless frequencies and channel management in A+ Core 1. In a crowded 2.4 GHz environment, the best practice is to use one of the non-overlapping channels, typically 1, 6, or 11 in regions that support them, and keep channel width at 20 MHz to reduce overlap and interference. The 2.4 GHz band has limited usable spectrum, so wider channels such as 40 MHz often degrade performance in real-world office deployments. While 5 GHz can offer better performance due to additional spectrum and less congestion, it may not support all legacy devices. Best practices reflected here align with common wireless deployment guidance from Wi-Fi vendors and networking documentation covering 2.4 GHz channel planning and interference mitigation.
- A. Correct.
Correct. In the 2.4 GHz band, interference is commonly reduced by selecting a non-overlapping channel and using a narrower 20 MHz channel width. In most regions, channels 1, 6, and 11 are the standard non-overlapping choices for 2.4 GHz Wi-Fi. Choosing one of these based on the site survey helps minimize adjacent-channel interference while maintaining compatibility with older 2.4 GHz devices.
- B. Incorrect.
Incorrect. Although 40 MHz can increase theoretical throughput, it consumes more of the already crowded 2.4 GHz spectrum and typically worsens interference in congested environments. This is a common mistake when trying to improve speed without considering frequency overlap and channel contention.
- C. Incorrect.
Incorrect. Moving to 5 GHz would often improve performance because that band usually has more available channels and less interference, but the scenario specifically requires keeping all current devices connected. Older devices may only support 2.4 GHz, so disabling 2.4 GHz would break compatibility.
- D. Incorrect.
Incorrect. Encryption settings do not solve RF interference or channel congestion. WEP is also obsolete and insecure. Someone might choose this if they confuse connection/authentication problems with frequency-related interference, but lowering security is not an appropriate or effective fix.