CWNA: Certified Wireless Network Administrator v108 — Question 20

You manage a WLAN with 100 802.11ac access points. All access points are configured to use 80 MHz channels. In a particular BSS, only 40 MHz communications are seen. What is the likely cause of this behavior?

Answer options

• A. All clients implement single spatial stream radios
• B. The clients are all 802.11n STAs or lower
• C. The AP is improperly configured to use only 40 MHz of the 80 MHz allocated bandwidth
• D. The short guard interval is also enabled

Correct answer: B

Explanation

The correct answer is B because if all clients are 802.11n or older, they cannot take advantage of the 80 MHz channels provided by the 802.11ac access points, limiting their communication to 40 MHz. Option A is incorrect because single spatial stream radios do not inherently prevent the use of 80 MHz channels; they just do not utilize the full capacity. Option C suggests a configuration error, but the scenario indicates that the clients are the limiting factor. Option D is irrelevant to the channel width being used.