A customer has recently implemented a new wireless infrastructure using WLC-5520s at a site directly next to a large commercial airport. Users report that they intermittently lose Wi-Fi connectivity, and troubleshooting reveals it is due to frequent channel changes. Which two actions fix this issue? (Choose two.)

A. Remove UNII-2 and Extended UNII-2 channels from the 5 Ghz channel list
B. Restore the OCA default settings because this automatically avoids channel interference
C. Disable DFS channels to prevent interference with Doppler radar
D. Enable DFS channels because they are immune to radar interference
E. Configure channels on the UNII-2 and the Extended UNII-2 sub-bands of the 5 Ghz band only

A customer has recently implemented a new wireless infrastructure using WLC-5520s at a site directly next to a large commercial airport. Users report that they intermittently lose Wi-Fi connectivity, and troubleshooting reveals it is due to frequent channel changes. Which two actions fix this issue? (Choose two.)

A. Remove UNII-2 and Extended UNII-2 channels from the 5 Ghz channel list
B. Restore the OCA default settings because this automatically avoids channel interference
C. Disable DFS channels to prevent interference with Doppler radar
D. Enable DFS channels because they are immune to radar interference
E. Configure channels on the UNII-2 and the Extended UNII-2 sub-bands of the 5 Ghz band only

Correct Answer: AC

DFS is Dynamic Frequency Selection, which is a function of using 5 GHz Wi-Fi frequencies that are generally reserved for radar. Because the 2.4Ghz band is free of radar, the DFS rules only apply to the 5.250 – 5.725 Ghz band.

UNII-2 (5.250-5.350 GHz and 5.470-5.725 GHz) shared with radar systems. Therefore, APs operating on UNII-2 channels are required to use Dynamic Frequency Selection (DFS) to avoid interfering with radar signals.