Channels 52 through 144 in the 5 GHz band (shown as UNII-2, UNII-2-Extended, and some adjacent channels) are marked in regulatory domains as DFS (Dynamic Frequency Selection) channels.
DFS channels must be monitored for radar activity (such as weather radar). If radar is detected, the AP must switch channels to avoid interference.
These channels can be used, but only if the AP supports DFS and performs the necessary checks before use.
WIDS can scan these channels but that’s not the defining characteristic.
Regulatory restrictions (B) apply only if DFS is not supported, which is rare on modern equipment.
Radio Resource Provisioning (C) is unrelated to DFS usage.
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