+
+== Notes on DFS in various modes ==
+
+A VAP interface can be used in several modes:
+* IEEE80211_M_STA "sta" : DFS is implemented as "slave"
+* IEEE80211_M_IBSS "adhoc" : DFS is implemented as "master"
+* IEEE80211_M_AHDEMO "ahdemo" : DFS is implemented as "master"
+* IEEE80211_M_HOSTAP "ap" : DFS is implemented as "master"
+* IEEE80211_M_MONITOR "monitor" : DFS is not implemented
+* IEEE80211_M_WDS "wds" : DFS is implemented as "master"
+
+== Implementation notes ==
+
+sc->sc_curchan.privFlags & CHANNEL_DFS is set if ETSI/FCC compliance is
+required by regulation. It does not mean that 802.11h is required. This flag
+is automatically adjusted by ath_radar_correct_dfs_flags() according to the
+regulation for the specified frequency.
+
+ic->ic_flags & IEEE80211_F_DOTH is set if IEEE 802.11h is required. It matches
+dot11SpectrumManagementRequired as described in IEEE 802.11h. Default value is
+1 and can be changed at anytime by the user through iwpriv.
+
+ETSI/FCC mechanisms (Channel Availability Check, In-Service Monitoring, Channel
+Shutdown, Non-Occupancy Period) and IEEE 802.11h magnums (Selecting and
+advertising a new channel, ...) are implemented ONLY if both flags are set.
+