README.dfs

2007-10-11 Benoit PAPILLAULT <benoit.papillault@free.fr>

Conformance testing to the following standards:
* ETSI 301 893 v1.4.1 (dated 2007-07)
* FCC
* IEEE 802.11h-2003 (dated 2003-10-14)

ETSI and FCC defines the regulation constraints and defines several roles :
* "master"
* "slave without radar detection"
* "slave with radar detection"

Frequencies & channels where DFS is applicable:
* ETSI : 5250-5350MHz , 5470-5725MHz
* IEEE 802.11 center frequencies : 
  5260, 5280, 5300, 5320
  5500, 5520, 5540, 5560, 5580, 5600, 5620, 5640, 5660, 5680, 5700
* IEEE 802.11 channels :
    52,   56,   60,   64
   100,  104,  108,  112,  116,  120,  124,  128,  132,  136,  140

Simulating a radar pulse:
echo "<tsf> <rssi> <width>" > /proc/sys/dev/wifi0/radar_pulse

Simulating a radar detected event:
iwpriv wlan0 doth_radar

== 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.