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DFS is short for Dynamic Frequency Selection. It plays a role in 5GHz frequencies that are shared with weather radar.

It is related to 802.11h. DFS support can play a role when using ACS/“survey” in hostapd to find and select free WLAN channels.

Many countries regulate operation on some parts of the 5GHz spectrum - see List_of_WLAN_channels.

:!: Due to fast development, changing hardware, regulatory changes and compliance issues there can be interoperability issues.

:!: OpenWrt uses Open Source drivers which might be abandoned by manufactorer or no longer support some 5GHz operation due to regulatory changes.

:!: Original factory drivers can offer DFS when OpenWrt does not.

:!: There are different DFS schemes: DFS-FCC (USA), DFS-ETSI (Europe), DFS-JP (Japan).

:!: Try to use the non DFS channels if you have old hardware/clients.

DFS support

DFS status unknown

  • ath9k_htc
  • wlcore, wl18xx (allow using dfs channels,add radar_debug_mode debugfs file for DFS testing)
  • brcmfmac
  • brcmsmac
  • b43

No DFS support

  • mwl8k
docs/techref/dfs.txt · Last modified: 2018/02/20 18:51 by bobafetthotmail