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wlan - generic 802.11 link-layer support



      wlan - generic 802.11 link-layer support


      device wlan


      The wlan module provides generic code to support 802.11 drivers.  Where a
      device does not directly support 802.11 functionality this layer fills
      in.  The wlan is required for the an(4), ath(4), awi(4), ipw(4), iwi(4),
      ral(4), rum(4), ural(4), wi(4), and zyd(4) drivers, with other drivers to
      The wlan module supports multi-mode devices capable of operating in both
      2.4GHz and 5GHz bands and supports numerous 802.11 protocols: 802.11a,
      802.11b, and 802.11g.  The WPA, 802.11i, and 802.1x security protocols
      are supported through a combination of in-kernel code and user-mode
      applications.  The WME and WMM multi-media protocols are supported
      entirely within the wlan module but require a suitably capable hardware
      The wlan module defines several mechanisms by which plugin modules may be
      used to extend functionality.  Cryptographic support such as WEP, TKIP,
      and AES-CCMP are implemented as modules that are loaded on demand (if not
      statically configured into a system).  Similarly there is an authentica‐
      tor framework for defining 802.11 authentication services and a framework
      for integrating access control mechanisms specific to the 802.11 proto‐


      If the associated interface is marked for debugging with, for example,
            ifconfig wi0 debug
      then messages describing the operation of the 802.11 protocol will be
      sent to the console.  Complete debugging controls are available using:
            sysctl net.wlan.X.debug=mask
      where X is the number of the wlan instance and mask is a bit-or of con‐
      trol bits that determine which debugging messages to enable.  For exam‐
            sysctl net.wlan.0.debug=0x00200000
      enables debugging messages related to scanning for an access point, adhoc
      neighbor, or an unoccupied channel when operation as an access point.
      The 80211debug tool provides a more user-friendly mechanism for doing the
      same thing.
      Many drivers will also display the contents of each 802.11 frame sent and
      received when the interface is marked with both debugging and link2;
            ifconfig wi0 debug link2
      Beware however that some management frames may be processed entirely
      within the device and not be received by the host.


      The module name of wlan was used to be compatible with NetBSD.
      an(4), ath(4), awi(4), ipw(4), iwi(4), netintro(4), ral(4), rum(4),
      ural(4), wi(4), wlan_acl(4), wlan_ccmp(4), wlan_tkip(4), wlan_wep(4),
      wlan_xauth(4), zyd(4)


      More information can be found in the IEEE 802.11 Standard.


      The wlan driver first appeared in FreeBSD 5.0.


      Atsushi Onoe is the author of original NetBSD software from which this
      work began.  Sam Leffler brought the code into FreeBSD and then rewrote
      it to support multi-mode devices, 802.11g, WPA/802.11i, WME, and add the
      extensible frameworks for cryptographic, authentication, and access con‐
      trol plugins.  This manual page was written by Tom Rhodes


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