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     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
     authenticator framework for defining 802.11 authentication services and a
     framework for integrating access control mechanisms specific to the
     802.11 protocol.


     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
     control bits that determine which debugging messages to enable.  For

           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
     control plugins.  This manual page was written by Tom Rhodes