AN(4)							   BSD Kernel Interfaces Manual 						     AN(4)

NAME
     an -- Aironet Communications 4500/4800 wireless network adapter driver

SYNOPSIS
     To compile this driver into the kernel, place the following lines in your kernel configuration file:

	   device an
	   device wlan

     Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

	   if_an_load="YES"

DESCRIPTION
     The an driver provides support for Aironet Communications 4500 and 4800 wireless network adapters and variants, including the following:

	   o   Aironet Communications 4500 and 4800 series
	   o   Cisco Aironet 340 and 350 series
	   o   Xircom Wireless Ethernet Adapter

     Support for these devices include the ISA, PCI and PCMCIA varieties.  The Aironet 4500 series adapters operate at 1 and 2Mbps while the
     Aironet 4800 series and Cisco adapters can operate at 1, 2, 5.5 and 11Mbps.  The ISA, PCI and PCMCIA devices are all based on the same core
     PCMCIA modules and all have the same programming interface, however unlike the Lucent WaveLAN/IEEE cards, the ISA and PCI cards appear to the
     host as normal ISA and PCI devices and do not require any PCCARD support.

     The PCMCIA Aironet cards require PC Card support, including the kernel pccard(4) driver.  ISA cards can either be configured to use ISA Plug
     and Play or to use a particular I/O address and IRQ by properly setting the DIP switches on the board.  (The default switch setting is for
     Plug and Play.)  The an driver has Plug and Play support and will work in either configuration, however when using a hard-wired I/O address
     and IRQ, the driver configuration and the NIC's switch settings must agree.  PCI cards require no switch settings of any kind and will be
     automatically probed and attached.

     All host/device interaction with the Aironet cards is via programmed I/O.	The Aironet devices support 802.11 and 802.3 frames, power manage-
     ment, BSS (infrastructure) and IBSS (ad-hoc) operation modes.  The an driver encapsulates all IP and ARP traffic as 802.11 frames, however it
     can receive either 802.11 or 802.3 frames.  Transmit speed is selectable between 1Mbps, 2Mbps, 5.5Mbps, 11Mbps or "auto" (the NIC automati-
     cally chooses the best speed).

     By default, the an driver configures the Aironet card for infrastructure operation.

     For more information on configuring this device, see ifconfig(8).

DIAGNOSTICS
     an%d: init failed	The Aironet card failed to become ready after an initialization command was issued.

     an%d: failed to allocate %d bytes on NIC  The driver was unable to allocate memory for transmit frames in the NIC's on-board RAM.

     an%d: device timeout  The Aironet card failed to generate an interrupt to acknowledge a transmit command.

SEE ALSO
     altq(4), arp(4), miibus(4), netintro(4), wlan(4), ancontrol(8), ifconfig(8)

HISTORY
     The an device driver first appeared in FreeBSD 4.0.

AUTHORS
     The an driver was written by Bill Paul <wpaul@ee.columbia.edu>.

BSD								   July 16, 2005							       BSD