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     an — Aironet Communications 4500/4800 wireless network adapter driver


     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



     This driver is scheduled for removal prior to the release of FreeBSD 13.0


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

              Aironet Communications 4500 and 4800 series
              Cisco Aironet 340 and 350 series
              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 management, 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 automatically chooses the best

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

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


     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.


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


     The an device driver first appeared in FreeBSD 4.0.


     The an driver was written by Bill Paul <>.