an(4) 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 loader.conf5:



The 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 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 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 speed).

By default, the 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.


The device driver first appeared in Fx 4.0 .


The driver was written by An Bill Paul Aq [email protected] .