BWI(4)

NAME
bwi - Broadcom AirForce IEEE 802.11b/g wireless network device

SYNOPSIS
bwi* at cardbus?
bwi* at pci?

DESCRIPTION
The bwi driver provides support for Broadcom AirForce based PCI/Cardbus network adapters.

These are the modes the bwi driver can operate in:

BSS mode
    Also known as infrastructure mode, this is used when associating with an access point, through which all traffic passes. This mode is the default.

monitor mode
    In this mode the driver is able to receive packets without associating with an access point. This disables the internal receive filter and enables the card to capture packets from networks which it wouldn't normally have access to, or to scan for access points.

The bwi driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA-PSK and WPA2-PSK). WPA is the de facto encryption standard for wireless networks. It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it. The bwi driver relies on the software 802.11 stack for both encryption and decryption of data frames.

The transmit speed is user-selectable or can be adapted automatically by the driver depending on the received signal strength and on the number of hardware transmission retries.

The bwi driver can be configured at runtime with ifconfig(8) or on boot with hostname.if(5).

FILES
The driver needs a firmware file which is loaded when an interface is brought up:

/etc/firmware/bwi-airforce

A prepackaged version of the firmware, designed to be used with pkg_add(1), can be found at:

    http://firmware.openbsd.org/firmware/bwi-firmware-1.4.tgz

HARDWARE
The following cards are among those supported by the bwi driver:
Card | Chip | Bus | Standard
Apple Airport Extreme | BCM4306 | PCI | b/g
Apple Airport Extreme | BCM4318 | PCI | b/g
ASUS WL-138g | BCM4318 | PCI | b/g
Buffalo WLI-CB-G54 | BCM4306 | CardBus | b/g
Compaq R4035 onboard | BCM4306 | PCI | b/g
HP nx6125 | BCM4319 | PCI | b/g
Linksys WPC54G Ver 3 | BCM4318 | CardBus | b/g
Linksys WPC54GS Ver 2 | BCM4318 | CardBus | b/g
TRENDnet TEW-401PCplus | BCM4306 | CardBus | b/g
US Robotics 5411 | BCM4318 | CardBus | b/g

EXAMPLES
The following hostname.if(5) example configures bwi0 to join whatever network is available on boot, using WEP key “0x1deadbeef1”, channel 11, obtaining an IP address using DHCP:

    dhcp NONE NONE NONE nwkey 0x1deadbeef1 chan 11

Configure bwi0 to join network “my_net” using WPA with passphrase “my_passphrase”:

    # ifconfig bwi0 nwid my_net wpakey my_passphrase

Join an existing BSS network, “my_net”:

    # ifconfig bwi0 192.168.1.1 netmask 0xffffff00 nwid my_net

SEE ALSO
arp(4), cardbus(4), ifmedia(4), intro(4), netintro(4), pci(4), hostname.if(5), ifconfig(8)

HISTORY
The bwi driver first appeared in OpenBSD 4.3.

AUTHORS
-nosplit The bwi driver was written for DragonFlyBSD by Sepherosa Ziehau and ported to OpenBSD by Jonathan Gray and Marcus Glocker.

CAVEATS
Some chips are incorrectly calibrated due to the lack of documentation, which can slow the amount of traffic to the point of being unusable. Furthermore this driver only supports firmware version 3.