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 can be installed using fw_update(1).
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 example scans for available networks:
# ifconfig bwi0 scanThe following hostname.if(5) example configures bwi0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:
nwid mynwid wpakey mywpakey dhcp
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
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.