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NetBSD 6.1.5 - man page for atw (netbsd section 4)

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ATW(4)				   BSD Kernel Interfaces Manual 			   ATW(4)

NAME
     atw -- ADMtek ADM8211 802.11 wireless network driver

SYNOPSIS
     atw* at cardbus? function ?
     atw* at pci? dev ? function ?

DESCRIPTION
     The atw driver supports PCI/CardBus 802.11b wireless adapters based on the ADMtek ADM8211.

     The ADM8211 is a bus-mastering 802.11 Media Access Controller (MAC) which is derived from
     ADMtek's Tulip clones (see tlp(4)).  It supports contention-free traffic (with an 802.11
     Point Coordinator), 64/128-bit WEP encryption, and 802.11 power-saving.  The ADM8211 inte-
     grates an RF3000 baseband processor (BBP) by RF Microdevices.

     In a typical application, the ADM8211 is coupled with an RF front-end by RFMD and a Silicon
     Laboratories Si4126 RF/IF synthesizer.

     With the ADM8211, the division of labor between the host and NIC is different than with
     firmware-based NICs such as an(4), awi(4), and wi(4).  The ADM8211 is still responsible for
     real-time 802.11 functions such as sending ACK/RTS/CTS/ATIM frames, sending beacons, and
     answering CF polls from the access point, but the host takes responsibility for providing
     802.11 functions such as scanning, association, and authentication.  The host is also
     responsible for programming both the BBP and the RF/IF synthesizer.

     atw contains incomplete support for the ADM8211's WEP encryption/decryption engine.  atw
     does not yet support hardware WEP decryption, however, it will use the ADM8211's crypto
     engine to encrypt transmitted frames.  Documentation from ADMtek claims that, in addition to
     the 4 128-bit shared WEP keys, the ADM8211 will store WEP key pairs for up to 20 peers.  The
     documentation provides no details, hence atw does not support the 20 key-pairs.

     The ADM8211 operates in 802.11 infrastructure mode (with an access point) and in 802.11 ad
     hoc mode (without an access point) at 1, 2, 5.5, and 11Mbps.  ADMtek says that the ADM8211
     cannot operate as an access point.

     The operating mode is selected using the ifconfig(8) utility.  For more information on con-
     figuring this device, see ifconfig(8) and ifmedia(4).

HARDWARE
     Cards supported by the atw driver include:

	   D-Link DWL-650 Rev. ?? CardBus card
	   D-Link DWL-520 Rev. C1 PCI card
	   LanReady WP2000 PCI card
	   TrendNet TEW-221PC CardBus card
	   Xterasys XN2511B PCI card

DIAGNOSTICS
     atw0: failed to tune channel %d  The driver failed to tune the radio to a new channel.  The
     radio remains tuned to the old channel.

     atw0: atw_si4136_write wrote %08x, SYNCTL still busy  The driver waited 100ms without seeing
     an indication that the ADM8211 had finished writing a register on the Si4126 RF/IF synthe-
     sizer.

     atw0: device timeout  The ADM8211 failed to generate an interrupt to acknowledge a transmit
     command.

SEE ALSO
     arp(4), cardbus(4), ifmedia(4), netintro(4), pci(4), ifconfig(8)

     ADMtek, http://www.admtek.com.tw.

     Silicon Laboratories, http://www.silabs.com.

     RF Microdevicdes, http://www.rfmd.com.

HISTORY
     The atw device driver first appeared in NetBSD 2.0.

AUTHORS
     The atw driver was written by David Young <dyoung@NetBSD.org>.  For features which the
     ADM8211 has in common with the DECchip 21x4x, code was liberally borrowed from tlp(4) by
     Jason Thorpe <thorpej@NetBSD.org>.

BUGS
     The author does not fully understand what processing the duration fields for the PLCP header
     and the 802.11 header undergo before they are applied to a transmitted frame.  If the dura-
     tion fields in transmitted frames are incorrect, the performance of your network may suffer.

     The driver does not provide rate control when the media type is set to autoselect.

     The driver lets you change to hostap mode, but it does not work and it probably never will.

     The driver will sometimes complain that it cannot re-tune the radio because the transmit
     process has not gone idle.  The author is investigating.

     Many features are still missing, especially WEP decryption and 802.11 power-saving.

     The ad hoc mode has not been rigorously tested.  IBSSs with the same SSID may not coalesce,
     but this should not matter for most applications.

     The driver is untested in the ad-hoc demo mode of Lucent WaveLAN cards.

     The ADM8211 supports 802.11 power-saving, however, atw does not support it yet.  For time-
     bounded service, the ADM8211 will interoperate with an access point which implements the
     802.11 Point Coordination Function, however, this is also not supported.

     Combinations of an ADM8211 with either an Intersil or a Marvell RF front-end are not sup-
     ported.

BSD					   June 5, 2004 				      BSD
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