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RTW(4) NetBSD Kernel Interfaces Manual RTW(4)
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rtw -- Realtek RTL8180L IEEE 802.11b wireless network driver
rtw* at cardbus? function ?
rtw* at pci? dev ? function ?
The rtw driver supports PCI/CardBus 802.11b wireless adapters based on
the Realtek RTL8180L.
A variety of radio transceivers can be found in these devices, including
the Philips SA2400A, Maxim MAX2820, and GCT GRF5101, though not all of
them are currently supported.
These are the modes the rtw driver can operate in:
BSS mode Also known as infrastructure mode, this is used when asso-
ciating with an access point, through which all traffic
passes. This mode is the default.
IBSS mode Also known as IEEE ad-hoc mode or peer-to-peer mode. This
is the standardized method of operating without an access
point. Stations associate with a service set. However,
actual connections between stations are peer-to-peer.
Host AP In this mode the driver acts as an access point (base sta-
tion) for other cards.
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.
rtw supports software WEP. Wired Equivalent Privacy (WEP) is the de
facto encryption standard for wireless networks. It can be typically
configured in one of three modes: no encryption; 40-bit encryption; or
104-bit encryption. Unfortunately, due to serious weaknesses in WEP pro-
tocol it is strongly recommended that it not be used as the sole mecha-
nism to secure wireless communication. WEP is not enabled by default.
The rtw driver can be configured at runtime with ifconfig(8) or on boot
with ifconfig.if(5) using the following parameters:
Set the desired BSSID.
-bssid Unset the desired BSSID. The interface will automatically select
a BSSID in this mode, which is the default.
chan n Set the channel (radio frequency) to be used by the driver based
on the given channel ID n.
-chan Unset the desired channel to be used by the driver. The driver
will automatically select a channel in this mode, which is the
The rtw driver supports the following media types:
autoselect Enable autoselection of the media type and options.
DS1 Set 802.11b DS 1Mbps operation.
DS2 Set 802.11b DS 2Mbps operation.
DS5 Set 802.11b DS 5.5Mbps operation.
DS11 Set 802.11b DS 11Mbps operation.
The rtw driver supports the following media options:
hostap Select Host AP operation.
ibss Select IBSS operation.
monitor Select monitor mode.
Disable the specified media options on the driver and return it
to the default mode of operation (BSS).
Set the network ID. The id can either be any text string up to
32 characters in length, or a series of hexadecimal digits up to
64 digits. An empty id string allows the interface to connect to
any available access points. By default the rtw driver uses an
empty string. Note that network ID is synonymous with Extended
Service Set ID (ESSID).
Enable WEP encryption using the specified key. The key can
either be a string, a series of hexadecimal digits (preceded by
`0x'), or a set of keys of the form ``n:k1,k2,k3,k4'', where `n'
specifies which of the keys will be used for transmitted packets,
and the four keys, ``k1'' through ``k4'', are configured as WEP
keys. If a set of keys is specified, a comma (`,') within the
key must be escaped with a backslash. Note that if multiple keys
are used, their order must be the same within the network. rtw
is capable of using both 40-bit (5 characters or 10 hexadecimal
digits) or 104-bit (13 characters or 26 hexadecimal digits) keys.
-nwkey Disable WEP encryption. This is the default mode of operation.
Enable WEP encryption with the persistent key stored in the net-
The following adapters should work:
Belkin F5D6020 V3 CardBus
Buffalo WLI-CB-B11 CardBus
Corega CG-WLCB11V3 CardBus
D-Link DWL-610 CardBus
Level-One WPC-0101 CardBus
Linksys WPC11 v4 CardBus
Netgear MA521 CardBus
Ovislink AirLive WL-1120PCM CardBus
Planet WL-3553 CardBus
TrendNET TEW-266PC CardBus
VCTnet PC-11B1 CardBus
The following ifconfig.if(5) example creates a host-based access point on
inet 192.168.1.1 255.255.255.0 NONE media autoselect \
mediaopt hostap ssid my_net chan 11
Configure rtw0 for WEP, using hex key ``0x1deadbeef1'':
# ifconfig rtw0 nwkey 0x1deadbeef1
Return rtw0 to its default settings:
# ifconfig rtw0 -bssid -chan media autoselect \
ssid "" -nwkey
Join an existing BSS network, ``my_net'':
# ifconfig rtw0 192.168.1.1 netmask 0xffffff00 ssid my_net
arp(4), cardbus(4), ifmedia(4), intro(4), netintro(4), pci(4),
The rtw device driver first appeared in NetBSD 3.0 and then in
The rtw driver was written by David Young <dyoung@NetBSD.org> and ported
to OpenBSD by Jonathan Gray <firstname.lastname@example.org>, who wrote this man page.
Only the Philips SA2400A and Maxim MAX2820 RF transceivers are known to
work. Devices incorporating a GCT RF transceiver are not supported due
to a lack of documentation from GCT.
While PCI devices will attach most of them are not able to transmit.
NetBSD 9.2 December 29, 2004 NetBSD 9.2