RTW(4) BSD Kernel Interfaces Manual RTW(4)
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 associating 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 station) 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
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
protocol it is strongly recommended that it not be used as the sole mechanism to secure wireless communication. WEP is not enabled by
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 network card.
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 boot:
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), ifconfig.if(5), ifconfig(8)
The rtw device driver first appeared in NetBSD 3.0 and then in OpenBSD 3.7.
The rtw driver was written by David Young <dyoung@NetBSD.org> and ported to OpenBSD by Jonathan Gray <email@example.com>, who wrote this man
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.
December 29, 2004 BSD