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RTW(4) Device Drivers Manual RTW(4)

rtwRealtek RTL8180L IEEE 802.11b wireless network device

rtw* at cardbus?
rtw* at pci?

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.

These are the modes the rtw driver can operate in:

BSS mode
Also known as 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 mode or 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 access points.

The rtw driver can be configured to use software Wired Equivalent Privacy (WEP). It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it.

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

The following adapters should work:

SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
GRF5101 CardBus
GRF5101 CardBus
SA2400 CardBus
MAX2820 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
SA2400 CardBus
? CardBus
SA2400 CardBus
SA2400 CardBus
GRF5101 CardBus

The following hostname.if(5) example configures rtw0 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

The following hostname.if(5) example creates a host-based access point on boot:

inet NONE media autoselect \
	mediaopt hostap nwid 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 \
	nwid "" -nwkey

Join an existing BSS network, “my_net”:

# ifconfig rtw0 netmask 0xffffff00 nwid my_net

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


The rtw device driver first appeared in OpenBSD 3.7.

The rtw driver was written by David Young ⟨⟩ and ported to OpenBSD by Jonathan Gray ⟨⟩.

GCT refuse to release any documentation on their GRF5101 RF transceiver.

While PCI devices will attach most of them are not able to transmit.

Host AP mode doesn't support power saving. Clients attempting to use power saving mode may experience significant packet loss (disabling power saving on the client will fix this).

September 3, 2011 OpenBSD-5.1