RTW(4) - Device Drivers Manual #

RTW(4) - Device Drivers Manual

NAME #

rtw - Realtek RTL8180L IEEE 802.11b wireless network device

SYNOPSIS #

rtw* at cardbus? rtw* at pci?

DESCRIPTION #

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 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 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.

In BSS mode, the driver supports powersave mode, which can be enabled via ifconfig(8).

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

HARDWARE #

The following adapters should work:

*Card*                            *Radio*    *Bus*  
`Allnet ALL0182`                  SA2400     CardBus  
`Belkin F5D6020 V3`               SA2400     CardBus  
`Buffalo WLI-CB-B11`              SA2400     CardBus  
`Corega CG-WLCB11V3`              SA2400     CardBus  
`D-Link DWL-610`                  ?          CardBus  
`Edimax EW-7106`                  SA2400     CardBus  
`GigaFast WF721-AEX (R* serial)`  GRF5101    CardBus  
`Jensen AirLink 6011`             GRF5101    CardBus  
`Level-One WPC-0101`              SA2400     CardBus  
`Linksys WPC11 v4`                MAX2820    CardBus  
`Netgear MA521`                   SA2400     CardBus  
`Ovislink AirLive WL-1120PCM`     SA2400     CardBus  
`Planet WL-3553`                  SA2400     CardBus  
`Q-Tec 770WC`                     SA2400     CardBus  
`Q-Tec 775WC`                     SA2400     CardBus  
`Roper FreeLan 802.11b`           SA2400     CardBus  
`SAFECOM SWLCR-1100`              SA2400     CardBus  
`TRENDnet TEW-226PC`              ?          CardBus  
`VCTnet PC-11B1`                  SA2400     CardBus  
`Winstron CB-200B`                SA2400     CardBus  
`Zonet ZEW1000`                   GRF5101    CardBus

EXAMPLES #

The following example scans for available networks:

# ifconfig rtw0 scan

The following hostname.if(5) example configures rtw0 to join network “mynwid”, using WEP key “mywepkey”, obtaining an IP address using DHCP:

nwid mynwid nwkey mywepkey
inet autoconf

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

mediaopt hostap
nwid mynwid nwkey mywepkey
inet 192.168.1.1 255.255.255.0

HISTORY #

The rtw device driver first appeared in OpenBSD 3.7.

AUTHORS #

The rtw driver was written by David Young <dyoung@NetBSD.org> and ported to OpenBSD by Jonathan Gray <jsg@openbsd.org>.

CAVEATS #

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).

OpenBSD 7.5 - March 31, 2022