RTW(4) | Device Drivers Manual | RTW(4)

# NAME

`rtw` —
Realtek RTL8180L IEEE 802.11b wireless network driver

# SYNOPSIS

`rtw* at cardbus? function ?`
`rtw* at pci? dev ? function ?`

# 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, 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 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 protocol it is strongly recommended that it not be used as the sole mechanism to secure wireless communication. WEP is not enabled by default.

# CONFIGURATION

The `rtw` driver can be configured at runtime with ifconfig(8) or on boot with ifconfig.if(5) using the following parameters:

`bssid` bssid
  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 default.
`media` media
  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.
`mediaopt` opts
  The `rtw` driver supports the following media options:

  `hostap`
    Select Host AP operation.
  `ibss`
    Select IBSS operation.
  `monitor`
    Select monitor mode.
`-mediaopt` opts
  Disable the specified media options on the driver and return it to the default mode of operation (BSS).
`ssid` id
  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).
`nwkey` key
  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.
`nwkey persist`
  Enable WEP encryption with the persistent key stored in the network card.

# HARDWARE

The following adapters should work:

Card | Bus
`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

# EXAMPLES

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

# SEE ALSO

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

Realtek, http://www.realtek.com.tw.

# HISTORY

The `rtw` device driver first appeared in NetBSD 3.0 and then 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>, who wrote this man page.

# BUGS

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 | NetBSD 9.4