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NAME

rum — Ralink Technology USB IEEE 802.11a/b/g wireless network device

SYNOPSIS

rum* at uhub? port ?

DESCRIPTION

The rum driver supports USB 2.0 and PCI Express Mini Card wireless adapters based on the Ralink RT2501USB and RT2601USB chipsets.

Ralink PCI Express Mini Card adapters show up as normal USB 2.0 devices and are thus handled by the rum driver.

The RT2501USB chipset is the second generation of 802.11a/b/g adapters from Ralink. It consists of two integrated chips, an RT2571W MAC/BBP and an RT2528 or RT5226 radio transceiver.

The RT2601USB chipset consists of two integrated chips, an RT2671 MAC/BBP and an RT2527 or RT5225 radio transceiver. This chipset uses the MIMO (multiple-input multiple-output) technology with multiple antennas to extend the operating range of the adapter and to achieve higher throughput.

These are the modes the rum 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 rum driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA-PSK and WPA2-PSK). WPA is the de facto encryption standard for wireless networks. It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it. The rum driver relies on the software 802.11 stack for both encryption and decryption of data frames.

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

FILES

The following firmware file is loaded when an interface is brought up:

HARDWARE

The following adapters should work:

EXAMPLES

The following example scans for available networks:

The following hostname.if(5) example configures rum0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:

nwid mynwid
wpakey mywpakey
dhcp

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

inet 192.168.1.1 255.255.255.0
mediaopt hostap
nwid mynwid
wpakey mywpakey

DIAGNOSTICS

rum0: error N, could not read firmware ...

For some reason, the driver was unable to read the microcode file from the filesystem. The file might be missing or corrupted.

rum0: could not load 8051 microcode

An error occurred while attempting to upload the microcode to the onboard 8051 microcontroller unit.

rum0: device timeout

A frame dispatched to the hardware for transmission did not complete in time. The driver will reset the hardware. This should not happen.

SEE ALSO

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

Ralink Technology: http://www.ralinktech.com/

HISTORY

The rum driver first appeared in OpenBSD 4.0.

AUTHORS

The rum driver was written by Niall O'Higgins <niallo@openbsd.org> and
Damien Bergamini <damien@openbsd.org>.

CAVEATS

The rum driver supports automatic control of the transmit speed in BSS mode only. Therefore the use of a rum adapter in Host AP mode is discouraged.

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).