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NAME

ral — Ralink Technology IEEE 802.11a/g/n wireless network device

SYNOPSIS

ral* at cardbus?
ral* at pci?

DESCRIPTION

The ral driver supports PCI/PCIe/CardBus wireless adapters based on the Ralink RT2500, RT2501, RT2600, RT2700, RT2800 and RT3090 chipsets.

The RT2500 chipset is the first generation of 802.11b/g adapters from Ralink. It consists of two integrated chips, an RT2560 MAC/BBP and an RT2525 radio transceiver.

The RT2501 chipset is the second generation of 802.11a/b/g adapters from Ralink. It consists of two integrated chips, an RT2561 MAC/BBP and an RT2527 radio transceiver. This chipset provides support for the IEEE 802.11e standard with multiple hardware transmission queues and allows scatter/gather for efficient DMA operations.

The RT2600 chipset consists of two integrated chips, an RT2661 MAC/BBP and an RT2529 radio transceiver. This chipset uses the MIMO (multiple-input multiple-output) technology with multiple radio transceivers to extend the operating range of the adapter and to achieve higher throughput. However, the RT2600 chipset does not support any of the 802.11n features.

The RT2700 chipset is a low-cost version of the RT2800 chipset. It supports a single transmit path and two receiver paths (1T2R). It consists of two integrated chips, an RT2760 or RT2790 (PCIe) MAC/BBP and an RT2720 (2.4GHz) or RT2750 (2.4GHz/5GHz) radio transceiver.

The RT2800 chipset is the first generation of 802.11n adapters from Ralink. It consists of two integrated chips, an RT2860 or RT2890 (PCIe) MAC/BBP and an RT2820 (2.4GHz) or RT2850 (2.4GHz/5GHz) radio transceiver. The RT2800 chipset supports two transmit paths and up to three receiver paths (2T2R/2T3R). It can achieve speeds up to 144Mbps (20MHz bandwidth) and 300Mbps (40MHz bandwidth.)

The RT3090 chipset is the first generation of single-chip 802.11n adapters from Ralink.

These are the modes the ral 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 ral 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 ral driver relies on the software 802.11 stack for both encryption and decryption of data frames on the RT2500, RT2501 and RT2600 chipsets. On the RT2700 and RT2800 chipsets, the ral driver offloads both encryption and decryption of data frames to the hardware for the WEP40, WEP104, TKIP(+MIC) and CCMP ciphers.

The transmit speed is user-selectable or can be adapted automatically by the driver depending on the number of hardware transmission retries.

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

FILES

The RT2501, RT2600, RT2700 and RT2800 chipsets require the following firmware files to be loaded when an interface is brought up:

The RT2500 chipset does not require a firmware to operate.

HARDWARE

The following PCI adapters should work:

The following CardBus adapters should work:

The following Mini PCI adapters should work:

EXAMPLES

The following hostname.if(5) example configures ral0 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 192.168.1.1 255.255.255.0 NONE media autoselect \
	mediaopt hostap nwid my_net chan 11

Configure ral0 to join network “my_net” using WPA with passphrase “my_passphrase”:

# ifconfig ral0 nwid my_net wpakey my_passphrase

Join an existing BSS network, “my_net”:

# ifconfig ral0 192.168.1.1 netmask 0xffffff00 nwid my_net

DIAGNOSTICS

ral%d: error %d, could not read firmware %s

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

ral%d: could not load 8051 microcode

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

ral%d: timeout waiting for MCU to initialize

The onboard 8051 microcontroller unit failed to initialize in time.

ral%d: 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), cardbus(4), ifmedia(4), intro(4), netintro(4), pci(4), hostname.if(5), hostapd(8), ifconfig(8)

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

HISTORY

The ral driver first appeared in OpenBSD 3.7. Support for the RT2501 and RT2600 chipsets was added in OpenBSD 3.9. Support for the RT2800 chipset was added in OpenBSD 4.3. Support for the RT2700 chipset was added in OpenBSD 4.4. Support for the RT3090 chipset was added in OpenBSD 4.9.

AUTHORS

The ral driver was written by Damien Bergamini ⟨damien@openbsd.org⟩.

CAVEATS

The ral driver does not make use of the hardware cryptographic engine present on the RT2500, RT2501 and RT2600 chipsets.

The ral driver does not support any of the 802.11n capabilities offered by the RT2700 and RT2800 chipsets. Additional work is required in ieee80211(9) before those features can be supported.

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).

Some PCI ral adapters seem to strictly require a system supporting PCI 2.2 or greater and will likely not work in systems based on older revisions of the PCI specification. Check the board's PCI version before purchasing the card.