WirelessDistributionSystem (WDS) is a mechansism for connecting AccessPoints to other AccessPoints using the HostApMode driver for Linux (or possibly *BSD?).
Here's a config example from TerrySchmidt that shows how to bridge two WDS interfaces using his Linux distribution Pebble.
{{{AP-A configuration:
iwpriv wlan0 wds_add 00:22:22:22:22:22 brctl addbr br0 brctl addif br0 eth0 brctl addif br0 wlan0 brctl addif br0 wlan0wds0 ifconfig eth0 0.0.0.0 ifconfig wlan0 0.0.0.0 ifconfig wlan0wds0 0.0.0.0 ifconfig br0 192.168.1.1 up
AP-B configuration:
iwpriv wlan0 wds_add 00:11:11:11:11:11 brctl addbr br0 brctl addif br0 eth0 brctl addif br0 wlan0wds0 ifconfig eth0 0.0.0.0 ifconfig wlan0wds0 0.0.0.0 ifconfig br0 192.168.1.2 up }}}