> By connecting each device directly to a port on the switch, either each port on a switch becomes its own collision domain (in the case of half-duplex links), or the possibility of collisions is eliminated entirely in the case of full-duplex links. For Gigabit Ethernet and faster, no hubs or repeaters exist and all devices require full-duplex links.

So is a wifi connection full or half duplex?

I don't think you understand collision domains.