For the AP to get an IP , this can be done from Controller ( if DHCP server is enabale on it ) or using external DHCP server
if i used external DHCP server , do i need to do any additional configuration on the DHCP server rather then what i do for normal wired Pcs to get an IP from this DCHP Server ( do i need to do what is called DHCP Option 43 on DHCP Server sothat AP can get an IP , why ? )