During centralized WLC 7500 controller connectivity with branch office AP , can we use the public IP address in WLC management , in case we are not having VPN connectivity between Remote to branch location & only had a internet in both end . Will my remote end AP associate with the centralized WLC controller via public IP ( not a private local IP ) or VPN / MPLS solution is must for communication between WLC & Remote AP.
You can configure OfficeExtend on those AP's. You would enable NAT address on the management and put your public address there. Then you would open udp 5246 and udp 5247 from the public side to the WLC management. Then enable data encryption on the AP after it joins. The AP can be in local FlexConnect mode. Here are some links to look at.