We totally have 20 automous access points in several remote sites. We probably expand the current wireless network in the future. Say 50 will be enough. We plan to change these automous AP to lightweight ones. Get the WLC to control them. My question is: Can WLC communicate to lwap through lwapp at layer 3? If so, we only need one WLC sitting at HQ datacenter.
Yes, LWAPP (or CAPWAP if you use more recent versions of WLC code) can use Layer 3 for communication between the WLC and APs.