central Hotspot server for multiple remote APs

Hello,

I would like to centralize multiple Mirkotik APs.
Each AP has a local hotspot server and internet connection.

My goal is to make “roaming” network. Simpler put clients dont need to reauthenticate when they move through town and different APs. WLAN SSID will be same but on different channels.

Can I somehow make a Centralized Hotspot page (ie http://wiki.mikrotik.com/wiki/HotSpot_external_login_page)
and RADIUS authentification.

Because it is mainly used for free internet for limited time/day I must authenticate TRIAL users to the central location and disconnect them when they reach limit (6h or 500MB).

What about IP address for clients.. Can they be in different subnets or must I create somekind of tunel (EoIP, IPSEC, PPTP) to have one big segment (ie 172.30.0.0/16).

Since there are over 40 APs this means quite a lot of tunnels. And If for example I create a EoIP tunnel can remote IPs only use Authentification and DHCP server from CORE router and traffic would go over its own internet connection not over EoIP and CORE router.

Thanks for help and advice…

dear

http://wiki.mikrotik.com/wiki/Centralized_Authentication_for_Hotspot_user
i think above link will help you