(RADIATOR) Radius and Wireless APs

[jai]

Hi,   I have two APs one from cisco and other one D-link, APs Configuration has Radius Server Authentication option, As i am new to Wireless, i am having following questions   1. How can use Radiator or radius server to authenticate like the normal Dialup ??   2. If the User moves from one Access Point i.e from cisco to another one i.e D-Link ..is it needed to authenticate again. if not    what are the changes need in radiator server or wireless.   I think these questions might be irrelevant in this mailing list !!... but could someone guide me links which might help....   Thanks.   Rgds Jai