VPN active RAT

The process of active RAT re-selection at the UEinvolves discovering available networks for each RAT,evaluation of the potential handover candidates (bytaking into account operator policies, user preferences,and signal conditions), and the inter-technology handover trigger if the conditions are right.Starting with Release 8, 3GPP defined the accessnetwork discovery and selection function [3] in thenetwork to provide UE with the available access network information and associated service provider policies. UE can obtain the IP address of the ANDSF aspart of host IP information on initial network entry.