Cisco recently has made a small step to improve ASA and has implemented logical tunnels, what means we got route based VPN! Really? Did we? Not so fast. Yes, we got route based VPN but still we have to add routes manually.
VTI – Virtual Tunnel Interface has been invented as a simple deployment of VPN in conjunction with IPSec. Easiness of implementation, multicasts and QoS support, makes VTI interesting alternative to GRE Tunnel.