VPN IP sessioncontinuity

Networking standards outline the basics of multiradio UE behavior to support inter-technology handoverswith IP session continuity. In order to satisfy interworking requirements and service provider policiesfor different access technologies, UE needs to supporta variety of mobility modes to maintain IP sessioncontinuity on inter-RAT handovers. In addition, trulyseamless handover requires special functions andoperation procedures at the UE device to minimizeor eliminate packet data stream impairment, e.g.,minimize handover latency, packet loss and reordering, and QoS degradation. This section highlights suchUE procedures for loosely coupled interworking architecture. Note that a tightly coupled architecture modelfurther increases the network role in seamless interworking, allowing implementation of some of thedescribed procedures (e.g., intelligent buffering) inthe network instead of in the UE.