The Network Mobility Engine™ (NME) provides a policy-based framework for seamless handover of IP-based services (voice, data and video) between network transports without requiring any modification in the network infrastructure or the IP applications. The NME framework, based on a la Mobile's patent-pending Multi-Mode IP™ technology, gives a network operator the flexibility to deliver IP services based on a pre-defined set of policies, such as available network service, best costs, or application bandwidth requirements. It also allows for automatic selection of appropriate network transport when service is acquired or lost.