  Smart environment requires uninterrupted connection when moving from one
network to another. This is best accomplished at the network level (L3). Full
interoperability and integration of heterogeneous networks is necessary for
communication session continuity. Software Defined Networking (SDN) with
virtual IP addresses solves the problem. Implementing a homogeneous SDN is
expensive, given the enormous investments in existing networks. To solve this
second problem, we deploy the least set of SDN features to provide full L3
mobility. We use a common controller to manage the IP address translations.
