A method for communicating Internet Protocol data over a network, comprises providing an IPv4 data stream and providing an IPv6 data stream. An encrypted Internet Protocol communications tunnel is established through the network between a roaming mobile device and a further computing device. The IPv4 and IPv6 data streams are combined for encapsulation within and transmission through said encrypted tunnel. Continual secure communications of the encapsulated IPv4 and IPv6 data streams is maintained between said roaming mobile device and the further computing device while the roaming mobile device roams between network access points. The encapsulated, transmitted IPv4 and IPv6 data streams are received from said tunnel, and the received IPv4 and IPv6 data streams are demultiplexed.