Tunnel-accessed NATs for always-best-connected and application mobility

We describe the design, implementation and performance of a Remote NAT that can be used to provide an ‘always-best-connected’ service. In this service a mobile host will connect through the best possible network. Switching between the networks (even with IP address changes) will be transparent to the application. The solution that we propose is different from traditional mobility solutions like MSOCKS and Mobile IP and requires no support from the networks to which the mobile host connects. The solution involves an ‘ABC daemon’ on the mobile host and a ‘remote NAT’ that is used to provide a consistent interface to the remote host during a connection oriented application. We also describe the prototype implementation and preliminary experimental results.