Mobility is ultimately the result of two combined elements:

• Seamless Roaming
  The key to seamless roaming, as perceived by the user, is to ensure that the user is required to authenticate only once to the network, regardless of how often their device later moves to a new subnet or network - whether that be a wireless access point, a physical jack in the wall, a hotel hotspot, or a cable modem. SecuredMobile performs any subsequent authentications to the infrastructure, thereby giving the user the seamless experience of a single, unified network.


• Application Continuity
  SecuredMobile employs the concept of virtual IP addressing to ensure that application sessions are kept active in the mobile environment. As the user moves across subnet or network boundaries, the SecuredMobile Connection Client on the device picks up each IP address that is dynamically assigned by the network. This is mapped to a static virtual IP address that is seen by the applications, thereby ensuring that applications do not detect the roaming activity and avoid disruption to the user session.

Protocol Wrapping to Protect the Wireless Connection
While TCP is a powerful protocol for wired connections, it has two main drawbacks for "hostile" connections such as wireless:

• TCP is not well suited to tearing down and re-establishing new connections rapidly enough to avoid application interruption. But this will happen frequently in the case of wireless signal strength that "yo-yos" between strong and weak.
• TCP incorporates various packet timers that slow the data flow if it senses a quality degradation in the link. In a wireless environment where connections quickly come and go, however, these timers will have the effect of slowing the overall link throughput.

To solve these and other problems, SecuredMobile creates a connectionless transport mechanism for carrying the application's TCP traffic. "Wrapping" the connection-oriented TCP traffic with the connectionless mechanism retains the benefits of TCP/IP while hardening it for the mobile environment. The net result is faster mobile throughput and network handoff that is fast and seamless.