In recent years, the wireless communication technology rapidly develops and the mobile devices are in widespread used. The IETF Mobile IP working group has proposed the Mobile IP to support IP mobility, and it keeps a session connected when a mobile node roams from subnet to subnet. Novel network type is the mobile ad hoc network (MANET) which is formed by a set of mobile devices with limited power and using multi-hop communication capabilities without through any infrastructure. In order to move to an all-IP environment, we use Mobile IP to provide global Internet connectivity for ad hoc...