IP is the prevalent standard for communications on the Internet. An IP address is used to route a packet from a source to a destination, possibly via intermediate routers. IP was designed at a time when computers remain at fixed location. An Internet address implicitly specifies a computer’s physical location.
The proliferation of mobile devices coupled with mobility proved that IP is incapable of supporting seamless mobility. An IP address can no longer be used to determine the location of a destination node, therefore, IP had to be extended to incorporate mobility support. Mobile IPv6 is a protocol that allows a mobile node to move from one network to another without losing its connection.
Most Internet traffic uses TCP connection, which is defined by the combination of IP address and port number at both endpoints. If any of these number changes, the communication is disrupted and has to be re-established. If a mobile node connects to a different access point to the network, it needs a new IP address.
Mobile IP allows a mobile node to move to a different connection point without changing its IP address by assigning the node two IP addresses, namely a home address (static and does not change) and a care-of address (changes depending on the network the mobile node is currently attached to). The handover is handled at the network layer.
