As such the basic idea of Mobile IPv6 is to provide a second IPv6 address to an IPv6 host as an identifier in addition to the address that is usually assigned to the node from the attached network as a locator. The second address is fixed to the home position of the host and never changes even if the host moves. The fixed address is called a “ home address. ” As long as the host uses its home address as its connection information, the connection between the host and other nodes will not be terminated when the mobile host moves.
The concept of a home address provides another useful feature to a host that supports Mobile IPv6. Any IPv6 nodes on the Internet can access a host which supports Mobile IPv6 by specifying its home address, regardless of the location of the host. Such a feature will make it possible to create a roaming server. Since the home address of the roaming server never changes, we can constantly reach the server at the home address. For example, anyone could run a web server application on a notebook computer which supports Mobile IPv6 and everyone could access it without any knowledge of where the computer is located.
Source of Information : Elsevier Wireless Networking Complete 2010