AAA and Network Security for Mobile Access: Radius, Diameter, EAP, PKI and IP Mobility

5.1. Mobile IP

Mobile IP is widely proposed to be the protocol of choice to provide routing services to nodes that need to change their points of attachment to the network. The concept of Mobile IP is a lot like mail forwarding. While Joe Smith lives in Chicago and has a permanent address of "1000 Industrial Drive, Chicago", when he moves to live with his mother in Seattle at "10 Easy Street, Seattle" for two months, he simply notifies his local post office in Chicago about his temporary address in Seattle as a "care of" address. None of the people who need to send mail to Joe Smith during those two months need to know his temporary address. They simply send his mail to his permanent address. The local post office intercepts the mail and, based on the stored temporary address for Joe Smith, forwards his mail to his mother's house in Seattle. In the same manner, a host that is otherwise assigned an IP address by its local network may require further IP addresses and receive forwarding services while away from home:

• Home address: The home address (HoA) is a "permanent" IP address that is assigned to a mobile node (MN) by its home network, which is fixed and known to associated with the mobile node. The home address is attached to the home network, i.e. the network prefix of the HoA matches that of the home subnet. The mobile node should use this address and network prefix only when residing at its home subnet. If the mobile node moves to another subnet and still insists on using ...