address-The care-of address is the termination point of the tunnel toward the mobile node when it is not in the home network. Correspondent node-The correspondent node is the device that the mobile node is communicating with, such as a Web server. To accomplish seamless communication between a mobile node device and a packet network, such as the Internet, Mobile IP establishes the visited network as a foreign node and the home network as the home node. Mobile IP uses a tunneling protocol to allow messages from the packet network to be directed to the mobile node's IP address. This is accomplished by way of routing messages to the foreign node for delivery via tunneling the original IP address inside a packet destined for the temporary IP address assigned to the mobile node by the foreign node. The home agent and foreign agent continuously advertise their services on the network through an agent discovery process, enabling the home agent to recognize when a new foreign agent is acquired and allowing the mobile node to register a new care- of address. This method allows for seamless communications between the mobile Mobile IP Home Network Foreign Network Server Switch Foregn Agent Agent Workstation Mobile Node Mobile Node Foreign Location Home Location Care-of Address Home Address Routers #1-to home address Internet or IP Network #2-tunnel to foreign agent Router care-of address Remote Client #3-to mobile node (Correspondent Node) Figure 16.1 Elements of a Mobile IP network node and applications residing on the packet network, providing seamless, always- on connectivity for mobile data applications and wireless computing. The many applications for Mobile IP include support of VoIP, streaming video and audio, VPN clients (who can stay connected to the office without having to reauthenticate themselves when they switch networks), access to all database applications using remote connections (e.g., in customer relationship management and similar applications), any kind of peer-to-peer applications on the Internet, chat