Cisco Cisco IOS Software Release 12.4(9)T

agent advertisement—An advertisement message constructed by an attachment of a special extension 
to a ICMP Router Discovery Protocol (IRDP).

care-of address—The termination point of the tunnel to a mobile node or mobile router. This can be a 
collocated care-of address, by which the mobile node or mobile router acquires a local address and 
detunnels its own packets, or a foreign agent care-of address, by which a foreign agent detunnels packets 
and forwards them to the mobile node or mobile router.

foreign agent—A router on the visited network of a foreign network that provides routing services to 
the mobile node while registered. The foreign agent detunnels and delivers packets to the mobile node 
or mobile router that were tunneled by the home agent of the mobile node. For packets sent by a mobile 
node, the foreign agent may serve as a default router for registered mobile nodes.

home agent—A router on a home network of the mobile node or that tunnels packets to the mobile node 
or mobile router while they are away from home. It keeps current location information for registered 
mobile nodes called a mobility binding.

home network—The network, possibly virtual, whose network prefix equals the network prefix of the 
home address of a mobile node.

mobile network—A network that moves with the mobile router. A mobile network is a collection of 
hosts and routes that are fixed with respect to each other but are mobile, as a unit, with respect to the rest 
of the Internet.

mobile node—A host or router that changes its point of attachment from one network or subnet to 
another. A mobile node may change its location without changing its IP address; it may continue to 
communicate with other Internet nodes at any location using its home IP address, assuming that 
link-layer connectivity to a point of attachment is available.

mobile router—A mobile node that is a router. It provides for the mobility of one or more entire 
networks moving together, perhaps on an airplane, a ship, a train, an automobile, a bicycle, or a kayak. 
The nodes connected to a network served by the mobile router may themselves be fixed nodes or mobile 
nodes or routers.

mobility binding—The association of a home address with a care-of address and the remaining lifetime.

registration—The process by which the mobile node is associated with a care-of address on the home 
agent while it is away from home. Registration may happen directly from the mobile node to the home 
agent or through a foreign agent.

roaming interface—An interface used by the mobile router to detect foreign agents and home agents 
while roaming. Registration and traffic occur on the interface.

tunnel—The path followed by a packet while it is encapsulated from the home agent to the mobile node. 
The model is that, while it is encapsulated, a packet is routed to a knowledgeable decapsulating agent, 
which de-encapsulates the datagram and then correctly delivers it to its ultimate destination.

See 

 for terms not included in this glossary.