Mobile Inter-networking with IPv6 : Concepts, Principles and Practices

12

Dynamic Home Agent Discovery

No computer has ever been designed that is ever aware of what it’s doing; but most of the time, we aren’t either.    –Marvin Minsky

—

12.1 MOTIVATION

The Mobile IPv6 protocol allows a mobile node to discover its home agent without relying on static configuration. This is useful since the home network may undergo reconfiguration or renumbering that results in a "change of guards" so that a previously configured home agent may not be available for the mobile node. It is also often mentioned that dynamic home agent discovery is useful in balancing the load across multiple home agents in certain deployments. In addition to the mobile node discovering one or more home agents, the home agents can discover each other as well. Finally, home network prefix discovery is closely related to home agent discovery in which a mobile node can learn or refresh its knowledge of prefixes that are currently being supported.

This short chapter describes the essential parts of the Mobile IPv6 specification which deal with home agent discovery and prefix discovery.

12.2 HOME AGENT AND PREFIX DISCOVERY

12.2.1 Dynamic Home Agent Discovery

The mobile node may choose to perform home agent discovery at any time, and the events that cause it to perform the discovery operation are not specified. For instance, a configuration profile may force the mobile node to perform discovery ...