Mobility Support Using Mobile IP
An elephant is a mouse with an operating system. –Donald Knuth
In this chapter, we first discuss the mobility events and actions that take place in the seemingly simple process of a mobile node moving from one network to another. We then discuss how Mobile IP addresses these events, emphasizing the concepts. Many of these events and actions are then presented in great detail in the subsequent chapters.
As always, the IP address used by the mobile node on a visited network is called the "care-of address"
5.2 MOBILITY EVENTS AND ACTIONS
We can identify several relevant events that are important for mobility management at the IP layer:
• Link detections
• Link establishment
• Subnet detection
• Care-of Address allocation
• Access authorization
• Enabling packet forwarding
• Informing correspondent nodes about the new location
• Upon returning home, taking appropriate actions
Some of these do not require network-layer support in every instance. For instance, the method used for link detection is typically specialized for the kind of physical link involved. However, when a link is detected, it may trigger certain network-layer activities.
Some mobility events are not really within the design space of Mobile IP. In particular, due to process considerations and in order to focus the Mobile IP effort within the IETF, Mobile IP does ...