Chapter Overview

When a node changes its location, not only does it change its links, but most often, it also changes its network of attachment and, as a consequence, its IP address, too. The mechanisms that exist in IPv4 and IPv6 for a node to automatically obtain a new address cannot prevent existing connections to be terminated when the node moves.

A mobile node is an Internet-connected device whose location and point of attachment to the Internet may change frequently. It can be a cellular phone, a handheld device, a laptop computer, a router, and so on. Mobile IP (MIP) is a standard that enables a mobile node to arbitrarily change its location on an IP network while maintaining existing connections.

Full terminology is provided in RFC 3753.

This chapter focuses more than other chapters of the book on discussing the protocol aspects of this rapidly evolving technology. It also presents its current trends and potential deployment opportunities.

From "Internet car" to "fleet in motion," from "personal network" to "home network," deployment experiments of IPv6 mobility carry so many promises that one can expect this technology to become a key enabler for IPv6 success in the near future (see the "Practical Use Cases" section of this chapter for details on these examples).

This chapter explores IP mobility starting from the established standards to a vision of pervasive computing and networking. The following topics are covered in respective sections:

• The "IP Host Mobility" section reviews Mobile IPv6 technology, as well as current IP mobility limitations and challenges.

• The "Network Mobility" section reviews network mobility, and presents a set of deployment examples, mostly technology experiments and previews.

• The "IP Mobility in Nonmobile Scenarios" section covers areas where the technology can be used outside the mobility context, such as for hiding the topology of a private network, or building communities of interest.

• The "Next Steps in Mobility" section covers improvements being currently discussed at the standards bodies, such as fast movement detection, and finishes with a short description of the pervasive computing vision.