Chapter 1
IMS Vision: Where Do We Want to Go?
Third generation (3G) networks aim to merge two of the most successful paradigms in communications: cellular networks and the Internet. The IP (Internet Protocol) Multimedia Subsystem (IMS) is the key element in the 3G architecture that makes it possible to provide ubiquitous cellular access to all the services that the Internet provides. Picture yourself accessing your favorite web pages, reading your email, watching a movie, or taking part in a videoconference wherever you are by simply pulling a 3G hand-held device out of your pocket. This is the IMS vision.
1.1 The Internet
The Internet has experienced dramatic growth over the last few years. It has evolved from a small network linking a few research sites to a massive worldwide network. The main reason for this growth has been the ability to provide a number of extremely useful services that millions of users like. The best known examples are the World Wide Web and email, but there are many more, such as instant messaging, presence, VoIP (Voice Over IP), videoconferencing, and shared whiteboards.
The Internet is able to provide so many new services because it uses open protocols that are available on the web for any service developer. Moreover, the tools needed to create Internet services are taught at university and are described in large numbers of books.
A widespread knowledge of Internet protocols has an important implication: people who develop new services are the ones who ...
