If you need to know the IMS vision you need to read this book....The IMS (IP Multimedia Subsystem) is the exciting new technology that will merge the Internet with the cellular world. It will make Internet technologies such as the web, email, instant messaging, presence, and videoconferencing available nearly everywhere.The 3G IP Multimedia Subsystem (IMS) provides a thorough overview of the IMS and its technologies. Throughout, the authors first describe how each technology works on the Internet and then explain how the same technology is adapted to work in the IMS, enabling readers to take advantage of any current and future Internet service.Presents an introduction to the IMS - its goals, history, vision, the organizations involved in its standardization and architectureDiscusses the signalling plane of the IMS including protocols, such as SIP and Diameter, used between the IMS architectural entities. Also describes how the IETF developed these protocols and how they are used in the IMS architectureDescribes the media plane of the IMS and discusses Internet protocols that are not currently used in the IMS but may be in the futureProvides SIP-based service examples such as presence, instant messaging and Push-to-TalkEngineers, programmers, business managers, marketing representatives, and technically aware users will all find this book invaluable as it will help them to understand how the IMS works and the business model behind it.