Internet telephone and, in general, Internet multimedia, is the new revolution today and SIP is the key protocol which allows this revolution to grow. This book explains, in tutorial fashion, the underlying technology that enables real-time IP multimedia communication services on the Internet (voice, video, presence, instant messaging, online picture sharing, white-boarding, etc.). Focus on session initiation protocol (SIP), but also covers session description protocol (SDP), Real-time transport protocol (RTP), and message session relay protocol (MSRP). Throughout this book, in addition to snippets of code, the reader is guided to build a simple but functional IP soft phones that show the theory with practical examples. This book includes an IP multimedia from a theoretical and practical point of view focusing on letting the reader understand the concepts and put them into practice using Java. It includes lots of pictures, diagrams protocols, UML sequence diagrams and code snippets that allow the reader to quickly grasp the concept. KEY FEATURES * Focus on HOW multimedia communications over the Internet works to allow readers to truly understand and apply technology * Explains how SIP works, including many programming examples so that readers can understand abstract concepts such as SIP dialogs, SIP transactions, etc. look at a variety of enhanced communications services related to SIP allows the reader put this technology in practice. * Includes nearly 100 references to the latest standards and activities in the IETF working group, bringing the reader fully up to date.