IMS 扫盲书。 PART I IMS ARCHITECTURE AND CONCEPTS 1 1 Introduction 3 1.1 What is the Internet Protocol Multimedia Subsystem (IMS)? 3 1.2 Example of IMS services 5 1.3 Where did it come from? 6 1.3.1 From GSM to 3GPP Release 7 6 1.3.2 3GPP Release 99 (3GPP R99) 6 1.3.3 3GPP Release 4 7 1.3.4 3GPP Release