chapter 1 Introduction -- chapter 2 Internet Telephony: The Evolution to a Service-Oriented Architecture -- chapter 3 Background: Providing Telephony Service -- chapter 4 Comparative Analysis of Signaling Protocols -- chapter 5 Crossover Services Originating on the Internet -- chapter 6 Crossover Services Originating on the Public Switched Telephone Network -- chapter 7 Smart Spaces in the Telecommunications Domain -- chapter 8 Conclusions.