Securing VoIP Networks: Threats, Vulnerabilities, and Countermeasures

Chapter 1. Introduction

The convergence of land-line, wireless, and Internet communications has stimulated the development of new applications and services which have revolutionized communications. The interconnection between PSTN (Public Switch Telephone Network) and IP (Internet Protocol) networks is referred to as the Next Generation Network (NGN). And the interconnection of Internet and wireless is referred to as IP Multimedia Subsystem (IMS). Both architectures play an important role in our evolution from traditional telecommunications to multimedia communications. You might also have heard of the term triple play, which refers to a service provider’s ability to offer voice, video, and data to subscribers as a bundled service. Similarly, ...