Securing VoIP Networks: Threats, Vulnerabilities, and Countermeasures

Chapter 2. VoIP Architectures and Protocols

The transition from legacy Public Switched Telephone Network (PSTN) into communications using IP-based networks has sparked the development of real-time multimedia applications with many sophisticated features at a lower cost. VoIP is one of the applications that provides global interconnectivity at a low cost. And in cases where calls are established between peers in an IP network the cost is negligible or non-existent. This chapter focuses on the most commonly used architectures of VoIP communications and discusses the protocols and components that are used to support VoIP and generally any multimedia application. Chapter 10, “Provider Architectures and Security” and Chapter 11, “Enterprise Architectures ...