ABSTRACT
This chapter reviews architectures, protocols, features, quality-of-service, and security issues associated with traditional circuit-based landline and wireless voice communication. It examines convergence architectures, the effects of evolving standards-based protocols, new quality-of-service methods, and related security issues and solutions. Voice communications is in the midst of an evolution toward network convergence. Over the past several decades, the coalescence of voice and data through the circuit-based, voice-centric public switched telephone net-work has been limited. Communication between central offices connected via trunks is performed through a hierarchy of switches related to call patterns. Many signaling techniques are utilized to perform call control functions. Carriers experienced fraud prior to the proliferation of SS7 out-of-band signaling utilized for the communication of call establishment and billing information between switches. Threats to voice communication systems increase given the move to the inherently open Internet.
