In This Chapter
Supporting VoIP over the PSTN
Controlling millions of calls
Understanding quality of service issues
In previous chapters, I discuss the beginnings of the public switched telephone network, or the PSTN. I also outline some history of the PSTN. Perhaps the most significant piece of history was the development and deployment of digital telephony services in the early 1960s. Since then, the PSTN has experienced other significant transport line and service developments, including ISDN and DSL. In the consumer market, these newer transports and services are provided over the existing POTS line, providing greater bandwidth.
Today the PSTN is also known simply as the switched network . This chapter provides you with the details you need to understand the other transports in the switched network. Also covered are VoIP services available on the PSTN and how calls are controlled on the PSTN.
Understanding How the PSTN Supports VoIP
No other network in the world can compare to the reliability of the U.S. switched network. (Granted, a handful of disasters have disrupted PSTN services in specific regions, but these are the exceptions, not the rule.) ...