CCIE Fundamentals: Network Design and Case Studies, Second Edition

Appendix G. Packet Voice Primer

Overview

The telephone is the most pervasive of all technology instruments, particularly in business. Every day, businesses make literally thousands of calls, and although the cost of an individual call is often low, the accumulated cost to business is significant.

For many companies, a portion of that cost is avoidable. Traditional public voice telephony is a complex tapestry of tariffs and subsidies, often resulting in situations where calling from "A" to "B" costs a fraction of the rate from "B" to "A." Companies have long relied on private, leased-line networks to bypass public telephone charges, but rates applied to leased lines are also often high. Many have looked for alternative strategies.

In today's networking, ...