It's a pleasant dream, but the reality is that while you can escape the tyranny of long distance charges, it will still cost something. You have to pay for bandwidth and equipment, and invest some time and skill in running your Asterisk server. And the telcos are understandably unhappy at the idea of losing all that revenue, even as we still use their wires. I can't predict how they will ultimately react to the upheaval caused by VoIP and Asterisk, but something is going to change sooner or later.

Whatever the future brings, for now you can enjoy saving money and having greater flexibility by peering with other Asterisk servers. Suppose you have far-flung branch offices, or vendors or other business partners that you need to talk to a lot. You can set up your own private network of Asterisk servers and bypass the telcos entirely. In typical Asterisk fashion there are a number of ways to do this. We will look at two: using DUNDi, the Distributed Universal Number Discovery protocol, and using a central directory service like Free World Dialup. Today we'll learn how to use Free World Dialup. DUNDi is distributed protocol that eliminates the need for a central provider; we'll learn how to implement it next week.

Source: LinuxWorld