In order for VOIP to work, there must be a PBX switch at most locations around the country, in order to convert the data packets back into analog and be routed through the local phone lines. That way VOIP customers can call analog phone customers.
Ok, so there are many providers out there, and I know they don't all own such switches around the country. They must be either renting/leasing those switches, or are just reselling. How does this work and which companies handle this?
Second question. For internal routing, such as when VOIP user A calls VOIP user B, the signal is obviously not being converted back into analog and passed through the local phone company. My question is, how is the signal able to find its way to user B? By IP address? What if user B's IP is dynamic or he moves his IP phone to another network connection? I'm guessing that whenever the phone is plugged in, it's sending a signal back to the company telling it its IP address.