re: How could you possibly limit VOIP calls to certain servers?
I'm out of my depth here. Networking and internet design are not my strong suit. I understand that addresses can be forced to funnel through a specific server at the origin point. Beyond that, sky's the limit. I think nations like China and others use this technique to control access.
Now, if someone would just get a cheap, powerful satellite-only access system going for the small user. No dish, just a stub antenna. Would need a BIG satellite.