David Beckemeyer has a nice post clarifying the distinction between the current voice over broadband deployments and “real” end-to-end voice over IP (via James Seng).
However, it’s important not to dismiss the former because it relies on
interconnection with the old public switched telephone network.
Voice over broadband, which is what Vonage and most of the recent
carrier announcements use, crystallizes the new reality of voice as an
application. The application provider doesn’t need the
cooperation of the network operator, just as eBay or Amazon.com didn’t
need to pay America Online for the privilege of offering their sites on
the Web. Of course, the network operators don’t like that
separation of applications and transport. That’s why they are
pushing for regulatory changes that would allow them to use their
control over last-mile pipes to ban or tax third-party