said by ISurfTooMuch:While you may be correct on the issue of whether the data leaves their network or not, I wonder if a big file transfer between two AT&T customers is also going to be exempted. This would actually be pretty easy to set up and test. If I were a betting man, I'd wager that the meter would indeed be running.
So long as the data doesn't traverse the Internet, it isn't subject to network neutrality, so AT&T can choose to count it or not, as they see fit.