It's not credible to suppose that Comcast's network is built around equal exchange of traffic. The broadband connections they provide are wildly asymmetrical, often by an order of magnitude.
"[W]hen we ask [ISPs] if we too would qualify for no-fee interconnect if we changed our service to upload as much data as we download—thus filling their upstream networks and nearly doubling our total traffic—there is an uncomfortable silence," Netflix CEO Reed Hastings wrote last month. "That's because the ISP argument isn't sensible. Big ISPs aren't paying money to services like online backup that generate more upstream than downstream traffic. Data direction, in other words, has nothing to do with costs."
And then there's this: http://arstechnica.com/information-technology/2014/04/bittor...
"[W]hen we ask [ISPs] if we too would qualify for no-fee interconnect if we changed our service to upload as much data as we download—thus filling their upstream networks and nearly doubling our total traffic—there is an uncomfortable silence," Netflix CEO Reed Hastings wrote last month. "That's because the ISP argument isn't sensible. Big ISPs aren't paying money to services like online backup that generate more upstream than downstream traffic. Data direction, in other words, has nothing to do with costs."