In Atlanta, for example, Comcast provided hourly median download speeds over a CDN called GTT of 21.4 megabits per second at 7pm throughout the month of May. AT&T provided speeds over the same network of ⅕ of a megabit per second. When a network sends more than twice the traffic it receives, that network is required by AT&T to pay for the privilege. When quizzed about slow speeds on GTT, AT&T told Ars Technica earlier this year that it wouldn’t upgrade capacity to a CDN that saw that much outgoing traffic until it saw some money from that network (as distinct from the money it sees from consumers).

Source: Major internet providers slowing traffic speeds for thousands across US | Technology | The Guardian