T-Mobile’s Binge On Optimization is Just Throttling, Applies Indiscriminately to All Video

The Electronic Frontier Foundation decided to test T-Mobile's Binge On Optimization by posting a video on one of tour servers and tried accessing it via a T-Mobile LTE connection using various methods and under various conditions.

The first result of our test confirms that when Binge On is enabled, T-Mobile throttles all HTML5 video streams to around 1.5Mps, even when the phone is capable of downloading at higher speeds, and regardless of whether or not the video provider enrolled in Binge On. This is the case whether the video is being streamed or being downloaded—which means that T-Mobile is artificially reducing the download speeds of customers with Binge On enabled, even if they’re downloading the video to watch later. The second major finding in our tests is that T-Mobile is throttling video downloads even when the filename and HTTP headers (specifically the Content-Type) indicate the file is not a video file. We asked T-Mobile if this means they are looking deeper than TCP and HTTP headers, and identifying video streams by inspecting the content of their customers’ communications, and they told us that they have solutions to detect video-specific protocols/patterns that do not involve the examination of actual content. Our last finding is that T-Mobile’s video “optimization” doesn’t actually alter or enhance the video stream for delivery to a mobile device over a mobile network in any way. This means T-Mobile’s “optimization” consists entirely of throttling the video stream’s throughput down to 1.5Mbps. If the video is more than 480p and the server sending the video doesn’t have a way to reduce or adapt the bitrate of the video as it’s being streamed, the result is stuttering and uneven streaming—exactly the opposite of the experience T-Mobile claims their “optimization” will have. In other words, our results show that T-Mobile is throttling video streams, plain and simple.