• by Wendy Davis  @wendyndavis, November 8, 2018

The major U.S. wireless carriers are slowing streaming video traffic, according to a new report by researchers investigating net neutrality.

“Net neutrality violations are rampant,” states the report, issued by researchers at Northeastern University, University of Massachusetts-Amherst and Stony Brook University. They add the throttling practices they observed are creating “an unlevel playing field for video streaming providers while also imposing engineering challenges.”

The report is based on data collected this year from more than 100,000 people who use the Wehe app. Most U.S. carriers -- including Verizon, AT&T, Mobile and Sprint -- were found to throttle at least one online video provider. 

No carrier throttled all video providers, according to the report. The throttled speeds varied based on factors including subscribers' plans, the report says. In many cases, the throttled connections were 1.4 Mbps -- which is around the minimum needed to stream standard definition video, but too slow for high definition.

Until this June, the Obama-era net neutrality rules prohibited carriers from blocking or throttling traffic. The Federal Communications Commission officially repealed the Obama-era rules in June, replacing them with a mandate that carriers disclose their traffic management practices.

But even under the prior rules, carriers were allowed to engage in reasonable network management practices -- which could include slowing down mobile video. The Obama-era FCC specifically approved of T-Mobile's BingeOn program, which involves throttling video to 1.5 Mbps.

The new report says T-Mobile currently begins to stream video at 25 Mbps -- a process the report calls “boosting” -- but then slows down traffic after a short period of time that varies by provider. T-Mobile slows down Netflix and NBC after they have streamed 7 MB of data, but slows down Amazon Prime after 6 MB. T-Mobile doesn't throttles YouTube without “boosting” it at all, but doesn't throttle or boost Vimeo, according to the report.

The researchers say these disparities may skew performance. “There is fundamentally no way to treat all video services the same (because not all video services can be identified), and any additional content-specific policies -- such as boosting -- can lead to unfair advantages for some providers, and poor network performance for others,” the report states.

Researchers also say Sprint is slowing mobile broadband connections to some customers -- primarily ones with Android devices -- when they use Skype.

“Skype throttling was detected regularly over the course of the year, and spread geographically across the US,” the report states.

Sprint denies slowing Skype traffic. “Sprint does not single out Skype or any individual content provider in this way,” a company spokesperson said in an email to MediaPost. "We are not throttling Skype, and our own network tests found no degradation in Skype user experience."

Researchers said they weren't able to reproduce throttling with the data plan they purchased, leading them to speculate that Sprint only slowed down service to people with certain plans.