A new study from Stanford University claims that T-Mobile's "Binge On" promotion violates key net neutrality rules and is "likely illegal."

The company's new promotion allows users to stream as many videos from streaming services as they want without counting the data toward monthly caps. The Stanford study says that the offering from T-Mobile is harmful to competitors, The Verge reports.

"T-Mobile's Binge On is aptly named - it feels good in the short-term but harms consumers in the long run," says Barbara van Schewick, the net neutrality expert and law professor who authored the Stanford study. "The program limits user choice, distorts competition, stifles innovation, and harms free speech on the Internet. If more ISPs offer similar programs, these harms will only grow worse."

'Binge On' Unfair for Some Providers

Schewick claims that "Binge On" is not fair for customers who want to use unsupported streaming services. The promotion supports Vevo TV for watching music videos, but YouTube and Vimeo are not supported. Customers who want to watch unsupported streaming services like YouTube would not receive unlimited streaming as they would on supported streaming services, giving an unfair advantage to certain streaming platforms.

Larger Providers Have Advantage

The Stanford study also claims that it is not as easy for companies to set up "Binge On" as T-Mobile claims and that the company is giving an advantage to larger streaming providers. Smaller providers and start-ups will struggle to get their content on "Binge On," the study says.

Schewick claims that the mainstream content provider Amazon Prime Video was not initially allowed to participate in the promotion. T-Mobile added the streaming service on Thursday.

Still, T-Mobile CEO John Legere thinks that "Binge On" can be a good thing for both consumers and providers.

FCC Must Decide on Violation

The FCC must decide if T-Mobile is violating the 2015 Open Internet order that was established to maintain net neutrality. That rule states that companies cannot block content, create fast lanes or throttle data. The Stanford study claims that T-Mobile is blocking content from some providers and giving other providers preferential treatment, violating the conditions of the order.