T-Mobile announced today that it’s giving away a 12 months of DirecTV Now, AT&T’s new live TV service, to customers who switch from AT&T. The company says you’ll only need to migrate one number to T-Mobile and it will give you a $35 credit on your bill for the next year. However, you will have to sign up for T-Mobile One, the company’s confusing new unlimited plan, and open two lines with the company. Also, the $35 credit is the price of DirecTV Now’s cheapest plan, and that plan does not include add-ons like HBO or select sports channels from higher-tier plans. The full details of the promotion can be found here.

The goal, of course, is to try and publicly poke holes in AT&T’s mobile offering. Since the launch of DirecTV Now, T-Mobile CEO John Legere has been openly bragging about his company’s commitment to the potentially net-neutrality-violating practice of zero-rating, which exempts select internet services from counting toward a customer’s data cap. AT&T is zero-rating DirecTV Now for customers who use its cell network, and the practice could be harmful to the open internet. Nonetheless, Legere sees zero-rating as a benefit it offers, and T-Mobile has pretty much written the book on how to get away with it using its Binge On and Music Freedom initiatives.

1/ A few weeks ago, @ATT high-fived themselves for zero-rating #DTVNow, but guess what??? We already do that to all video w/ #TMobileONE! — John Legere (@JohnLegere) December 15, 2016

So while this new promotion might seem like a bit of corporate trolling — and it definitely is — there is more at stake here. Large telecoms are trying to outdo each other when it comes to giving away stuff for free, sometimes in ways that may have lasting ripple effects on the state of the internet. And no company loves to up the ante more than T-Mobile.

Update 3:23PM ET, 12/15: Clarified that T-Mobile’s promotion involves signing up for its new unlimited plan, as well as opening two lines.