It doesn't work. The first information from sunrise (they used to give Fritz Box routers) was: "You won't get a Fritz Box router from us, but you can buy one yourself". So I bought one, but it can't be installed without access data from sunrise. So I lost time again in the call centre, now they first say it's the wrong router. But it's the right one, it could connect to sunrise. Next call, now they say it could take 2-3 hours for the thing to fetch the access data itself. Not true, of course. Then in the shop the promise that they might make an exception and get back to me, which of course doesn't happen. Then the definitive information that sunrise NEVER gives out the access data for a foreign router. Conclusion: Due to the usual poor support from sunrise, I wasted many hours and bought a useless router.

No, you can't. Sunrise does not support foreign routers