Off-world communication systems are serious business, especially for sending messages between entire star systems several lightyears apart. Fortunately, the router systems humanity has deployed is able to bridge most communication gaps down to milliseconds of delay. The tech itself requires a lot of power as well, and is highly specialized, so it makes for a significant target in warfare.

Art by the amazing Lionel Schramm https://www.artstation.com/lionel_schramm