Distributed Denial of Service. Basically what you do is you flood a server with garbage requests-your computer, when it accesses a web page, sends a little packet that asks "are you there?" to the server. If you have a bunch of computers all flooding a server with those "are you there?" packets, the servers eventually cannot handle legitimate users that are also sending those "are you there?" packets. That's the short version, it's slightly more complicated then that, but I figured this attack would come with the Empire shutting down communications. You do that by crashing the network, and the fastest, bluntest way to do that is to DDoS it.