Intermittently, I get a message that I am not connected to the internet, and I can see that the first of the three lights on the base station is not lit. It says Airport is connected, but there are no networks. Occasionally, if I unplug it, and plug it in again, everything comes back. Sometimes, it just reappears by itself. I am not sure whether this is an Airport problem, or a Cablevision problem. How do I check this out? Thanks, in advance.