Best thing you can do is if you know how to monitor your net traffic see if anything is fluctuating weirdly. Even if one can say "but everything else work!" think about this: Even if you have a shoddy net connection you can still stay connected to and use Skype, as well as any other programs yet regular net browsing won't work. This problem I don't have currently but whenever I do get a D/C spree it's almost always due to ISP settings based on what I've found out.

The routing of some ISPs to Japan is in such an odd route that a lot actually pass through the eastcoast (which is being battered atm) then europe then on it's way to Japan. SE will always state if there's a problem with servers or it's stability or everything is crashing outside of wards because no one would be able to connect or stay connected to the servers, so there's a good possibility there's ISP issues atm, I know I've been having unrelated XIV disconnect issues lately.