I've been working with my ISP (Time Warner Cable) since FFXIV release. I get disconnected usually about 30min to 1hr (some days it is worse, like today).

One of the tests I did was to tracert to the FFXIV server. I then ping'd the first IP past my gateway (a TWC internal IP). Whenever I disconnect from the game (90000) I see about 1-4 "request timed out" in the command log. Which makes me think it is an ISP issue. But! I ran this test while connected to the game server for about 12 hours. I lost about 1.5% of packets. However, after I shut down the game, I lose about 0.2% of packets. Not sure what is up with that...

Another thing, in FFXI, when your connection was spotty, you'd go "LD/redball" for 60 seconds before the game server would kick you. Here in FFXIV? Seems like it is 1-2 seconds before disconnect. Quick patch on their end would be to extend the "disconnect timer."