I have a DI 624 router. I've got a similar problem as to not being able to make connection frequently. I also noticed that every time the prolem shows up all the lights on the router go off and windows reports that network cable has been unplugged. Within seconds it come back on.
I have no clue as to what's going on. Anyway I've just reconfigured NIC setting. I don't know whether it solves the problem yet. I hope so.