[hug]

Yes and no.

An AD DC can be offline for as long as 60 days (by default, since the actual length of time is covered by AD's tombstone lifetime, which is configurable) and recover just fine, assuming you're not to worried about the intrinsic fact that changes at or affecting that site aren't replicated immediately.

And assuming you plug the site back into the network somehow, under your 60 day limit, AD will largely just keep truckin'. If you've got sites that are offline for more than 60 days at a time due to unforseen circumstances, well, maybe those sites need some other solution.

Spotty connectivity is just fine for AD, though, especially if you're designing things properly.