Have a 7206 router as the 'core' of our wan. It's running a T-3 card
w/ channelized T-1's on it (19 of them).

Everything's been fine for years, now having an issue where one site
cannot connect. Have not changed anything on this router in a LONG
time, but starting late friday afternoon, this site cannot connect.

We can't see their network at all, even the actual T-1 network which
consists of our subinterface and the interface on their router.

Of course the guy we deal w/ on the other end says everything is up &
the problem is on our end (std response). I'm just having a hard time
finding where the problem is, when all of our other T-1s are fine, and
the config on our router is consistent between T-1s.

Any ideas?