I've got four T1 lines that are bonded together apart of a PPP multilink group. It's the same on both sides, with the actual serial interfaces not having IP addresses and the multilink interface doing all the L3 talking. A few days ago one of the T1 lines went down. I checked out the controller on side A and all was good. I checked out the controller on side B and all was good. The physical line -being the controller and the link were Up, but the protocol on the serial interface was down. I opened a ticket with the LEC, and they found nothing wrong. I did BERT tests for five minutes on both ends, with the far end looped towards me, and absolutely no bit errors. I also changed the DS1 cards on both ends thinking it could be the controllers. At this point, I've done everything including rebuilding the channel groups to re-establish the Serial interfaces but got no results. The only errors I can find are done via sh int serial1/0/1:1, which shows input errors, a few CRCs, a few frames and a whole lot of Aborts; everything on the output side is 0. I know the Aborts and the errors are bad, but I've checked the config so many times and verified it's not the circuit that I cant figure out whats wrong.
Here's the config on the A side:
no ip address
on the B side:
no ip address
ppp multilink group 1
Also: on the B side I don't see any errors on the sh int serialx/x/x:x
Help is appreciated. Thanks