have a 3600 series router configured for frame-relay. T1 has 6 PVCs configured on this router in multiple states. All has been in service & working fine for years. 4 days ago started experiencing an issue. Can log in to the primary router and all routers where the PVCs are configured but if we try to access devices on the network or if I try to do a sh run or sh frame p router sits at the prompt and eventually times out. I have had the T1 tested and not indicating any errors. Any thoughts?