I have a Cisco 3640 router. On this router I have 12 serial ports and 1 fastethernet port.
Only 6 of the serial ports are active, the others are shutdown. 2 of the 6 are connected to T1's to the same router on the other end and configured to load-balance the two liones. Also connected between these routers is a ISDN line setup as a Dial-On-Demand for backup.
The problem is that at random times, the core router stops routing to the endpoint with the 2 T1's. The router continues to route to all other routes including other far ends. Just to the one destination does it stop. From the ethernet interface side, I cannot ping through the router, but from a telnet seesion into the core router I can ping all locations.
It seems the route to the one destination will stop going through the router. If I reset the ethernet interface on the core router (the place where the routing stops) routing will resume. Any Ideas on what to look at or for?