I have connected two c7200 back to back over gigabit interfaces and enabled MPLS on them to act as PE routers. I have also created two virtual circuits between them, one over ethernet subinterfaces, the other over serial interafces.
Both virtual circuits come up and I can ping the CE routers from each other on their ethernet interfaces but not on their serial interfaces.
When I display serial interfaces on PE routers, I see up-up, LCP closed as expected. On CE routers, serial interface shows up-down. Situation does not change when HDLC is used instead of PPP.
MTU on PE routers have been changed to 1526, but the situation has not changed.
Would you mind posting your configuration please? Also, if you are configuring MPLS L2 pseudowires, can you attach the output of the show mpls l2transport command?
What i understood is the issue between your PE and CE Serial connection, where line protocol is down, have you configured the Clock rate on the DCE end of the interface ??