I'm having a major problem with a brand new Cisco 2951 router. The router is going to replace a Cisco 2811. Currently there are two P2P T1's connected to the 2811 configured with ppp multilink. When I move the circuits over to the 2951 they remain in a down / down state. If I loop the T1 controllers on the 2951 (via the "loopback local payload" command") then remove the loop the T1 circuits will come up and I can ping the router on the other end of the links. The problem is if the router is rebooted both circuits remain in a down / down state until the controllers have a loop applied then removed. I'm baffled as to why this is happening. The links are connected to separate VWIC's on the 2951 so it can't be a bad card since the problem is occurring on both. When the circuits are plugged back into the 2811 they come up and work perfectly. It is not a TelCo issue, it has to be something with the 2951. I have verified that the controller and interface configuration is identical between the 2811 and 2951 Both routers are configured for - Framing is ESF, Line Code is B8ZS, Clock Source is Line. The router on the other end of the circuits is configured the exact same. I have no idea why the circuits won't come up on the 2951. I don't understand why they will work if they are looped then unlooped. Unfortunately they won't stay up. I have tried both the 15 and 15.1 versions of the IOS.
Can anyone provide any insight as to why this is happening? Any assistance would be greatly appreciated.