Cisco Support Community
Community Member

WAN interface keeps going to Up/Down State

I have a point to point T1 between two cisco 2800 routers. Bellsouth admitted the circuit had breaks in it. They tested the line for 8 hours and traced the circuit back and repaired the line. But I still get line protocol as being down. I configured both routers to use ESP and B8ZS as was told to do so by Bellsouth. Also one router is set to internal clocking and the other router is set to line. I mean come on its a simple P2P line how hard can it get? The status will go UP/UP but drop back to UP/Down in about 10 secs. I also get huge frame errors and CRC's etc. Do you think its a failing WIC card or possible physical layer problem to the T1 Demarc? Thanks

Community Member

Re: WAN interface keeps going to Up/Down State

Normally it's a telco issue with what your describing, but just to be safe and test your WICs, I would do a local loopback test and replace any wiring possible. If you have access to a T Bird that would help isolate it the problem very quickly but I rarely see these in a switch room at most sites. Post a "show controllers T1" from one if not both routers.

Community Member

Re: WAN interface keeps going to Up/Down State

Thanks for the help. I proved it was not in my hands by taking the router out and bringing it to the field site and plugging a T1 crossover cable between the two routers and the interface came right up and worked flawlessly. Sad part is its the Telco's problem and they have tested, retested, and tested again and cant find the problem. It's amazing how the telco lies and tells the customer everything is working fine when its not. Just makes me have to do more work.

CreatePlease to create content