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T1 CRC and FRAME Errors


Receiving a considerable amount for input - framing and CRC errors across 4 T1's we recently had install. It appears the issue is on the providers end but they and Verizon have been pointing the finger. Not a router guru by any stretch. But need to identify and correct this issue.

I understand that these are commonly caused by hardware problems but we have tested fine. Verizon tested fine from our house to isp on a loop so this points to problems on ISP's end. Of course, he says he's fine.

What can be causing these??



Re: T1 CRC and FRAME Errors

More than likely it is a carrier issue , If you have an external CSU give yourself a dte loop, you should see your interface go up up (looped) , then ping yourself with about 1000 ping 1500 byte size , If there are no drops get the carrier on the line and have him give you a loop toward yuour router from there closest test point, do the same ping test , if pings are good have them move back a test point if pings drop then there is a problem between the CSU and the first test point. Keep working with the provider using loopback tests eventually you will find the dirty segment. Make sure you are on the line with the carrier when they are testing .

New Member

Re: T1 CRC and FRAME Errors

Thanks for the reply. We pretty much did this yesterday with the Verizon tech that was here. I was present and could see that each test, Our closet back to us. Their closet back to us was good showing no line issues I assume. But the ISP refuses to accept that the problem is on his end or at least has no idea of what to look for and how to correct.

Very very frustrating.

Thanks again


Re: T1 CRC and FRAME Errors

You need to get all parties on the line at the same time , After verizon loops toward you have them turn the loop around and have the ISP ping themselves , they should see drops, It may not be an ISP issue aren'e they leasing the same line from Verizon ?

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