What's causing CRC errors on serial interfaces in multilink T1 group

Unanswered Question
Aug 26th, 2008

I have a 2xT1 running multilink PPP. When I "show interface serial xxx" for the two serial interfaces, both are showing increamenting CRC errors. What can be the cause of it?

Thanks a lot

I have this problem too.
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JORGE RODRIGUEZ Tue, 08/26/2008 - 14:19

There could be number of reasons.

Have a look here , go over the check list.


You may also want to check the output of controllers


show controllers t1

look for line code violation, path code violations, if any clear counters , clearing counters will clear serial counters as well but will give you sort of a start base line , if line code violations or path violation I would recommend to contact your circuit provider to check on the circuit, this could be contributor of crc. Go over the link above for other reasons.



Rupesh Kashyap Tue, 08/26/2008 - 14:21

Hi ,

This is due to two problems

1. Your Duplex & Speed of physical interface is mis-matching

2. There is physical Cable problem

gwhuang5398 Wed, 08/27/2008 - 08:20

I found maybe the clock source on the interfaces are not configured right. Right now both end of the T1 are "clock source local". I'll try changing one end to "line"

Thanks a lot


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