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New Member

The Serial Interface reseting

I have cisco 3660 router for my WAN connection and I am using 12.1(3)T cisco IOS for it but problem is that I am facing lot of CRC at my router serial.I have checked my local lead and as well as my whole physical connetivity.The physical connectivity of both end routers is good.

since I am using dynamic routing between routers and sometimes a routing loop is present at remote end.when I checked the router CRC(from my end router) at the time of routing loop then I watched my serial interface is reseting again and again when routing loop is occured and after some time period hardly 1 to 2 minuts the routing loop is finished.

I thing this routing loop is occured due to serial interface reseting.

since I have 1MB data circuit (bandwidth) and I am using only 50% of whole bandwidth due this problem and bandwidth is stuck at 50 to 60% of whole bandwidth.

I dont know why the serial interface is reseting.Kindly help me and solve my problem as soon as posible.


Re: The Serial Interface reseting

The focus of this board is Network Management of Virtual Private Networks, however, there are a number of professionals online who may be able to assist you. We are always considering additional forums for such topics and I will make a note of your post.

If you don't get a suitable response to your post, you may wish to review our resources at the online Technical Assistance Center ( or speak with a TAC engineer. You can open a TAC case online at

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.

Re: The Serial Interface reseting

eventhough u have said that the cable is ok.. i think the problem is with the cable.. try swapping the cable or interface to another one.. bcoz crc error can occur due to noise.. if the cable is not shielded properly, then bits may be changed due to interference with noise.. and CRC errors occur.. try doing that.. and please acknowledge this mail..

bye 4 now


New Member

Re: The Serial Interface reseting

Try grounding the chasis of the router

New Member

Re: The Serial Interface reseting

I am sure you have checked this,still check the duplex on both ends. I have seen routers giving problem if they are set to auto negotiate. I will say force them to 10 or 100 half/ full at both end. they should be same at both end.

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