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New Member

Many CRC and Frame Errors

I have a P2P link between a 2610 and a 2621 router that is experiencing heavy CRC and Frame errors. We replaced the 2621 router outright with an 1841 thinking the issue was on that end. When we did this, the site went down completely until we swapped it back(the 2621 will bounce, but never go down completely). I have read that these errors point to bad hardware, could it be the router module on the 2610? That router has another P2P and a frame-relay connection that don't seem to have problems, so the error would most likely have to be in the module itself. We have also tested the cabling from the 2621 to the dmarc and it was fine, and telco says there is nothing wrong with the circuit. Any advice would be greatly appreciated.



Re: Many CRC and Frame Errors


Do you have any spare WIC cards to test? CRC errors are always due to some physical problems, either with the circuit, or with some modems/router ports connected to the circuit.. you can actually do the following things:

1) Check the local DOT patch cable.

2) Check the modem if it works fine.. see if you can generate some error messages to be seen on the modem..

3) check the V.35 cable going from the modem to the router.. change it if possible and see..

4) u said u already had a working P2P link.. During off peak hours, try swapping the cable to the working WIC slot and see if the CRC is increasing.. This will eliminate all your doubts..

5) If the CRC doesnot increase with the working WIC, you can swap a new WIC and see if the CRC stops...

6) Really not sure why your 1841 circuit does not come up !!!! have u configured it right? it should work with any router, since the WIC cards are forward/backward compatible..

Hope this helps.. al the best.. rate replies if found useful..


New Member

Re: Many CRC and Frame Errors

Thanks Raj, Apparently we have already tried another module and that one also had problems. We have an open slot on the router, and another module, so we will try that and hopefully it is the slot. I appreciate your response


Re: Many CRC and Frame Errors

Get your Telco to come out and "Prove the SmartJack/NIU" ... this involves putting a hard loopback device in the equipment side of the SmartJack.

The "backside" (equipment side) of the SmartJack can be bad, but would be missed by conventional loop-up by Telco (the loop is in the "middle" of the SJ/NIU).

As an alternative, make sure that loop is enabled on that interface, and ask them to test to the CSU.

Another alternative is to put in a hard loop at the end of the cable that plugs into your CSU/WIC (1->4, 2->5, 4->1, 5->2) and ask them to test to the CSU.

If the tests pass (five patterns, five minutes or so each), then it's probably your WIC.

Good Luck