[c-nsp] CRC Errors on Ethernet Router

[Kasper Adel]

Hi,

Usually when Cyclic Redundancy Check (CRC) errors are incrementing in the
show interface command output, it indicates that the cyclic redundancy
checksum generated by the originating LAN/WAN device does not match the
checksum calculated from the data received. On a LAN, this usually indicates
noise or transmission problems on the LAN interface or cable. A high number
of CRCs is usually the result of collisions or a station transmitting bad
data.

So we can safely assume that CRCs are a very critical alarm and it can not
be ignored so I don’t think there should be a threshold in general, the NMS
should monitor interfaces for CRCs and if the number increments then an
immediate check is needed, we are talking on the core links here. So we cant
wait till the counter increments.

Once we have CRCs, then we have a bad cable, port or router and this needs
immediate attention.

Regards,
Kim

On Wed, Feb 23, 2011 at 3:53 PM, Harold 'Buz' Dale <buz.dale at usg.edu> wrote:

> First thing I would do would be to check for a duplex mismatch and then
> check the wiring (either by replacing the cable if it's a simple patch or
> using a cable tester over the span.) You might also just physically trace it
> and see if someone decided to hang a fluorescent light off of it or
> something too.
> Luck,
> Buz
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:
> cisco-nsp-bounces at puck.nether.net] On Behalf Of alex nyagah
> Sent: Wednesday, February 23, 2011 6:19 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] CRC Errors on Ethernet Router
>
> Hi All,
>
> I am noting CRC errors on my Ethernet port on my cisco router, what could
> it
> be causing it..
>
> --
> **
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