[c-nsp] Need help troubleshooting CRC errors

[Gert Doering]

Hi,

On Thu, Sep 17, 2009 at 10:39:21AM -0400, Steven Pfister wrote:
> that pretty much every one of them is showing what I think is a
> rather high receive error count on the 3640 end of the OC3 connection,
> and it all seems to be CRC errors. Not much of any errors are
> showing up on the 8510 end of the OC3 connection. For example, one
> site yesterday late afternoon showed 63, 763 receive errors for
> the day. Several others were in the 20Ks. I'm not really certain
> what the cause might be, or where to start. Can anyone help?

Is there a carrier network in between?  In our cases, whenever we saw
ATM CRC errors, it was due to dropped cells in the carrier network
(overloaded).  If the receiving router cannot reassemble a packet due
to missing cells -> CRC error.

If the STM-1 is "direct", no carrier ATM gear in between (just SDH/SONET)
gear, it be a bad line.   In that case it won't be cell drops.

gert
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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