[c-nsp] ATM CRC errors

[Andy Dills]

On Wed, 27 Oct 2004, James Hamilton wrote:

> Hi there, we've got an ATM DS3 to Qwest (our telco) for Qwest based T1s and
> DSL.  It's taken ~588 input CRC errors in the last 20 minutes.  The count for
> the last week was ~140,000 CRC's.  I've been unable to match these CRC errors
> to the counters for my interfaces.  There were about 100,000 CRC's that I
> couldn't match to any interface except the main atm1/0 interface.
>
> We've checked the physical line, Qwest has monitored the port.  They are
> telling me that discarded cells are the cause.  If that is the case shouldn't
> I be able to match the main interface CRC counter to the CRC counters for all
> my subinterfaces?  Any insight would be appreciated.

No, CRC errors are not associated with discarded cells. That's ridiculous.
CRC is a method of verifying the packets were transmitted properly by
verifying the supplied checksum against the calculated checksum. Demand
escalation if that's the nonsense you're being fed.

Chances are, it's running too hot. How long is the cable?

You may find, if it's a very short run, that the either you need to insert
some attentuators, or preferrably, get Qwest to adjust the LBO on their
equipment.

Andy

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Andy Dills
Xecunet, Inc.
www.xecu.net
301-682-9972
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