From: Jung, Jin (jin.jung@lmco.com)
Date: Thu May 08 2003 - 09:37:35 GMT-3
I thinks someone else from IPEXPERT send out some info on this,
Here is formular for reliablilty
"Reliability is calculated using the following formula:
reliability = number of errors / number of total frames"
By default it 255/255 - this is good sign.
Number of error normally means input, output and of course CRC . ... Runt
giant ....
http://www.cisco.com/warp/public/121/crc_tshooting.html
"CRC errors typically indicate noise, gain hits or transmission problems on
the data link, or on the interface itself. On an ethernet segment, CRC
errors result from collisions or from a station transmitting bad data. On an
ATM interface, CRC errors also occur when the ATM network provider drops
some cells of a total packet in the switch "cloud". This can be done to
police the number of cells and bits per second you are transmitting. You can
obtain more information on policing by clicking here. The ATM interface
detects these lost cells when the segmentation and reassembly (SAR) function
reassembles the cells to create a complete packet again. Thus, CRC errors on
ATM interfaces may point to a mismatch in traffic shaping and traffic
policing parameters.
Note: The input errors counter tracks the total number of CRCs, "no
buffers", runts, giants, frames, overruns, ignored, aborts and other
input-related errors. The input errors counter is therefore either the same
as, or higher than, the CRC counter. The occurence of errors and the input
and output difference should not exceed one percent (1.0 %) of traffic on
the interface."
I am not sure this is what you are looking for, but I hope this helps.
-----Original Message-----
From: Sean C [mailto:Upp_and_Upp@hotmail.com]
Sent: Tuesday, May 06, 2003 6:22 PM
To: Jung, Jin; ccielab@groupstudy.com
Cc: Brian Dennis
Subject: Re: EIGRP and ATM CRCs
Jung,
Do you have a CCO link that discusses how the reliability metric is based
off of CRCs? I can't find anything on the website discussing how the
reliability metric, itself, is computed. I can see the metric being based
off of up/down status and the line bouncing, but is that metric also
including CRCs in particular?
Thx, Sean
----- Original Message -----
From: "Jung, Jin" <jin.jung@lmco.com>
To: "Sean C." <Upp_and_Upp@hotmail.com>; <ccielab@groupstudy.com>
Sent: Tuesday, May 06, 2003 8:32 AM
Subject: RE: EIGRP and ATM CRCs
> I believe that question looks like metric adjustment question,,
>
> You have to think that what in EIGRP metric can "ATM CRC" cause to
> change its metric.
>
> Bandwidth delay reliability load MTU,,
> ????
>
> -- by default only the bandwidth and delay K value can reflect EIGRP
metric,
>
> In this case, you need to enable one of above K value to 1 ,,
>
> My guess would be you have to enable reliability for EIGRP...
>
>
> Jin jung...
>
> -----Original Message-----
> From: Joe Chang [mailto:changjoe@earthlink.net]
> Sent: Monday, May 05, 2003 9:35 PM
> To: Sean C.; ccielab@groupstudy.com
> Subject: Re: EIGRP and ATM CRCs
>
>
> Decrease the EIGRP hello interval, and decrease the hold time so that
> it
is
> something closer to the hello interval. For example 10 seconds hello,
> 20 seconds hold time.
>
> ----- Original Message -----
> From: "Sean C." <Upp_and_Upp@hotmail.com>
> To: <ccielab@groupstudy.com>
> Sent: Monday, May 05, 2003 8:48 PM
> Subject: EIGRP and ATM CRCs
>
>
> > Hello all,
> >
> > Found this question on the sample exam from IPExperts and I can't
> > figure
> out
> > the answer. Any clues??
> > http://www.ipexpert.net/products/itemdetail.asp?SKU=ip0001
> >
> > "It has seen lots of time that ATM interface generates CRC errors.
> > Configure EIGRP such upon getting such errors on any particular
> > router
> will
> > automatically reflect to EIGRP toplolgy of all routers in EIGRP AS."
> >
> > TIA,
> > Sean
>
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