[mrtg] Re: Babkbone Total Utilization = 143,2 %

[David C Prall]

> I'm monitoring a 64Kbps serial in a Cisco 2501 router.
> My config is the folowing:
>
> # Add a WorkDir: /some/path line to this file
> WorkDir: c:\InetPub\wwwroot\ci\redes\mrtg
> IconDir: ..\icons
>
> Directory[_]: routers
> Options[_]: bits growright
> WithPeak[_]: ymw
> Suppress[_]: ymw
> YLegend[_]: Bits por Segundo
> Xsize[_]: 580
> Ysize[_]: 180
> ShortLegend[_]: bps
> Legend1[_]: Trafego de Entrada em Bits por Segundo
> Legend2[_]: Trafego de Saida em Bits por Segundo
> Legend3[_]: Trafego Maximo de Entrada em 5 Minutos
> Legend4[_]: Trafego Maximo de Saida em 5 Minutos
> LegendI[_]:  Entrada:
> LegendO[_]:     Saida:
> AddHead[_]: <base
> href="http://intranet.positivo/ci/redes/mrtg/routers/">
> ..
> Target[posinfo.cisco.2501.ser1]: 2:public at 172.19.2.1
> Unscaled[posinfo.cisco.2501.ser1]: ymwd
> MaxBytes[posinfo.cisco.2501.ser1]: 8000
> Title[posinfo.cisco.2501.ser1]: Cisco 2501 - Serial 1/2
> PageTop[posinfo.cisco.2501.ser1]: <H2>Roteador Cisco 2501 Posinfo</H2>
>  <TABLE>
>    <TR><TD>Interface:</TD><TD>Serial 1/2</TD></TR>
>    <TR><TD>Velocidade:</TD><TD>64 Kbps</TD></TR>
>  </TABLE>
> ..
>
> I'd like to understand why the current percentages sum exceeds 100%.
Is
> this right or not ?
>
>  Max IN:        63.6 kbps (99.4%)
>  Average IN:    35.3 kbps (55.1%)
>  Current IN:    61.1 kbps (95.4%)
>
>  Max OUT:        53.0 kbps (82.9%)
>  Average OUT:    10.3 kbps (16.0%)
>  Current OUT:    30.6 kbps (47.8%)
>
A leased line is actually a asynchronous connection. A 64K line has two
channels, transmit and receive. Both sides have 64K of available
bandwidth. You can transmit 64K and receive 64K at the same time. Each
will impact the other. If you are transmitting at 64K you will not be
able to receive at 64K as well, since one side will receive at 100% the
other must be able to acknowledge. World Wide Web surfing might give you
100% input/receive while only using 5% of the transmit bandwidth. Once
you hit 100% on one side, you may hit 100% on the other side but
normally not. Therefore a 64K connection is actually a 128K connection,
but not really do to the Asynchronous nature of data.

Hope this helps,
David C Prall, MCNE MCSE          DCP Technologies
dcp at dcptech.com                       http://www.dcptech.com
dcppage at dcptech.com


--
* To unsubscribe from the mrtg mailing list, send a message with the
  subject: unsubscribe to mrtg-request at list.ee.ethz.ch
* The mailing list archive is at http://www.ee.ethz.ch/~slist/mrtg