[mrtg] Re: Monitoring Gigabit Ethernet ports...

[Marc Duchesneau]

Lars,

What is this 64-bit interface you mentionned?  Is this another MIB ?


At 08:35 PM 5/18/2001 +0200, Lars Holmström wrote:

>This has been discussed on this list before.
>
>One limitation to keep in mind is that the default configuration file 
>generated
>by MRTG cannot accurately measure bandwidth above about 114 Mbps (Megabits per
>second). The reason is that the default interface counter is a 32-bit number,
>and a 32-bit number will rollover twice in a period of 5 minutes at more than
>114 Mbps. (232 = 4,294,967,296 bytes, multiplied by 8 (bits in a byte), 
>divided
>by 300 seconds in 5 minutes, is 114,532,641 bits per second, or roughly 114
>Mbps.) MRTG or any other SNMP program cannot correctly account for a double
>rollover. The graph will appear to peak at about 114 Mbps and never go beyond
>that, when in reality the interface could be running well beyond that rate. To
>get around this, you must change the configuration file to pole a special 
>64-bit
>interface counter, or poll MRTG more frequently than 5 minutes.
>
>I do not believe the SSR has 64 bit counters.
>
>/Lars
>
>"Cihan Subasi (Garanti Teknoloji)" wrote:
>
> >         Hi,
> >
> >         I am trying to monitor Gigabit Ethernet port usage on Cabletron
> > SSR8000 chassis....Graphs seems ok when traffic is low (10-20 Mbits/s) but
> > when traffic goes higher than those values graphs becomes flat (my
> > understanding is because mrtg cannot get a new value from the port 
> keeps the
> > last one...Anybody every experienced similar things on Gigabit port
> > monitoring? Thanks
> >
> > *****************************************************************
> > Cihan Subasi
> > Garanti Technology
> > Network Services - Project Manager
> > *       +90 212 478 3426
> > GSM:    +90 533 2701915
> > mailto:cihans at garanti.com.tr
> > http://www.garantiteknoloji.com.tr
> > *****************************************************************
> >
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Marc Duchesneau
Technicien Réseau
Les Systèmes Électroniques Matrox
1055 St-Régis
Dorval, Québec
H9P 2T4

tél.: (514) 822-6000 ext.2321
fax:  (514) 822-6262
www.matrox.com
E-Mail:mduches1 at matrox.com
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