[mrtg] 64-bit counters with SNMPv1?

Forthofer Russ Russ.Forthofer at ssfhs.org
Mon Mar 26 23:38:08 CEST 2007

I ran some additional tests, and it appears to me the 64-bit data may be
bogus.  It would report 4K utilization on a link that should be about
50M or better.

I did find out from Nortel that the OM3500 does NOT support SNMPv2 -
only SNMPv1.  (I was hoping I just had to flip a switch somewhere.)
So, it appears that my only option is to increase my polling frequency.

I have not checked the enterprise MIB, as you suggested, but I will do
that now.  Not really holding too much hope for that, though.

Thanks for your help.

-----Original Message-----
From: Stuart Kendrick [mailto:skendric at fhcrc.org] 
Sent: Thursday, March 22, 2007 11:37 AM
To: Forthofer Russ
Cc: mrtg at lists.oetiker.ch
Subject: Re: [mrtg] 64-bit counters with SNMPv1?

hi forthofer,

i don't have an answer for you, this is just a ramble:

i find this puzzling.  i thought that one of the few differences between
SNMPv1 and SNMPv2c was support for 64-bit counters.  and yet, you seem
to be retrieving the value of a 64 bit counter, using an SNMPv1 GET

what are you getting, when you issue your v1 request for this 64bit
counter?  just 32 bits of the full 64 bits?  curiousity ...

i would be surprised if this box supported only v1

that being said, i've run into a manufacturer (NetApp) which supports
only v1 ... however, they provide access to 64 bit counters by providing
two variables for each counter, e.g. miscHighNetRcvdBytes and
miscLowNetRcvdBytes ... where the High counter contains the top 32 bits
and the Low counter contains the bottom 32 bits.  i retrieve both and
perform a string concatenation, all done in MRTG's Target line.  if
Nortel does only support v1, perhaps they also support some scheme like
this, in order to deliver access to 64 bit counters.  this would be
visible in one of their enterprise MIBs


Forthofer Russ wrote:
> I have a device (a Nortel OM3500) which has high-speed interfaces.  
> So, I need to retrieve traffic counts using ifHCInOctets, etc....i.e.,
> counters.   It appears to me that MRTG uses the 64-bit counters when 
> SNMPv2 is used.  However, in this case, v2 is apparently not
> To verify this, I entered the following commands:
> snmpget -c commstr -v 2c xx.xx.xx.xx   
> (response: Timeout: No Response from xx.xx.xx.xx)
> snmpget -c commstr -v 1 xx.xx.xx.xx
> (response: IF-MIB::ifHCInOctets.17 = Counter64: 6058121224)
> This suggests to me that the box does not support SNMPv2.  Is there a 
> way for me to make use of the 64-bit  counters, while using SNMPv1?  
> (Or if someone knows of a way to enable SNMPv2 on a Nortel OM3500, 
> that would also be a quite acceptable - perhaps preferable -  
> solution.)
> Any help would be greatly appreciated.
> Russ

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