RE: [cacti-user] Re: Initial release of the Bacula SNMP Subagent - v1.2

[Dave S. <D.T...@cs...>]

On Fri, 2005-10-21 at 17:32 -0500, Les Mikesell wrote:
> What's supposed to happen when the value doesn't fit in a Counter32?

The Counter32 value will report the bottom 32-bits
(with the higher bits simply being discarded).

Remember that in the SNMP world, an individual Counter-based value
has no meaning.  Counter32 (and Counter64) object are used to
monitor the *difference* between two successive readings.


So:
    ifconfig eth1 ; sleep 60 ; ifconfig eth1

might report
    eth1   TX bytes:33033390619 (31503.0 Mb)
    eth1   TX bytes:33033391619 (31503.0 Mb)


while
    snmpget eth0 ; sleep 60 ; snmpget eth0

might report

    ifOutOctets.1 = 149182455
    ifOutOctets.1 = 149183455


The raw numbers are different, but the delta:

  33033391619 - 33033390619  = 1000
  149183455   - 149182455    = 1000

 is the same.   That's how SNMP Counters work.



Dave