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Cisco bandwidth shows "0" inbound and outbound



We are licensed for PRTG-1000 - but we recently asked for, and have received, a demo license so we could advocate for consolidating all monitoring in our local data center to PRTG. The last version we downloaded and installed before we applied the demo license is:

PRTG Network Monitor

Our problem is that we are seeing some very weird behavior on one of our SNMP Bandwidth monitors... about every 40 minutes or so, we will see the Inbound traffic drop to 0... which seems impossible as this is our Internet router. Our regular business hours traffic is close to 16-20 mbps, but every 40 minutes, we will get a 1-minute interval reading of 0 on the interface directly connected to our ISP.

For testing - I setup another monitor for this same device in another group to see if we would get the same results, and they are almost identical... the specific timing of the SNMP query being off by a few seconds only.

I also have access to another PRTG install at one of our corporarte remote locations, and they are also monitoring this same router and interface. However, they do not show any 1-minute intervals with 0 bits transferred. The version of PRTG they are using is:

PRTG Network Monitor

I am curious if there is a bug in the version we are currently using (, as I can reproduce the error under this version, but not on the older version.


bandwidth snmp snmp-traffic

Created on Aug 20, 2012 8:42:38 PM

3 Replies




which SNMP version are you using for the device?

If it is SNMP v1, please switch to SNMP v2 and add the sensors again.

Just changing the SNMP version in the device settings alone will not make a change to the counters the sensors use.

Only if you recreate them they will use the 64bit traffic counters.

Then please check if the issue returns.

Created on Aug 21, 2012 9:46:11 AM by  Aurelio Lombardi [Paessler Support]



We were using SNMP v1 when the monitors were created - I've rebuilt the device as a test in another Group using SNMP v2, and so far it appears that the problem is resolved.

So to understand - 64-bit counters are only created when using SNMP v2..? What are the advantages of 64-bit counters.

Also, I can say with 100% certainty that all of our network device (bandwidth) based monitors were setup using SNMP v1... should I recreate all of these..?

Thanks for your help.

Created on Aug 21, 2012 5:03:38 PM

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