Valued Contributor
Re: ifutil mib expression
I was sometime back searching HP support site to understand how interface utilization is computed and this exactly what I got...


The If%util and IfHC%util expressions that are provided out of the box with NNMi uses the following formula:

If%util = ((((ifInOctets + ifOutOctets) * 8) / ifSpeed) * 100) / (sysUpTime * 0.01))

IfHC%util = ((((ifHCInOctets + ifHCOutOctets) * 8) / ifSpeed) * 100) / (sysUpTime * 0.01)

For the the Interface Utilization to be calculated using the max of interface utilization (in, out), the NNM iSPI Performance for Metrics is required.

Below is the way it works with this NNM iSPI Performance for Metrics:

1.NNMi is computing the Interface Utilization in each direction separately: ifInUtilizationPct and ifOutUtilizationPct. It uses the interface High Capacity (HC) counters or Low Capacity (LC) counters according to RFC 2233.
2.NNMi is then passing the information to the Network Performance Server (NPS)
3.The iSPI Performance for Metrics on the NPS server side takes the larger of In or Out. It is also able to compute an Average from a number of samples.
Best Regards,
Gopinath Manickam

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