HighErrorRate event logic explanation

Products

• VMware Smart Assurance

Issue/Introduction

What OIDs does Smarts IP Performance Manager (PM/APM) poll and use to calculate a HighErrorRate event?

Environment

SMARTS - 10.1.x

Resolution

• The HighErrorRate event in Smarts PM is calculated based on the values of the following OIDs:
  • ifHCOutUcastPkts = ".1.3.6.1.2.1.31.1.1.1.11" 
  • ifHCOutMulticastPkts = ".1.3.6.1.2.1.31.1.1.1.12" 
  • ifInDiscards = ".1.3.6.1.2.1.2.2.1.13" 
  • ifInErrors = ".1.3.6.1.2.1.2.2.1.14" 
  • ifInUnknownProtos = ".1.3.6.1.2.1.2.2.1.15"

 

• To calculate a HighErrorRate event, Smarts PM needs to have multiple polling of the above OIDs during the timeframe when the event is active. 

 

• Smarts PM defines the rate function as the absolute difference of two successive IfInErrors values between polling intervals that are divided by the pollingInterval as follows:

rate( IfInErrors, pollingInterval ) = absolute( ( IfInErrors1 - IfInErrors2) ) / pollingInterval )

 

• Smarts PM uses the following equation to generate the HighErrorRate event. This statement must return TRUE for a HighErrorRate event to be generated:

( InputPacketErrorRate > MinimumErrorRate ) && ( InputPacketErrorPct > ErrorThreshold )

 

• The following sections of this Fix statement explain how the values in the above calculation are calculated.
  • InputPacketErrorPct
    The InputPacketErrorPct value is calculated using the following equation:

    InputPacketErrorPct = ( ( InputPacketErrorRate / InputPacketRate) * 100 )

         where InputPacketErrorRate = ifInErrorsRate.

 

• • InputPacketRate

                 The InputPacketRate value in the InputPacketErrorPct equation is derived from the following equation:

       InputPacketRate = ifInUcastPktsRate + ifInNUcastPktsRate + ifInDiscardsRate + ifInErrorsRate + ifInUnknownProtosRate

 

• • The following sections show the equations that provide the values in the above InputPacketRate equation.

• • • ifInUcastPktsRate
      ifInUcastPktsRate = rate( ifHCOutUcastPkts, pollingInterval )

ifInNUcastPktsRate
ifInNUcastPktsRate = rate( ifHCOutMulticastPkts, pollingInterval )

ifInDiscardsRate
ifInDiscardsRate = rate( ifInDiscards, pollingInterval )

ifInErrorsRate
ifInErrorsRate = rate( IfInErrors, pollingInterval )

ifInUnknownProtosRate
ifInUnknownProtosRate = rate( ifInUnknownProtos, pollingInterval )

Additional Information

MinimumErrorRate calculation explanation is available at MinimumErrorRate Explained