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OIDs for Utilization

  • 2 February 2021
  • 5 replies
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I would really like to graph utilization for our AP230s and 250s.  I’m looking at the AH-INTERFACE-MIB and the only options I see are ahRadioTxAirtime and ahRadioRxAirtime, which are counters that pull airtime in microseconds.

When in the CLI you can run show int wifi0 or show int wifi1 and get utilization data like:

Rx airtime=634.69 s; Tx airtime=7564.03 s; CRC error airtime=764.45 s;

Rx airtime percent=0.00%; Tx airtime percent=0.00%; CRC error airtime percent=5%;

Tx utilization=3%; Rx utilization=5%; Interference utilization=10%; Total utilization=18%;


All nice metrics that would be useful in graph form.  I’m curious how they are calculated and if those metrics are available via snmp?  

 

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Best answer by reinhardg 17 February 2021, 09:48

In our case (HiveManager Classic on-prem) we had also to delete some characters in some Object Identifiers: The file “ah_smi_mib.txt” contains 4 identifiers that contain an underline-character: ahAPHiveAP*. We had to remove these underline-characters.

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Userlevel 2

Call snmpwalk and have a look to the result. You mac start at the OID given below:

snmpwalk -M path_to_MIB-files -v 2c  -c your_community  IP_of_AP .1.3.6.1.4.1.26928.1.1.1.2.1.3.1

 

I’ve done that. /opt/librenms/aerohive contains the AH-TRAP-MIB, AH-INTERFACE-MIB, AH-SMI-MIB and AH-SYSTEM-MIB

snmpwalk -M /opt/librenms/aerohive -v 2c  -c community  10.19.102.5 .1.3.6.1.4.1.26928.1.1.1.2.1.3.1

I get a list like:

iso.3.6.1.4.1.26928.1.1.1.2.1.3.1.22.7 = Counter32: 326896141
iso.3.6.1.4.1.26928.1.1.1.2.1.3.1.22.8 = Counter32: 922876642
iso.3.6.1.4.1.26928.1.1.1.2.1.3.1.23.7 = Counter32: 3852580482
iso.3.6.1.4.1.26928.1.1.1.2.1.3.1.23.8 = Counter32: 2098351997

 

Not sure why I don’t see the pretty names… regardless… as I look through the mibs there is nothing defined for Tx Utilization, Rx Utilization, Interference Utilization or Total Utilization.

The only relevant counters I see are the 4 above, which are ahRadioTxAirtime and ahRadioRxAirtime for wifi0 and wifi1 respectively.  These are cumulative measures in microseconds.  Possibly usable, but would require a bit of coding to get deltas, and divide by the polling period.
 

 

 

Here is another wrinkle…  the AH-INTERFACE-MIB shows:

ahRadioTxAirtime OBJECT-TYPE    
    SYNTAX        Counter64
    MAX-ACCESS  read-only
    STATUS        current
    DESCRIPTION "The accumulative transmit time in microseconds (us)
            from the given Radio."
    ::=  {  ahRadioStatsEntry  22 }

 

But if you run snmpwalk you see what I pasted above…  all Counter 32.   

Userlevel 2

Please check whether the path to your MIB-files is correct and whether your MIB-files are in the proper format. On Linux I had to replace “Carriage return (+ Linefeed)” with Linefeed.

Userlevel 2

In our case (HiveManager Classic on-prem) we had also to delete some characters in some Object Identifiers: The file “ah_smi_mib.txt” contains 4 identifiers that contain an underline-character: ahAPHiveAP*. We had to remove these underline-characters.

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