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Get PoE Information via SNMP on Stacked 3850 Switchs



I am trying to read PoE Information via SNMP from stacked 3850 Switchs.

I manage to do it on non-stacked 3850, on 3750 Stacked or not, and 3560 Switchs.

The stacked 3850 are running IOS-XE 03.03.01SE.

The Problem I meet is not to read the PoE Information, but to correlate the PoE-Port-Index, with de physical index.

I use

$MibcpeExtPsePortEntPhyIndex = ""; # The entPhysicalIndex that identifies the Port


$MibentPhysicalDescr = ""; # A textual description of physical entity

to do the corelation.

On stacked Switchs, the SNMP request for MibcpeExtPsePortEntPhyIndex Returns the same value for all Interfaces of Switch#1 and another one, for all Interfaces of Switch#2.

Example on a non stacked device :  PoE-Index 1.1 refers Physical 1008, ... etc. OK

[jur466@nocu07 ~]$ snmpwalk -c toto lish01

. = INTEGER: 1008

. = INTEGER: 1009


On stacked devices: All PoE Indexes refers to physical Index 57 for Switch#1 and physical Index 113 for the Switch#2

[jur466@nocu07 ~]$ snmpwalk -c toto monr02

. = INTEGER: 57

. = INTEGER: 57

. = INTEGER: 57

skipped lines

. = INTEGER: 57

. = INTEGER: 57

. = INTEGER: 113

. = INTEGER: 113

. = INTEGER: 113

skipped lines

. = INTEGER: 113

Has it to do with the IOS Version ?

Best regards


4 Replies 4

LJ Gabrillo

Dude you are not a computer, use an NMS software that will translate that for you.
Solarwinds NPM is a good one, w/c has 30 days free trial.
PRTG has free 10 sensors as well

If you want to be a computer, you need to reference the OID Table on the MIB file and that SNMP message you get

Shure I am not a computer,... I am much cleverer than that.

The Problem lies not in saying

 iso. org. dod. internet. private. enterprises. cisco. ciscoMgmt. ciscoPowerEthernetExtMIB. cpeExtMIBObjects. cpeExtPsePortTable. cpeExtPsePortEntry. cpeExtPsePortEntPhyIndex.cpeExtPsePortEntPhyIndex


. .

I can cope with both representation.

The Problem is that the retuned value is always the same, wich is simply impossible.

No Computer will tell you that.

What I am saying is  that if the SNMP query Returns that :

Interface Gi1/0/1 delivers 15.4 W and that

Interface Gi1/0/1 delivers 7.2 W and that

Interface Gi1/0/1 delivers 30 W and that... and so on

 , even the best NMS will just "translate that for me".

So my question is : is there a known bug  in the IOS my devices are running, explaining this behaviour ?

Best regards