LibreNMS dbm threshold values

How does Libre get the different threshold values for transceivers , I noticed some discrepancies.
ie on a Nexus5548

The graph has a threshold of -3.7 but “show int eth1/17 transceiver details” has no such threshold.


another example:
Dbm Ethernet1/22(Rx-dBm) - Ethernet1/22(Rx-dBm) under threshold: -1.456 (< -1.4532 )


If your device send wrong/not send thresholds, LibreNMS will do a +/- “x” to the current value.
I dont know the value of X, sorry.

On some ports i reads the current value, but miss the prefix .

ie. current reads as A instead of mA. but the threshold values are off
this is from a cisco Nexus5548
BIOS: version 3.6.0
Microcontroller Firmware: version v1.2.0.1
kickstart: version 7.1(3)N1(2)
system: version 7.1(3)N1(2)
System version: 7.1(3)N1(2)


You should have a look how sensor data is displayed from LibreNMS perspective, that is, via SNMP. Launch discovery with debug and search for sensors data in the output (that way you will also see what MIBs are in use with the request, which may be helpful with further troubleshooting). As an alternative, you can snmpwalk the necessary tree to see how device exposes the data via SNMP (and not how LibreNMS reads it).

It all sums up in how SNMP server displays the thresholds and how LibreNMS sees them. But you can inspect this only via SNMP, not internal device CLI.