Observed that Gigabit interface max utilization crossing near 1Gbps. But, its sub-interfaces utilization is not going above 2% (20Mbps).
How is this possible, shouldn't the sub-interface utilization add up to the total utilization of the parent interface?
DX NetOps CAPM Release : 20.2 or later
This issue is caused by the MIB data sent back from the device. This can be identified by running a MIB walk on it via sapwalk2.
Take the following example device data and look through it to find the indexes of interfaces that exhibit this issue:
So the parent interface 436224000.has an Index of
The sub-interface 436227001.has an index of
And the other sub-interface' 436227002.index is
The metric equation for Bits/In is:
Since the speed is greater than 20000000, it uses the 188.8.131.52.184.108.40.206.1.1.6.OID whose field number is
Searching for this OID in the MIB data for each of the 3 indexes of the interfaces:
For sub-interface ifHCInOctets. Same for the other sub-interface:, it has a value of 0 for
However, when you look at the parent interface, it has a significant value:
If the Bits/In (ifHCInOctets) value for the parent was the sum of the two sub-interfaces, then they should have non-zero values that add up to the value in the parent (10717544238782). But they clearly don't, so this is a configuration issue on the device side.
Check with the device owner to see if they've configured the sub-interfaces to correctly report their values to the SNMP agent of the device.