What MIB does NPM use to gather interface utilization data?
They are polled using OIDs described here:support.solarwinds.com/.../What-object-IDs-OIDs-does-NPM-poll-for-interface-information
Calculation here:https://support.solarwinds.com/SuccessCenter/s/article/Calculate-interface-bandwidth-utilization?language=en_US