This is the average value over the current performance-monitoring interval of the actual optical carrier frequency measured at this port's input during the current performance-monitoring interval, expressed in MHz. The average frequency over the interval is what's compared against the ITU-grid channel frequency this port was provisioned for, to check for any systematic offset. For example, if inOpticalFrequencyAvg is consistently offset from the nominal ITU-grid value by more than the transponder's tolerance, an admin would investigate whether the far-end laser needs recalibration.