This is the highest value recorded during 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 highest frequency recorded in the interval helps characterize how far the incoming signal has drifted high, which similarly points to laser aging or a wavelength-selective-switch misalignment. For example, if inOpticalFrequencyMax briefly spikes during a specific interval and then returns to normal, an admin would suspect a momentary wavelength-locker glitch at the far-end transmitter rather than a hardware failure.