This is the average value over the current performance-monitoring interval of the optical signal-to-noise ratio (OSNR) measured on this channel during the current performance-monitoring interval, expressed in dB. The average OSNR over the interval is the figure most often compared against the transponder's minimum required OSNR to judge how much operating margin the channel still has. For example, an admin planning to add more wavelengths to an already busy amplified link would check osnrAvg on the existing channels to confirm there's still enough margin before the new channels reduce it further.