This is the lowest value recorded during 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 lowest OSNR seen in the interval matters most, because it represents the worst-case signal quality moment, the point closest to where the receiver could lose lock entirely. For example, if osnrMin for a channel dips close to the transponder's minimum OSNR requirement during a specific nightly interval, an admin would investigate what's different about the network at that time, such as a scheduled amplifier gain adjustment on a shared span.