nbsCohpmCurrentMaxQ is read-only and holds a live statistic for the reporting interval now in progress for the maximum Q factor on this coherent optical interface, i.e. a composite signal-quality figure of merit derived from the coherent receiver's error statistics, where a higher value means a cleaner, lower-error signal; not-supported is encoded as 0xFFFFFFFF. Unit measurement: 0.1 dB. A sysadmin polls it to watch this metric evolve in real time during the interval still underway, and compares it against the matching nbsCohpmThresholdsMaxQ alarm setting to see how close the link is running to its configured limit.