This read-only CienaGlobalState object reports the operational state of the interface being monitored by a PM instance, per its description, distinct from the instance's own operational state, cienaCesPmInstanceOperState. This lets an engineer immediately tell whether a PM instance shows no fresh data because the monitoring instance itself is disabled, or because the underlying interface it watches is actually down. An engineer seeing a PM instance's counters stop incrementing would check this field first to rule out the simplest explanation, that the monitored interface itself went down, before investigating the PM instance configuration.