This reports the PmBinState of this bin -- whether it is still collecting, complete, or otherwise not yet in a final, comparable state. State is what tells you whether the rest of the counters in the current, still-accumulating short interval bin for this PM instance can be trusted at face value -- a bin still marked as collecting hasn't finished accumulating, so comparing it directly against a completed neighboring bin will make this port's traffic look artificially low. For example, State reading partial rather than complete on this in-progress short-interval bin for a port you just brought up explains why its byte counters look tiny next to the previous, fully-closed interval.