This PmBinState field reports whether this bin's collection period completed normally, is still in progress, or was affected by a problem such as a device restart or a data gap. Because this is the currently open, still-accumulating measurement interval that keeps climbing until its boundary is reached and it rolls off into the history table, State is what you check before trusting the counters in the row at all — a bin marked as partial or invalid means the accompanying byte/frame/error counts under-represent what actually happened and should not be compared directly against a normal full-length bin. For example, if this field reports something like 'partial' immediately after a card reset, you would discount the traffic totals in that same row rather than concluding traffic genuinely dropped to near zero.