The ordering period is how long a vehicle stays open for business, often five years or so once options are included, though it varies by contract. Once it ends, no new task orders can be placed, even if the ceiling was never reached, though orders already placed can usually still run to completion. It is a different clock from a task order's own period of performance, which is just how long that one specific job runs.

In a sentence

"The ordering period for this IDIQ runs five years from the date of award." That is the window for placing new orders, not how long any single order lasts, so a vehicle with years left on its ordering period can still be worth pursuing even late in its life.