What does Air Traffic Controller (ATC) experience mean?

Experience working as an air traffic controller (ATC) that involved the full-time active separation of air traffic after receiving an air traffic certification or ATC facility rating. The experience must be acquired while serving at one of the following: A FAA air traffic control facility; A civilian or military air traffic control facility of the Department of Defense (DoD); A tower operating under contract with the FAA under 49 U.S.C. § 47124.