 Each Sub-division (one for each district, the physical building is sometimes referred to as "detachment", a holdover term from the OPP program) employs a number of Sergeants who answer to the sub-division commander in the day-to-day operations.Front line policing is performed by officers with the rank of Constable.After graduating from Ontario Police College and a probationary period, each recruit is granted the rank of Fourth Class constable, promoted based on experience and performance, and reaching the rank of First Class constable within three years.