More or less the equivalent of the french "Appellations d'Origine Contrôlée" the Denominazione di Origine Controllatas define geographical areas of production, varities to be grown and eventually their proportion in blends, and winemaking constraints with eventually criterias for the attribution of more distinctive denominations such as "Classico", "Superiore" or "Riserva".
The system is not under few critic as some see few sense in some of the limitations it includes while claiming also that it poorly guarantees quality.
Perfection is hardly met in this world and I appreciate that the system protects the typicities of the wines.