A system of centralized network administration, in which the permissions that grant access to resources in the network are maintained in one or more servers called "domain controllers" (see PDC). Domain-based networks use a hierarchical structure that enables assigning permissions to users who collaborate with different departments in an organization. Microsoft's Active Directory is based on the domain system. Domain Based Vs. Workgroup Based Domain-based networks are used in large companies due to their versatility, while home networks and small businesses typically use workgroup-based networks. The latter has no central administration, and any computers or printers can be part of a group by assigning the devices themselves to the same group name, the default being WORKGROUP. The domain system is by far the most flexible and secure but naturally more complex to administer. See workgroup-based network, Active Directory and PDC.