To provide high performance, availability, and flexibility in distributed environments, the Active Directory uses multi-master replication. As illustrated in Figure 3 below, this lets organisations create multiple copies of the directory, known as directory replicas, and place them throughout the network.

Changes made anywhere on the network are automatically replicated throughout the network. This is in contrast to single-master replication in which all changes must be made to a single, authoritative directory replica.

Figure 3: Active Directory supports multi-master replication

For example, fully synchronised directory replicas can be made available to each location in a wide area network (WAN). Such a process can give users faster performance because they can locate resources using the local directory service rather than by traversing the WAN. These same directories could be managed locally or remotely depending on available administrative resources.