The process of replicating updates to Active Directory on different domain controllers in the network. Directory replication ensures that users have access to resources on the network by ensuring that information about users, groups, computers, file shares, printers, and other directory objects is current on all domain controllers in the network.
Directory replication of Active Directory on a Microsoft Windows 2000–based network takes place in two ways, depending on whether the participating domain controllers are in the same site.
Within a site, intrasite replication between domain controllers uses remote procedure calls (RPCs) by means of a dynamically allocated port number. This replication takes place automatically every five minutes. Domain controllers within a site exchange update information in a ring fashion, from one domain controller to another.
This ring topology is established by a periodically running process called the Knowledge Consistency Checker (KCC) and ensures a minimum of two replication paths between each pair of domain controllers and a maximum replication hop count of three hops to support efficient replication and fault tolerance.
Between sites, intersite replication can use RPCs if the local area network (LAN) or wide area network (WAN) connection supports them or some other method such as Simple Mail Transfer Protocol (SMTP) e-mail messages. Intersite replication uses a compressed format for more efficient use of slow WAN links and is easier to schedule and manage than intrasite replication.
To take advantage of the greater flexibility of intersite replication and to use it instead of intrasite replication, configure your domain controllers to belong to more than one physical site.