A+ Study Tips - Replication

What is replication?

Replication is a process through which the changes made to a replica on one domain controller are synchronized to replicas on all the other domain controllers in the network. Each domain controller stores three types of replicas:

1. Schema partition: This partition stores definitions and attributes of objects that can be created in the forest. The changes made in this partition are replicated to all the domain controllers in all the domains in the forest.
2. Configuration partition: This partition stores the logical structure of the forest deployment. It includes the domain structure and the replication topology. The changes made in this partition are replicated to all the domain controllers in all the domains in the forest.
3. Domain partition: This partition stores all the objects in a domain. Changes made in this partition are replicated to all the domain controllers within the domain.

Note: Windows Server 2003 supports a new type of directory partition named Application directory partition. This partition is available only to Windows 2003 domain controllers. The applications and services use this partition to store application-specific data.

Creating, modifying, moving, and deleting an object trigger a replication between domain controllers. Replications are of two types:

Intrasite: An intrasite (within a site) replication mostly uses LAN connections. As intrasite replication does not compress data, it saves a computer's CPU time. In an intrasite replication, the replication partners poll each other periodically and notify each other when changes need to be replicated, and then pull the information for processing. Active Directory uses a remote procedure call (RPC) transport protocol for intrasite replication.
1. Intersite: As an intersite (between sites) replication uses WAN connections, a large amount of data is compressed to save WAN bandwidth. For the same reason, the replication partners do not notify each other when changes need to be replicated. Instead, administrators configure the replication schedule to update the information. Active Directory uses an IP or SMTP protocol for intersite replication.
   For intrasite replication to take place, connection objects are required. The Active Directory automatically creates and deletes connection objects as and when required. Connection objects can be created manually to force replication.