The Sun Java System Directory Server topology includes four preferred Directory Server and four master replicas. Directory Server is the corporate directory server used to control access to web-based applications. The directory server has a single root suffix, dc=gt,dc=com. Information about users is stored in the ou=people, dc=gt,dc=example,dc=com container with uid as the naming attribute.
Two preferred Directory Server and two master replicas are located in the United States (a separate configuration directory in the United States stores configuration information for these systems).
Two preferred Directory Server and two master replicas are located in Europe (a separate configuration directory in Europe stores configuration information for these systems).
Identity Synchronization for Windows treats hub replicas the same as read-only replicas. In many scenarios, using a hub replica is preferred to using a read-only replica because a hub can be easily promoted to a preferred Directory Server.