Several object replication attributes are also used to determine the replication state of individual objects in the directory, including the following. You can view these object attributes in the Administrator program in raw mode by viewing the raw properties of the object:
For example, the following illustration shows the USN-changed value for Bill Lee's mailbox on Boston01.
Every object in the directory is uniquely identified by its Obj-Dist-Name (Object Distinguished Name). The Obj-Dist-Name is an X.500-type address composed of the containers it is a member of and its directory name(RDN). For example, in the NAmerica-E site in the Ferguson and Bardell organization, the Recipients Container Obj-Dist-Name would be /o=Fab/ou=NAmerica-E/cn=Recipients. A mailbox called Bill Lee would have an Obj-Dist-Name of /o=Ferguson&Bardell/ou=NAmerica-E/cn=Recipients/cn=Bill Lee.
Every object in the organization has an Object-Version. The Object-Version is the version of the object or the number of changes it has had, including creation. The Object-Version should be the same on all servers in the organization if replication has completed.
The DSA-Signature of an object is the Invocation-ID of the last directory to modify the object. The Invocation-ID is used to uniquely identify each directory in an organization, and can be determined by viewing the raw attributes of the server's directory service.
Every directory keeps track of changes to its own database through Unique Sequence Numbers (USNs). Each directory increments its USNs separately from other Microsoft Exchange Server directories and applies these values to the objects in its directory database. Every time there is a change to the directory, the USN value is used to track the change, and the USN counter is incremented.
These changes are tracked through the USN-Changed attribute. The USN-Changed attribute is the USN value assigned by the local directory for the latest change, including creation.
The USN-Created attribute is the USN-Changed value assigned during object creation.
The USN-Source is the value of the objects USN-Changed attribute on the remote directory that replicated the change to this server, except on the originating directory at creation.