2.7.5.2 Replicate Changes to a GC or a Partial Replica by Using RPC - Domain Controller
In this use case, replication of changes is performed periodically between a domain controller that is a full replica and a global catalog (GC) or a partial replica in another domain by using RPC.
Goal
Replicate changes to a GC or partial replica.
Context of use
Changes have to be replicated between two domain controllers, where one is a full replica and the other is a GC or a partial replica in another domain. This scenario works in a replication topology that was built by the KCC, as described in section 1 and [MS-ADTS] section 6.2.

Figure 33: Use case diagram for replicating changes in a full replica to a GC or a partial replica
Actors
Domain Controller 1 (GC)
Domain Controller 1, or DC1, is the primary actor that has not yet received the originating updates that were applied to DC2. DC1 is a GC or partial replica and a replication partner of DC2.
Domain Controller 2 (DC2)
DC2 is the supporting actor that has originating updates to its domain data.
Stakeholders
Domain administrators and applications
Domain administrators and applications are the entities that change attribute values in domain data.
Preconditions
The environment described in section 2.5 is in place and the system-wide preconditions described in section 2.6 are satisfied. The Active Directory system completes initialization, as described in section 2.6.
The KCC has created the replication topology of the domain; that is, the physical connections among the domain controllers of the domain that are used for replication traffic.
DC1 and DC2 are in different domains.
DC1 has a partial replica of the domain in which DC2 resides.
Main Success Scenario
Trigger: A domain administrator changes an attribute's value for an object in the domain data. The change is manifested as an originating update on DC2.
Depending on the replication interval calculated by the KCC ([MS-ADTS] section 6.2), DC1 sends a request to DC2 to obtain new values of only the attributes of the objects that are present in the DC1 partial replica.
DC2 responds to DC1 with the new values.
DC1 applies the changes to its replica.
Postcondition
Replication changes to the attributes that are present in the partial replica are updated to the new values that are present in the full replica.
Extensions
None.
Variation
Replicate changes to a GC or a partial replica by using SMTP
All the details in the preceding scenario are the same except that there are additional preconditions as follows:
The domain controllers require the ability to send and receive SMTP messages using any SMTP mail transfer agent, as specified in [RFC2821].
There are additional conditions that the configurations of the domain controllers have to meet before the DRS Protocol Extensions for SMTP can be used to replicate state between the domain controllers, as described in [MS-SRPL] sections 1.5 and 3.1.3.