3.6 Netlogon NT Replication Details
Netlogon replication is a single master replication in which the PDC serves as the replication master. The PDC maintains a state for each BDC that includes the database serial number of the BDC database. The PDC periodically sends announcement messages to BDCs with out-of-sync database serial numbers to notify them about database changes accumulated during the period. In response, BDCs receiving the message update their database by making synchronization calls to the PDC using RPC. The PDC updates the database serial number in the local state information for the BDC after processing the synchronization call from that BDC.
Figure 8: PDC States
Figure 9: BDC States