To upgrade resource domains, choose domains in which new applications will require Windows 2000 platform or features first. Then choose domains with many clients. Finally choose domains that are targets for restructure. Cannot add BDC any longer. Only Active Directory multiple-master replication between domain controllers is active.
All domain controllers can now perform directory updates.
All pre-Windows 2000 clients will use the PDC emulator to locate the PDC and perform password changes. PDC emulator appears as a Windows 2000 domain controller to other Windows 2000 computers, and as a Windows NT PDC to pre 2000 computers. The PDC emulator can still be used to create new security principals and to replicate these changes to the Windows NT BDCs, and if the PDC emulator becomes unavailable, and if another Windows 2000 domain controller exists in the domain, then that domain controller will need to be made as the PDC emulator. The bottom line is, when everything is W2K, you do not need PDC emulator at all. After the upgrade, Windows NT local groups become Windows 2000 local groups, and Windows NT global groups become Windows 2000 global groups.