With the introduction of new revisions to Microsoft products—for example, Windows, Exchange, and Communications Server—we have seen a trend toward “roles” within each product, as opposed to the various products being an all-in-one type of solution (as with Exchange 2007), or being additional features that work as a snap-in, such as DNS in Windows 2003.
With earlier versions of Windows Server 2000 or 2003, an Active Directory server was just that—an Active Directory server. What we are trying to say here is that it was more-or-less an “all-or-nothing” deal when creating a domain controller in Windows 2003. Very little flexibility existed in the way a domain controller could be installed, with the exception of whether a domain controller would also be a global catalog server or flexible single master operation (FSMO) server.
