MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

Lesson 1 Overview of Active Directory
14-13
❑ An OU is a container used to organize objects within a domain into logical
administrative groups. An OU can contain objects such as user accounts,
groups, computers, printers, applications, file shares, and other OUs.
❑ A tree is a grouping or hierarchical arrangement of one or more Active Directory
domains that share a contiguous namespace.
❑ A forest is a grouping or hierarchical arrangement of one or more trees that
forms a disjointed namespace.
■ The physical structure of Active Directory is based the underlying network. Major
components of the physical structure include the following:
❑ A domain controller is a computer running Windows 2000 Server or Windows
Server 2003 that stores a replica of the domain directory (local domain database).
You can create any number of domain controllers in a domain. Each
domain controller in a given domain has a complete replica of that domain’s
directory partition.
❑ A site is a combination of one or more IP subnets connected by a high-speed
link.
■ Within a site, Active Directory automatically generates a ring topology for replication
among domain controllers in the same domain. The ring structure ensures
that there are at least two replication paths from one domain controller to another;
if one domain controller is down temporarily, replication continues to all other
domain controllers.