Active Directory needs information about the underlying network to determine how domain controllers should replicate and what domain controller(s) are optimal for a given client to authenticate with. This network information is often referred to as the site or replication topology, and it consists of numerous object types that represent various aspects of the network.
At a high level, a site is a logical collection of high-speed LAN
segments. One or more subnets can be associated with a site, and this
mapping is used to determine which site a client belongs to, based on its
IP address. Sites are connected via site links, which are analogous to WAN
connections. Finally, each domain controller in a site has one or more
connection objects, which define a
replication connection to other domain controllers.
These site topology objects are contained under the
Sites container within the Configuration naming
context. Figure 11-1 shows an example of
the site topology hierarchy using the Active Directory Sites and Services
Directly under the
container are the individual site containers, plus containers that store
the site link objects (
Transports) and subnets (
cn=Subnets). Three objects are included within a
NTDS Site Settings
(nTDSSiteSettings) object that contains attributes that can
customize replication behavior for the whole site
License Site Settings
(licensingSiteSettings) object that can be used to direct hosts ...