Active Directory Cookbook

Chapter 11. Site Topology

Introduction

Active Directory needs information about the 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 consists of numerous object types that represent various aspects of the network.

At a high level, a site is a 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 (based on IP address) belongs to. 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 defines a replication connection to another domain controller.

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 snap-in.

Figure 11-1. Site topology hierarchy

Directly under the Sites container are the individual site containers, plus containers that store the site link objects (cn=Inter-site Transports) and subnets (cn=Subnets). There are three objects included within a site, an NTDS Site Settings (nTDSSiteSettings) object that contains attributes that can customize replication ...