Creating a Site Link Bridge Design

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

A site link bridge connects two or more site links. Figure 3.19 shows the steps for creating a site link bridge design.

Figure 3.19   Creating a Site Link Bridge Design

A site link bridge enables transitivity between site links. Each site link in a bridge must have a site in common with another site link in the bridge. The Knowledge Consistency Checker (KCC) uses the information on each site link to compute the cost of replication between sites in one site link and sites in the other site links of the bridge. Without the presence of a common site between site links, the KCC also cannot establish direct connections between domain controllers in the sites that are connected by the same site link bridge.

By default, all site links are transitive and it is recommended to keep transitivity enabled by not changing the default value of Bridge all site links (enabled by default). However, you will need to disable Bridge all site links and complete a site link bridge design if:

• Your IP network is not fully routed. When you disable Bridge all site links, all site links are considered nontransitive, and you can create and configure site link bridge objects to model the actual routing behavior of your network.

  –Or–

  You need to control the replication flow of the changes made in Active Directory. By disabling Bridge all site links for the site link IP transport and configuring a site link bridge, the site link bridge becomes the equivalent of a disjointed network. All site links within the site link bridge can route transitively, but they do not route outside of the site link bridge.

For more information about how to use Active Directory Sites and Services to disable the Bridge all site links setting, see "Enable or disable site link bridges" in Help and Support Center for Windows Server 2003.