Site-link costs

The cost for an Active Directory site link defines the weight of the link. An Active Directory site link with a high cost tells domain controllers, member servers, and devices that the link is less preferable to use compared to an Active Directory site link with a lower cost.

The following factors that would cause a higher cost when designing the Active Directory site link layout:

• The available bandwidth for Active Directory traffic on the networking connection (the networking connection might be flooded with other traffic already)
• The reliability of the networking connection, in terms of unavailability, such as traffic loss or service level

In complex networking environments, where the ring, hub-and-spoke, and mesh topologies are used, end-to-end costs for traversing site links should also be taken into consideration.

The default cost of an Active Directory site link is 100.