The infrastructure master is responsible for updating references from objects in its domain to objects in other domains. The infrastructure master compares its data with that of a global catalog. Global catalogs receive regular updates for objects in all domains through replication, so the global catalog's data will always be up-to-date. If the infrastructure master finds data that is out-of-date, it requests the updated data from a global catalog. The infrastructure master then replicates that updated data to the other domain controllers in the domain.
Important
If all of the domain controllers in a domain are also hosting the global catalog, all of the domain controllers will have the current data and it does not matter which domain controller holds the infrastructure master role.
For more information about operations master roles see Single master operations For information about transferring operations master roles see Transferring operations master roles