The video shows how to authorize a DHCP server in Active Directory Domain Services.
In Active Directory replication, the bridgehead server is a contact point in a site, which is used to exchange or replicate directory information between Active Directory sites. It acts as a gateway. When a bridgehead server is used, all Exchange traffic is channeled through that server, which transfers the data to the appropriate site.
The global catalog is built automatically by the Active Directory replication system. All directory partitions on a Global Catalog server, whether full or partial partitions, are stored in a single directory database (NTDS.DIT) on the same server.
When a new domain is added to the forest, the information about the new domain is stored in the configuration directory partition. This directory partition reaches the Global Catalog server (and all domain controllers) through the replication of forest-wide information.
Note: When a new Global Catalog server is designated, this information is also stored in the configuration directory partition and replicated to all domain controllers in the forest