Final answer:
The process is known as replication and it is essential for maintaining consistent data across domain controllers in a network.
Step-by-step explanation:
The process of copying directory data to multiple domain controllers is known as replication. In the context of computer networks, particularly those using Active Directory, replication ensures that each domain controller has an up-to-date copy of the directory for the domain.
This is crucial for the domain's operation because it allows users and computers within the domain to have consistent access to resources regardless of which domain controller they connect to.