Flexible Single Master Operation

Multimaster replication is used to replicate the main domain database. This means that there is no central point of failure. The Active Directory provides normal functionality even if a domain controller is offline.

There are five critical operations that are handled by a single master which holds the FSMO Flexible Single Master Operation role.

Forest-wide - One for the entire forest

• Schema master handles schema changes
• Domain naming master checks names when creating new domains

Domain-wide - One for each domain

• RID pool master manages the allocation of domain SID numbers to ensure that they are unique.
• PDC emulator emulates an NT 4 Primary Domain Controller
• Infrastructure master, maintains cross-domain links