The FSMO Roles on windows Server 2012 also known as Flexible single master operation are the 5 core roles that needed to operate the Windows Active Directory Infrastructure.
The roles divided to 3 Domain roles below and two Forest Roles.
Domain roles (each new domain will have):
- PDC Emulator (primary Domain controller ) – Sync the time to all computers in the forest
- RID Master – Assign SID to each object in the domain
- Infrastructure Master – update cross domain references from global catalog when adding users to security groups from two different domains
Forest roles only:
- Scheme Master – replicate Schema changes to all domain controllers In the forest
- Domain Naming Master – Used when adding or removing domains from the forest