Configuring Active Directory Infrastructure - domain and forest functional levels
Configure a forest or a domain
Raising the Domain and Forest Functional Levels
To leverage more advanced features in Active Directory, you can raise the domain and forest functional levels within Active Directory after you have retired any domain controllers that are running down-level operating systems, such as Windows 2000.
Domain and forest functional levels are available to provide backward compatibility with previous Windows Server operating systems. Migrating your network to one consistent platform provides many administrative benefits and can lower the overall network cost of ownership. Prior to raising the domain functional levels, verify that any previous Microsoft Windows network operating systems are not needed in the domain. Careful planning will be required for each company and their current network structure.
If an organization is interested in any future acquisitions or mergers, raising the domain level could have an impact, and this should be taken into careful consideration. For example, if an enterprise organization is growing rapidly by buying up the competition, it would be safe to assume that not all of the new acquisitions are running Windows Server 2008. Deciding how to integrate network structures into your corporate enterprise will be a challenge because many networks will have a mixed bag of operating systems. The Windows Server 2008 family provides several new enhancements to assist in making the transition easier. Note the following key facts and requirements for raising domain and forest functional levels:
- This is a one-way operation. Raising the domain and forest functional levels cannot be reversed without a complete reinstallation of the domain or forest.
- Each domain can be handled independently, thereby allowing a phased approach to increasing functionality. This allows corporations sufficient transition time to upgrade each location or domain. Some locations may need to purchase new hardware or upgrade existing infrastructure prior to a migration.
- The forest functional level cannot be raised until all domains in a forest have been raised to at least the corresponding Domain Functional Level.
- You must be logged on as a member of the Domain Admins group to raise the domain functional level.
- You must be logged on as a member of the Enterprise Admins group to raise the forest functional level.