Domain Functional Level
There are four types of Domain functional level:-
1) Windows 2000 mixed (default)
2)Windows 2000 native
3)Windows Server 2003 interim
4)Windows 2003 Server
Here is more detial on domain functional level. Changing a domain functional level is a one-way process only.
Here are some related links.
Exam tips:- Remember the domain functional levels and the various domain controllers supported in each functional level.To raise the domain and forest functional level one must be a member of either Domain Admins group of that domain or the Enterprise Admins group in the forest of the root domain.