OU design takes administrative control into consideration before building the OU structure for Group Policy application. This allows for an organization to build an efficient administrative design, thus reducing the amount of administrative overhead that will be incurred by the organization. If properly planned out, the administrative control of the objects within Active Directory will be very straightforward and easy to maintain.
OUs will also allow you to easily upgrade or restructure Windows NT 4.0 domains into a single administrative unit. The original domain owners could become OU owners and the account and resource domains can either take on the same structure that was utilized within the NT 4 environment, or the entire structure can be redesigned and collapsed into a new administrative design.
In the next chapter, we are going to look at strategies used in designing an OU structure to allow for the efficient application of group policies. Because group policies and administrative designs do not always work out to be the same design methodology, we will also look at some of the trade-offs that you may have to make to design the best of both worlds .