In our PacktBiz.local forest, we have created ITBooks.local, BusinessBooks.local, and ScienceBooks.local tree domains. Inside the ITBooks.local tree domain, we have created a child domain, SysAdmin.ITBooks.local. As you can see, all these tree domains share a common namespace within a forest. This is known as a contiguous namespace (see Figure 4.12):
Figure 4.12. The namespace concept in AD DS