The CDS namespace is the part of the DCE namespace that resides in the local cell's CDS. DCE itself is made up of components that, like the applications that use them, are distributed client/server applications. These components rely on the CDS to make themselves available as services to DCE applications. This requires that the structure of the cell namespace be stable, known, and have parts that are not alterable by casual users or applications.
More:
CDS Entries and CDS Attributes