Figure 4-12 A DIT with a virtual DIT view hierarchyThe sub-tree ou=People contains the real Entry A and Entry B entries.The sub-tree ou=Location Views is a view hierarchy.

The leaf nodes ou=Sunnyvale and ou=Mountain View each contain an attribute, nsviewfilter, which describes the view.

These are leaf nodes because they do not contain the real entries. However, when a client application searches these views, it finds Entry A under ou=Sunnyvale and Entry B under ou=Mountain View. This virtual search space is described by the nsviewfilter attributes of all ancestor views. A search made from a view returns both entries from the virtual search space and those from the actual search space. This enables the view hierarchies to function as a conventional DIT or change a conventional DIT into a view hierarchy.

4.4.2Advantages of using virtual DIT viewsThe deployment decisions become easier with virtual DIT views because:

Views facilitate the use of a flat namespace for entries, because virtual DIT views provide navigational and managerial support similar to those provided by traditional hierarchies.

In addition, whenever there is a change to the DIT, the entries never need to be moved; only the virtual DIT view hierarchies change. Because these hierarchies contain no real entries, they are simple and quick to modify.

Oversights during deployment planning are less catastrophic with virtual DIT views. If the hierarchy is not developed correctly in the first instance, it can be changed easily and quickly without disrupting the service.

View hierarchies can be completely revised in minutes and the results instantly realized, significantly reducing the cost of directory maintenance.

Changes to a virtual DIT hierarchy are instantly realized. When an organizational change occurs, a new virtual DIT view can be created quickly. The new virtual DIT view can exist at the same time as the old view, thereby facilitating a more gradual changeover for the entries themselves and for the applications that use them. Because an organizational change

4.4 Virtual directory information tree views

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