Links between tables produce an effect similar to paths, except that the link involves a search through only one table: the remote table. With a search path, NIS+ first searches the local table, and only if it is unsuccessful does it search the remote table. With a link, the search moves directly to the remote table. In fact, the remote table virtually replaces the local table. The benefit of a link is that it allows a lower domain to access the information in a higher domain without the need to administer its own table.
Deciding whether to use a path or to link NIS+ tables in a domain is a complex decision, but here are some basic principles:
Every domain must have access to every standard table.
Volatile, frequently accessed data should be located lower in the hierarchy. Such data should be located closer to where it is used most often.
Data that is accessed by several domains should be located higher in the hierarchy, unless the domains need to be independent.
Figure 2-7 summarizes this principle.