NIS and NIS+ share little more than their name and a common goal. NIS+ is structured in an entirely different way. Instead of a flat name space with disjoint NIS domains, it uses a hierarchical name space similar to that of DNS. Instead of maps, so called tables are used that are made up of rows and columns, where each row represents an object in the NIS+ database, while the columns cover those properties of the objects that NIS+ knows and cares about. Each table for a given NIS+ domain comprises those of its parent domains. In addition, an entry in a table may contain a link to another table. These features make it possible to structure information in many ways.
Traditional NIS has an RPC version number of-2, while NIS+ is version-3.
NIS+ does not seem to be very widely used yet, and I don't really know that much about it. (Well, almost nothing). For this reason, we will not deal with it here. If you are interested in learning more about it, please refer to Sun's NIS+ administration manual ([]).