NIS and NIS+ share little more than their name and a common goal. NIS+ is
structured entirely differently from NIS. Instead of a flat namespace with
disjoint NIS domains, NIS+ uses a hierarchical namespace similar to that of
DNS. Instead of maps, so-called tables are used that
are made up of rows and columns, in which each row represents an object in the
NIS+ database and the columns cover 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
NIS+ additionally supports secure and encrypted RPC, which helps greatly to
solve the security problems of NIS.
Traditional NIS has an RPC Version number of 2, while NIS+ is Version 3.
At the time we're writing, there isn't yet a good working implementation
of NIS+ for Linux, so it isn't covered here.