NIS and NIS+ have several differences that have an impact on a transition. For example, NIS uses a flat, non-hierarchical namespace for each domain. NIS+ introduces a more complex domain hierarchy, similar to that of DNS. Before converting to NIS+, you must plan your networking needs and design the NIS+ namespace.
Also, NIS+ provides security, which limits access not only to the information in the namespace but also to the structural components of the namespace. Users, groups, access rights, and other security issues should be analyzed.
NIS+ is not simply an upgrade to NIS but entirely replaces it. Therefore, the transition from NIS to NIS+ is largely directed by the differences between the products, and understanding these differences is critical to a successful transition to NIS+. Differences are described in NIS and NIS+ Differences.