NIS+ has some major advantages over NIS:
Secure data access
Hierarchical and decentralized network administration
Very large namespace administration
Access to resources across domains
Within the security system described in NIS+ Security, you can control a particular user's access to an individual entry in a particular table. This approach to security helps to keep the system secure and administration tasks to be more broadly distributed without risking damage to the entire NIS+ namespace or even to an entire table.
The NIS+ hierarchical structure allows for multiple domains in your namespace. Division into domains makes administration easier to manage. Individual domains can be administered completely independently, thereby relieving the burden on system administrators who would otherwise each be responsible for very large namespaces. As mentioned above, the security system in combination with decentralized network administration allows for a sharing of administrative work load.
Even though domains may be administered independently, all clients can be granted permission to access information across all domains in a namespace. Since a client can only see the tables in its own domain, the client can only have access to tables in other domains by explicitly addressing them.
Incremental updates mean faster updates of information in the namespace. Since domains are administered independently, changes to master server tables only have to be propagated to that master's replicas and not to the entire namespace. Once propagated, these updates are visible to the entire namespace immediately.