NIS is a dedicated name service subsystem, designed only to serve Posix-style naming information.
LDAP’s design allows it to be a highly adaptable tool, and has many uses. NIS’s limitation in flexibility and scalability allow its design to be much simpler and thus able to achieve higher through-put than an LDAP directory server. Some of the significant factors that differentiate performance between NIS and LDAP:
- The NIS protocol runs on top of UDP. This is a connectionless protocol, and has less overhead than the TCP protocol used by LDAP.
- NIS uses a simple key-to-entry query scheme to find data. LDAP uses a flexible, but complex, base/scope/filter search criteria.
- NIS does not perform authentication. LDAP performs authentication.
- NIS does not perform access control to data. LDAP servers can restrict access to certain data sets using highly flexible access control mechanism.
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