The Lightweight Directory Access Protocol (LDAP) is a directory service protocol that runs on a layer above the TCP/IP stack. It provides a mechanism used to connect to, search, and modify Internet directories.
The LDAP directory service is based on a client-server model. The function of LDAP is to enable access to an existing directory.
The data model (data and namespace) of LDAP is similar to that of the X.500 OSI directory service, but with lower resource requirements. The associated LDAP API simplifies writing Internet directory service applications.