What is Active Directory?

The Active Directory is the central repository in which all objects in an enterprise and their respective attributes are stored. 
Active Directory provides a variety of network services, including Lightweight Directory Access Protocol. LDAP is the industry standard directory access protocol, making Active Directory widely accessible to management and query applications. 
Active Directory provides:- 

• Lightweight Directory Access Protocol LDAP is the industry standard directory access protocol, making Active Directory widely accessible to management and query applications. Active Directory supports LDAPv3 and LDAPv2.
• Kerberos -based authentication
• DNS -based naming and other network information
• Central location for network administration and delegation of authority
• Information security and single sign-on for user access to networked based resources
• Central storage location for application data