Controls and Extensions were added to version 3 of the LDAP protocol. In version 2, there was no standard mechanism to extend the protocol, requiring developers to extend the protocol in non-standard ways. In version 3, extensions and controls were defined to provide consistent expansion of the protocol.
NOTE:The LDAP and eDirectory guide contains a good introduction to LDAP controls and extensions, and contains information you need to be aware of when using these controls with eDirectory. It is recommended that you read the LDAP Controls and the LDAP Extensions chapters in the integration guide.