What is the Difference between a LDAP client Prompting for Password as opposed ...

Hello All, Scenario: OpenLDAP Client Machine <-----talking------> OpenLDAP Server Machine. Both Client and Server are two different machines. What is the Difference between an OpenLDAP client Prompting for Password and then authenticating with the OpenLDAP server via TLS as opposed to : An OpenLDAP client redirecting the authentication request to an OpenLDAP server to prompt for the password and do the authentication. What kind of setup would we require if we want the OpenLDAP Server to prompt for the password and do the authentication for an end user to login onto the OpenLDAP client machine. Any thoughts will be of great help!!! Thank you, Amit