To maintain schema-consistency in an LDAP Directory Information Tree (DIT), the LDAP standard specifies that:

A.
The client first downloads the DIT schema from the server and then makes sure every request it sends conforms to the schema;
The server therefore doesn’t have to check DIT for consistency

B.
The operator periodically scans the DIT to check that the schema is not violated, and manually corrects any inconsistencies
caused by clients

C.
The server periodically scans the DIT to check that the schema is not violated, and sends a notification to the operator when it
finds an inconsistency caused by clients

D.
The server periodically converts the DIT to an SQL database; Schema-checking is done by the SQL engine and then the database
is converted back to a DIT

E.
The server checks every client operation for schema consistency, and ignores requests that would result in a DIT inconsistency