You can specify multiple directory services for high availability failover protection.
Not every directory service in the list must be an LDAP server. Any type of LDAP service, whether it is an actual server or a gateway to other LDAP services, is called an LDAP server.
For example:
[DIRECTORY]
ldap=libsybdladp.so ldap://test:389/dc=sybase,dc=com ldap=libsybdldap.so ldap://huey:11389/dc=sybase,dc=com
In this example, if the connection to test:389 fails, the connection fails over to the DCE driver with the specified DIT base. If this also fails, a connection to the LDAP server on huey:11389 is attempted. Different vendors employ different DIT base formats.