Batching on SQL directories is handled by NXP-5301, but other kinds of directories should comply to this API too.
Copied notes from Olivier about LDAP implementation:
Ordering the results according to the content of a specified attribute/field for LDAP this is not possible for all server implementations: OpenLDAP for instance does not implement the VLV extension  that would be required to implement such a feature.
For the multi, this can be implemented if the underlying backend implement it too.
 VLV extension: http://tools.ietf.org/html/draft-ietf-ldapext-ldapv3-vlv-04