There were some questions related to dxsearch tool, in particular these extensions:
[!]sync=ro[/cookie] (LDAP Sync refreshOnly)
rp[/cookie][/slimit] (LDAP Sync refreshAndPersist)
dxsearch tool is based on ldapsearch from OpenLDAP and therefore inherits the parameters of ldapsearch command, including refreshOnly/refreshAndPersist extensions.
These search extensions are used in LDAP Content Synchronization Operation protocol. LDAP CSO protocol (RFC-4533) was experimental and never became a standard.
Some of the LDAP servers support LDAP CSO, for example OpenLDAP.
CA Directory is fully X.500 compatible and does not support LDAP CSO.
Instead replication in CA Directory is done by using either Broadcom proprietary Multi-Write replication or standard X.500 DISP shadowing protocol.
Recommended is Multi-write replication with DISP recovery.