How to get the event notifications from LDAP server on changes/updates?

Did anybody have used the pub.client.ldap:registerNotification service to register a event notification.
I have a requirement to get event notifications from the LDAP Servers on changes/additions/updates, based on that, target servers have to be synchronized.
Can anybody please advise me on this, how to proceed.?
I have tried to register a notification using above mentioned service and created target service to process the received input.But i am not seeing any input in the target service pipeline.