I just wanted to know what background process does ARS do to provision objects to AD. Is it LDAP or any scripts that it run in background.
The Active Roles service uses a component called the "ADSI Provider" to communicate with Active Directory. The component is provided by Quest / OneIdentity but is based on Microsoft's implementation of an LDAP-compliant API. The principles are the same as those used for ADSI Powershell scripting.
ADSI = Active Directory Services Interface.
Out of the box, Active Roles itself doesn't use any scripts for operations against AD but any "add-ons" you create ("script activities" and "policy scripts") can be built as Powershell scripts.
It might be helpful to provide some background on your question to help us to provide a better / more complete answer.
It is a question to Product Management. My understanding:
Legacy version 5.x, 6.x based on VBScript MSFT platform used "wrappers" around ADSI/LDAP API for AD and MAPI for Exchange 2000/2003, Win32 for Window OS. Was it VBScript or compiled .exe - it is question to devs.
New 7.x version was recoded based on ADSI/LDAP and PS1 scripting for AD and Exchange 2010 and upper - the "wrappes" around native MSFT platform API. Is it .NET or PS1 scripting in the code: probably both.