Nathan Muggli, Lead Program Manager, presented a discussion of MS-ADSO, a system overview document at the 2009 Active Directory Windows Protocols Plugfest. Suneel Parthasarathy, Lead Developer, and Matthew Rimer, Senior Developer, answered protocol interoperability questions. MS-ASDO, to be delivered in an upcoming Windows Protocol Document release, describes the relationships of the system of protocols that comprise client-server behavior of the Active Directory System. MS-ADSO describes the intended client-server functionality of the Active Directory System and how the protocols in this system interact. System architecture, abstract data models and use cases including domain join are covered as well.