AD LDS Technical specifications
Microsoft Open Specifications are the references that Microsoft provide for developers working on interoperability and integration. They are also an invaluable source of information for architects working with Microsoft technologies. The two key references for Active Directory technology are MS-ADTS (the AD Technical Specification) and MS-DRSR (the replication specification); the latter being largely a protocol implementation reference for developers whilst the former is more generally readable. For AD LDS three important documents are:
to be found amongst the other Windows Server Protocol Specifications here.