We have been asked more than once for documentation on the RDP protocol, UDP transport, RD Gateway protocol, etc. So we have put a list together of this kind of documentation. RDP Protocol Specifications are at MSDN. Go to the  MSDN Library > Open Specifications >. Then go to navigate to Protocols > Windows Protocols > Technical Documents>

The RDP specs are way down in that list under [MS-RDP…]

There are also some listed under [MS-TS….]

You can also download the Windows Protocols Documentation zip file, unzip the archive and pull out the PDFs for RDP and TS.

Other helpful links: