Remote Differential Compression (RDC) is a client–server synchronization algorithm that allows the contents of two files to be synchronized by communicating only the differences between them. It was introduced with Microsoft Windows Server 2003 R2 and is included with later Windows client and server operating systems. RDC is similar in many ways to the older (1996) rsync protocol, but with some useful innovations, in particular the recursive algorithm and cross-file RDC.