Remote Differential Compression
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Remote Differential Compression (RDC) is a client-server synchronization protocol that allows the contents of two files to be synchronized by communicating only the differences between them. It was introduced with Windows Server 2003 R2 and is included with later Windows client and server operating systems.
Unlike Binary Delta Compression (BDC), which is designed to operate only on known versions of a single file, RDC does not make assumptions about file similarity or versioning. The differences between files are computed on the fly, therefore RDC is suitable for efficient synchronization of files that have been updated independently, network bandwidth is small or in scenarios where the files are large but the differences between them are small.
The Client Side Caching (CSC) feature in Windows Vista makes use of the technology for the first time, allowing file types such as Microsoft Outlook personal folders (*.pst) to be made available offline. Previously, Windows XP used only file metadata to test if a .pst file had changed. However Microsoft Outlook "touches" a .PST file's date, even when it does not make any changes, causing CSC in Windows XP to recopy these large files unnecessarily.
[edit] External links
- Introduction to DFS replication
- About Remote Differential Compression
- Optimizing File Replication over Limited-Bandwidth Networks using Remote Differential Compression
