Cross-file RDC allows DFS replication to use RDC even when a file with the same name does not exist at the client end (provided either the client or server is running Windows Server 2003 R2, Enterprise Edition). Cross-file RDC uses a heuristic to determine files that are similar to the file that needs to be replicated, and uses blocks of the similar files that are identical to the replicating file to minimize the amount of data transferred over the WAN. Cross-file RDC can use blocks of up to five similar files in this process.