UDR is a wrapper around rsync that enables rsync to use UDT protocol and
thus improves throughput of large data transfers over long distances.

UDT is a UDP-based, application level protocol. It is designed to
support transferring large datasets over high speed wide area networks,
where TCP has been known to be extremely ineffective.

UDR does not change rsync, it works by creating a UDT connection and
then places the connection between the rsync client and server.

To use UDR, prefix the current rsync command used to transfer data with
'udr', for example:

udr rsync -avz /home/user/dir/ user@example.com:/home/user/dir

Any rsync options can be used.

UDR must be on the client and server machines that data will be
transferred between. UDR uses ssh to do authentication and automatically
start the server-side UDR process. At least one UDP port needs to be
open between the machines.