Do you know this problem. You are copying a large file via scp to a server and than the connection is lost. Actually you can resume the scp prozess for the file. This is for copying a file from a server to your machine.
rsync --partial --progress --rsh=ssh user@host:remote_file local_file
and this is for copying a file from your machine to a server:
rsync --partial --progress --rsh=ssh