This enumerated field selects which file-transfer protocol a recurring, scheduled full-state backup policy configured for a UCS domain uses to reach its remote destination server. The choice here determines exactly which network port and authentication mechanism a BackupPolicy needs open and working between the UCS domain's management network and the destination server — an admin who moves a backup target behind a firewall needs to make sure the matching protocol's port is allowed. Supported values include ftp, tftp, scp, sftp, and http, with scp/sftp being the common choice where encryption in transit matters.