NMS EPON OLT device tftp operation status. When the value 'upload(1)' is set, all the value in this mib file would be read into system and cresponding file in destination would be uploaded into flash. As the value 'download(2)' is set, the file in the flash would be downloaded into local machine. After all the operations finish, the value would be set as 'disable(3)' automatically.