def normalize_lun(scsi_id):
    """Normalize the lun id to Big Endian

    :param scsi_id: Volume lun id
    :return: Converted LUN id in Big Endian as per the RFC 4455
    """
    # PowerVM keeps LUN identifiers in hex format.
    lun = '%x' % int(scsi_id)
    # For drivers which support complex LUA lun-id exceeding more than 2
    # bytes in such cases we need to append 8 zeros else 12 zeros to
    # pass 8 byte lun-id
    if len(lun) == 8:
        lun += "00000000"
    else:
        lun += "000000000000"

    return lun