XFDU for TGFT
9 May 2017
John Pietras
Global Science and Technology, Inc.
Outline

Concept for using XFDUs for TGFT

Simplification of XFDU Manifest for TGFT (component
by component)

File naming conventions

Extending XFDU with TGFT-specific and TGFT-usingservice-specific metadata

Example XFDU Manifest
www.ccsds.org
2
Concept for using XFDUs for TGFT (1 of 2)
Provider CSSS A,
Provider Node A1
Mission B,
Earth User Node B2
recipient service
entities locate and
extract their
respective XFDU
Packages
XFDU
Packages +
destination
in-tray URL
Service M
Provider (source)
(sender)
(receiver)
Service N
Provider (source)
TGFT
Service X Provider
(recipient)
Service Y Provider
(recipient)
Mission
B
in-tray
Service N User
(recipient)
TGFT
Service X User
(source)
(receiver)
recipient service
entities locate and
extract their
respective XFDU
Packages
www.ccsds.org
P-CSSS
A
in-tray
Service M User
(recipient)
(sender)
Service Y User
(source)
XFDU
Packages +
destination
in-tray URL
3
Concept for using XFDUs for TGFT (2 of 2)
XFDU Package (ZIP, TAR)
XFDU Mainifest (XML)
Package Header
Information Package Map
Metadata Section
External
metadata
Embedded
Embedded
Metadata
Metadata
Data Object Section
Embedded
Embedded
Data
Data
No external
XXXXXXXXXXXXXXXXXXXXXXX Data for TGFT
Behavior Section
Metadata file
Metadata file
www.ccsds.org
Data file)
Data file)
4
Simplification of XFDU Manifest for TGFT
(Component by Component)

In the Tech Note, section 2 provides the rationale fro inclusion/exclusion
of attributes and parameters, and section 3 provides the resulting
composition rules

The standard CCSDS XFDU Manifest comprises five major components





www.ccsds.org
Package Header
Information Package Map
Data Object Section
Metadata Section
Behavior Section
5
Top-Level XFDU Manifest Schema
xfdu:XFDUType
attributes
ID
objID
textInfo
Version of the XFDU specification.
For TGFT, value is “1.0”
version
XFDU
packageHeader
inform ationPackageMap
m etadataSection
dataObjectSection
Intended to contain
executable code
– not used for TGFT
behaviorSection
www.ccsds.org
6
Package Header
For TGFT, default value is “PkgHdr”, but services
may redefine (e.g., for sequences of XFDUs)
attributes
ID
xfdu:volum eInfoType
specificationVersion
xfdu:sequenceInform ationType
packageHeaderType
volum eInfo
attributes
packageHeaderTy pe:
C omplex Ty pe for metadata
about the
mapping of the logical
packages to the phy sical
structures. The
package header ty pe
has tw o elements:
-v olumeInfo contains XF DU
v olume related metadata
(i.e., XF DU specification
v ersion
and sequence information
- env ironmentInfo
contains application specific
information either defined by
an extension of the XF DU
S chema or by
freeform XM L.
packageHeaderTy pe
has a single attribute, ID: an
XM L ID.
sequenceInform ation
sequencePosition
sequenceSize
xfdu:environm entInfoType
xfdu:xm lDataType
xm lData
0..¥
any ##any
1..¥
xfdu:extensionType
environm entInfo
0..¥
attributes
any ##other
extension
For TGFT, at least one instance is
required, containing a required
extension element
www.ccsds.org
any ##other
7
Information Package Map
For TGFT, this is required and is used
to identify the service to which the
XFDU belongs
For TGFT, required for XFDU
Packages containing more than one
Payload data file
Points to the set of metadataObjects
associated with the payload data file
For this content unit
For TGFT, used to add per-payloaddata-file, TGFT-specific and TGFTusing-service-specific metadata
One Content Unit
per payload
data file
Points to Data Object
for the payload data file
For TGFT, only one
Data Object per
Content Unit
www.ccsds.org
8
Data Object Section
Pointed to by dataObjectID attribute of
informationPackageMap:contentUnit:dataObjectPointer
element
For TGFT, this is always “URL”
For TGFT, only
one byteStream
per dataObject
www.ccsds.org
For TGFT, is the URL of the
payload data file within the
same zipped/tarred
XFDU Package
9
Metadata Section
For TGFT, this is either absent
or “OTHER” (use defined by service)
Pointed to by anyMdID
attribute of content unit(s)
For TGFT, this is either absent
or “OTHER” (use defined by service)
For TGFT, this is either absent or the
name of the service-specific classification
For TGFT, this is either absent or the
name of the service-specific category
For TGFT, this is
always “URL”
For TGFT, is the URL of the
metadata file within the
same zipped/tarred
XFDU Package
-ORFile at remote location
www.ccsds.org
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File Naming and Packaging Conventions

XFDU Package

Packaged as a zipped/tarred folder containing
•
•
•

XFDU Manifest file
One or more payload data files
Zero or more metadata files
XFDU Package name =
<service-specific part>+<timestamp part>.zip|tar
•
•
<service-specific part> constrained to the character set {[a-z], [0-9], -, _, .}
<timestamp part> is a modified CCSDS ASCII Time Code B:
<YYYY>-<DDD>T<hh>-<mm>-<ss>Z
(dashes instead of colons in HHMMSS substring)

XFDU Manifest file naming convention is left to the service, except that the
file extension type shall be “.xfdu”

Payload data file naming convention is left to the service

Embedded metadata file naming convention is left to the service

Remote metadata file naming conventions are left to the creators of those
files
www.ccsds.org
11
Extending XFDU with TGFT-Specific and TGFTUsing-Service-Specific Metadata

Two TGFT XFDU extension schema types are defined



www.ccsds.org
TgftXfduExtensionType to add TGFT-standard metadata parameters that
apply to the XFDU Package as a whole
TgftContentUnitExtensionType to add metadata parameters that apply to
individual payload data files
Actual TGFT parameters of both schema types are still TBD: the following are
examples
12
Candidate TGFT XFDU Extension Metadata
Parameters Identified at Rome Meeting (1 of 2)

Number of Files: Not covered by XFDU standard; could be added to
TgftXfduExtensionType

File Name: Covered by XFDU standard

File version: Not covered by XFDU standard; could be added to
TgftContentUnitExtensionType

Creation Date (of individual payload files): Not covered by XFDU
standard; could be added to TgftContentUnitExtensionType

File Content Type (not sure what this means. XFDU has mime and
unitType attributes that may service this purpose)

File size: Covered by XFDU standard

File encoding (binary, ASCII, etc.): Not covered by XFDU standard; could
be added to TgftContentUnitExtensionType

Security Credentials (per each payload data file?): Not covered by XFDU
standard; could be added to TgftContentUnitExtensionType
www.ccsds.org
13
Candidate TGFT XFDU Extension Metadata
Parameters Identified at Rome Meeting (2 of 2)

Originator: Not covered by XFDU standard; could be added to
TgftXfduExtensionType

Recipient: Not covered by XFDU standard; could be added to
TgftXfduExtensionType

Valid dates (start/end times): Not covered by XFDU standard;

Is this for the whole XFDU Package or for each individual payload data file?

Description/Reason: Presumably covered by the various text attributes

Checksum: Covered by XFDU standard

Category: Not covered by XFDU standard; what does this mean? (could
be added to TgftContentUnitExtensionType)

Identifier: Multiple identifiers throughout the XFDU Manifest, but do they
service the purpose intended by this?

Sequence Number: Covered by the order attribute of the Content Unit
www.ccsds.org
14
Example XFDU Manifest (XmlSpy Grid View)
SANA repository
.tdm
TDM file embedded in XFDU Package
www.ccsds.org
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