2004 International Telemetering Conference20 October 20041 CCSDS FILE DELIVERY PROTOCOL...
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Transcript of 2004 International Telemetering Conference20 October 20041 CCSDS FILE DELIVERY PROTOCOL...
2004 International Telemetering Conference20 October 2004 1
CCSDS FILE DELIVERY PROTOCOL
INTER-IMPLEMENTATION TESTING FINAL REPORT
TESTING OF A DTN PROTOCOL
RICHARD D. CARPER1
Consultant, Space Data Systems
MASSIMILIANO CICCONE2
European Space Agency
KATHY BRYAN ROCKWELL1
Jet Propulsion Laboratory,California Institute of Technology
1This work was performed in part at and under the direction of of the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration.
2This work was performed in part at and under the direction of the European Space Agency.
2004 International Telemetering Conference20 October 2004 2
TextTextTextTextTextTextTextText
• The CCSDS has for over twenty years developed and promulgated space link standards for the use of the international space-faring community
• Over 250 spacecraft have used or are using these standards
• Some of the CCSDS member Agencies, most specifically JPL, are presently developing standards which will extend the Internet into the space data domain.
256 Missions now usingCCSDS Space Link Protocols
2004 International Telemetering Conference20 October 2004 3
CCSDS File Delivery Protocol (CFDP)
Provides international standard file delivery:
•in both reliable and expedited modes•across both short haul and Deep Space links•across single or multi-hop (store and forward) links• re-creates the user’s product directly for transfer to user’s processing•automated protocol improves link utilization and reduces operational costs and complexity
2004 International Telemetering Conference20 October 2004 4
Objectives of Interoperability Test Program
Objectives of the Test Program were to:
Validate the protocol specification
Clarify the wording of the specification, reducing the possibility of differing interpretations
Demonstrate the interoperability of independent implementations
Provide tested reference implementations for potential users
2004 International Telemetering Conference20 October 2004 5
Three Levels of CFDP Protocol Capability
Core Proceduresoperate point-to-point across a single link.
Extended Proceduresproviding an end-to-end store-and-forward functionality across an
arbitrary network, containing multiple links with disparate availability,
as well as subnetworks with heterogeneous protocols.
Store and Forward Overlay (SFO) ProceduresProvide an alternative to the Extended Procedures and operate at the
Application layer, utilizing only the Core Procedures
2004 International Telemetering Conference20 October 2004 6
Three Configurations for Testing
“Face-to-Face” Initial Tests
Worldwide Distributed Testing via the Internet
“Absentee Owner” Testing in a Protocol Testing Laboratory
2004 International Telemetering Conference20 October 2004 7
“Face-to-Face” Tests
The first Testing Workshop was hosted in May, 2000, at APL, Columbia, Maryland It was sufficiently productive that it resulted in a series of Workshops
Further face-to-face Workshops were held at DERA, Farnborough UK, in November 2000, and then at JPL, Pasadena, USA, in May, 2001
Following the Pasadena Workshop the testing migrated to what became a distributed international Inter-Agency Testbed, operating over the Internet
2004 International Telemetering Conference20 October 2004 8
CFDP Distributed Tests
The CFDP Core Procedures were tested in this configuration.15 Test Sessions of approximately 4 hours each were held with implementers and a proctor. 490 tests were conducted.Areas of the specification which were subject to different interpretations were found, but no true errors in the protocol
2004 International Telemetering Conference20 October 2004 9
Protocol Test Lab Tests
The Extended Procedures and the Store and Forward Overlay procedures were tested in the JPL Telecommunications Section’s Protocol Test Laboratory
Both the ESA implementation and the JPL implementation were installed (as multiple instances) in the Lab’s host systems.
Unlike previous tests, the software, set-up and tests were all conducted by Lab personnel, rather than by the Implementers.
2004 International Telemetering Conference20 October 2004 10
Protocol Test Lab Tests (2)
A special tool was developed by the ESA implementer which allowed him to receive hex dumps, via email, of PDUs causing problems and re-insert those PDUs into his local system at ESA ESTEC in Noordwijk, Holland, thus exactly recreating the problem encountered in the Lab at JPL in Pasadena.
This enabled a kind of “batch remote debugging” operation during the initial installation and start-up phase.
2004 International Telemetering Conference20 October 2004 11
Added Capabilities of a Test Lab
CFDP
User App
CFDP/UDP
Ethernet
CFDP
User App
CFDP/UDP
Ethernetinternet
CFDP
User App
CFDP
User App
CCSDS Link CCSDS Link
Radio Radio
Face-to-Face andDistributed TestingVia the Internet
Testing within aSpecialized Test Lab
Noisy,Noisy,AsymmetricAsymmetric
radio linkradio link
2004 International Telemetering Conference20 October 2004 12
Results of Testing
“Face-to-Face” Test ResultsThe CFDP Core Procedures were tested in this configuration. The tests were primarily developmental in nature, and were successful in terms of necessary precursor work and experience.
Distributed Test ResultsThe CFDP Core Procedures were tested in this configuration.15 Test Sessions of approximately 4 hours each were held with implementers and a proctor. 490 tests were conducted.Areas of the specification which were subject to different interpretations were found, but no true errors in the protocol
Protocol Test Lab ResultsThe CFDP Extended Procedures and the Store and Forward Overlay procedures were tested in this configuration. (RESULTS TO BE SUPPLIED)
2004 International Telemetering Conference20 October 2004 13
Lessons Learned
Testing of an in-design protocol by using independently created implementations greatly improves the protocol and the specification document, and increases confidence in them
Face-to-face testing workshops, distributed testing via the Internet, and testing in specialized Protocol Test Laboratories are all valuable and complimentary
To keep testing focused, organized, and moving, it is essential to have a set of common test plans/descriptions for all to use in inter-implementation testing
2004 International Telemetering Conference20 October 2004 14
Conclusions
The CFDP Interoperability Test Program -
Validated the protocol specification
Clarified the wording of the specification, reducing the possibility of differing interpretations
Demonstrated the interoperability of independent implementations
Provided tested reference implementations for potential users
2004 International Telemetering Conference20 October 2004 15
Untethered, disconnectedExtreme mass/power constraintsMobile, ad-hoc, self organizing
Space missions are increasingly moving from point-to-point to networked architectures -- internal to each spacecraft -- on and around other planetsJust like the terrestrial Internet, standardized space networking allows us to build low-cost, reusable infrastructure that can be shared by many diverse space missions
Mars Region 1
Mars Region 2
Mars Orbit Region
Terrestrial RegionDeep Space Backbone Region
A Step on the Road to Interplanetary DTNs
2004 International Telemetering Conference20 October 2004 16
Questions?