An overview of activities of the CCSDS (Consultative Committee for Space Data Systems) USLP (Unified Space Data Link Protocol) implementation

Pitts, Lee

NASA Technical Reports Server

1 12/20/2017Ok for Public Release, distribution unlimited
CCSDS USLP Activities
Nov 2017 
Lee Pitts
Deutsches Zentrum für Luft National Aeronautics and
Raumfahrt e. V. Space Administration
https://ntrs.nasa.gov/search.jsp?R=20170012462 2019-08-30T16:39:30+00:00Z
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Outline
• USLP implementation
– Overview
• Participants
• Test configuration
– Current status 
– Plan for testing
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• Two USLP implementations are being developed by DLR and MSFC/NASA
• Stefan Veit at DLR
• Kevan Moore at MSFC/NASA (Huntsville Operations Support Center)
• 3rd test team in the UK is generating an implementation
• Preliminary connection information has been exchanged between 
parties
• HOSC paper work is ready for approval  
• The implementations are being conducted remotely over a VPN 
• Each end has been developing and testing incrementally 
• Current testing has been on Red-2 with Red-3 updates
Overview
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• Test configuration use a reciprocal test mechanism
• Tester 1 generates a test activity and forwards to Tester 2
• Tester 2 receives and operates on the data and retransmits to tester 1
• Tester 1 receives and operates on the data
• Allows multiple test 
• Multiple independent test with only minor participation of a secondary 
tester.
• In the process of generating the formal test plan for acceptance of USLP
• Test goal is non-performance related
• Functional testing
• Basic framework
• Earliest opportunity
Current Status
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• Using a two pass scenario for testing
• First pass is a procedure check for completeness
• Second pass is on automatic and will vary conditions more widely
• Doing fixed and variable length frames 
• Using a known pattern for checking
• Use of CRC for automated checking
• Permutation of absence/presence of every optional field has been tested
• The next phase will be used to generate a yellow book
• Requires support beyond the current test configuration
Plan for testing
6 12/20/2017Ok for Public Release, distribution unlimited
PICS compliance
• Red 3 PICS has been evaluated for compliance. 
Following is a status of Annex A.
– Overall evaluation and verification of compliance 
is greater than 70% by both parties
– Some requirements will be untestable under the 
current techniques
• FECF defined in Annex B
• Performance numbers over a space link
– Most construction areas have been evaluated
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PICS Summart
Annex A REQUIREMENTS LIST MSFC DLR
Table A-1: USLP Service Data Units 6 100% 6 100%
Table A-2: Service Parameters
MAP Packet Service Parameters 5 62.50% 3.5 43.75%
MAPA Packet Service Parameters 4 66.67% 3.5 58.33%
MAP Octet Stream Service Parameters 3 60.00% 3.5 70.00%
MC_OCF Service Parameters 2 66.67% 3 100.00%
VCF Service Parameters 2 66.67% 3 100.00%
MCF Service Parameters 2 66.67% 3 100.00%
Insert Service Parameters 2 66.67% 3 100.00%
COPs Management Service Parameters 0 0.00% 0 0.00%
Table A-3: Service Primitives
MAP Packet Service Primitives 3 100.00% 2 66.67%
MAPA Service Primitives 3 100.00% 2 66.67%
MAP Octet Stream Service Primitives 2 100.00% 2 100.00%
MC_OCF Service Primitives 2 100.00% 2 100.00%
VCF Service Primitives 2 100.00% 2 100.00%
MCF Service Primitives 2 100.00% 2 100.00%
Insert Service Primitives 2 100.00% 2 100.00%
COPs Management Service Primitives 0 0.00% 0 0.00%
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PICS Summart
Annex A REQUIREMENTS LIST MSFC DLR
Table A-4: USLP Protocol Data Unit 6 100.00% 6 100.00%
Table A-5: Protocol Procedures 16 100.00% 14 87.50%
Table A-6: Management Parameters
Parameters for a Physical Channel 9 75.00% 8 66.67%
Managed Parameters for a Master Channel 3 75.00% 4 100.00%
Managed Parameters for a Virtual Channel 10 66.67% 9 56.25%
Managed Parameters for a MAP Channel 3 100.00% 3 100.00%
Managed Parameters for a Packet Transfer 3 100.00% 0 0.00%
Table A-7: Protocol Specification with SDLS Option 12 85.71% 12 85.71%
Table A-8: Additional Managed Parameters with SDLS Option 4 100.00% 4 100.00%
Table A-9: Frame Error Control Field Coding Procedures 0 0.00% 0 0.00%
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BACKUP
10 12/20/2017Ok for Public Release, distribution unlimited
• MSFC HOSC
• Based on CCSDS Red-2 and 3
• 64 bit
• Executing on SuperMicro/KVM virtual servers (Will be migrating to 
DELL/VMWare virtual servers)
• Linux based on RHEL5.11 (Moving to RHEL 7)
Current Status


CCSDS USLP Activities

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