File Transfer with CFDP in the Operational Environment

1
File Transfer with CFDP in the Operational
Environment

• SpaceOps 2004

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Introduction

• CCSDS File Delivery Protocol
• Objectives, Concepts
• Principle Advantages
• Case Study
• Planetary Lander
• Ground Software (SCOS-2000)
• On-Board Software
• Prototype Deployment

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CCSDS File Delivery Protocol (CFDP)

• Automation of Reliable bulk data transfer
• unreliable networks
• complex, disjoint networks
• Advent of On-board file stores
• Management needed
• On-board compression
• No tolerance to data loss, gaps etc
• Advent of complex space communities
• Interoperability

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CFDP Principal Advantages

• Store and Forward Networking
• Multiple intermediaries
• Disjoint connectivity (e.g. Time disjoint)
• Continuous File Delivery
• Unbounded Datastreams
• Negative ARQ scheme
• Minimal Traffic
• Effective over LEO and Deep Space
• Effective via unbalanced bandwidths
• Architecturally Flexible can be used over
• CCSDS and other subnetworks
• Network layers
• Transport layers

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Reference Scenario Planetary Lander
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Protocol Configuration
Unbounded Stream (TM Packets)
Lander OB S/W
SCOS 2000
SFO
DPM
SFO
SFO
DPM
CFDP
CFDP
CFDP
Extended Procs
Extended Procs
Extended Procs
Filestore
Filestore
Filestore
CCSDS TM/TC Packets
Proximity-1
CCSDS TM/TC Packets
Proximity-1
CCSDS TM/ TC Packets
SLE/IP/Frame Relay
CCSDS TM/ TC Frames
SLE/IP/ Frame Relay
CCSDS TM/ TC Frames
Control Centre
SGT
Orbiter (Waypoint)
Lander
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Protocol Configuration

• CFDP class 2 (reliable) over
• CCSDS TM/TC Frames (expedited - no COP-1)
• Proximity-1 (unreliable no COP-P)
• tcp/ip
• Extended Procedures vs Store-and-Forward
• SFO simpler, complete files
• EP supports unbounded filestreams
• Data Product Manager
• File segmentation
• For transmission along parallel waypoint paths

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Deployment in MCS (SCOS-2000)

• Deploy generic file transfer services
• File data services
• Time-Tagged Schedule
• Recorded TM data Dump
• On-Board Memory Load/Dump
• Discrete TC/TM via Unbounded file
• GUI
• Manage Local and Remote Filestores
• View status
• Issues
• Harmony with PUS
• TC Verification
• PDU / Packet Archive
• Persistence (resilience to MCS restarts/failover)

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MCS Deployment
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On-Board Deployment

• Autonomous telemetry downloads
• Replace Large Data Transfer function
• memory management, science data
• Integrate TM/TC handling (unbounded files)
• Housekeeping TM general TC (unbounded)
• Potentially requires virtual filestore
• Existing electronics not file based
• CFDP User
• Respond to proxy operations (send file)
• No need to initiate proxy operations

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On-Board Deployment
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CFDP entities

• ESTECs implementation
• Delphi
• Used as a reference for testing
• On-Board Implementations
• SciSys prototype
• Written in C
• Design for integration into SCOS-2000
• Potential for ground on-board use

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Future

• End-to-End demonstrator
• Lander Control Centre link
• CORBA or TCP/IP Transport
• User GUI
• FTP Replacement
• Data Product Manager (DPM)

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