Evaluation of ccsds file delivery protocol over delay tolerant networks
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Evaluation of CCSDS File Delivery Protocol over Delay Tolerant Networks. Giorgos Papastergiou, Hellenic Aerospace Industry S.A, Schimatari, Greece Democritus University of Thrace , Xanthi, Greece E. Koutsogiannis and V. Tsaoussidis

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Evaluation of CCSDS File Delivery Protocol over Delay Tolerant Networks

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Evaluation of ccsds file delivery protocol over delay tolerant networks

Evaluation of CCSDS File Delivery Protocol over Delay Tolerant Networks

Giorgos Papastergiou,

Hellenic Aerospace Industry S.A, Schimatari, Greece

Democritus University of Thrace , Xanthi, Greece

E. Koutsogiannis and V. Tsaoussidis

Department of Electrical and Computer Engineering, Democritus University of Thrace, Xanthi, Greece

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Work summary

Work summary

Investigation of how CFDP can serve as the file transfer protocol within the DTN architecture

Initial evaluation of its performance

  • integration of ESA/ESTEC CFDP with JPL ION DTN implementation

  • Evaluation using a space-oriented Testbed

    Conclusion: CFDP can rely on DTN for naming,

    routing, SFO and reliability

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


What gap does this work fill in

What gap does this work fill in

During the last decade CCSDS has developed CFDP as a file transfer protocol for space communications

  • CFDP is a ready-to-flight product

  • Future missions will support it

  • CFDP relies on current space infrastructure (SPP, TM/TC, AOS)

    DTN will be the future communication architecture

    When migrating to DTN how can we take advantage of the already developed CFDP protocol?

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Current state

Current state

Increased number of space elements need for more automated and flexible communications

Current space communication protocols rely on static routing,

  • while the number of alternative communication paths in space increases

    Space communication protocols have a rather cross-layer functionality

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Protocols with cross layer funcionality

Protocols with cross-layer funcionality

Space Packet Protocol

  • is really an application layer artifact

  • has a simple naming mechanism (APID)

  • static routing through LDPs

    CCSDS File Delivery Protocol

  • has transport layer functionalities as well

  • supports store-and-forward

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Ccsds file delivery protocol 1 2

CCSDS File Delivery Protocol 1/2

  • Application Layer Protocol for file transferring

  • Transport Layer Functionalities

    • Two modes of operation (unacknowledged / acknowledged mode)

    • Three file delivery services (Core / Extended Procedures / SFO)

    • Four ACK modes (Deferred / Immediate / Prompted / Asynchronous

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Ccsds file delivery protocol 2 2

CCSDS File Delivery Protocol 2/2

CFDP is unsuitable when communication complexity increases

  • No dynamic routing

  • No file distribution through multiple relay points in parallel

  • No advanced retransmission mechanisms

  • No end-to-end security

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Towards delay tolerant networking

Towards Delay Tolerant Networking

New protocols and mechanisms for routing and transfer reliability are needed in order to deal with:

  • Alternative communication paths

  • Intermittent connectivity

  • Large propagation delays

  • High BER

  • Resource sharing among space agencies

    DTN Architecturetends to dominate the field

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Dtn architecture

DTN Architecture

  • Store and Forward message switching

  • Custody Transfer

  • Reliability of lower layer (LTP, DS-TP, etc)

  • Proactive and Reactive Fragmentation

  • Flexible naming scheme with Late Binding

  • Dynamic Routing

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Dtn architecture1

DTN Architecture

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


The problem

The problem

Space agencies will continue to use current infrastructure

  • legacy mission support

  • financial reasons

    Questions:

  • How CFDP cooperates with DTN?

  • Is there any functionality overlapping?

  • How it performs?

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Cfdp and dtn comparison

CFDP and DTN comparison

  • Solution: keep all the file management features and

  • disable all other

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Evaluation scenario

Evaluation scenario

  • COMNET lab’s space oriented communication Testbed

  • CFDP over DTN (ION)

    • Each CFDP PDU is encapsulated in a “bundle”

    • CFDP at the endpoints

  • Simple 2-node topology

  • 1Kbyte CFDP PDU size

    • Data aggregation/segmentation is left to the underlying network

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Comnet lab s testbed 1 2

COMNET lab’s Testbed 1/2

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Comnet lab s testbed 2 2

COMNET lab’s Testbed 2/2

Distributed nodes

  • COMNET Lab, DUTH, Xanthi, Greece

  • Hellenic Aerospace Industry, Athens, Greece

  • Massachusetts Institute of Technology, USA

    Protocols Implemented:

  • ESA/ESTEC CFDP implementation

  • 2 Bundle Protocol Implementations (ION and DTN2)

  • LTP

  • CCSDS Space Packet Protocol (soon)

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Terrestrial and geostationary links

Terrestrial and Geostationary links

  • CFDP/BP/TCP

  • 10 MByte file size

  • 1 Mbps/ 256 Kbps

  • 50-300 ms propagation delay

  • 0 – 10% PER

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Deep space links

Deep-space links

  • CFDP/BP/LTP and CFDP/UDP

  • 5 and10 MByte file size

  • 1 Mbps/ 256 Kbps

  • 30 sec propagation delay

  • 0 – 10% PER

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Conclusions

Conclusions

  • It is feasible to operate CFDP only as a file application protocol over DTN (ION)

  • Advantages of such integration could be :

    • the exploitation of the advanced BP features (such as SFO, coarse grained reliability, routing, naming, fragmentation)

    • the exploitation of the enhanced (re)transmission ability (LTP, DS-TP)

  • Further results are still needed to identify potential trade-offs and the mechanisms required to maximize performance

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


Thank you

Thank you

  • Any questions?

International Workshop on Satellite and Space Communications 2008, IWSSC 2009, 9-11 September 2009, Siena, Italy


References

References

ComNet Group:http://comnet.ee.duth.gr

ESA Project Site: http://www.hai- rt.gr/Projects/ExtendingInternet IntoSpace/ home.aspx

ESA DTN Testbed: C. Samaras, I. Komnios, D. Sotirios, E. Koutsogiannis, V. Tsaoussidis, G. Papastergiou and N. Peccia, "Extending Internet into Space – ESA DTN Testbed Implementation and Evaluation", 1st International Conference on Mobile Lightweight Wireless Systems, Workshop on Research activities funded by ESA in Greece, Athens, Greece, May 18-20, 2009.

DS-TP: Giorgos Papastergiou, Ioannis Psaras and Vassilis Tsaoussidis"Deep-Space Transport Protocol: A Novel Transport Scheme for Space DTNs"Computer Communications (COMCOM), Elsevier Science, Special Issue on Delay-/Disruption-Tolerant Networks, 2009.

International Workshop on Satellite and Space Communications 2009, IWSSC 2009, 9-11 September 2009, Siena, Italy


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