© 2004 the mitre corporation. all rights reserved consultative committee for space data systems...

© 2004 The MITRE Corporation. All rights reserved

Consultative Committee for Space Data Systems

Cislunar Networking Working Group

Keith Scott

JPL Cislunar Workshop

16 June 2004

Pasadena, CA

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Background

MITRE– Not for profit, non-competitive, chartered in the public interest

Work in partnership with government, applying systems engineering and advanced technology to issues of national importance

– The MITRE corporation runs three Federally Funded Research and Development Centers:

DOD FAA IRS

– Networking Center Tactical military networks, Navy ForceNet, NCW, SATCOM, MobileIP,

… Previous and current work with NASA/DoD on space

communications protocols and tactical applications

– Asked by Code-M to lead CCSDS working group on cislunar and in-situ communications

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CCSDS

Consultative Committee for Space Data Systems (CCSDS)– Members: Various nations’ space agencies

They fund people to work on CCSDS

– Develops international standards for communicating with and among spacecraft

Standards enable (international) cross-support Pool the small market for space communications hardware/software Adopt, adapt, develop Product: standards, some prototype implementations

– Six main areas within CCSDS: System Engineering Spacecraft On-board Interfaces Space Internetworking Space Link

Cislunar Working Group Cross Support Mission Operations and

Information Management

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Cislunar Working Group

Kickoff meeting 14 May 2004 at Spring meetings– International participation (ESA, BNSC, CSA, …)– Presentations on:

Environment Architectures CCSDS and other protocols / capabilities

– Draft Charter

Current Status– CCSDS has voted to form the working group– In the process of allocating resources

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Cislunar WG Work Items

Define baseline communications architecture to support lunar and in-situ communications– Human and robotic– Reuse (of existing technology, of this technology into future

environments, e.g. Mars in-situ) Examine existing CCSDS protocols to determine how they

can be applied to the baseline architecture– Centered on network, transport layers– Update existing standards where appropriate– Issues discovered related to link and application protocols will

be referred to relevant CCSDS areas (Space Link Services, Applications)

Research new protocols for adoption by CCSDS*– IETF standards (SCTP, LEMONADE, DCCP, and MIDCOM

working groups, …)

*Probably not in time for 2008 lunar mission.

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Lunar Communications Requirements

1969 Moon shot– Voice– Video– Minimal Data

2020 Moon shot– Voice– Videoconference– HDTV downlink– “Everyday” applications (email, web, …)– Operation in intermittently- connected

environments?– Tele-operation of robots

– Lots of “stuff”

Networked architecture, nota bunch of point-to-pointlinks

WASHINGTON (CNN) -- Saying "the desire to explore and understand is part of our character," President Bush Wednesday unveiled an ambitious plan to return Americans to the moon by 2020 and use the mission as a steppingstone for future manned trips to Mars and beyond.

WASHINGTON (CNN) -- Saying "the desire to explore and understand is part of our character," President Bush Wednesday unveiled an ambitious plan to return Americans to the moon by 2020 and use the mission as a steppingstone for future manned trips to Mars and beyond.

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Networked Architecture

Efficient use of links, especially as the number of users increases

vs.

Support for disconnected operations– What if there’s no end-to-end path?

Simplified management: get away from “one spacecraft, one (DTE) link”

f f

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Communications Links

Adapted from “LDRM Communication Operations Concept (Laura Hood, JSC)

SurfaceEVA(s)

LunarRover

LunarLander

ScienceInst.

Lunar Surface

Earth

Lunar VicinityLunar

Orbiters

Camera

Earth

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NetworkingServices

Space TransportServices

Space ApplicationServices

End-to-EndSpace Applications




End-to-End Networking Architecture

Terrestrial LinkServices


Space LinkServices

Onboard LinkServices


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Terrestrial NetworkingServices

Terrestrial TransportServices




Onboard TransportServices



TerrestrialTransportServices

SpaceTransportServices

SpaceTransportServices

OnboardTransportServices

Space NetworkingServices

Onboard NetworkingServices


Space LinkServices

Space LinkServices


Gatewayed Transport / Networking Architecture

GroundStation

GatewayInternet

OnboardGateway

App App

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Space Networking Services

SpaceNetworkingServices



TCP

CCSDS AOS, TM, TC

CCSDS AOS/TM/TC Coding

CCSDS RF & Mod

CCSDS Proximity 1

CCSDS Prox-1 Coding

CCSDS RF & Mod

Currently Unspecified



End-to-End Space Applications

CCSDS Path IPSec, CCSDS SP

FTP, CCSDS FPCFDP

UDP

IPv4, IPv6, CCSDS NP

Space Long Haul Space Proximity Space Surface

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Protocols

SpaceNetwork(TDRS)

Deep SpaceNetwork (DSN)

GroundNetwork

(NASA /commercial)

SurfaceEVA(s)

LunarRover

LunarLander

ScienceInst.

Lunar Surface

Earth

Lunar VicinityLunar

Orbiters

Camera

Earth

Surface Proximity Link

CCSDS Advanced Orbiting Sytems (AOS), TC/TM

CCSDS Prox-1

[CCSDS TC/TMCCSDS AOS]



ExistingGroundEquip.

ExistingRadios

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Existing CCSDS Capabilities

Availability– Commercial companies support CCSDS protocols

Speed– CCSDS TC/TM/AOS Telemetry Processors available up to

400Mbps– CCSDS Prox-1 implementation speeds?

Application support– Support for streaming applications (voice)– Support for applications built over IPv4, IPv6

Cross-Support– Prox-1 cross-support demonstrated at Mars

image.gsfc.nasa.gov/publication/ document/dmr/image_dmr_5.html

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Related Technologies

Lemonade– Enhancements and profiles of Internet email submission,

transport, and retrieval protocols to facilitate operation on platforms with constrained resources, or communications links with high latency or limited bandwidth

Datagram Congestion Control Protocol (DCCP)– A minimal general purpose transport-layer protocol providing:

setup, maintenance and teardown of unreliable packet flows congestion control of those flows.

Stream Control Transmission Protocol (SCTP)– Think of it as “TCP+”: message boundaries, multiple streams,

support for multi-homing, … Middlebox Communications (Midcom)

– How end hosts can discover and interact with proxies in the middle of the network

IP-over-DVB (and other link technologies)

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Participation

CCSDS Information (participation, meeting schedule):– http://www.ccsds.org

Cislunar WG mailing list:– http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-csi

Me:– [email protected]

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Conclusions

Baseline architecture– Looking at both end-to-end and gatewayed architectures– CCSDS Protocol Suite

Flight-proven hardware and software Supports target application set CCSDS protocols installed and running in ground stations Standards, interoperability, international cross-support

Lunar Relay Orbiter Recommendations– Networked architecture. Go to at least layer 3 (network) in the

spacecraft Because we want to get away from “one spacecraft, one DTE link” If at all possible, provide the ability to experiment with technologies

like CFDP and DTN to support communications over disconnected paths

– Support CCSDS AOS and Prox-1 protocols for Earth and Lunar element comms., respectively

Existing commercial hardware, Software Defined Radio, …

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Strawman LRO Capabilities

SurfaceEVA(s)

LunarRover

LunarLander

ScienceInst.

Lunar Surface

Earth

Lunar Vicinity

LRO

Camera

Earth

Surface Proximity Link

CCSDS Advanced Orbiting Sytems (AOS)

CCSDS Prox-1


Questions?

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Backups

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Some Data Points

Earth-Moon distance is 384,748 km (~1.28s one-way) Earth-Mars distance varies between ~4 minutes and ~20

minutes (one-way)

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IETF Datagram Congestion Control Protocol (dccp) The Datagram Control Protocol working group is chartered

to develop and standardize the Datagram Congestion Control Protocol (DCCP). DCCP is a minimal general purpose transport-layer protocol providing only two core functions:– The establishment, maintenance and teardown of an unreliable

packet flow.– Congestion control of that packet flow.

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IETF LEMONADE

Lemonade is tasked to provide a set of enhancements and profiles of Internet email submission, transport, and retrieval protocols to facilitate operation on platforms with constrained resources, or communications links with high latency or limited bandwidth. A primary goal of this work is to ensure that those profiles and enhancements continue to interoperate with the existing Internet email protocols in use on the Internet, so that these environments and more traditional Internet users have access to a seamless service.

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IETF SCTP (RFC2960)

SCTP is a reliable transport protocol operating on top of a connectionless packet network such as IP. It offers the following services to its users:– acknowledged error-free non-duplicated transfer of user data,– data fragmentation to conform to discovered path MTU size– sequenced delivery of user messages within multiple streams,

with an option for order-of-arrival delivery of individual user messages

– optional bundling of multiple user messages into a single SCTP packet

– network-level fault tolerance through supporting of multi-homing at either or both ends of an association.

The design of SCTP includes appropriate congestion avoidance behavior and resistance to flooding and masquerade attacks.

32


Middlebox Architectures

IETF midcom working group– As trusted third parties are increasingly being asked to make

policy decisions on behalf of the various entities participating in an application's operation, a need has developed for applications to be able to communicate their needs to the devices in the network that provide transport policy enforcement. Examples of these devices include firewalls, network address translators (both within and between address families), signature management for intrusion detection systems, and multimedia buffer management. These devices are a subset of what can be referred to as 'middleboxes.'

SCPS-TP Gateways

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Space Transport Services

Space Long-Haul Data Link

Space Long-Haul Coding

Space Long-Haul Channel

Space Proximity Data Link

Space Proximity Coding

Space Proximity Channel

Space Surface Data Link

Space Surface Coding

Space Surface Channel

End-to-End Space Applications

Space Application Services


Space Link Services

Space Long Haul Space Proximity Space Surface

SP

AC

E P

RO

TO

CO

L M

OD

EL

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End-to-End Data Flow

Subnet

PathService

BitstreamService

VirtualChannelAccessService

VirtualChannel

DataUnit

InsertService

Physical Channel

Virtual Channel

SubnetSubnet Subnet MultiplexingBit

stream

Packet Transfer

Onboard Network Space Link Subnetwork

IP

Internet

PathProtocol

InternetService

ApplicationServices

Encap.

EncapsulationService

InternetInternet

Packet Transfer

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Subnet

PathService

BitstreamService

VirtualChannelAccessService

VirtualChannel

DataUnit

InsertService

Physical Channel

Virtual Channel

SubnetSubnet Subnet MultiplexingBit

stream

Packet Transfer

Onboard Network Space Link Subnetwork

IP

Internet

PathProtocol

InternetService

ApplicationServices

Encap.

EncapsulationService

InternetInternet

Packet Transfer

End-to-End Data Flow

Email,Web, Chat

Voice

CCSDS Internet Service:Provided IP or IP-likeend-end data transfer

CCSDS Path Service:Provides efficient managed

end-end data transferCCSDS Encapsulation Service:

Wraps delimited data unitsfor space link transfer

CCSDS Multiplexing Service:

Switches packets in/outof CCSDS Frames

CCSDS Virtual ChannelAccess Service:

Relays a block of octetsacross link via CCSDS Frame

CCSDS VirtualChannel Data Unit

Service: InterleavesCCSDS Framesfrom different

spacecraft

CCSDS InsertService:

Transferssmall blockof octets

isochronously

CCSDS Bitstream Service:

Relays a stream of bitsacross link via CCSDS

Frame

© 2004 the mitre corporation. all rights reserved consultative committee for space data systems...

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