Operations Concept for a Solar System Internetwork

SISG
IOAG Space Internetworking
Strategy Group
CNES DLR ESA JAXA NASA
Operations Concept for a
Solar System Internetwork
Charles D. Edwards
Jet Propulsion Laboratory, California Institute of Technology
Michel Denis
European Space Operations Centre
Lena Braatz
Booz Allen Hamilton
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SISG
Introduction
�The Interagency Operations Advisory Group (IOAG)
has established a Space Internetworking Strategy
Group (SISG)
� The SISG was chartered to provide recommendations
to the IOAG for a strategy to implement space
internetworking
� One element of this work involves the development
and documentation of an operations concept for a
solar system internetwork (SSI)
�In 2009-2010, the SISG worked to establish this SSI
operations concept, leading to the release of
“Operations Concept for a Solar System Internetwork
(SSI)” in Oct 2011
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SISG
�Co-chairs:
� Wolfgang Hell – ESA ESOC
� John Rush – NASA HQ
�Members:
� Francois Allard – ESA ESTEC
� Erik Barkley – NASA JPL
� Lena Braatz** - NASA/Booz Allen
Hamilton
� Fred Brosi – NASA/GST
� Scott Burleigh – NASA JPL
� Gian Paolo Calzolari – ESA ESOC
� Vint Cerf - NASA/Google
� Matthew Cosby – UK Space
Agency/QinetiQ
� Michel Denis* - ESA ESOC
� Robert Durst – NASA/MITRE
� Chad Edwards* - NASA JPL
� Roy Gladden – NASA JPL
� Adrian Hooke – NASA HQ
� Dave Israel – NASA GSFC
� Narita Kaneaki - JAXA
* Co-author ** Editor
SISG Membership
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Participation from ESA, NASA,
ASI, CNES, DLR, JAXA, et al.
� Greg Kazz – NASA JPL
� Mike Kearney – NASA MSFC
� Paolo Maldari – ESA ESOC (ret)
� Jane Marquart – NASA GSFC
� Gilles Moury - CNES
� John Pietras – NASA/GST
� Martin Pilgram - DLR
� Luca Salotti - ASI
� James Schier – NASA HQ
� Michael Schmidt – ESA ESOC
� Klaus-Juergen Schulz – ESA ESOC
� Keith Scott – NASA/Mitre
� Peter Shames – NASA JPL
� Jason Soloff – NASA JSC
� Wallace Tai – NASA JPL
� Chris Taylor - ESA ESTEC
� Takahiro Yamada - JAXA
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SISG
The Need for an SSI
�To date, most space communications scenarios have
involved simple point-to-point links
� Supported via standardized CCSDS link layer
protocols (e.g., TM/TC, AOS)
�Future space exploration scenarios will move beyond
this simple point-to-point paradigm:
� More complex topologies involving multiple spacecraft
� Data flowing over multiple hops via intermediate relay
spacecraft
� Data flowing to multiple destinations, with data-driven
routing
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SISG
The Need for an SSI (cont’d)
�The SSI drives the need for a functional network
layer
� Like terrestrial Internet, provides a simple,
standardized network interface
� A pair of applications at disjoint nodes would be able
to seamlessly exchange data, with the network layer
handling the intermediate routing
User
App
SI
Landed
Spacecraft
SI SI SI SI SI SI SI SI SI
SI: Space Internetworking Protocol
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Earth
Statio
n
Space Internetwork Terrestrial Internetwork
Application data transfer
User
App
Landed
Spacecraft
MOC
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SISG
�Service User
nodes
� Reside at periphery
of SSI
� Can access SSI
service, but cannot
provide network
layer forwarding
capability
�Service Provider
nodes
� Can provide network
layer forwarding
capability
General Description of the SSI
Planetary
WAN
Planet
Spacecraft
Landed
Spacecraft
Planetary
Station
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Relay
Spacecraft
Spacecraft
Earth
Station
SSI Node w/ forwarding capability
(“Service Provider” or “Service User”)
SSI Node w/out forwarding capability
(“Service User” only)
Spacecraft
Landed S/C
Landed MOCs S/C
MOC
MOC
Earth Station
Control Center
Earth
Science Ops
Center
Terrestrial
WAN
Planetary Station
Control Center
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Key SSI Principles: Management
SISG
� Asset Responsibility: Each agency is responsible for the planning,
control, and operations of its own assets
� Communications Protocols: The operations concept shall, as far
as possible, be independent of the communications protocols below
the network layer
� Addressing: Asset addressing must be constructed and managed
at the network level; the SSI will require an entity to manage and
maintain a repository of addresses.
� Network Services: The defining characteristic of the SSI end state
operations concept is the presence of a functional network layer in
the protocol stack; application layer functionality is only present at
the endpoints of an end-to-end service
� Interoperability: To provide a functional network layer in the
protocol stack, all nodes that agree to provide SSI services will offer
an agreed set of interoperable IP and/or DTN protocol services
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Key SSI Principles: Planning
SISG
� Network Planning and Management: The SSI requires network
planning and management functions to develop the network contact
plan and execute network services
� Overall Planning: The planning entities of the provider and user
agencies must coordinate at long-term (typically geometry or flight
dynamics), medium-term (typically resources or mission planning),
and short-term (typically service request and delivery) levels
� Contact Plan: Network planning and execution in the SSI end state
hinge on a network contact plan, which establishes the temporal
windows and communications capabilities (e.g., bandwidth) of
individual node-to-node network links
� Peering Agreements: Peering agreements will be used to
implement interagency interfaces within the SSI. When planning
mission communications, an individual user will arrange for service
with its agency-level provider, who will, in turn, employ peering
agreements to arrange end-to-end data flows that use different
agencies’ provider nodes.
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Key SSI Principles: Execution
SISG
� Monitoring/Reporting: The SSI providers shall provide the user
MOC with feedback on the progress and success of the intermediate
steps in the relaying process.
� Transparency: Each node agreeing to participate in the network
shall be indifferent and transparent to any contents of the transferred
data units
� Integrity: The SSI shall be capable of delivering complete, gap-free
data products between any two nodes
� User Emergency: The SSI shall allow for defining and using, under
pre-agreed conditions, a path from the user MOC to the user node
that is completely deterministic in geometry and timing (e.g., to
recover from anomalies in the network and/or the user node)
� Routing Functions: The SSI end state operations concept supports
data flow over multiple possible network data paths
� Forwarding of information is based on static or dynamic routing
tables in the network-layer protocol with forwarding decisions based
on information in the network-layer Protocol Data Units (as opposed
to being driven by metadata or manually sequenced operations)
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�The SSI is a
confederation of
network elements from
multiple international
space agencies
� Each agency serves
as an “SSI Service
Provider” for its user
nodes (Iike a
terrestrial ISP)
� “Peering
agreements” are
used to access
services from other
providers
Overview of SSI Coordination
mission
lifecycle
comm rqts
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User
User Nodes
User Nodess
Nodes
Agency
B
Agency
A
Develop/maintain mutuallysupportive
cross-support
service & peering agreements
SSI
Coordination
Function
Provider Provider Provider
Nodes Nodes Nodes
Agency
C
Capabilities/
provisioning rqts
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SISG
SSI Contact Planning Process
�A key element of SSI
operations involves the
development and
distribution of a
contact plan
� Describes the temporal
connectivity and
bandwidth capabilities of
the network
� Is essential to enable
routing and forwarding
decisions by individual SSI
nodes in support of endto-end
network data
delivery
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�Space link performance extraction
�Network data volume and latency
calculations, reports
Network
Utilization,
Monitoring,
Reporting
Mutual Contact
Determination
Contact Plan
Release +
Verification (of
Release)
�Trajectory predictions
�Communications geometry
�Spacecraft constraints
Contact Plan
Generation
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SISG
User S/C MOC
User MOC
Mission
Planning
Flight Sys
Analysis
Contact
Opportunities,
Requests &
Constraints
User MOC
SSI Contact Planning Process
Navigation Mission
Planning
Science
Planning
Contact
Plan
Provider S/C MOC
User MOC
Flight Sys
Analysis
Contact
Opportunities,
Requests &
Constraints
User MOC
Confederated Contact Planning Process
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Navigation
Science
Planning
(for Hybrid
Asset)
Contact
Plan
Earth Station
Control
User MOC
User Center MOC
Earth
Station
Network
Scheduling
Contact
Opportunities,
Requests &
Constraints
Earth
Station
N/W Asset
Monitoring
Contact
Plan
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SISG
User MOC
Application Layer
Network Layer
Link Layer
SSI Run-Time Operations
SSI Network
Service
Link Layer
Service
Intermediate
Provider
Node(s)
End-to-End SSI Service
Network Layer
Link Layer
Network Monitoring
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SSI Network
Service
Link Layer
Service
User S/C
Application Layer
Network Layer
Link Layer
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SISG
Conclusions
� The IOAG’s Space Internetworking Strategy Group has
established an operations concept for a solar system
internetwork
� Provides robust and efficient end-to-end data services spanning
terrestrial and space links up to interplanetary scales
� Utilizes a standard network layer (IP or DTN)
� Incorporates many aspects of the terrestrial Internet, while
reflecting the unique challenges of space communications
� A key aspect of the SSI operations concept involves the
development and dissemination of the contact plan describing
the temporal connectivity of SSI nodes and the bandwidth
characteristics of individual links
� Once this contact plan has been established, network
communication can proceed in a highly automated fashion, with
intermediate nodes using knowledge of the contact plan to drive
forwarding and routing decisions
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BACKUP
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Acknowledgments
�The authors thank all the members of the Space
Internetworking Strategy Group for their many
valuable inputs in reviewing and refining this SSI
operations concept
�Part of the research described in this paper was
carried out at the Jet Propulsion Laboratory, California
Institute of Technology, under a contract with the
National Aeronautics and Space Administration
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