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The Fifth Space Internetworking Workshop SIW-5
NASA Home Page

September 12 - 13, 2006

Ramada Inn, BWI Airport
7253 Parkway Drive
Hanover, Maryland 21076
(410) 712-4300

SIW-5 Abstracts

Session Title Presenter
Session A

Network Architecture & Infrastructure
Flow-aware Networking - Solving the Quality of Service (QoS) Challenge for IP Converged Networks Mike Raymond
Support for the Internet Paradigm in the Transformational Satellite Communications System (TSAT) Carl Sunshine
A Security Model for Space Based Communications Thom Stone,
Ken Freeman,
Ray Gilstrap
A Preferred Service Architecture for Payload Data Flows Ray Gilstrap,
Ken Freeman,
Thom Stone
Utilization of Commercial Wireless Networking Technology in Simulated Martian Environments Philip DeLeon,
Stephen Horan,
Deva Borah,
Using Networking Protocols in the Design of a Nanosatellite Stephan Horan,
George Kuchera
Session B

Onboard Networking
Internetworking Over SpaceWire: A Link-Layer Broadcast Service for Network Stack Support Robert Klar
Lessons Learned using Flight IP on Moderate Fidelity Testbed with Radhard Cisco Router Gregory Menke
Low Cost Communication for Pico-Satellites-Experience from the cubeSat UWE-I Mission Marco Schmidt,
Florian Zieger,
Michael Menth,
Klaus Schilling
SIGMA: An End-to-End Mobility Management Scheme for Space Networks Mohammed Atiquzzaman,
William Ivancic
Session C

Space Networking
Practical use of the Internet Protocol to Command Satellite and Payloads Lloyd Wood
A Systemic View to the Nature of Mobility and Connectivity in Space and Implications on the Design of Space Network Protocol Suits Javed Khan,
Brenda Ellis,
Larry McFarland,
Chuck Putt
IP For Responsive Spacecraft A Practical Approach Assi Friedman,
Jeffrey Janicik
VOIP over Space Links Clay Okino,
Winston Kwong,
Jay Gao,
Jackson Pang,
Loren Clare
On NASA Earth Sciences representative Instrument & Sensor Web Framework Semion Kizhner,
Wesley Powell,
Umesh Patel,
Meg Vootukuru
Session D

Protocols & Technology
Getting to Lunar Sorties: The need for IP protocols and industrial-strength solutions for near-term lunar human mission goals Stephen Braham,
Simon Fraser
Space OSPF - Shortest Delay Intermittent Pathway Routing With Mobile Routers Nouman Bantan,
Javed I. Khan
Simulation of Delay-Tolerant Network Protocols in Space Networks Esther Jennings,
John SeGui
Modeling Sparse, Mobile Ad Hoc Networks with Strong Physical Layer Interactions David Finkleman
Dynamic Bandwidth Allocation for a Space-to-ground Relay Network Hui Zeng,
Michael Hadjitheodosiou,
John S. Baras
Design of a Fault-Tolerant Satellite Cluster Link Establishment Protocol Stephan Horan,
Praveen Thonour


Flow-aware Networking – Solving the Quality of Service (QoS) Challenge for IP Coverged Networks

Mike Raymond








Practical Use of the Internet Protocol to Command Satellites and Payloads

Lloyd Wood

Cisco Systems


Work with CLEO, the Cisco router in Low Earth Orbit, and with the Disaster Monitoring Constellation built by Surrey Satellite Technology Ltd, has shown how the Internet Protocol can be successfully used for satellite platforms and for payload communications. This work validates and builds on Keith Hogie et al's earlier demonstration work on SSTL's UoSAT-12, using the simple architectural approach outlined in [1]. Reasons why this architectural approach is compelling and useful are discussed.


[1] K. Hogie, E. Criscuolo and R. Parise, Using standard Internet Protocols and applications in space, Computer Networks, special issue on Interplanetary Internet, vol. 47 no. 5, pp. 603-650, April 2005.



A Systemic View to the Nature of Mobility and

Connectivity in Space and Implications on the

Design of Space Network Protocol Suits


Prepared As a part of

NASA Faculty Fellowship Program

August 2005 by:


By NASA Fellow


Dr. Javed I. Khan

Media Communications and Networking Research Lab

Department of Computer Science

Kent State University, Kent OH 44242


along with

NASA Colleagues


Brenda L. Ellis, Larry McFarland, and Chuck Putt


Office of the CIO

Computational Environments Branch

NASA Glenn Research Center

21000 Brookpark Road, MS 142-1

Cleveland, Ohio 44135

Phone: (216) 433-5214


What if the righteous place to implement “hop-and-forward” mechanism is in the network layer but not at application or transport layer?  Is it possible that congestion is an earthly phenomena- byproduct of human freewill and hardly be an issue in cold lifeless space until it is deeply colonized? Can one conceive a space routing protocol which will require zero inter-router communication and still route packets with absolute precision? In this report we examine the technical nature of the notion of ‘mobility’ and ‘connectivity’ in the context of space networking and seek answers to the questions like above.



Support for the Internet Paradigm in the Transformational Satellite Communications System (TSAT)


Carl Sunshine

The Aerospace Corporation



TSAT is being designed to provide a combination of circuit and packet communications services for mobile and deployed military users in the next decade.  TSAT will extend Internet technology into space, with attention to the extra security, endurance, and priority requirements necessary in a military environment.  The briefing will summarize the baseline Government Reference Architecture for the system, with emphasis on meeting the challenges of extending the Internet architecture into a military space environment.






Getting to Lunar Sorties: The Need for IP Protocols and Industrial-Strength Solutions for Near-Term Lunar Human Mission Goals

Stephen Braham, Simon Fraser University PolyLAB, Vancouver, Canada






Internetworking Over SpaceWire: Design of a Non-Broadcast Address Resolution Protocol and Encapsulation Service

Sandra G. Dykes, Robert Klar, Allison Roberts, Buddy Walls, Mark A. Johnson, Kristian Persson

{sandra.dykes, robert.klar, allison.roberts, buddy.walls, mark.johnson, kristian.persson}

Southwest Research Institute

6220 Culebra Rd., San Antonio TX, 210.522.3329


Standard communication protocols and existing OS network stacks can reduce software development time, cost, and errors. For this reason, spacecraft onboard communication systems are gradually moving from shared bus architectures to switched networks and standard protocols.

Ethernet is the dominant switched network technology on Earth, and is one contender for the space environments. In Ethernet, the switches are responsible for link-layer broadcasts. To avoid forwarding loops, the switches must continuously learn network topology and build a minimum spanning tree for message delivery. However, these algorithms add complexity and circuitry which increases mass and power requirements.

SpaceWire, a recent ESA standard, is gaining popularity because of its simple circuitry, low power consumption, and high-link speed. Although SpaceWire has many advantages, it lacks a link-layer broadcast mechanism. Broadcasts are necessary to support automatic network configuration and discovery software such as the Address Resolution Protocol (ARP) and Dynamic Host Configuration Protocol (DHCP). Address resolution tables and host IP addresses are manually configured on SpaceWire networks. Moreover, the SpaceWire standard does not yet specify a method for supporting multiple upper layer protocols such as IP and CCSDS.

This presentation will describe the design of a link-layer broadcast service and an encapsulation service for SpaceWire. The encapsulation service provides a message multiplexing / demultiplexing functionality that enables multiple higher-layer protocols to operate over the same physical link. Implementing this service in the host driver software enables SpaceWire to automatically and simultaneously support IPv4, IPv6 and CCSDS SCPS-NP protocol stacks, as well as high-performance custom applications that interface directly to the driver.

Our link-layer broadcast mechanism is implemented at the hosts rather than at the SpaceWire routers. The design is compliant with the SpaceWire specification and can be implemented solely within the driver software. No changes are required to the SpaceWire specification, routers, or host interface hardware. The algorithm introduces the concept of a SpaceWire subnet, which consists of a router and its directly connected hosts. The advantage of this approach is that it avoids configuration by using either SpaceWire port addressing or its packet distribution mechanism.

We believe the ability of our protocols to simplify network management and to support IP and other higher-layer protocols is an important step forward and will lead to more rapid adoption of SpaceWire for future missions.



Space OSPF - Shortest Delay Intermittent Pathway Routing With Mobile Routers

Nouman Bantan & Javed I. Khan

Internetworking and Media Communications Research Laboratories

Department of Computer Science, Kent State University

233 MSB, Kent, OH 44242 USA &


OSPF routing protocol has powerful scalability and stability features because of its ability to divide routing domain into areas and messages into short on-demand link state messages. Recently, we have proposed a space version of OSPF routing called Space OSPF. This protocol is capable of handling intermittent paths and model-based router mobility in addition to its powerful scalability features. It can compute shortest delay paths over conventional concurrent link based pathways as well as on intermittent non-concurrent link based pathways for store-and-forward communication. In this paper we will present the performance of this new protocol in real space scenarios. It dramatically improves on several other routing algorithms proposed for space with near optimum routing performance.




Lessons learned using Flight IP on moderate fidelity testbed with Radhard Cisco router



Greg Menke

NASA Goddard Spaceflight Center


Hugh Arif

Global Defense, Space and Security Group

Cisco Systems, Inc.


NASA Goddard Spaceflight Center has many initiatives exploring the use of IP in space missions.  One missing element in the communications chain has been a COTS flight-qualified, rad-hard IP router.  Recognizing that, Cisco Systems and NASA Goddard teamed to work together in developing a port of Cisco's IOS (Internet Operating System) to a rad-hard platform with widely accepted flight credentials.


This paper contains the benchmark and testing results of a flight-qualified, rad-hard Cisco router acting as the primary communications interface of a simulated spacecraft with IP as the end-to-end communications protocol.


CPU and memory utilization figures are given for clear text and encrypted space-link communications.  Operational configuration scenarios are discussed and conclusions are reached about the unique

requirements COTS IP routers must work under when integrated into spacecraft.



IP For Responsive Microsats – A Practical Approach

Assi Friedman,

Jeffrey Janicik,


Innoflight Inc.

5850 Oberlin Dr.

Suite 340

San Diego, CA 92121

Phone: (858) 638-1580

Fax: (858) 638-1581


Using Internet Protocols on smallsats started as a grass roots effort to take advantage of commercial hardware and software and save development time, money, and reduce risk.  These premises are still exist today within the community.   In addition, even though the primary users of microsats nowadays are government customers (in the U.S.) the motivation for fast responsive microsats is inline with the original premises.


There are many  spacecraft tracking stations available for government and commercial networks in the U.S. yet only few can support IP operations as a standard feature.  Capitalizing on the benefits that IP can provide to us will come into play only if we can establish an operational baseline that is cost effective and easy for spacecraft designers to implement.  Using protocol on protocol or unique and proprietary encoding methods defeats the point as it is as efficient as designing your own in-house system.


Innoflight has been working on a number of microsat IP technology solutions that will enable spacecraft builders to purchase COTS IP enabled hardware and software package for both the ground and flight segments.  This presentation will describe how Innoflight integrated traditional IP/HDLC with CCSDS standards, and Type-1 encryption to provide users with secure, high performance IP link between the spacecraft LAN and the ground segment.


VOIP over Space Networks

C. Okino, W. Kwong, J. Pang, J. Gao, and L. Clare

Jet Propulsion Laboratory


In this work, we examine the use of off-the-shelf Voice-over-IP (VOIP) for the space environment. Our initial focus is on VOIP based on open source implementations of the Session Initiation Protocol SIP (RFC 3261) and the Real Time Protocol RTP (RFC 3550). We also investigate SIP extensions to enable voice operations in situations where potentially there is only a simplex link or one direction of the duplex path suffers a substantial outage during a connection. We examine the use of VOIP applications for lunar space scenarios. Results are derived using our space communications testbed, which incorporates underlying space network protocols and captures channel error and propagation delay effects. We address the impacts of the unique characteristics and needs of the space environment in the performance measurements for voice.


Clayton Okino

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 393-6668

Winston Kwong

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-5953

Jackson Pang

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 393-0466

Jay Gao

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-9528

Loren Clare

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-1650


A Security Model for Space Based Communications

Thom Stone

Computer Sciences Corporation

NASA Ames Research Center

M/S 258-6

Moffett Field, CA 94035


Raymond Gilstrap, Kenneth Freeman

NASA Ames Research Center

M/S 258-5

Moffett Field, CA 94035

650.604.3844. 650.604.1263

{ray.gilstrap, kenneth.freeman-1}


As space missions become more complex and interactive the need for a comprehensive and rigorous security infrastructure becomes obvious. This framework should include all elements including space assets, ground systems, and distribution of data products.


Although a myriad of security products and solutions have been developed recently, a comprehensive, directed methodology for implementing the correct technologies for space missions has not been developed. Based on our experience with securing NASA’s supercomputer assets and a high-speed wide area network we will present the requirements for space mission security. This will include an overview of current Internet-based security technologies and how they were assessed for inclusion in the NASA Research and Engineering Network (NREN) security plan and later implemented. Further discussion will include strategies for developing a viable security framework, security for onboard payload, operations in a secure environment and securing data products distributed to a wide array of off-site and out of agency principal investigators.




A Preferred Service Architecture for Payload Data Flows

Ray Gilstrap

Ken Freeman

Thom Stone






Simulation of Delay-Tolerant Network Protocols in Space Networks


John Segui and Esther Jennings

Jet Propulsion Laboratory

4800 Oak Grove Drive, Pasadena, Ca 91109,

(818) 354 9191, (818) 354 1390


In space exploration missions, the coordinated use of spacecraft as communication relays increases the efficiency of the endeavors. To conduct trade-off studies of the performance and resource usage of different communication protocols and network designs, JPL designed a comprehensive extendable tool, the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE). The design and development of MACHETE began in 2000 and is constantly evolving.


Currently, MACHETE contains Consultative Committee for Space Data Systems (CCSDS) protocol standards such as Proximity-1, Advanced Orbiting Systems (AOS), Packet Telemetry/Telecommand, Space Communications Protocol Specification (SCPS), and the CCSDS File Delivery Protocol (CFDP). MACHETE uses the Aerospace Corporation’s Satellite Orbital Analysis Program (SOAP) to generate the orbital geometry information and contact opportunities. Matlab scripts provide the link characteristics. At the core of MACHETE is a discrete event simulator, QualNet.


Delay Tolerant Networking (DTN) is an end-to-end architecture providing communication in and/or through highly stressed networking environments. Stressed networking environments include those with intermittent connectivity, large and/or variable delays, and high bit error rates. To provide its services, the DTN protocols reside at the application layer of the constituent internets, forming a store-and-forward overlay network. The key capabilities of the bundling protocols include custody-based reliability, ability to cope with intermittent connectivity, ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses.


In this presentation, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the use of MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions.






Modeling Sparse, Mobile Ad hoc Networks with Strong Physical Layer Interactions

David Finkleman

Anlaytical Graphics, Inc.









Dynamic Bandwidth Allocation for a

Space-to-ground Relay Network


Hui Zeng*, Michael Hadjitheodosiou & John S. Baras

HyNet, Institute for Systems Research

University of Maryland, College Park,

MD 20742

E-mail: {zengh, michalis, baras}


We focus on the allocation of bandwidth in a space relay network that supports several scientific spacecraft with a number of different streams on-board sharing a broadband satellite channel to send traffic to the ground. Our system model includes a number of mobile spacecraft (MS) in Lower Earth Orbit (LEO), a Geo-synchronous (GEO) relay satellite, and the ground network consisting of several ground stations (GS). The downlink channel of the relay satellite is shared by these spacecraft, which we model as streams with different priority levels going through a common queue and a router. The data will be delivered to the ground station through this relay.


It is shown that a carefully designed time-varying bandwidth allocation based on the instant or statistical traffic from all users/flows performs better in terms of throughput and end-to-end delay. However, only short-term (time varying) bandwidth allocation may cause instability and will have difficulties in providing QoS guarantees and managing the long-term (average) behavior of all the users/flows. Hence, we propose a two-level bandwidth allocation in our implemented TDMA scheme. For a well-coupled framework with per user/flow average bandwidth management, we derive our long-term bandwidth allocation problem from the model discussed by Kelly, and draw some ideas from some other work. In addition, for instantaneous bandwidth management, we incorporate ideas from some recent work to formulate the short-term timeslot assignment problem and find the solution for optimal timeslot scheduling.


By using simulation, the performance of a suitable MAC protocol with two-level bandwidth allocation is analyzed and compared with that of the existing static fixed-assignment scheme in terms of ETE delay and successful throughput. We also study the fairness among all the users under a special scenario and find that the pseudo-proportional fairness is achieved for our hybrid protocol.


*Corresponding Author:


Hui Zeng

HyNet, Institute for System Research,

A.V. Williams Building, University of Maryland, College Park, MD 20742

Tel: +301-405-7904  Fax:+301-314-8586




Utilization of Commercial Wireless Networking Technology in Simulated Martian Environments


Authors: Phillip DeLeon, Stephen Horan, Deva Borah, et al.

Affiliation: Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, NM, 88003-8001

Corresponding Author: Stephen Horan (505-646-3117;


This paper describes a three-part investigation into using commercial wireless technology to estimate the performance of 802.11-type networks in an outdoor planetary environment. The specific environment chosen for the studies is the landing environment of the Mars rovers. The general technique that has been developed can be applied to any location where suitably-detailed terrain information is available.

The first phase of the project concerned acquiring high-resolution terrain data for the candidate landing sites and then making that data accessible for importation into commercial link planning software. The link planning software chosen was that used for planning cellular telephone links. This software uses ray-tracing techniques for radio propagation from a source to destination and not statistical estimation techniques.

The second phase of the project is to use the terrain data and the link planning software to obtain RF coverage estimates and power delay profiles. These estimates are gotten at a number of locations within the predicted MER landing ellipses to see what variations can be found. The simulation estimates are validated against measurements made with local terrain features.

The third phase of the project is to use the link predictions to estimate the effective performance of 802.11 wireless links in the outdoor environment. From the terrain data, we obtain estimates of the percent coverage, expected throughput of 802.11a and 802.11b links, and expected throughput based on modulation types (PSK-based or OFDM).

This technique can be applied to other terrain environments, e.g. the lunar environment, if sufficient imaging and terrain composition details are known to generate the coverage models.



Low Cost Communication for Pico-Satellites – Experience from the CubeSat UWE-I Mission


Marco Schmidt, Florian Zeiger, Michael Menth, and Klaus Schilling

January 24, 2005

The pico-satellite UWE-1 (University of Wuerzburg’s Experimental Satellite 1) was lau-

nched in the context of the ESA SSETI-Initiative from the Russian launch site Plesetsk on October 27th, 2005. UWE-1 was built in the scope of the international Cubesat program initiated by Stanford University and is restricted to a size of 1 dm3 and a mass of up to 1 kg. The pico-satellite is a fully functional but highly integrated space vehicle. In contrast to normal satellites, a pico-satellite has relatively hard constraints for energy consumption, bandwidth, size, and weight. Its topology is based on commercial-of-the-shelf (COTS) components which makes UWE-1 to an ideal low-cost testbed for software and hardware. The core consists of a Hitachi H8S processor with a complete Linux operating system (µClinux). The integration of a Linux operating system provides a high degree of flexibility in terms of developing mission specific software or even using free software components. The communication subsystem relies on a PR430 radio to establish a basic communication link to the ground station using an amateur radio frequency.


The mission objectives of the UWE-1 project comprise the test of new solar cells in space

environment as well as the adaptation and optimization of existing communication technology and Internet protocols for pico-satellites. We used a modification of the 6pack protocol for the control of the Terminal Node Controller (TNC) and tuned the parameters of the AX.25 link layer protocol to maximize the data throughput. We compared the efficiency of the communication link on earth and in orbit under different weather conditions and distance.  Thus, we have demonstrated with UWE-1 a proof of concept for a low-cost, flexible orbital test platform consisting of COTS components which uses communication protocols conform to Internet standards.


The work explains the engineering constraints of our low-cost pico-satellite in particular

regarding the communication part. It shows the adaptation and optimization of the proto-

col layers and a practical assessment of the quality of the communication channel that we

performed after UWE-1 was launched.




Design of a Fault-Tolerant Satellite Cluster Link Establishment Protocol


Authors: Stephen Horan and Praveen G. Thonour

Affiliation: Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, NM, 88003-8001

Corresponding Author: Stephen Horan (505-646-3117;


In our previous presentations, we gave the basic design for a link establishment protocol designed for a satellite cluster environment. This basic design was for a single cluster of satellites where channel errors are expected to occur and so the design would need to allow the cluster to be automatically established even in this error environment. This basic method was built around a UDP-based protocol developed at NMSU and programmed in LabVIEW for development and ANSI C for use in the NASA/GSFC software radio laboratory.

In this paper, we will describe improvements made over the past year to the initial algorithm. Enhancements made to this algorithm include

• Utilize multicast messaging to improve channel use efficiency,

• Permitting cluster members to enter and leave the cluster,

• Provide a method to allow new members to join the cluster,

• Provide a method to partition the cluster into smaller partitions of single-hop neighbors, and

• Provide a means for gateways between partitions.


These algorithm enhancements were made in the same mode as the initial algorithm development: UDP-based communications protocol, a LabVIEW development environment, and translation to C for incorporation in the GSFC laboratory.



Using Networking Protocols in the Design of a Nanosatellite


Authors: Stephen Horan and George Kuchera

Affiliation: Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, NM, 88003-8001

Corresponding Author: Stephen Horan (505-646-3117;


One of the goals of the University Nanosatellite program is to have rapid design and integration of the spacecraft components. A suite of networking protocols has been chosen for the design of the NMSUSat as part of this program to allow the design to rapidly progress from concept to working prototype. In particular, the design is explicitly using standard protocols that are available to run on the flight computer and the university’s ground station. The satellite flight computer is based on a commercial PC-104 computer running Linux. The ground station uses a PC running WindowsXP and tied to the campus network backbone. Typical applications for the satellite design include:


• NTP for synchronizing the satellite CPU clock to the NMSU campus time server

• MDP for file transfer applications

• Secure Shell for login


The goal is to enable the student designers to rapidly configure and operate the satellite with minimal coding. The NMSUSat is currently in the prototype construction phase with the final satellite build required to be done in spring 2007. Because of the constraints of the Nanosat design environment, the design of the communications is especially constrained. In this presentation, we will show the design configuration and the results obtained to date with the prototype hardware and software.




On NASA Earth Sciences Representative Instrument and Sensor Web Framework1,2


Semion Kizhner, Wesley Powell and Umesh Patel

National Aeronautics and Space Administration

Goddard Space Flight Center

Greenbelt Road, Greenbelt MD, 20771



Meg Vootukuru

Syneren Technologies


Abstract—Transparent network-based adaptation and sharing of space flight mission resources, including those of the Space-Ground/Control-User-Communications segments, could greatly benefit from utilization of Internet devices and protocols applied for Space or SpaceIP. This had been demonstrated, in principle, by a few recent spaceflight experiments. However, while the terrestrial part of the SpaceIP is well developed and understood, the flight segment of SpaceIP is still in its infancy. Progress in the developments of Space Segment enabled SpaceIP components will largely determine the SpaceIP progress and acceptance in years to come. In this paper we present an approach in developing related and enabling instrument-level technologies based on the concept of Instrument Sensor Web. This paper presents a two-fold approach, first in developing the theoretical framework for instrument sensor webs and secondly - in developing an instrument electronics component aspect of instrument sensor web which, in turn, will enable the internetworking for space flight missions. The present view of a sensor web is as of a distributed instrument comprised of many sensors and interconnected by a heterogeneous communications system. We propose a different view of an instrument as a sensor web, called Instrument Sensor Web. This concept is new and different from the heritage concept of sensor web and it is a view from the engineering perspective. This new view of an instrument as a sensor web is amendable to earth science spaceflight missions (especially the missions presently in proposal phase), such as Ocean Carbon, Ecosystem and Near Shore mission. The sensor signal processing electronics building blocks for this representative mission can be viewed as a sensor web with heterogeneous sensors and heterogeneous interfaces, and with a combination of heritage electrical and wireless interfaces. The topologies for these electronics building blocks can be developed into enabling SpaceIP architectures, which will result in low cost, redundant and intelligent on-board data pre-processing, solid state recorder multi-function data housing, data compression, and data downlink protocols based on SpaceIP. In this paper we present the outline of the theoretical framework for an instrument sensor web and the signal and information processing elements’ system architectures required in smart sensor readout and information processing integrated electronics circuits for the earth science class of spaceflight missions.


1 U.S. Government work not protected by U.S. copyright

2 Space Internetworking Workshop-2006 May 2-4, 2006



SIGMA: An End-to-End Mobility Management

Scheme for Space Networks[1]


Mohammed Atiquzzaman

School of Computer Science

University of Oklahoma

Norman, OK 73019-6151

William Ivancic

NASA Glenn Research Center

Cleveland, OH.





National Aeronautical and Space Administration (NASA) has been experimenting with Mobile IP to manage handovers of spacecrafts between ground stations. Mobile IP is an industry-standard that has been developed to handle mobility of Internet hosts at the network layer. Mobile IP, however, suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions.


Researchers at NASA Glenn Research Center and University of Oklahoma have been investigating a new end to end mobility management scheme, called Seamless IP diversity-based Generalized Mobility Architecture (SIGMA), for managing handovers in space networks. In this paper, we describe the architecture and principles of SIGMA which utilizes IP diversity to achieve seamless handover, and is designed to solve many of the drawbacks of Mobile IP, including requirement for changes in infrastructure. The performance of SIGMA has been thoroughly evaluated for both terrestrial and space networks using analytical modeling, ns-2 simulation and Linux-based laboratory prototype.  


The centralized DNS-based location management scheme of SIGMA provides for high survivability. The paper will compare the survivability of SIGMA with that of Mobile IP. SIGMA can interoperate with existing network security infrastructures such as Ingress filtering and IPSec fairly easily. The paper also describes the application of SIGMA to manage satellite handovers in space networks.



[1] The work reported in this paper was funded by National Aeronautics and Space Administration (NASA) grant no. NAG3-2922
















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