Lloyd Wood's publications

Academic research and technical publications by Lloyd Wood, listed in reverse-chronological order, most recent first. Comments on publications are welcomed at L.Wood@society.surrey.ac.uk.

Related slides from presentations and talks given are listed separately.

Research areas include satellite constellations, intersatellite links, internet networking in space, the Interplanetary Internet, delay-tolerant networking, networking for the Square Kilometre Array, and router-modem integration. These short summary papers, each only two pages, will give a quick overview of our work:

Some of our work in progress as internet-drafts can also be read, as can patent applications.

The papers below are listed in ResearchGate, in Mendeley, in Google Scholar, in IEEExplore, in arXiv and in Microsoft Academic Search. A summary reference list and h-index evaluation of this research output are available.

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2014
Revisiting elliptical satellite orbits to enhance the O3b constellation
Lloyd Wood, Yuxuan Lou, Opeoluwa Olusola.
Discusses satellite constellations. Uses SaVi and ns satellite network plot scripts.
Peer-reviewed journal paper, Journal of the British Interplanetary Society, vol. 67, no. 3, pp. 110-118, March 2014.
We propose an addition of known elliptical orbits to the new equatorial O3b satellite constellation, extending O3b to cover high latitudes and the Earth's poles. We simulate the O3b constellation and compare this to recent measurement of the first real Internet traffic across the newly deployed O3b network.
See also:
MEO and HEO satellite orbits, AMSAT UK, 12 July 2014.
O3b Launches Four More Satellites To Bring Internet To 'Other 3 Billion', Slashdot, 11 July 2014.

Revisiting elliptical satellite orbits to enhance the O3b constellation (829K)

JBIS 2014.67.110 | issue summary | arXiv: 1407.2521.

2012
SELECTIVE PERFORMANCE ENHANCEMENT OF TRAFFIC FLOWS. US Patent 8,305,896, granted 6 November 2012.
US Patent 8,305,896
Selective performance enhancement of traffic flows
Lloyd Wood, Daniel Floreani, Richard Shao, Ken Durazzo.
with Larry Donovan of Tucker Ellis, agent.
US Patent 8,305,896, published 6 November 2012.
a method for selective performance enhancement of traffic flows, such as a Transmission Control Protocol (TCP) flow, on devices where enhancement of a limited number of concurrent flows is supported, or where a limited number of TCP accelerated or IP (Internet Protocol) compressed flows are supported.

Selective performance enhancement of traffic flows (134K)

US patent office | Free Patents Online | PatentBuddy.

Modem Link-Property Advertisements
Will Ivancic, Lloyd Wood, Dan Shell, Daniel Floreani, Rajiv Asati.
Discusses router-modem integration. Related: modemLPA draft and code.
Peer-reviewed conference paper, IEEE Aerospace conference, Big Sky, Montana, March 2012.
In order to autonomously condition traffic and allow the network to get the most out of the modem's link capacity, the upstream devices and applications need to be informed of the modem's link conditions.
Modem Link-Property Advertisements (424K)
Modem Link-Property Advertisements slides (112K) presented by Will, 9 March 2012.

DOI: 10.1109/AERO.2012.6187146

2011
Saratoga: scalable, speedy data delivery for sensor networks
Lloyd Wood.
Discusses Saratoga and its use in the Interplanetary Internet and for radio astronomy and the Square Kilometre Array.
Peer-reviewed conference paper, two-page summary of previous work, First Annual CCSR Research Symposium (CRS 2011), Centre for Communication Systems Research, 30 June 2011.
This brief paper outlines the reasons for the creation and adoption of this protocol, discusses how it differs from and complements other protocols, and summarises the worldwide collaboration that is making this development possible.
Saratoga: scalable, speedy data delivery for sensor networks (284K)
Saratoga slides (701K)

arXiv: 1204.3263

SaVi: satellite constellation visualization
Lloyd Wood.
Discusses SaVi and its uses in simulating satellite constellations.
Peer-reviewed conference paper, two-page summary of previous work, First Annual CCSR Research Symposium (CRS 2011), Centre for Communication Systems Research, 30 June 2011.
SaVi" SaVi is introduced and described briefly here.
SaVi: satellite constellation visualization (1M)
SaVi poster (362K)

arXiv: 1204.3265

Assessing and improving an approach to delay-tolerant networking
Lloyd Wood.
Discusses the Bundle Protocol.
Peer-reviewed conference paper, two-page summary of previous work, First Annual CCSR Research Symposium (CRS 2011), Centre for Communication Systems Research, 30 June 2011.
We have found architectural weaknesses in the Bundle Protocol that may prevent engineering deployment of this protocol in realistic delay-tolerant networking scenarios, and have proposed approaches to address these weaknesses.
Assessing and improving an approach to delay-tolerant networking (150K)
DTN poster (142K)

arXiv: 1204.3264

Taking Saratoga from Space-Based Ground Sensors to Ground-Based Space Sensors
Lloyd Wood, Charles Smith, Wes Eddy, Will Ivancic, Chris Jackson.
Discusses use of Saratoga for radio astronomy and the Square Kilometre Array.
Peer-reviewed conference paper, IEEE Aerospace conference, Big Sky, Montana, March 2011.
This is intended to prototype delivery of data across dedicated astronomy radio telescope networks on the ground, where networked sensors in Very Long Baseline Interferometer (VLBI) instruments generate large amounts of data for processing and can send that data across private IP- and Ethernet-based links at very high rates.
Taking Saratoga from Space-Based Ground Sensors to Ground-Based Space Sensors (266K)
Saratoga sensor slides (3.9M), presented by Will, 9 March 2011.

DOI 10.1109/AERO.2011.5747332 | arXiv:1101.2172

A Sender-based TFRC for Saratoga: A Rate Control Mechanism for a Space-Friendly Transfer Protocol
Abu Zafar M. Shahriar, Mohammed Atiquzzaman, Will Ivancic, Lloyd Wood.
Discusses adding congestion control to Saratoga.
Peer-reviewed conference paper, IEEE Aerospace conference, Big Sky, Montana, March 2011.
This sender-based TFRC is shown to share the bottleneck-bandwidth fairly under various network conditions, allowing Saratoga to be adapted for shared links or for the congested Internet, while still supporting the asymmetric environments that Saratoga was originally developed for.
A Sender-based TFRC for Saratoga (285K)

DOI 10.1109/AERO.2011.5747333

2010
Large File Transfers from Space using Multiple Ground Terminals and Delay-Tolerant Networking
Will Ivancic, Phil Paulsen, Dave Stewart, John Taylor, Scott Lynch, Jay Heberle, James Northam, Chris Jackson, Lloyd Wood.
Describes use of Saratoga with the Bundle Protocol for delay-tolerant networking to conduct further Interplanetary Internet tests in space.
Peer-reviewed conference paper, IEEE Global Communications Conference (Globecom 2010), Miami, Florida, December 2010.
We use Delay-Tolerant Networking (DTN) to break control loops between space-ground communication links and ground-ground communication link to increase overall file delivery efficiency, as well as to enable large files to be proactively fragmented and received across multiple ground stations.
Large File Transfers from Space using Multiple Ground Terminals and Delay-Tolerant Networking (693K)

DOI 10.1109/GLOCOM.2010.5683304 | cites in Google Scholar

Experience with delay-tolerant networking from orbit
Will Ivancic, Wes Eddy, Dave Stewart, Lloyd Wood, James Northam, Chris Jackson.
Describes use of Saratoga with the Bundle Protocol for delay-tolerant networking to conduct the first Interplanetary Internet tests in space.
Refereed journal paper, International Journal of Satellite Communications and Networking, special issue for best papers of the Fourth Advanced Satellite Mobile Systems Conference (ASMS 2008), vol. 28, issues 5-6, September-December 2010, pp. 335-351.
We describe the first use from space of the Bundle Protocol for Delay-Tolerant Networking (DTN), and lessons learned from experiments made and experience gained with this protocol.

Experience with delay-tolerant networking from orbit (972K)

DOI 10.1002/sat.966 | 40+ cites in Google Scholar | earlier version published at ASMS 2008: DOI 10.1109/ASMS.2008.37

Virtual Mission Operations of Remote Sensors with Rapid Access to/from Space
Will Ivancic, Phil Paulsen, Dave Stewart, Jon Walke, Larry Dikeman, Steven Sage, Eric Miller, James Northam, Chris Jackson, Lloyd Wood, John Taylor, Scott Lynch, Jay Heberle.
Describes use of CLEO and VMOC.
Paper AIAA-2010-2305, Proceedings of AIAA SpaceOps 2010, a SpaceOps conference, 25-30 April 2010, Huntsville, Alabama.
This paper describes network-centric operations, where a virtual mission operations center autonomously receives sensor triggers, and schedules space and ground assets using Internet-based technologies and service-oriented architectures.

Virtual Mission Operations of Remote Sensors with Rapid Access to/from Space (2M)

DOI 10.2514/6.2010-2305 | AIAA archive | Also known as NASA Technical Memorandum TM-2010-216364.

Using Light-Emitting Diodes for intersatellite links
Lloyd Wood, Will Ivancic, Klaus-Peter Dörpelkus.
Discusses intersatellite links. Related: patent application.
Peer-reviewed conference paper, IEEE Aerospace Conference, Big Sky, Montana, March 2010.
We examine the utility of Light-Emitting Diodes (LEDs) for short-range intersatellite links (ISLs), and compare and contrast LEDs with existing laser technologies used for long-distance ISLs.

Using Light-Emitting Diodes for intersatellite links (316K)
LED ISL presentation slides, given by Will Ivancic, 10 March 2010. (704K. Images from DARPA F6 and NASA, used with attribution.)

DOI 10.1109/AERO.2010.5446711 | CiteSeer

2009
Moving data in DTNs with HTTP and MIME: Making use of HTTP for delay- and disruption-tolerant networks with convergence layers
Lloyd Wood, Peter Holliday, Daniel Floreani, Ioannis Psaras.
Describes HTTP-DTN.
Peer-reviewed conference paper, Proceedings of the Workshop on the Emergence of Delay-/Disruption-Tolerant Networks (E-DTN), one of a number of workshops of the International Conference on Ultra Modern Telecommunication (ICUMT), St. Petersburg, Russia, 14 October 2009.
Taking MIME and HTTP as a starting point, and adopting the well-understood need for different "convergence layers" to carry HTTP in different challenged environments where TCP may not be suitable, this paper outlines work in progress to run HTTP over different transports, and how this can be used to create a simple, yet powerful, approach to relaying content in delay- and disruption-tolerant networks (DTNs).

Moving data in DTNs with HTTP and MIME (100K)
HTTP-DTN slides presented by Ioannis. (96K)

DOI 10.1109/ICUMT.2009.5345656 | CiteSeer.

Sharing the dream: The consensual networking hallucination offered by the Bundle Protocol
Lloyd Wood, Peter Holliday, Daniel Floreani, Wes Eddy.
Describes the Bundle Protocol.
Peer-reviewed conference paper, Proceedings of the Workshop on the Emergence of Delay-/Disruption-Tolerant Networks (E-DTN), one of a number of workshops of the International Conference on Ultra Modern Telecommunication (ICUMT), St. Petersburg, Russia, 14 October 2009.
This position paper is intended to encourage discussion of the role, scope, and adoption of the Bundle Protocol.

Sharing the dream (65K)
Sharing the dream slides presented by Ioannis. (99K)

DOI 10.1109/ICUMT.2009.5345655 | CiteSeer.

A Bundle of Problems
Lloyd Wood, Wes Eddy, Peter Holliday.
Describes the Bundle Protocol.
Peer-reviewed conference paper, IEEE Aerospace conference, Big Sky, Montana, March 2009.

We examine the Bundle Protocol and its related architecture closely, and discuss areas where we have found that the current Bundle approach is not well-suited to many of the operational concepts that it was intended to support.

A Bundle of Problems (288K)
A Bundle of Problems slides, presented 11 March 2009 (3.8M)

DOI 10.1109/AERO.2009.4839384 | 50+ cites in Google Scholar

2008
Investigating operation of the Internet in orbit: Five years of collaboration around CLEO
Lloyd Wood, Will Ivancic, Wes Eddy, Dave Stewart, James Northam, Chris Jackson.
Summarises our experience with the CLEO Cisco router in Low Earth Orbit and with delay-tolerant networking for the Interplanetary Internet.
two-page summary of previous work, article for IEEE Communications Society Satellite and Space Communications Technical Committee newsletter, vol. 18 no. 2, pp. 10-11, November 2008.
The team of NASA Glenn Research Center, Cisco Systems and Surrey Satellite Technology Ltd has now gained considerable practical experience and leadership both with taking the Internet into space, and with delay-tolerant networking.

Investigating operation of the Internet in orbit: Five years of collaboration around CLEO (1.3M)

arXiv: 1204.3261 | Cites in Google Scholar.

Use of the Delay-Tolerant Networking Bundle Protocol from Space
Lloyd Wood, Will Ivancic, Wes Eddy, Dave Stewart, James Northam, Chris Jackson, Alex da Silva Curiel.
Describes use of Saratoga with the Bundle Protocol for delay-tolerant networking to conduct the first Interplanetary Internet tests in space. Read and cite the later IJSCN journal paper on DTN space testing above instead.
Conference paper IAC-08-B2.3.10, Proceedings of the 59th International Astronautical Congress, Glasgow, September 2008, vol. 5 pp. 3123-3133.
This is the first successful use of the DTNRG Bundle Protocol in a space environment.

Related: UK-DMC satellite first to transfer sensor data from space using 'bundle' protocol, SSTL press release, 11 September 2008.

See also:
CLEO Orbital Internet earns Time Magazine award, Robin Wolstenholme, Surrey Satellite Technology space blog, 14 November 2008.
TIME's Best Inventions of 2008: #9 The Orbital Internet, Jeremy Caplan et al., Time Magazine, vol 179 no. 19, 10 November 2008.

Use of the Delay-Tolerant Networking Bundle Protocol from Space (1.1M)
Slides for Use of the Delay-Tolerant Networking Bundle Protocol from Space (4.7M)

IAC Archive | CiteSeer | 10+ cites in Google Scholar | Also known as NASA Technical Memorandum TM-2009-215582.

a T-shirt from Vint Cerf
Vint Cerf, T-shirt (de?)signer.
Delay/Disruption-Tolerant Network Testing Using a LEO Satellite
Will Ivancic, Wes Eddy, Lloyd Wood, Dave Stewart, Chris Jackson, James Northam, Alex da Silva Curiel.
Describes use of Saratoga with the Bundle Protocol for delay-tolerant networking to conduct the first Interplanetary Internet tests in space. Read and cite the later IJSCN journal paper on DTN space testing above instead.
Eighth Annual NASA Earth Science Technology Conference (ESTC 2008), University of Maryland, June 2008.
This paper describes the first DTN bundle protocol testing from space, using the United Kingdom Disaster Monitoring Constellation (UK-DMC) satellite in Low Earth Orbit (LEO).

Delay/Disruption-Tolerant Network Testing Using a LEO Satellite (300K)

CiteSeer | 20+ cites in Google Scholar | later published at ASMS 2008: DOI 10.1109/ASMS.2008.37.

IPv6 and IPsec Tests of a Space-Based Asset, the Cisco router in Low Earth Orbit (CLEO)
Will Ivancic, Dave Stewart, Lloyd Wood, Chris Jackson, James Northam, James Wilhelm.
Describes use of the CLEO Cisco router in Low Earth Orbit to test IPv6 in space.
NASA Technical Memorandum TM-2008-215203, May 2008. Read the related IAC 2007 paper below.
On Thursday, 29 March 2007, NASA Glenn Research Center, Cisco Systems and SSTL performed the first configuration and demonstration of IPsec and IPv6 onboard a satellite in low Earth orbit.

Related: Cisco router on UK-DMC first to use IPv6 onboard a satellite in orbit, SSTL news item, 29 March 2007.

IPv6 and IPsec Tests of a Space-Based Asset, the Cisco router in Low Earth Orbit (CLEO) (1.2M)

NASA Technical Memorandum TM-2008-215203 | cites in Google Scholar.

2007
IPv6 and IPsec on a satellite in space
Lloyd Wood, Will Ivancic, Dave Stewart, James Northam, Chris Jackson, Alex da Silva Curiel.
Describes use of the CLEO Cisco router in Low Earth Orbit to test IPv6 in space.
Conference paper IAC-07-B2.6.06, Proceedings of the 58th International Astronautical Congress, Hyderabad, India, 24-28 September 2007, vol. 5, pp. 2986-2992.
This is the first time that IPsec and IPv6 have been operated onboard a satellite in orbit.

Related: Cisco router on UK-DMC first to use IPv6 onboard a satellite in orbit, SSTL news item, 29 March 2007.

IPv6 and IPsec on a satellite in space (1.2M)
IPv6 and IPsec on a satellite in space - presentation slides (1M)

IAC archive | CiteSeer | cites in Google Scholar.

TCP's protocol radius: the distance where timers prevent communication
Lloyd Wood, Cathryn Peoples, Gerard Parr, Bryan Scotney, Adrian Moore.
Peer-reviewed conference paper, Proceedings of the International Workshop on Space and Satellite Communications (IWSSC '07), Salzburg, Austria, 13-14 September 2007, pp. 163-167.
We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limited range of path delays and distances between communicating endpoints.
Errata: Figure 5's y axis has values that should be multiplied by 8, thanks to dividing goodput in bytes per second by throughput in bits per second. The graph is otherwise correct, and the axis is shown correctly in the presentation slides.

This paper led to a change in ns behaviour to vary the number of TCP SYNs sent.

See also: Using Opnet 11.5 to Determine the Protocol Radius of TCP, p. 9-11, Ulster Opnet usage summary, 2008.

TCP's protocol radius (203K)
Cathryn Peoples' protocol radius presentation (145K) and photos of Salzburg.

DOI 10.1109/IWSSC.2007.4409409 | 10+ cites in Google Scholar.

Saratoga: a Delay-Tolerant Networking convergence layer with efficient link utilization
Lloyd Wood, Wes Eddy, Will Ivancic, Jim McKim, Chris Jackson.
Describes Saratoga.
Peer-reviewed conference paper, Proceedings of the International Workshop on Space and Satellite Communications (IWSSC '07), Salzburg, Austria, 13-14 September 2007, pp. 168-172.
We examine how Saratoga can be adapted to serve as an efficient convergence layer for Delay-Tolerant Networking (DTN), by transferring DTN bundles as well as files.
Saratoga (1M)
Wes Eddy's Saratoga slides (1.1M)

DOI 10.1109/IWSSC.2007.4409410 | CiteSeer | 60+ cites in Google Scholar.

Using Internet nodes and routers onboard satellites
Lloyd Wood, Will Ivancic, Dave Hodgson, Eric Miller, Brett Conner, Scott Lynch, Chris Jackson, Alex da Silva Curiel, Dave Cooke, Dan Shell, Jon Walke, Dave Stewart.
Describes the CLEO Cisco router in Low Earth Orbit.
Refereed journal paper, special issue on Space Networks, International Journal of Satellite Communications and Networking, vol. 25 issue 2, pp. 195-216, March/April 2007. Preprint revised for publication 3 January 2007. Includes and expands on all content of our earlier End-to-end, Small Satellite Conference and IAC conference papers.
Putting this Cisco router in Low Earth Orbit (CLEO) onboard a small satellite is one step towards extending the terrestrial networking model to the near-Earth space environment as part of a merged space-ground architecture.
Using Internet nodes and routers onboard satellites (3.2M)

DOI 10.1002/sat.870 | CiteSeer | 40+ cites in Google Scholar.

2006
Operating a terrestrial Internet router onboard and alongside a small satellite
Lloyd Wood, Alex da Silva Curiel, Will Ivancic, Dave Hodgson, Dan Shell, Chris Jackson, Dave Stewart.
Describes the CLEO Cisco router in Low Earth Orbit. Read and cite the later IJSCN journal paper on CLEO above instead.
Acta Astronautica, volume 59, issues 1-5, July-September 2006, pp. 124-131. Conference paper IAC-05-B-05-03, Selected Proceedings of the 56th International Astronautical Congress, Fukuoka, Japan, 17-21 October 2005.
After twenty months of flying, testing and demonstrating a Cisco mobile access router, originally designed for terrestrial use, onboard the low-Earth-orbiting UK-DMC satellite as part of a larger merged ground/space IP-based internetwork, we use our experience to examine the benefits and drawbacks of integration and standards reuse for small satellite missions.
Operating a terrestrial Internet router onboard and alongside a small satellite (725K)

DOI 10.1016/j.actaastro.2006.02.026 | IAC archive | AIAA archive | CiteSeer | cites in Google Scholar

2005
CLEO and VMOC: enabling warfighters to task space payloads
Lloyd Wood, Dan Shell, Will Ivancic, Brett Conner, Eric Miller, Dave Stewart, Dave Hodgson.
Describes the CLEO Cisco router in Low Earth Orbit.
Refereed conference paper, unclassified track, Proceedings of IEEE Milcom 2005, Atlantic City, New Jersey, 17-20 October 2005, vol. 5 pp. 3052-3058.
The combination of the CLEO and VMOC initiatives together provides a framework to define, test, and field a 'system of systems' based on the Internet Protocol (IP), capable of supporting secure distributed mission operations of IP-based platforms and sensors.

CLEO and VMOC were demonstrated at the Cisco Systems booth in the Milcom exhibition, with live satellite telemetry and live access to the onboard router.

CLEO and VMOC: enabling warfighters to task space payloads (US letter, 400K)
CLEO and VMOC slides (8.8M)

DOI 10.1109/MILCOM.2005.1606128 | CiteSeer | cites in Google Scholar.

Packet Magazine
Packet magazine cover.
Internet to orbit
Daniel Floreani, Lloyd Wood.
Describes the CLEO Cisco router in Low Earth Orbit and intersatellite links.
Magazine article, Cisco Systems Packet Magazine, ISSN 1535-2439, vol. 17 no. 3, pp. 19-23, third quarter 2005.
Given a Cisco Achievement Program (CAP) team award by Packet Magazine.
With governments no longer able to afford or justify unrestricted budgets, and with a new generation of space enthusiasts mastering the principles of space technology and rocket propulsion, the commercial market has stepped up its involvement in space activity.
Internet to orbit (334K)

Japanese translation of Internet to Orbit from Packet Japan, Winter 2005, pp. 26-31. See also Japanese papers on UK-DMC testing.
Chinese translation of Internet to Orbit (textual summary) from Cisco Networking China, fifth issue of 2005, no. 32, pp. 36-39.
Reprinted condensed as Make Internet Available on the Aerospace Orbit, China New Telecommunications, no. 12, 2006, pp. 81-83 (textual summary, abstract, abstract).

cites in Google Scholar.

Adopting Internet standards for orbital use
Lloyd Wood, Will Ivancic, Alex da Silva Curiel, Chris Jackson, Dave Stewart, Dan Shell, Dave Hodgson.
Describes the CLEO Cisco router in Low Earth Orbit. Read and cite the later IJSCN journal paper on CLEO above instead.
Conference paper SSC05-IV-03, Session 4: The year in retrospect, 19th Annual AIAA/USU Conference on Small Satellites, Logan, Utah, 8-11 August 2005.
After a year of testing and demonstrating a Cisco mobile access router intended for terrestrial use onboard the low-Earth-orbiting UK-DMC satellite as part of a larger merged ground/space IP-based internetwork, we reflect on and discuss the benefits and drawbacks of integration and standards reuse for small satellite missions.
Adopting Internet standards for orbital use (724K, portrait US letter)

Also known as NASA Technical Memorandum TM-2005-213881 | CiteSeer | cites in Google Scholar.

Secure, Network-Centric Operations of a Space-Based Asset: Cisco Router in Low-Earth Orbit (CLEO) and Virtual Mission Operations Center (VMOC)
Will Ivancic, Dave Stewart, Dan Shell, Lloyd Wood, Phil Paulsen, Chris Jackson, Dave Hodgson, James Northam, Neville Bean, Eric Miller, Mark Graves, Lance Kurisaki.
Describes the CLEO Cisco router in Low Earth Orbit.
NASA Technical Memorandum TM-2005-213556, May 2005.
a Cisco Internet router (Cisco Systems, Inc., San Jose, CA) was launched into low Earth orbit onboard the UK-DMC, the disaster-monitoring satellite built by Surrey Satellite Technology Limited (SSTL, Guildford, UK). This router has since been successfully tested and demonstrated by an international government and private sector collaboration, showing how IP can be used to communicate with satellite payloads in space.
full NASA memorandum

NASA Technical Memorandum TM-2005-213556 | CiteSeer | abridged report (proceedings of Earth-Sun System Technology Conference 2005)

20+ cites in Google Scholar

Testing a router onboard a satellite in space
Lloyd Wood.
Describes the CLEO Cisco router in Low Earth Orbit. Read and cite the later IJSCN journal paper on CLEO above instead.
Seminar paper, pp. 83-85, Proceedings of The End-to-End Challenges of Broadband via Satellite, IEE Savoy Place, London, 26 January 2005, ISBN 0-86341-491-5.
A Cisco Internet router is orbiting onboard the UK-DMC satellite as a secondary experimental payload, and has been tested successfully.
Print errata: p. 2: NASA Glenn's headquarters.
Testing a router onboard a satellite in space (42K, portrait A4)

Cites in Google Scholar.

2004
Advice for Internet subnetwork designers
Phil Karn (ed.), Carsten Bormann, Gorry Fairhurst, Dan Grossman, Reiner Ludwig, Jamshid Mahdavi, Gabriel Montenegro, Joe Touch, Lloyd Wood.
Request for Comments document in the Best Current Practices series, Internet Engineering Task Force.
IETF RFC3819/BCP89, July 2004.
This document provides advice to the designers of digital communication equipment, link-layer protocols, and packet-switched local networks (collectively referred to as subnetworks), who wish to support the Internet protocols but may be unfamiliar with the Internet architecture and the implications of their design choices on the performance and efficiency of the Internet.
RFC3819 (RFC3819/BCP89 published as paginated text)

110+ cites in Google Scholar | CiteSeer.

2003
Slot clouds: getting more from orbital slots with networking
Lloyd Wood, Alex da Silva Curiel, Javad Anzalchi, Dave Cooke, Chris Jackson.
Discusses intersatellite links.
Conference paper IAC-03-U.4.07, 54th International Astronautical Congress, Bremen, Germany, 29 September - 3 October 2003.
The co-located satellites in the orbital slot together form a network and, particularly when using and communicating with the Internet Protocol, can be viewed as a network 'cloud' that provides functionality in a flexible manner.
Slot clouds paper (79K)
Slot clouds slides, originally presented Thursday 2 October 2003. (2.6M, landscape US letter)

DOI 10.2514/6.IAC-03-U.4.07 | cites in Google Scholar | CiteSeer. AIAA archive. Also given as Surrey Space Centre Guest Lecture, Tuesday 28 October 2003.

Satellite constellation networks
Lloyd Wood.
Discusses satellite constellations with intersatellite links. Uses ns satellite network plot scripts.
Chapter 2, Internetworking and Computing over Satellite Networks, Yongguang Zhang (ed.), Kluwer Academic Press (now part of Springer), ISBN 1-4020-7424-7, pp. 13-34, March 2003.

Reviewed by Ioanis Nikolaidis, New Books and Multimedia Column, IEEE Network, vol. 17 no. 4, July-August 2003, p. 7.
Reviewed by Mile Stojcev, Microelectronics Reliability, vol. 44 issue 2, February 2004, pp. 363-364.
Photo of Zhang's Internetworking... volume, published by Kluwer.
Zhang with wood: blue-sky research

Chapter 2: Satellite constellation networks
Satellite constellations are introduced. The effects of their orbital geometry on network topology and the resulting effects of path delay and handover on network traffic are described. The design of the resulting satellite network as an autonomous system is then discussed.
Print errata: p. 29: a well-designed hierarchy of address blocks...
Chapter 2: satellite constellation networks (340K)
Book table of contents (17K)

cites in Google Scholar | CiteSeer | Internetworking and Computing over Satellite Networks is available from Amazon (UK, Canada, France, Germany, Japan).

2002
Advice to link designers on link Automatic Repeat reQuest (ARQ)
Gorry Fairhurst, Lloyd Wood.
Request for Comments document in the Best Current Practices series, Internet Engineering Task Force.
IETF RFC3366/BCP62, August 2002.
This document presumes that the designers wish to support Internet protocols, but may be unfamiliar with the architecture of the Internet and with the implications of their design choices for the performance and efficiency of Internet traffic carried over their links.
RFC3366 (RFC3366/BCP62 published as paginated text)

140+ cites in Google Scholar

2001
Internetworking with satellite constellations
Lloyd Wood.
Discusses satellite constellations with intersatellite links. Uses SaVi and ns satellite network plot scripts.
Thesis for award of Doctor of Philosophy (PhD), University of Surrey, June 2001.
Here, we examine networking and internetworking issues affecting satellite networking in complex satellite constellation networks, and determine what is needed in order to support services based on the TCP/IP suite well in satellite constellations.
Abstract and full PhD thesis

Managing diversity with handover to provide classes of service in satellite constellation networks
Lloyd Wood, George Pavlou, Barry Evans.
Discusses satellite constellations with intersatellite links. Uses SaVi and ns satellite network plot scripts.
conference paper, in the proceedings of the AIAA 19th International Communication Satellite Systems Conference (ICSSC '01), vol. 3, session 35, no. 194, Toulouse, France, 17-20 April 2001.
The rosette satellite constellation network with intersatellite links (ISLs) presents unique properties, in providing locally separate ascending and descending network surfaces of interconnected satellites with which the ground terminal can communicate. We present a novel approach exploiting this rosette geometry, by use of control of handover and management of satellite diversity, to determine which surface a ground terminal will select for communication.

Errata: the 'occasional (but small) gap in coverage' in the Celestri simulation was due to adding the phase offset when we should have been subtracting it -- but you still need broader beams to get double surface coverage. The SaVi Celestri simulation has been adjusted.

Managing diversity with handover to provide classes of service in satellite constellation networks. (242K, portrait/landscape A4)

10+ cites in Google Scholar.

Effects on TCP of routing strategies in satellite constellations
Lloyd Wood, George Pavlou, Barry Evans.
Discusses satellite constellations with intersatellite links. Uses ns satellite network plot scripts.
refereed journal paper, Special issue on Satellite-Based Internet Technology and Services, IEEE Communications Magazine, vol. 39, no. 3, pp. 172-181, March 2001.
The authors introduce the types of satellite constellation networks, and examine how overall performance of TCP communications carried across such a network can be affected by the choice of routing strategies used within the network.
Print errata: Figure 3(b)i reverses the colours of the seamed and seamless Teledesic delay traces, although the hop traces are correct. Figure 5(b)i has the legends for 50ms and 500ms reversed, as is clear from their positions.

This paper and Ch. 4 of my PhD thesis are not aware that real IP networking devices do load balancing by hashing on source and destination addresses, so that TCP flows are not reordered by round-robin multipath forwarding.

Effects on TCP of routing strategies in satellite constellations (187K, portrait US letter)

DOI 10.1109/35.910605 | 40+ cites in Google Scholar | CiteSeer.

IP routing issues in satellite constellation networks
Lloyd Wood, Antoine Clerget, Ilias Andrikopoulos, George Pavlou, Walid Dabbous.
Discusses satellite constellations with intersatellite links.
refereed journal paper, Special issue on IP, International Journal of Satellite Communications, vol. 19 no. 1, pp. 69-92, John Wiley & Sons, January/February 2001.
This paper examines strategies for implementing and operating IP routing effectively within satellite constellation networks, given known constraints on the constellation resulting from satellite mobility, global visibility, routing and addressing.

Preprint errata: Originally scheduled for November/December 2000, as indicated by the note on the first page. Published in the January/February 2001 issue.

IP routing issues in satellite constellation networks (124K, portrait A4)

DOI 10.1002/sat.655 | 150+ cites in Google Scholar (second most cited paper in that journal) | CiteSeer.

2000
A fair traffic conditioner for the assured service in a differentiated services Internet
Ilias Andrikopoulos, Lloyd Wood, George Pavlou.
refereed conference paper, in the proceedings of the IEEE International Conference on Communications (ICC 2000), vol. 2, pp. 806-810, New Orleans, 18-22 June 2000.
In this paper we present a traffic conditioner able to provide fairness between responsive and unresponsive flows originating from the same customer network, using a Fair Two-Rate Three-Color Marker. Its capability for fairness is based on the use of the FRED fair active buffer algorithm to control the token allocation of the token buckets residing in the traffic conditioner.
A fair traffic conditioner for the assured service in a differentiated services Internet (69K, portrait A4)

DOI 10.1109/ICC.2000.853610 | 40+ cites in Google Scholar | CiteSeer.

1999 and earlier
Supporting group applications via satellite constellations with multicast
Lloyd Wood, Haitham Cruickshank, Zhili Sun.
Discusses satellite constellations with intersatellite links. Uses SaVi.
refereed conference paper, pp. 190-194, Griffiths, O'Reilly et al. (ed.), Proceedings of the Sixth IEE Conference on Telecommunications (ICT '98), Edinburgh, United Kingdom, 29 March - 1 April 1998.
IEE Conference Publication no. 451, ISBN 0-85296-700-4, ISSN 0537-9989.
Here, the networking aspects of the broadband satellite constellations are discussed, and the suitability of the constellations for multicast is assessed.
Supporting group applications via satellite constellations with multicast (168K, portrait A4)
Supporting group application slides, presented 2pm, Tuesday 31 March 1998 (272K, landscape A4)

DOI 10.1049/cp:19980038 | 10 cites in Google Scholar | CiteSeer | IEEExplore | CAT.INIST full paper online.

Network performance of non-geostationary constellations equipped with intersatellite links
Lloyd Wood.
Discusses satellite constellations with intersatellite links.
Thesis for award of Master of Science (MSc) in Satellite Communication Engineering, University of Surrey, November 1995.
Work completed as Rapport 95-9, ENST site de Toulouse (old site), France.
An ideal, simplified, non-geostationary satellite constellation network, with varying numbers of intersatellite links on each satellite, is presented and analysed, using a minimum-path, circuit-switching approach.
Abstract and full MSc thesis

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Also noted

Early work in the 1990s included contributions to Bisante and to the COST 253 final report, which is available online (DOI 10.1002/0470845929) and from Amazon (UK, Canada, France, Germany, Japan).

I have also acted as an anonymous reviewer for conferences and journals. There is a page noting sundry acknowledgements.


Lloyd Wood (L.Wood@society.surrey.ac.uk)
this page last updated 22 June 2014