Research Project Descriptions and Briefings

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The Okefenokee Caravan, Walt Kelly

Ongoing Research Projects

Network Time Synchronization Project

icon• Researchers involved: David Mills, graduate students and many volunteers
• Funding: Defense Advanced Research Projects Agency (DARPA), National Science Foundation (NSF), Navy Surface Weapons Center (NSWC)
Project Description, Briefing Slides and Further Information

This project is an ongoing collaboration between over four dozen volunteer contributors and University of Delaware. It develops and maintains the Network Time Protocol software package for Unix, Windows and VMS. This package, which was developed and refined over two decades, is distributed with every major operating system and used in thousands and millions of computers and routers all over the world.

This project is also an ongoing collaboration between National Institutes of Science and Technology, US Naval Observatory and University of Delaware. It facilitates deployment of public primary time servers in the US and other countries and assists national metrology laboratories in setting up network time synchronization services.

Timekeeping in the Interplanetary Internet

icon• Researchers involved: David Mills, graduate students
• Funding: NASA/Jet Propulsion Laboratory
Project Description, Briefing Slides and Further Information

This is an ongoing collaboration between NASA/JPL and the University of Delaware. It is studying timekeeping issues in the Interplanetary Internet, specifically for Mars missions and supporting infrastructure. Currently, the clocks for all space vehicles are coordinated on Earth using a software library called SPICE. With new technology, timekeeping in space would be distributed so that timed experiments could be accurately controlled autonomously and without intervention from Earth.

Past Projects

Autonomous Networks

gif• Researchers involved: David Mills, graduate students
• Funding: Defense Advanced Research Projects Agency (DARPA)
Project Description, Briefing Slides and Further Information

This project is studying methodologies where autonomous and possibly mobile sensors are deployed ad-hoc over a battlefield or planetary surface and then organize themselves using a wireless infrastructure to support secure application services. There are two main work areas for this project, one studying methods in which a hierarchical, ubiquitous service such as network time synchronization can autonomously configure and survive in a possibly heavily damaged network infrastructure, and the other studying protocols and algorithms for efficient source authentication based on public key cryptography.

Precision Time Synchronization

icon• Researchers involved: David Mills, Jeffery Mogul, Poul-Henning Kamp, undergraduate and graduate students
• Funding: equipment grants from Arbiter, Austron, Bancomm, Cisco, Digital, Hewlett Packard, Spectracom, Sun Microsystems, TrueTime, US Coast Guard, US Naval Observatory
Project Description
• Briefing Slides: PostScript | PowerPoint | PDF
Further information

This project is an ongoing collaboration between Compaq Western Research Laboratory, FreeBSD Project and University of Delaware. It produces and maintains a software package for precision time synchronization. The package has been incorporated in the Unix kernels for Sun Solaris and SunOS, Hewlett Packard HP-UX and Tru64 (Alpha), Digital Ultrix, FreeBSD and Linux.

Internetworking Research Laboratory

icon• Researchers involved: David Mills and suffering students
• Funding: as needed and available; we accept gifts
Project Description, Briefing Slides and Further Information

The laboratory is used for ongoing research projects in internetworking architectures, protocols and applications development. It is equipped with a wide variety of workstations, personal computers, routers and measurement equipment and specially provisioned for precision time synchronization and network performance measurements. These resources are connected via the DCnet research network to The EECIS department network, UDel campus network, CAIRN research network and external networks at speeds to 100 Mb.

CAIRN/DARTnet Collaboration

icon• Researchers involved: David Mills, Jon Crowcroft (UCL), Kenneth Carlberg (SAIC), graduate students
• Funding: Defense Advanced Research Projects Agency (DARPA)
Project Description
• CAIRN/DARTnet Briefing Slides: PostScript | PowerPoint | PDF
• DCnet Briefing Slides: PostScript | PowerPoint | PDF
Further information

This project was a collaboration between University College London, Science Applications International and University of Delaware. The participants and students utilize the CAIRN research network for experiments in multimedia conferencing, multicast routing technology, network performance evaluation and precision time synchronization.

Advances in Computer Network Timekeeping

icon• Researchers involved: David Mills, Judah Levine (NIST), Richard Schmidt (USNO), graduate students
• Funding: National Science Foundation (NSF), Navy Surface Weapons Center (NSWC)
Project Description
• Briefing Slides: PostScript | PowerPoint | PDF
Further information

Simulation of Very Large Networks

icon• Researchers involved: David Mills, graduate students Robert Redwinski and Tamal Basu
• Funding: Defense Advanced Research Projects Agency (DARPA)
Project Description, Briefing Slides and Further Information

This project was based on two MSEE theses studying the behavior of networks with many thousands of nodes subject to various failure scenarios. The work was motivated by observations over two decades where interconnected network systems such as ARPAnet, MILnet, SATnet and NSFnet showed unexpected routing congestion which could not be explained by conventional theory.

Fault-Tolerant Time Synchronization

icon• Researchers involved: David Mills, graduate student Kenneth Monington
• Funding: US Navy Surface Weapons Center (NSWC)
Project Description
Further information

This project was based on a PhD dissertation studying algorithms to reliably synchronize clocks in a network including truechimers, which always present correct time, and falsetickers, which present incorrect or inconsistent time. The algorithms are based on Byzantine agreement principles in which clocks are compared in multiple rounds and falsetickers revealed by voting procedures.

Highball Project

icon• Researchers involved: David Mills, Charles Boncelet, John Elias, graduate students
• Funding: Defense Advanced Research Projects Agency (DARPA)
Project Description and Further Information
• Briefing Slides: PostScript | PDF

This project explored just-in-time packet switching technology for a lightwave network operating at gigabit speeds. Nodes are crossbar switches capable of connecting any input to one or more outputs. Packets are buffered only at the edges of the network and launched only when a collision-free path to the destination is available. Paths are dynamically determined using a self-configured, distributed scheduling algorithm.