D012 DARPA Progress Report 1996

Scalable, High Speed Time Synchronization

Objectives

The objectives of this work are: (1) develop autonomous peer discovery, configuration and deployment algorithms for a distributed time synchronization network in an arbitrary internet of thousands or millions of servers and clients, (2) significantly improve accuracy and reliability using distributed algorithms which take into account all locally available timekeeping information distributed by multicast and unicast means, (3) validate proof of concept of autonomous configuration technology as applicable to other distributed protocols, such as directory and routing services.

Approach

The approach is based on technology developed over the last decade for synchronizing computer network clocks in the Internet. The Network Time Protocol (NTP) is now deployed in an estimated total of over 100,000 hosts in the Internet. As this number grows, it is necessary to investigate protocols and algorithms which provide a autonomous, repairable configuration capability, in which an isolated client or server subnet can discover other servers and organize the topological connectivity to maximize the quality of synchronization, while obeying limits on network traffic and operating system overhead. The existing NTP Version 3 reference implementation will be used as the development vehicle in this investigation.

Recent Accomplishments

1. Completed analysis, design and documentation of a proposed security model and authentication scheme for NTP and other similar distributed, ubiquitous internet services.
2. Completed analysis, design and preliminary documentation of a proposed autonomous configuration scheme for NTP and other similar distributed, ubiquitous internet services.
3. Completed analysis, design, simulation and documentation of improved NTP clock discipline algorithms that increase synchronization accuracies up to ten times, when compared to current algorithms.
4. Developed and refined a formal specification document for Simple NTP, which is intended as guidance for commercial products such as integrated GPS/NTP servers and PC clients.

Current Plan

1. Implement the proposed security model and authentication scheme for NTP using the existing NTP Version 3 software for Unix and Windows as a base.
2. Implement the proposed autonomous configuration scheme for NTP using the existing NTP Version 3 software for Unix and Windows as a base.
3. Modify the existing NTP Version 3 clock discipline algorithm to incorporate the improvements found through simulation.

Technology Transition

Research findings, including results from analysis and experiment, as well as hardware and software descriptions, will be published in the open scientific literature. Sources and documentation for designated operating system software deliverables, including the proposed Network Time Protocol Version 4, will be freely available from Internet ftp servers. Hardware documentation in the form of circuit schematics, PCB artwork and drill templates will be freely available from Internet ftp servers. Protocol specifications and associated documentation will be published in RFC form for consideration by the IETF standards apparatus. Research findings will be presented to the DoD and HPCC community in regular meetings sponsored wholly or in part by ARPA. Assistance will be provided to government agencies of the U.S. and other countries in setting up and operating networks of NTP servers.