The Network Computer as Precision Timekeeper

Abstract

This paper describes algorithms to discipline a computer clock to a source of standard time, such as a GPS receiver or another computer synchronized to such a source. The algorithms are designed for use in the Network Time Protocol (NTP), which is used to synchronize computer clocks in the global Internet. They have been incorporated in the NTP software for Unix and Windows and, for the highest accuracy, in the operating system kernels for Sun, DEC, and HP workstations. Rms errors on LANs are usually less than 10 microsecond and on global Internet paths usually less than 5 ms. However, rare disruptions of one kind or another can cause error spikes up to 100 microsecond on LANs and 100 ms on Internet paths.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1996
Accession Number
ADA511728

Entities

People

  • David L. Mills

Organizations

  • University of Delaware

Tags

DTIC Thesaurus Topics

  • Accuracy
  • Application Software
  • Clocks
  • Computer Networks
  • Computers
  • Electrical Engineering
  • Engineering
  • Frequency
  • Local Area Networks
  • Measurement
  • Networks
  • Operating Systems
  • Oscillators
  • Precision
  • Reliability
  • Standards
  • Time Intervals

Fields of Study

  • Computer science

Readers

  • Database Systems and Applications
  • Positioning, Navigation, and Timing (PNT) Technology.

Technology Areas

  • Space