A Survey of the NTP Network

By Nelson Minar, written for Hari Balakrishnan's networking class, December 1999.

This paper is available as:

• HTML (120k)
• gzipped postscript (49k)
• uncompressed postscript (156k)

In addition, you can find:

• Talk slides
• The survey data
• The survey code

Abstract

The Network Time Protocol creates a network of hosts on the Internet that synchronize time. This paper describes the methods and results of a survey of the NTP network conducted by a "spider" that queried all findable NTP hosts on the Internet. This survey estimates the NTP network contains at least 175,000 hosts. An analysis of the survey data collects network size, timing, and topology information and compares them to results from previous surveys over ten years. An analysis of the stratum 1 clocks shows a surprising number of bad timekeepers.

BiBTeX citation

(I currently have no plans to publish this paper. Please contact me if you know of an appropriate venue.)

@Misc{minar99-ntpsurvey,
  author =       {Nelson Minar},
  title =        {A Survey of the NTP Network},
  month =        {December},
  year =         {1999},
  url =          {http://www.media.mit.edu/~nelson/research/ntp-survey99/}
}