[ntp:questions] Survey of NTP surveys

shoppa at trailing-edge.com shoppa at trailing-edge.com
Thu Nov 2 16:46:01 UTC 2006

The little I know about NTP surveys, in chronological order:

1989, Mills, http://www.eecis.udel.edu/~mills/database/papers/ccr.ps

1994, James Guyton, I only know of this because it is referenced in
Minar below.

1997, Mills,

1999, Nelson Minar,

2005, Cristina Duarte Murta and Pedro R. Torres Junior,

Any other URL's I should know of?

Interesting numbers for time evolution of count of stratum-1's:

1994: 66
1997: 220
1999: 957
2005: 533

Minar (1999) reveals that vast majority (657 of the 957) of claimed
Stratum 1's that he counted are in fact LCL (not obviously tied to a
refclock). The decrease between 1999 and 2005 numbers may reflect not a
decrease in Stratum 1's that are locked, but in fact a decrease in
misconfigured NTP hosts. (Minar identifies a specific Red Hat
distribution responsible for many of the misconfigurations, and I
suspect that few of these are still alive.)

I would be most interested if the 2005 survey (which the authors say is
in the publication process) reveals some details about the stratum-1's
and their diversity of refclocks. At the time of Minar's 1999 survey
GPS was far and away most common, and I suspect that diversity of
refclocks has degraded even more since then.


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