The Network Computer as Precision Timekeeper
David L. Mills · 1996
This paper describes algorithms to discipline a computer clock lo a source of standard time, such as a GPS receiver or aMIher 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 soware for Unix and Windows and, for the highest accuracy, in the operating system kernels for Sun, DEC, and H P workstations. Rms errors on LANs are usually less than I0 p and on global internet paths usuaUy less than 5 ms. However, rare disruptions of one kind or another can cause error spikes up to 100 p on LAh's and 100 ms on Internet paths. I 1