Author Information

David L. Mills (M '88 / ACM '63) received the BSE, MSE, MS and PhD
degrees from the University of Michigan in 1960, 1962, 1964 and 1971,
respectively. He is currently Professor of Electrical and Computer
Engineering, and Computer and Information Sciences at the University of
Delaware. He was formerly a Senior Research Scientist with COMSAT
Laboratories and later with M/A-COM Linkabit. His current research
interests are in computer network timekeeping, network security and very
large, self-configuring network systems. He can be reached at
mills@udel.edu and www.eecis.udel.edu/~mills.

Abstract for Database

.ti Adaptive Hybrid Clock Discipline Algorithm for the Network Time
Protocol

.pgs NA

.au1 David L. Mills
Electrical and Computer Engineering Department
University of Delaware
Newark, DE 19716
phone 302 831 8247, fax 302 831 4316
email mills@udel.edu, web www.eecis.udel.edu/~mills

.ab This paper describes the analysis, implementation and performance of
a new algorithm engineered 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 algorithm is intended for the Network Time
Protocol (NTP), which is in widespread use to synchronize computer
clocks in the global Internet, or with another functionally equivalent
protocol such as DTSS or PCS. It controls the computer clock time and
frequency using an adaptive-parameter, hybrid phase/frequency-lock
feedback loop. Compared with the current NTP Version 3 algorithm, the
new algorithm developed for NTP Version 4 provides improved accuracy and
reduced network overhead, especially when per-packet or per-call charges
are involved. The algorithm has been implemented in a special purpose
NTP simulator, which also includes the entire suite of NTP algorithms.
The performance has been verified using this simulator and both
synthetic data and real data from Internet time servers in Europe, Asia
and the Americas.

.in IEEE/ACM Transactions on Networking