Title :
Time synchronization over networks using convex closures
Author :
Berthaud, Jean-Marc
Author_Institution :
IBM Networking Div., La Gaude Lab., France
fDate :
4/1/2000 12:00:00 AM
Abstract :
This paper presents a general time synchronization algorithm that analyzes the time offset between any two computers clocks in a network and its evolution, by using mathematical topology properties. It builds a conversion function that produces precise and guaranteed bounds for each time conversion, and which provides accurate time synchronization. It is able to automatically adjust the observation process so as to maintain the error bound within some specified limit. It does not require adjustments to local clocks, and it features a way of filtering observation data based on a criterion of usefulness to improve precision, thus discarding only useless information. Advantages over approaches using other tools to filter out and analyze observation data (mean and variance, linear regression, midpoint functions, etc.) are exposed. Special attention is given to assessing the uncertainties and errors made in the observation process, and to their propagation in the estimation processes. The developed technique allows one to globally achieve a better precision than what has been reached on each single observation, given some conditions of operation that are explained
Keywords :
clocks; computer networks; network topology; set theory; synchronisation; computer clocks; computer network; conversion function; convex closures; error bound; error propagation; estimation processes; general time synchronization algorithm; guaranteed bounds; linear regression; mathematical topology properties; mean; midpoint functions; observation data; observation data filtering; observation process; precise bounds; time offset; uncertainties; variance; Algorithm design and analysis; Analysis of variance; Clocks; Computer errors; Computer networks; Information filtering; Information filters; Network topology; Nonlinear filters; Synchronization;
Journal_Title :
Networking, IEEE/ACM Transactions on