Probabilistic Internal Clock Synchronization
نویسندگان
چکیده
We propose an improved probabilistic method for reading remote clocks in systems subject to unbounded communication delays and use this method to design a family of fault-tolerant probabilistic internal clock synchronization protocols. The members of this family differ in the failure classes they tolerate, from crash to arbitrary. Because of probabilistic reading, our protocols achieve better synchronization precisions than those achievable by previously known deterministic algorithms. Another advantage of the proposed protocols is that they use a linear, instead of quadratic, number of messages, and that message exchanges are staggered in time instead of all happening in narrow synchronization intervals. The envelope and drift rates of the synchronized clocks are proven to be optimal.
منابع مشابه
Probabilistic Clock Synchronization Service in Sensor Networks
Recent advances in technology have made low cost, low power wireless sensors a reality. Clock synchronization is an important service in any distributed system, including sensor network systems. Applications of clock synchronization in sensor networks include data integration in sensors, sensor reading fusion, TDMA medium access scheduling, and power mode energy saving. However, for a number of...
متن کاملClock synchronization in virtual rings
A probabilistic algorithm for external clock synchronization is proposed. The algorithm works under the assumption that it is possible to identify a virtual ring among the servers involved, and does not require an upper bound to message trasmission delays. The approach is probabilistic, since clock synchronization is not guaranteed, but the probability of success can be made arbitrarily close t...
متن کاملLower Bounds for Function Based Clock Synchronization
We assume that each process has access to a local hardware clock and that the drift of correct hardware clocks is bounded by a given constant . Since we are in this paper only interested in internal clock synchronization algorithms capable of masking arbitrary failures, when we talk about a synchronization algorithm, we mean an internal clock synchronization algorithm tolerant of arbitrary fail...
متن کاملFault-Tolerant External Clock Synchronization
We address the problem of how to integrate faulttolerant internal and external clock synchronization. We propose a new algorithm which provides both external and internal clock synchronization for as long as no more than F reference time servers out of a total of 2F+1 are faulty. When the number of faulty reference time servers exceeds F , the algorithm degrades to a fault-tolerant internal clo...
متن کاملIntegrating Internal and External Clock Synchronization
We address the problem of how to integrate fault-tolerant external and internal clock synchronization. In this paper we propose a new external/internal clock synchronization algorithm which provides both external and internal clock synchronization for as long as a majority of the reference time servers (servers with access to reference time) stay correct. When half or more of the reference time...
متن کامل