A Novel Algorithm for Establishing a Balanced Synchronization Hierarchy with Spare Masters (BSHSM) for the IEEE 1588 Precision Time Protocol

Nguyen Tien,Jong Rhee

doi:10.3390/en10101469

Abstract

The best master clock (BMC) algorithm is currently used to establish the master-slave hierarchy for the IEEE 1588 Precision Time Protocol (PTP). However, the BMC algorithm may create an unbalanced hierarchy that contains several boundary clocks with a large number of slaves in comparison to other clocks. The unbalanced hierarchy can cause problems, such as high communication load and high bandwidth consumption in boundary clocks. Additionally, the BMC algorithm does not provide any fast recovery mechanism in the case of a master failure. In this paper, we propose a novel balanced synchronization hierarchy with spare masters (BSHSM) algorithm to establish a balanced master-slave hierarchy and to provide a fast recovery mechanism in the case of master failures for the PTP. The BSHSM algorithm establishes the master-slave hierarchy with boundary clocks that have a balanced number of slaves. In doing so, it solves the problems caused by the unbalanced master-slave hierarchy. Additionally, the BSHSM algorithm provides a fast recovery mechanism by selecting a spare master for each boundary clock; this allows a boundary clock to immediately select a new master clock when its current master has failed or is disconnected. The fast recovery mechanism reduces the period of running freely and clock drift in clocks, improving the synchronization quality of the PTP. Various simulations were conducted using the network simulation OMNeT++ v4.6 to analyze, evaluate, and compare the performance of the BSHSM and BMC algorithms. The simulation results show that the synchronization hierarchy of the BSHSM algorithm is much more balanced than the BMC algorithm, and it also has a shorter period of recovery.

Highlights

IntroductionTime synchronization is required to maintain high precision for distributed systems in many application domains, such as automation, testing and measurement, and telecommunications
Time synchronization is required to maintain high precision for distributed systems in many application domains, such as automation, testing and measurement, and telecommunications.The applications commonly use communication networks that link the distributed network nodes rather than building a dedicated synchronization infrastructure
In the master-slave hierarchy built by the best master clock (BMC) algorithm, Boundary clock (BC) 7, 13, and 19 have the highest the master-slave hierarchies established by the BMC and balanced synchronization hierarchy with spare masters (BSHSM) algorithms

Summary

Introduction

Time synchronization is required to maintain high precision for distributed systems in many application domains, such as automation, testing and measurement, and telecommunications. The applications commonly use communication networks that link the distributed network nodes rather than building a dedicated synchronization infrastructure. Clocks in the distributed systems are synchronized by means of dedicated messages and protocols. Two prevalent protocols are used for clock synchronization in these networks: Network Time Protocol (NTP) [1] and Precision Time Protocol (PTP) [2]. The NTP is widely used to synchronize computer clocks on the Internet. The purpose of the NTP is to convey timekeeping information from several primary servers to secondary time servers and clients via both private networks and the public Internet. While there can be multiple NTP servers within the synchronized subnet, Energies 2017, 10, 1469; doi:10.3390/en10101469 www.mdpi.com/journal/energies

Results

Discussion

Conclusion