A Design Approach for Self-Diagnosis of Faulttolerant Clock Synchronization

Abstract

faulttolerant clock synchronization (FTCS) is crucial for a distributed system with a desired degree of fault tolerance. Recently, various FTCS algorithms have been proposed to mask malicious faults of clocking modules. A common weakness of the mask-based algorithms is their inability to identify faulty clocking modules in the system for the purpose of repair. As a result, the usually required availability of correct clocking modules could not be maintained. A general design approach for self-diagnosis of faulty clocking modules in an FTCS system is presented. The approach is based on a statistical testing method. The major advantages are better self-stability control and lower overhead. With the support of a necessary repair technique, integration of the self-diagnosis algorithm into a mask-based FTCS algorithm can help achieve an ideal level of clock availability. A self-stability evaluation method is also discussed. © 1989 IEEE