Hardware Support for Clock Synchronization in Distributed Systems

This article presents a novel network interface hardware architecture, which enables clock synchronization in fault-tolerant distributed real-time systems with sub-μsrange accuracy. The proposed mechanism, which is applicable for any packet-oriented data network, inserts time information into data packets at the interface between the physical layer transceiver and the network controller upon packet transmission and receipt respectively. Local time is supplied by a high-resolution rate-adjustable adder-based clock, which also contains hardware support easing intervalbased external clock synchronization, like maintaining time and accuracy intervals and interfaces to GPS receivers. Keywords— Clock synchronization, distributed systems, network interface, GPS.