PSynUTC - Evaluation of a High Precision Time Synchronization Prototype System for Ethernet LANs

This article presents an overview and some evaluation results of our PSynUTC 1 prototype system for GPS time distribution and time synchronization in Ethernetbased LANs. PSynUTC does not need dedicated GPS receivers at every computing node but uses ordinary data packets for disseminating time information. High accuracy is achieved by combining (1) hardware packet timestamping at the network interface of nodes and switches, (2) high-resolution, high-frequency adder-based clocks with superior adjustment capabilities, and (3) clock rate synchronization algorithms compensating typical TCXO drifts. Our technology can be employed with any network controller chipset that supports the media-independent interface (MII) standard. Moreover, standard device drivers and protocol stacks can be used without any change. Our evaluation results show that PSynUTC will achieve a worst case synchronization accuracy in the 100 ns range, which is an improvement of at least 4 orders of magnitude over conventional software-based approaches like NTP.

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