PPSi - A free software PTP implementation
Pietro Fezzardi, Maciej Lipiński, Alessandro Rubini, Aurelio Colosimo · 2014
This paper describes a new open source implementation of the Precision Time Protocol (PTP) [1] called PTP Ported To Silicon (PPSi) [2]. It was developed to fill in a niche in the free software world for a PTP daemon that is easily portable to a wide range of architectures and highly modular to enable protocol extensions - two key requirements of its driving force, the White Rabbit (WR) Project [3] [4]. PPSi's core protocol code is common for all the supported architectures ranging from a Linux PC to a soft-core processor running in a Field Programmable Gate Array (FPGA) - a feature minimizing code duplication, easing debugging, and facilitating new developments. This paper gives an overview of PPSi's internals describing design choices as well as the means of achieving portability and extensibility. A detailed example of a simulator architecture proves the design advantages. With an increasing number of supported architectures and a wide use in WR networks, PPSi is becoming an appealing PTP implementation also outside of the White Rabbit Community.