How Precision Time Protocol is being deployed at Meta

What this post added

This post details the implementation of Precision Time Protocol (PTP) at Meta, migrating from NTP to achieve nanosecond precision for system synchronization. It outlines the technical challenges and solutions involved in deploying PTP at scale, including the PTP architecture (rack, network, client), hardware innovations like GNSS-over-fiber antennas and a new Time Appliance with FPGA-based Time Cards and Network Cards, and the development of a custom ptp4u solution to support millions of clients. The post also discusses the use cases for PTP, such as ensuring linearizability in distributed systems, and the monitoring strategies employed.