A Brief History of NTP Time: Memoirs of an Internet Timekeeper1

This paper traces the origins and evolution of the Network Time Protocol (NTP) over two decades of continuous operation. The technology has been continuously improved from hundreds of milliseconds in the rowdy Internet of the early 1980s to tens of nanoseconds in the Internet of the new century. It includes a blend of history lessons, technology milestones and series of experiments that shape, define and record the early history of the Internet and NTP. This narrative is decidedly personal, since the job description for an Internet timekeeper is highly individualized and invites very few applicants. There is no attempt here to present a comprehensive tutorial, only a almanac of personal observations, eclectic minutiae and fireside chat. Many souls have contributed to the technology, some of which are individually acknowledged in this paper, the rest too numerous left to write their own memoirs.