About Time

In this episode of PING, APNIC Chief Scientist Geoff Huston and I discuss Network Time Protocol or NTP. NTP is one of the older systems we depend on, designed and implemented by Dave Mills who died in 2024. Dave had been working on time synchronisation from the mid 1970s, and cared deeply about synchronising the emerging ARPAnet and the Internet, with the pre-existing worldwide collaborative framework which regulates our sense of time, and how it relates to the world of science, astronomy and civil society. Geoff has been musing about NTP, moves to secure NTP, and the many dependencies in the modern world on the underlying concepts of a coordinated sense of time. This dependency in the modern world on highly synchronised clocks cannot be overstated, it creeps into every sector of daily life from aircraft and space navigation, to finance systems, and event scheduling of all kinds. But our model of time is fundamentally based on the rotation of the earth, and the length of the second, and unfortunately while we now define the length of the second to astonishingly accurate levels, the rotation of the earth isn't as stable as we'd like. our model of time therefore has to make some adjustments To make matters worse, our model of time has been coded over the years to varying models of a start date known as an "epoch", and how we represent time inside the machines, systems and services isn't one unified model any more. It's all coming a bit un-stuck.