Modern society is a digital society and digital devices depend on time. We tend to take this for granted. When we open a laptop or glance at the phone, we see the time and assume it is correct. But the processes by which the correct time is synchronised across networks and devices – the processes by which time is calculated, calibrated, transported and monitored –  are extremely complex. Moreover, the social consequences of incorrect time are very serious indeed. When time is not accurately synchronised, secured and monitored, critical infrastructure is affected across sectors ranging from finance and cybersecurity to the media, transport and power. 

So, how do digital devices get accurate and reliable time? Read on to find out more.

Network Time Protocol 

Network Time Protocol (NTP) services play a critical role in ensuring the accuracy and synchronisation of time across devices, networks and countries. NTP is the most common protocol used to synchronise the clocks of computers and other network devices to a time source such as an atomic clock. 

NTP uses a stratum model with the hierarchy based on how close a time server is to the reference clock. The highest level of the hierarchy uses a primary reference time source such as an atomic clock. These sources are highly accurate and provide the most reliable time information. Read more about NTP here.

Network Time Security 

With many of today’s most important security processes dependent on accurate time, the consequences of receiving time from a malicious source are serious. Everything from establishing encrypted sessions and using DNSSEC to time-stamping financial transactions and preventing online fraud depends on accurate and secure time. By using NTS, you can be sure your devices are receiving accurate time from a reliable source. NTS is a free service available to anyone, anywhere in the world. The only thing you need is an NTS-enabled NTP client. Read more about NTS here.
 

Precision Time Protocol 

Precision Time Protocol (PTP) services provide the most accurate and secure time available to IP-based networks. With time traceable to UTC at the level of nanoseconds (billionths of a second), PTP is far more accurate than, for example, Network Time Protocol (NTP). PTP also avoids the security, stability and logistical issues that cause significant problems when using GNSS services.

PTP enables highly-accurate time synchronisation of clocks in IP based networks by sending packets between leader and follower clocks. The reference clock (also called a grandmaster) may be controlled by an atomic clock (such as the caesium clocks used by Netnod in its PTP time service). Read more about PTP services here. 

Modern time distribution: GNSS and terrestrial networks? 

Today time is distributed to digital networks in two main ways: via Global Navigation Satellite Systems (GNSS) or over a network using fibre, copper or wireless (with services that include NTP, NTS and PTP). Both methods have their pros and cons. For any service where time is mission critical, some combination of these methods is advisable. Read more here.