The Basic Idea of the Network Time Protocol (NTP)?

Reema Alzohairi
2 min readDec 19, 2020
Photo by Jon Tyson on Unsplash

In order to ensure that time in an instance is accurate, the Network Time Protocol is very crucial. But, what exactly is the Network Time Protocol?

The Network Time Protocol (NTP)

On the internet, atomic clocks are maintained to give very very very accurate UTC time. UTC time, also known as GMT, is the primary time standard. The idea of this protocol is to communicate this accurate UTC time to whoever needs it.

So, a system or an instance will communicate with a time source to get that accurate time that is originally obtained from the atomic clock available online. However, how can we ensure that a time source is believable enough to get time from it and consider it accurate?

Based on the protocol, a stratum number will is assigned to each possible source. This number will indicate the level of believability for a particular time source. In other words, it indicates the number of hops from the atomic clock. The following image shows stratum hierarchy.

For example, atomic clocks will always have stratum of level 0 and those obtaining time from an atomic clock will have stratum of level 1 and those obtaining time from a source of stratum 1 will have stratum 2 and so on. The highest stratum value is 15. Stratum 16 and higher indicates the source is unsynchronized and unreliable based on the protocol’s algorithm.