Posted by Stuart on October 20th, 2010
Time is essential for computers, networks and technology. It is the only reference technology has to ascertain if a task has happened or is due to take place. As time, in the from of timestamps, is so important for technology, when there is uncertainty over time, due to different devices on a network having different times, it can cause untold errors.
The problem with time in computing is that all devices, from routers to desktop PCs, have their own onboard timepiece that governs the system clocks. These system clocks are just normal electronic oscillators, they type commonly found in battery powered watches, and while these are adequate for humans to tell the time, the drifting of these clocks can see devices on a network, seconds and even minutes out of sync.
There are two rules for time synchronisation:
- All devices on a network should be synchronised together
- The network should be synchronised to UTC (Coordinated Universal Time)
To synchronise a network you need to make use of Network Time Protocol (NTP). NTP is designed for accurate network time synchronisation. IT works by using a single source of time which it then distributes it to all devices on the NTP network.
NTP continually checks the devices for any drift and then adjusts to ensure the entire network is within a few milliseconds of the reference time.
Coordinated Universal Time is a global timescale that is kept true by atomic clocks. By synchronising a network to UTC you are in effect ensuring your network is synchronised to every other UTC network on the planet.
Using UTC as a reference source is a simple affair too. NTP time servers are the best way to find a secure source of UTC time. They use either GPS (Global Positioning System) as a source of this atomic clock time or specialist radio signals keeping the UTC time source external to the network for security reasons.
A single NTP server can synchronise a network of hundreds and even thousands of devices ensuring the entire network is to within a few milliseconds of UTC.