Network Time Server Faq

What is a network time server?

A network time server is a hardware device that utilises a single time source and distributes it amongst a network to ensure all computers and devices are telling the same time.

What is NTP?

Network Time Protocol is a protocol designed to distribute time across computers. NTP uses an algorithm to work out drift and inaccuracies and compensates for them ensuring all devices on a network are synchronised.

What is UTC?

Coordinated Universal Time (UTC) is a global timescale used by computer networks throughout the world. It is based on the time told by atomic clocks but compensates for the slowing of the Earth’s rotation by adding Leap Seconds, this also keeps it inline with GMT (Greenwich Meantime).

How does a network time server receive UTC?

UTC is broadcast by several national time and frequency transmissions on long-wave. Not every country has one and the signals are finite and vulnerable to interference. Alternatively as GPS satellites (Global Positioning System) all transmit timing information from their onboard atomic clocks this can be used also as a timing source for network time servers.

Can’t I use the Internet as a timing source?

There are many sources of UTC time on the Internet but many are not very accurate and for those that are the distance away can cause a drop-off in precision. More importantly, Internet time sources can’t be authenticated. Authentication is a security measure that ensures that a timing reference is what it says it is.

Which method is best for me a radio referenced time server or one that utilises the GPS network?

This depends primarily on where the network time server is to be situated. If a national radio signal is available and local topography doesn’t cause interference then a radio referenced network time server is probably the best option. However, if a radio signal is unavailable then the GPS network would be an obvious solution. While GPS signals are available everywhere on the planet they do have a downside in that their antennas have to have a clear view of the sky to receive the signal, this can be problematic  if a server room is on the ground floor of a skyscraper – although it is possible to receive a GPS signal via window.

How accurate are time servers?

A radio referenced network time server can provide UTC time to an accuracy of 100 microseconds, while the GPS network can fare even better with accuracies of a few milliseconds reasonably possible.