Network time servers are responsible for providing a network’s time. Of course, all computers have their own onboard clocks built into the motherboards, but these devices are only cheap oscillators and are prone to drift. When you have a network of hundreds or even thousands of PCs and devices, if there was no synchronisation to a single network time source, all the machines could be relaying completely different times, often several minutes apart.
When it comes to network time synchronisation, Network Time Protocol (NTP) is by far the most widely used software protocol. Whether it’s for keeping a network of hundreds or thousands of machines synchronised, or keeping a single machine running true, NTP offers the solution. Without NTP, and the NTP server, many of the tasks we perform on the internet, from shopping to online banking, simply wouldn’t be possible.
Perhaps the safest and most accurate means of obtaining a time source is by utilising the time codes transmitted by the GPS (Global Positioning System). All that is required for picking up these GPS signals is a GPS NTP server, which will not only receive the time code, but also distribute it around the network, check for drift and maintain stable and precise time on all machines.
To synchronise a computer network or other technology systems to GPS time, all that is required is a GPS network time server. GPS network time servers are simple to install, simple to use and can maintain accuracy for all sorts of technologies. Used by organisations as diverse as stock exchanges, air traffic control and banking systems, GPS time servers provide an efficient and cost effective solution to maintain network synchronicity.
When a network loses time, you are at risk of losing far more than just what time of day it is. Time is an essential aspect of network security and any errors in a network time server can lead to catastrophic result. However, the solution for ensuring network security is fairly simple and relatively inexpensive – the NTP time server.
Network time protocol (NTP) is used as a synchronisation tool by most computer networks. NTP distributes a single time source around a network and ensures all devices are running in synchronisation with it. NTP is highly accurate and able to keep all machines on a network to within a few milliseconds of the time source. However, where this time source comes from can lead to problems in time synchronisation within a network.
As British summer time officially ended last weekend, with the clocks going back to bring the UK back to GMT (Greenwich Mean Time), the debate about the annual clock changing has started again. The Coalition Government has proposed plans to change the way Britain keeps time by shifting the clocks forward another hour, and in effect reverting to Central European Time (ECT)..
ECT, would mean that Britain would remain an hour ahead of GMT in the winter and two hours ahead in the summer, providing lighter evenings but darker mornings, especially for those north of the border.
However, any proposed plans have stiff opposition from the Scottish Government who suggest that by altering the clocks, many areas in Scotland wouldn’t see daylight during winter until about 10am, meaning many children would have to go to school in the dark.
Other opponents, include traditionalists, argue that GMT has been the basis for British time for over a century, and that any change would be simply … unBritish.
However, a change to ECT would make things easier for businesses that trade with Europe, keeping British workers on a similar timescale to their European neighbours.
Whatever the outcome of the proposed changes to GMT, little will change when it comes to technology and computer networks as they already keep the same timescale all over the globe: UTC (Coordinated Universal Time).
UTC is a global timescale kept true by an array of atomic clocks and is used by all sorts of technologies such as computer networks, CCTV cameras, bank telling machines, air traffic control systems and stock exchanges.
Based on GMT, UTC remains the same the world over, enabling global communication and the transfer of data across time zones without error. The reason for UTC is obvious when you consider the amount of trade that goes on across borders. With industries such as the stock exchange, where stocks and shares fluctuate in price continuously, split second accuracy is essential for global traders. The same is true for computer networks, as computers use time as the only reference as to when an event has taken place. Without adequate synchronisation, a computer network may lose data and international transactions would become impossible.
Most technologies keep synchronised to UTC by using NTP time servers (Network Time Protocol), which continually check system clocks across whole networks to ensure that they all are synced to UTC.
NTP time servers receive atomic clock signals, either by GPS (Global Positioning Systems) or by radio signal broadcast by national physics laboratories such as NIST in the United States or NPL in the UK. These signals provide millisecond accuracy for technologies, so no matter what time zone a computer network is, and no matter where it is in the world, it can have the same time as every other computer network across the globe that it has to communicate with.
Despite the use of UTC (Coordinated Universal Time) as the world’s timescale, time zones, the regional areas with a uniform time, are still an important aspect of our daily lives. Time zones provide areas with a synchronised time that helps commerce, trade and society function, and allow all nations to enjoy noon at lunchtime. Most of us who have ever gone abroad are all aware of the differences in time zones and the need to reset our watches.
Keeping track of time zones can be really tricky. Different nations not only use different times but also use different adjustments for daylight saving, which can make keeping track of time zones difficult. Furthermore, nations occasionally move time zone, normally due to economic and trade reasons, which provides even more difficulties in keeping track of time zones.
You may think that modern computers can automatically account for time zones due to the settings in the clock program; however, most computer systems rely on a database, which is continuously updated, to provide accurate time zone information.
The Time Zone Database, sometimes called the Olson database after its long-time coordinator, Arthur David Olson, has recently moved home due to legal wrangling, which temporarily caused the database to cease functioning, causing untold problems for people needing accurate time zone information. Without the time zone database, time zones had to be calculated manually, for travelling, scheduling meetings and booking flights.
The Internet’s address system, ICANN (Internet Corporation for Assigned Names and Numbers) has taken over the database to provide stability, due to the reliance on the database by computer operating systems and other technologies; the database is used by a range of computer operating systems including Apple Inc’s Mac OS X, Oracle Corp, Unix and Linux, but not Microsoft Corp’s Windows.
The Time Zone Database provides a simple method of setting the time on a computer, enabling cities to be selected, with the database providing the right time. The database has all the necessary information, such as daylight saving times and the latest time zone movements, to provide accuracy and a reliable source of information.
Or course, a synchronised computer networks using NTP doesn’t require the Time Zone Database. Using the standard international timescale, UTC, NTP servers maintain the exact same time, no matter where the computer network is in the world, with the time zone information calculated as a difference to UTC.
Most people will have heard of atomic clocks, most people, probably without realising have even used them; however, I doubt many people reading this will have ever seen one. Atomic clocks are highly technical and complicated pieces of machinery. Relying on vacuums, super-coolants such as liquid nitrogen and even lasers, most atomic clocks are only found in laboratories such as NIST (National Institute for Standards and Time) in the US, or NPL (National Physical Laboratory) in the UK.
No other form of timekeeping is as accurate as an atomic clock. Atomic clocks form the basis of world’s global timescale UTC (Coordinated Universal Time). Even the length Earth’s spin requires manipulation by the addition of leap seconds to UTC to keep the day synchronised.
Atomic clocks work by using the oscillating changes of atoms during different energy states. Caesium is the preferred atom used in atomic clocks, which oscillates 9,192,631,770 times a second. This is a constant effect too, so much so that a second is now defined by this many oscillations of the caesium atom.
Louis Essen built the first accurate atomic clock in 1955 at the National Physical Laboratory in the UK, since then atomic clocks have become increasingly more accurate with modern atomic clocks able to maintain time for over a million years without ever losing a second.
In 1961, UTC became the world’s global timescale, and by 1967, the International System of Units adopted the Caesium frequency as the official second.
Since then, atomic clocks have become part of modern technology. Onboard every GPS satellite, atomic clocks beam time signals to Earth, enabling satellite navigation systems in car, boats and aeroplanes to judge their locations precisely.
UTC time is also essential for trade in the modern world. With computer networks speaking to each other across timezones, using atomic clocks as a reference prevents errors, ensures security and provides reliable data transfer.
Receiving a signal from an atomic clock for computer time synchronisation is incredibly easy. NTP time servers that receive the time signal from GPS satellites, or those broadcast on radio waves from places NPL and NIST, enable computer networks across the globe to keep secure and accurate time.
A day is something most of us take for granted, but the length of a day is not as simple as we may think.
A day, as most of us know, is the time it takes for the Earth to spin on its axis. Earth takes 24 hours to do one complete revolution, but other planets in our solar system have day lengths far different to ours.
The largest planet, Jupiter, for instance, takes less than ten hours to spin a revolution making a Jovian day less than half of that of Earth, while a day on Venus is longer than its year with a Venusian day 224 Earth days.
And if you think of those plucky astronauts on the international Space Station, hurtling around the Earth at over 17,000 mph, a day for them is just 90 minutes long.
Of course, few of us will ever experience a day in space or on another planet, but the 24-hour day we take for granted is not as steadfast as you may think.
Several influences govern the revolution of the Earth, such as the movement of tidal forces and the effect of the Moon’s gravity. Millions of years ago, the Moon was much closer to Earth as it is now, which caused much higher tides, as a consequence the length of Earth’s day was shorter—just 22.5 hours during the time of the dinosaurs. And ever since the earth has been slowing.
When atomic clocks were first developed in the 1950’s, it was noticed that the length of a day varied. With the introduction of atomic time, and then Coordinated Universal Time (UTC), it became apparent that the length of a day was gradually lengthening. While this change is very minute, chorologists decided that to ensure equilibrium of UTC and the actual time on Earth—noon signifying when the sun is at its highest above the meridian—additional seconds needed to be added, once or twice a year.
So far, 24 of these ‘Leap Seconds’ have been since 1972 when UTC first became the international timescale.
Most technologies dependent on UTC use NTP servers like Galleon’s NTS 6001, which receives accurate atomic clock time from GPS satellites. With an NTP time server, automatic leap second calculations are done by the hardware ensuring all devices are kept accurate and precise to UTC.