Synchronization is vital for most computer networks. Timestamps are the only reference a computer can use to analyse when and if processes or applications are completed. Synchronized timestamps are also vital for security, debugging and error logging.

Failure to keep a network adequately synchronized can lead to all sorts of problems. Applications fail to commence, time sensitive transactions will fail and errors and data loss will become commonplace.

However, ensuring synchronization no matter the size of network is straight forward and not costly, thank to the dedicated network time server and the time protocol NTP.

Network Time Protocol (NTP)

NTP has been around even longer than the internet but is the most widely used synchronization protocol available. NTP is free to use and makes synchronization very straight forward. It works by taking a single time source (or multiple ones) and distributes it amongst the network. It will maintain high levels of accuracy even when it loses the original time signal and can make judgements on how accurate each time reference.

NTP Time Server

These come in several forms. Firstly there are a number of virtual time servers across the internet that distributes time free of charge. However, as they are internet based a network is taking a risk leaving a firewall port open for this time communication. Also there is no control over the time signal so if it goes down (or becomes unstable or wholly inaccurate) your network can be left without adequate synchronization.

Dedicated NTP time servers use GPS or radio references to receive the time. This is far more secure and as GPS and radio signals like WWVB (from NIST) are generated by atomic clocks there accuracy is second to none.

Because the NTP protocol is hierarchical it also means that only one dedicated time server needs to be used for a network, no matter the size, as other devices on the network can act as time servers after having rece9ved the time from the primary NTP server.

The NTP protocol (Network Time Protocol) has since the earliest days of the internet been responsible for synchronising the time across computer networks. Not only is NTP effective at this, but when connected to a source of UTC (Coordinated Universal Time) NTP is also extremely accurate.

Most computer networks connect to UTC via a dedicated NTP time server. These devices use an external connection to an atomic clock to receive the time and then distribute it across a network. By connecting externally, via GPS (Global Positioning System) or long wave radio , not only are NTP time servers incredibly accurate but they are also very secure as they don’t rely on an internet connection for the time.
NTP time servers are also increasingly being used for other new innovations. Not only have traditional technologies such as CCTV, traffic lights, air traffic control and the stock exchange, become reliant on time synchronisation with time servers but an increasing amount of modern technologies are too.

NTP time servers are now common in modern digital signage systems (the use of flat screen TVs for out of home advertising). These networked screens are often synchronised to allow scheduled and orchestrated campaigns.

A synchronized digital signage campaign is one method of making an out of home advertising campaign stand-out. This is increasingly important as more and more digital signage is being implemented making a conventional digital signage campaign difficult to engage and catch the eye.

By synchronising multiple screens together with a NTP time server and running a scheduled and timed campaign. This allows content to be scheduled or timed to maximise its impact.

Small time servers can eben be installed directly into the digital signage of LCD enclosure although as most of these tiem synchnisation devices require a GPS or long wave signal the antenna can be problamtic. A better solution is to network the digtal signage and use a single NTP server as a method fo synchonisation.

NTP may be the oldest protocol on the internet and NTP time servers have been around for nearly two decades but this comparatively antique technology and software has never been so much in demand.

Digital signage is advancing quite rapidly for such a burgeoning new industry. Fantastic new innovations and content styles are being developed all the time and there are some really fantastic campaigns out there and more and more adventurous implementations are springing up all the time.

One of a growing number of trends is the use of complicated, scheduled and synchronised campaigns on multiple machines. These are incredibly eye-catching especially when the content is synchronised to provide passers-by with an almost interactive experience.

Synchronised content can be really challenging to implement and this sort of content is certainly not for the beginner as setting up such a sophisticated campaign can be really difficult.

One of the essential aspects of these types of scheduled digital signage campaigns is to ensure all displays are synchronized together. Synchronization is perhaps the most crucial aspect of these types of sophisticated digital signage campaigns. There are multiple methods of synchronising this type of campaign.

One solution is to a network time server which receives a single time source and distributes it amongst all devices on that network using the time protocol NTP (Network Time Protocol).

NTP servers receive the time from an external source (normally GPS or long wave radio) so there is no need to have the network connected to the internet although it is just as possible to synchronise to an internet time source although this can be problematic if there is any disturbance in the internet connection.

Any large network of digital signage displays also need to be protected, especially if media players or PCs are being used to generate content. The best option for ensuring total security is to place both the screen and media device in a display enclosure, often referred to as an LCD enclosure.

One of the world’s most accurate atomic clocks is to be launched into orbit and attached to the International Space Station (ISS) thanks to an agreement signed by the French space agency.

The PHARAO (Projet d’Horloge Atomique par Refroidissement d’Atomes en Orbite) atomic clock is to attached to the ISS in an effort to more accurately test Einstein’s theory of relatively as well as increasing the accuracy of Coordinated Universal Time (UTC) amongst other geodesy experiments.

PHARAO is a next generation caesium atomic clock with an accuracy that corresponds to less than a second’s drift every 300,000 years. PHARAO is to be launched by the European Space Agency (ESA) in 2013.

Atomic clocks are the most accurate timekeeping devices available to mankind yet they are susceptible to changes in gravitational pull, as predicted by Einstein’s theory, as time itself is slewed by the Earth’s pull. By placing this accurate atomic clock into orbit the effect of Earth’s gravity is lessened allowing PHARAO to be more accurate than Earth based clock.

While atomic clocks are not new to orbit, as many satellites; including the GPS network (Global Positioning System) contain atomic clocks, however, PHARAO will be among the most accurate clocks ever launched into space, allowing it to be used for far more detailed analysis.

Atomic clocks have been around since the 1960’s but their increasing development has paved the way for more and more advanced technologies. Atomic clocks form the basis of many modern technologies from satellite navigation to allowing computer networks to communicate effectively across the globe.

Computer networks receive time signals from atomic clocks via NTP time servers (Network Time Protocol) which can accurately synchronise a computer network to within a few milliseconds of UTC.

There is a certain irony that the computer that sits on your desktop and may have cost as much as month’s salary will have a clock onboard that is less accurate than a cheap wristwatch bought at a petrol or gas station.

The problem is not that computers are in particularly made with cheap timing components but that any serious timekeeping on a PC can be achieved without expensive or advanced oscillators.

The onboard timing oscillators on most PCs are in fact just a back up to keep the computer clock synchronised when the PC is off or when network timing information is unavailable.

Despite these inadequate onboard clocks, timing on a network of PC’s can be achieved to within millisecond accuracy and a network that is synchronised to the global timescale UTC (Coordinated Universal Time) shouldn’t drift at all.

The reason this high level of accuracy and synchronicity can be achieved without expensive oscillators is that computers can use Network Timing Protocol (NTP) to find and maintain the exact time.

NTP is an algorithm that distributes a single source of time; this can be generated by the onboard clock of a PC - although this would see every machine on the network drift as the clock itself drifts - A far better solution is to use NTP to distribute a stable, accurate source of time, and most preferably for networks that conduct business across the internet, a source of UTC.

The simplest method of receiving UTC - which is kept true by a constellation of atomic clocks around the globe - is to use a dedicated NTP time server. NTP servers use either GPS satellite signals (Global Positioning System) or long wave radio broadcasts (usually transmitted by national physics laboratories like NPL or NIST).

Once received the NTP server distributes the timing source across the network and constantly checks each machine for drift (In essence the networked machine contacts the server as a client and the information is exchanged via TCP/IP.

This makes the onboard clocks of the computers themselves obsolete, although when the machines are initially booted up, or if there has been a delay in contacting the NTP server (if it is down or there is a temporary fault), the onboard clock is used to maintain time until full synchronisation is again achievable.

Time synchronization is a crucial aspect of computer networking. Ensuring all machines on a network are synchronised to the global timescale, UTC (Coordinated Universal Time), otherwise time sensitive transactions with other networks would be impossible.

Time synchronization is made easy thanks to the Network Time Protocol (NTP) which was devised in the early days of the Internet for that very purpose. It works be utilising a single time source (usually UTC) which is then distributed amongst all devices on the NTP network.

The UTC time source is often taken from the Internet on networks where security is not a great issue but as this involves leaving an open port in a network firewall for many networks the vulnerability this can leave isn’t worth the risk.

Dedicated network time servers (often referred to as NTP servers) are used by many networks as a secure and even more accurate method of receiving UTC. These devices receive the UTC time direct from an atomic clock source.

Furthermore, these dedicated time servers operate external to the firewall and network and use sources such as GPS or radio frequencies to pick up the time codes.

For ease of synchronisation there are various time synchronisation software packages that run hand-in-hand with NTP and allow, through browser interfaces, easy configuration of the time synchronization throughout the network.

Whilst these time synchronisation software packages aren’t essential in using most NTP servers, the standard software installed in operating systems is often lacking or quite complicated.

Most specialist producers of dedicated network time servers will produce a times service client to allow configuration and these are probably best suited for the device from that suppler. However, there are many freeware and open source time synchronisation software packages that are mostly compatible with many NTP servers.

Telling the time is something may of us learn when we are very small children. Knowing what time it is is an essential part of our society and we couldn’t function without it. Just imagine if we didn’t tell the time – when would you go to work? When would you leave and how would it be possible to meet other people or arrange any kind of function.

While telling the time is crucial to us, it is even more vital for computers who use time as the only point of reference and amongst computer networks time synchronisation is vital. Without recording the passing of time, computers couldn’t function as there would be no reference to order programs and functions.
But the way computers tell the time and date is far different to the way we record it. Rather than record a separate time, date and year - computer systems use a single number. This number is based on the number of seconds from a set point in time – known as the prime epoch.

When this epoch is, depends on the operating system or programming language in question. For instance, Unix systems have a prime epoch which starts at 1 January 1970 and the number of seconds from the epoch are counted in a 32 bit integer. Other operating systems, such as Windows, use a similar system but the epoch is different (Windows starts on 1 January 1601).

There are, however, disadvantages to this integer system. For instance as the Unix system is a 32-bit integer which started in 01 Jan 1970, by 19 January 2038 the integer will have exhausted every possible number and will have to return to zero’s. This could cause problems with systems reliant on Unix in a problem reminiscent of the Millennium bug.
There are other issues involving computer time also. Because of the global requirements of the Internet all computer time is now based on UTC (Coordinated Universal Time). However, UTC is altered on occasion by adding Leap Seconds to ensure the time matches the rotation of the Earth (the Earth’s rotation is never exact due to gravitational forces) so leap second handling has to be encompassed into a computer time systems.

Computer time is often associated with NTP (Network Time Protocol) which is used to synchronise computers often using a network time server.

Following years of wrangling and uncertainty, the European equivalent to the GPS (Global Positioning System), is finally beginning to take shape. The European Galileo system, which will complement the current USA system, is a step closer to completion.

Galileo, which will be the first operational global navigational satellite system (GNSS) outside the United States will provide positioning information for satellite navigation machines and timing information for GPS NTP servers (Network Time Protocol).

The system, being designed and manufactured by the European Space Agency (ESA) and the European Union (EU) and when it is operational it is expected to improve the availability and accuracy of timing and navigation signals transmitted from space.

They system has been dogged in political wrangling and uncertainty since its inception nearly a decade ago. Objections from the US that they will lose the ability top switch off GPS in times of military need; and economic restraints across Europe, meant that the project was nearly shelved several times.

However, the first four satellites are being finalised in a laboratory in southern England. These In-Orbit Validation (IOV) satellites will form a mini-constellation in the sky and prove the Galileo concept by transmitting the first signals so the European system can become a reality.

The rest of the satellite network should follow shortly after and. Galileo should eventually comprise over 30 of them which means that users of satellite navigation systems of GPS NTP time servers should get quicker fixes be able to locate their positions with an error of one metre compared with the current GPS-only error of five.

Keeping computers synchronized on a network is vitally important, especially if the network in question deals with time sensitive transactions. And failing to keep a network synchronized can cause havoc leading to errors, vulnerabilities and endless problems with debugging.

However with the amount of online time servers available from reputable places such as NIST or Microsoft it is often queried as to why computer networks need to be synchronised to an external NTP time server.

These dedicated NTP devices are often seen as an unnecessary expense and many network administrators simply forgo them and connect to an online time server, after-all, it does the same job doesn’t it?

Actually there are two major reasons why NTP time servers are not only important but essential for most computer networks and to overlook them could be costly in many ways.

Let me explain. The first reason why an external NTP server is important is accuracy. It’s not that internet time sources are generally inaccurate (although many are) but there is the question of distance the time reference has to travel. Furthermore, in times when the connection is lost -whether it’s because of a local connection fault or the time server itself goes down - the network will start to drift until the connection is restored.

Secondly and perhaps most important is the security issues involved in using an Internet time source. The main problem is that if your connection to a time server through the then a open port (UDP 123 fro NTP requests) has to be left open, And as with any open port that can used as a gateway for malicious software and users.

The reason dedicated NTP time servers are essential for computer networks is that they work completely independently and external to the network’s firewall. Instead of accessing a time source across the Internet they use either GPS or radio transmissions to get the time. And in doing so they can provide accurate time all the time without fear of losing a connection or allowing a nasty Trojan through the firewall.

We live in a fast paced world where time matters. In some industries even a second can make all the difference. Millions of dollars are exchanged hands in the stock exchange each second and share prices can rise or plummet.

Getting the right price at the right time is essential for trading in such a fast paced money market and perfect network time synchronization is the essential to be able to make that happen.

Ensuring every machine that deals in stocks, shares and bonds has the correct time is vital if people are going to trade in the derivatives market but when traders are sat in different parts of the world how can this possibly be achieved.

Fortunately Coordinated Universal Time (UTC), a global timescale developed after the development of atomic clocks, allows the same time to govern every trader, regardless of where they are in the world.

As UTC is based on atomic clock time and is kept accurate by a constellation of these clocks, it is high reliable and accurate. And industries like the stock exchange use UTC to govern the time on their computer networks.

Computer network time synchronization is achieved in computer networks by using the NTP server (Network Time Protocol). NTP servers receive a source of UTC from an atomic clock reference. This is either from the GPS network or through specialist radio transmissions (it is available through the internet too but is not as reliable).

Once received, the NTP server distributes the highly accurate time throughout the network, continually checking each device and workstation to ensure the clock is as precise as possible.

These network time servers can keep entire networks of hundreds and thousands of machines in perfect synchronization – to within a few milliseconds of UTC!