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!

We live and work in a totally different world to the one that many of us were born into. We are now as likely to buy something from across the internet as stroll down the coal high street. And big business and commerce has changed too with the marketplace becoming truly global and the internet being the most common tool for trade.

Trading globally does provide its problems though as different timescales govern the different countries across the globe. To ensure parity a global timescale was introduced in the 1970’s knows Coordinated Universal Time (UTC). However, as e-commerce advanced so did the need to ensure accurate synchronization to UTC.

The biggest problem is that most clocks and watches, including those inbuilt into computer motherboards, are susceptible to drift. And as different machines will drift at different rates, global communication and e-commerce could be impossible. Just think of the difference a second can make in marketplaces like the stock exchange, where fortunes are won or lost, or when you purchase seat reservations online, what would happen if somebody on a computer with slower clock booked the same seat after you, the computer’s timestamps will show the person booked before you.

Other unforeseen errors can result, even in internal networks, when computers are running different times. Data can get lost, errors can be difficult to log, track down and fix and malicious users can take advantage of the time confusion.

To ensure truly global synchronization, computer networks can synchronize to an atomic clock allowing all computers on a network o remain within a few milliseconds of UTC. Compute networks use NTP servers (Network Time Protocol) to ensure accurate synchronization, most NTP servers receive the atomic clock time from either GPS satellites of radio frequencies.

There is nothing worse than returning to your car only to discover that your parking meter time limit has expired and you’ve got a parking ticket slapped on to your windscreen.

More-often-than-not it’s only a matter of being a couple of minutes late before an over eager parking attendant spots your expired meter or ticket and issues you a fine.

However, as the people of Chicago are discovering, whilst a minute may be the difference between getting back to the car in time or receiving a ticket, a minute may also be the difference between different parking meters.

It seems the clocks on the 3000 new parking meter pay boxes in Cale, Chicago have been discovered to be unsynchronized. In fact, of the nearly 60 pay boxes observed, most are off at least a minute and in some cases, nearly 2 minutes from what is “actual” time.

This has posed a headache to the firm in charge of parking in the Cale district and they could face legal challenges from the thousands of motorists that have been given tickets from these machine.

The problem with the Cale parking system is that while they claim they regularly calibrate their machine there is no accurate synchronization to a common time reference. In most modern applications UTC (Coordinated Universal Time) is used as a base timescale and to synchronize devices, like Cale’s parking meters, a NTP server, linked to an atomic clock will receive UTC time and ensure every device has the exact time.

NTP servers are used in the calibration of not just parking meters but also traffic lights, air traffic control and the entire banking system to name but a few applications and can synchronize every device connected to it to within a few milliseconds of UTC.

It’s a shame Cale’s parking attendants didn’t see the value of of a dedicated NTP time server – I’m sure they are regretting not having one now.

Dedicated NTP time server devices are the easiest, most accurate, reliable and secure method of receiving a source of UTC time (Coordinated Universal Time) for synchronizing a computer network.

NTP servers (Network Time Protocol) operate outside the firewall and are not reliant on the Internet which means they are highly secure and not vulnerable to malicious users who, in the case of Internet time sources can use the NTP client signals as a method of accessing the network or penetrating the firewall.

A dedicated NTP server will also receive it’s time code direct from an atomic clock, this makes it a stratum 1 time server as opposed to online time servers which are stratum 2 time servers, that is they get the time from a stratum 1 server and so are not as accurate.

In using a NTP time server there is only really one decision to make and that is how the time signal is to be received and for this there is only two choices:

The first is to make use of the time standard radio transmissions broadcast by national physics laboratories such as NIST in the USA or the UK’s NPL. These signals (WWVB in the US, MSF in the UK) are limited in range although the USA signal is available in most parts of Canada and Alaska. However, they are vulnerable to local interference and topography as other long wave radio signals are.

The alternative to the WWVB/MSF signal is to utilise the GPS satellite network (Global Positioning System). Atomic clocks are used by GPS satellites as the basis for navigational information used by satellite receivers. These atomic clocks can be used by using a NTP time server fitted with a GPS antenna.

Whilst the GPS time signal is strictly speaking not UTC- it is 17 seconds behind as leap seconds have never been added to GPS time (as the satellites are unreachable) but NTP can account for this (by simply adding 17 whole seconds). The advantage of GPS is that it is available anywhere on the planet just as long as the GPS antenna has a clear view of the sky.

Duel systems that can utilise both types of signal are also available.

NTP (Network Time Protocol) is the protocol designed for time distribution amongst a network. NTP is hierarchical. It organises a network into strata, which are the distance from a clock source and the device.

A dedicated NTP server that receives the time from a UTC source such as GPS or the national time and frequency signals is regarded as a stratum 1 device. Any device that is connected to a NTP server becomes a stratum 2 device and devices farther down the chain become stratum 2, 3 and so on.

Stratum layers exist to prevent cyclical dependencies in the hierarchy. But the stratum level is not an indication of quality or reliability.

NTP checks the time on all devices on the network it then adjusts the time according to how much drift it discovers. Yet NTP goes further than just checking the time on a the reference clock, the NTP program exchanges time information by packets (blocks of data) but refuses to believe the time it is told until several exchanges have taken place, each passing a set of tests known as protocol specifications. It often takes about five good samples until a NTP server is accepted as a timing source.

NTP uses timestamps to represent the current time the day. As time is linear, each timestamp is always greater than the previous one. NTP timestamps are in two formats but they relay the seconds from a set point in time (known as the prime epoch, set at 00:00 1 January 1900 for UTC) The NTP algorithm then uses this timestamp to determine the amount to advance or retreat the system or network clock.

NTP analyses the timestamp values including the frequency of errors and the stability. A NTP server will maintain an estimate of the quality of both its reference clocks and itself.

Atomic clocks have, unbeknown to most people, revolutionised our technology. Many of the ways we trade, communicate and travel are now solely dependent on timing from atomic clock sources.

A global community often means that we have to communicate with people on other areas of the world and in other time zones. For this purpose a universal time zone was developed, known as UTC (Coordinated Universal Time), which is based on the time told by atomic clocks.

Atomic clocks are incredibly accurate, losing only a second in every hundred million years, which is staggering when you compare it to digital clocks that will lose that much time in a week.

But why do we need such accuracy in timekeeping? Much of the technology we employ in modern times is designed for global communication. The Internet is a good example. So much trade is done across continents in fields such as the stock exchange, seat reservation and online auctioning that exact time is crucial. Imagine you are bidding for an item on the Internet and you place a bid a few seconds before the end, the last and highest bid, would it be fair to lose the item because the clock on your ISP was a little fast and the computer therefore thought the bidding was over. Or what about seat reservation; if two people on different sides of the globe book a seat at the same time, who gets the seat. This is why UTC is vital for the internet.

Other technologies too such as global positioning and air traffic control are reliant on atomic clocks to provide accuracy (and in the case of air traffic is paramount for safety). Even traffic lights and speed cameras have to be calibrated with atomic clocks otherwise speeding ticket may not be valid as they could be questioned in court.

For computer systems NTP time servers are the preferred method for receiving and distributing a source of UTC time.

Computer networks and the internet have dramatically changed the way we live our lives. Computers are now in constant communication with each other making possible transactions such as online shopping, seat reservation and even email.

However, all this is only possible thanks to accurate network timing and in particular the use of Network Time Protocol (NTP) used to ensure all machines on a network are running the same time.

Timing synchronization is crucial for computer networks. Computers use time in the form of timestamps as the only marker to separate two events, without synchronization computers have difficulty in establishing the order of events or indeed if an event has happened or not.

Failing to synchronize a network can have untold effects. Emails may arrive before they are sent (according to the computer’s clock), data may get lost or fail to store and worst-of-all, the entire network could be vulnerable to malicious users and even fraudsters.

Synchronization with NTP is relatively straight forward as most operating systems have a version of the time protocol already installed; however, choosing a timing reference to synchronize to is more challenging.

UTC (Coordinated Universal Time) is a global timescale governed by atomic clocks and is used by nearly all computer networks across the globe. By synchronizing to UTC a computer network is essentially synchronizing the network time with ever other computer network in the world that uses UTC.

The internet has plenty of sources of UTC available but security issues with the firewall means the only safe method of receiving UTC is externally. Dedicated NTP time servers can do this using either long wave radio or GPS satellite transmissions.

Most computer networks have to be synchronized to some degree. Allowing the clocks on computers across a network to all be telling different times is really asking for trouble. All sorts of errors can occur such as emails not arriving, data getting lost, and errors get unnoticed as the machines struggle to makes sense of the paradoxes that unsynchronized time can cause.

The problem is computers use time in the form of timestamps as the only point of reference between different events. If these don’t match then computers struggle to establish not only the order of events but also if the events took place at all.

Synchronizing a computer network together is extremely simple, thanks largely to the protocol NTP (Network Time Protocol). NTP is installed on most computer operating systems including Windows and most versions of Linux.

NTP uses a single time source and ensures that every device on the network is synchronized to that time. For many networks this single time source can be anything from the IT manager’s wrist watch to the clock on one of the desktop machines.

However, for networks that have to communicate with other networks, have to deal with time sensitive transactions or where high levels of security are required then synchronization to a UTC source is a must.

Coordinated Universal Time (UTC) is a global timescale used by industry all over the world. It is governed by a constellation of atomic clocks making it highly accurate (modern atomic clocks can keep time for 100 million years without losing a second).

For secure synchronization to UTC there is really only one method and that is to use a dedicated NTP time server. Online NTP servers are used by some network administrators but they are taking a risk not only with the accuracy of the synchronization but also with security as malicious users can imitate the NTP time signal and penetrate the firewall.

As dedicated NTP servers are external to the firewall, relying instead on the GPS satellite signal or specialist radio transmissions they are far more secure.

The Network Time Protocol server is used in computer networks all over the world. It keeps an entire network’s systems and devices synchronised to the same time, normally a source of UTC (Coordinated Universal Time).

But is a NTP time server a necessary requirement and can your computer network survive without one?  The short answer is perhaps yes, a computer network can survive without a NTP server but the consequences can be dramatic.

Computers are meant to make our lives easier but any network administrator will tell you they can cause an awful amount of difficulty when they inevitably go wrong and without adequate time synchronisation, identifying an error and putting it right can be nearly impossible.

Computers use the time in the form of a timestamp as the only reference they have to distinguish between two events. Whilst computers and networks will still function without adequate synchronisation they are extremely vulnerable. Not only is locating and correcting errors extremely difficult if machines are not synchronised the network will be vulnerable to malicious users and viral software that can take advantage of it.

Furthermore, failing to synchronise to UTC can cause problems if the network is to communicate with other networks that are synchronised. Any time sensitive transactions could fail and the system could be open to potential fraud or other legal implications as proving the time of a transaction could be near impossible.

NTP servers are easy to install and receive the UTC time signal from either long wave transmissions or the GPS satellite network which they then distribute amongst the network’s machines. As a dedicated NTP time server operates externally to the network firewall it does so without compromising security.