Keeping Track of Global Time

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So much business these days is conducted across borders, countries and continents. Global trade and communication is an important aspect for all sorts of industries, trades and businesses.

Of course, communicating across borders often means communicating across time zones too, and this poses problems for both people and computers. When those in United States start work, Europeans are half way through their day, while those in the Far East have gone to bed.

Knowing the time in several countries is, therefore, important for many people, but fortunately, many solutions exist to help.

Modern operating systems like Windows 7 have facilities that allow you to show several time zones on the computer clock, while web pages and apps such as:  https://www.worldtimebuddy.com offer an easy way to work out the different time across time zones.

Many offices use multiple analogue and digital wall clocks to provide staff with easy access to the time in important trade countries, sometimes these use atomic clock receivers to maintain perfect accuracy, but what about computers? How do they deal with different time zones?

The answer lies in the global timescale UTC (Coordinated Universal Time). UTC was developed following the invention of atomic clocks. Kept precise by a constellation of these super-accurate clocks, UTC is the same across the globe enabling computers to communicate effectively without the differences in time zones affecting functionality.

To ensure preciseness in communication, computer networks need an accurate source of UTC as system clocks are nothing more than quartz oscillators, which can drift by several seconds a day—a long time for computer communication.

A software protocol, NTP (Network Time Protocol) ensures that this time source is distributed around the network, maintaining its accuracy.

NTP servers receive the source of UTC, often from sources such as GPS or radio referenced signals broadcast by NPL in the UK (National Physical Laboratory—transits the MSF signal from Cumbria) or NIST in the USA (National Institute of Standards and Time—transmits the WWVB signal from Colorado).

With UTC and NTP time servers, computer networks across the globe can communicate precisely and error-free enabling trouble free computing and truly global communication.

NTP server

Using NIST Time Servers

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The National Institute for Standards and Technology (NIST) is one of the world’s leading atomic clock laboratories, and is the leading American time authority. Part of a constellation of national physics laboratories, NIST help ensure the worlds atomic clock time standard UTC (Coordinated Universal Time) is kept accurate and is available for the American people to use as a time standard.

All sorts of technologies rely on UTC time. All the machines on a computer network are usually synchronised to source of UTC, while technologies such as ATM’s, closed-circuit television (CCTV) and alarm systems require a source of NIST time to prevent errors.

Part of what NIST does is to ensure that sources of UTC time are readily available for the technologies to utilise, and NIST offer several means of receiving their time standard.

The Internet

The internet is the easiest method of receiving NIST time and in most Windows based operating systems, the NIST time standard address is already included in the time and date settings, allowing easy synchronisation. If it isn’t, to synchronise to NIST you simply need to double click on the system clock (bottom right hand corner) and enter the NIST server name and address. A full list of NIST Internet servers, here:

The Internet, however, is not a particularly secure location to receive a source of NIST time. Any Internet time source will require and open port in the firewall (UDP port 123) for the time signal to get through. Obviously, any gap in a firewall can lead to security issues, so fortunately NIST provide another method of receiving their time.

NTP Time Servers

NIST, from their transmitter in Colorado, broadcasts a time signal that all of North America can receive. The signal, generated and kept true by NIST atomic clocks, is highly accurate, reliable and secure, received externally to the firewall by using a WWVB timeserver (WWVB is call sign for the NIST time signal).

Once received, the protocol NTP (Network Time Protocol) will use the NIST time code and distribute it around the network and will ensure each device keeps true to it, continually making adjustments to cope with drift.

WWVB NTP time servers are accurate, secure and reliable and a must-have for anybody serious about security and accuracy who wants to receive a source of NIST time.

Using Atomic Clock Time Signals

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Accuracy is becoming more and more relevant as technology becomes increasingly important to the functioning of our everyday lives. And as our economies become more reliant on the global marketplace, accuracy and synchronisation of time is very important.

Computers seem to control much our daily lives and time is essential for the modern computer network infrastructure. Timestamps ensure actions are carried out by computers and are the only point of reference IT systems have for error checking, debugging and logging. A problem with the time on a computer network and it could lead to data getting lost, transactions failing and security issues.

Synchronisation on a network and synchronisation with another network that you communicate with are essential to prevent the above mentioned errors. But when it comes to communicating with networks across the globe things can be even trickier as the time on the other-side of the world is obviously different as you pass each time-zone.

To counter this, a global timescale based on atomic clock time was devised. UTC – Coordinated Universal Time – does away with time-zones enabling all networks across the globe to use the same time source – ensuring that computers, no matter where they are in the world, are synchronised together.

To synchronise a computer network, UTC is distributed using the time synchronisation software NTP (Network Time Protocol). The only complication is receiving a source of UTC time as it is generated by atomic clocks which are multi-million dollar systems that are not available for mass use.

Fortunately, signals from atomic clocks can be received using a NTP time server. These devices can receive radio transmissions that are broadcast from physic laboratories which can be used as a source of time to synchronise an entire network of computers to.

Other NTP time servers use the signals beamed from GPS satellites as a source of time. The positioning information in these signals is actually a time signal generated by atomic clocks onboard the satellites (which is then triangulated by the GPS receivers).

Whether it’s a radio referenced NTP server or a GPS time server – an entire network of hundreds, and even thousands of machines can be synchronised together.

The Hierarchy of a NTP Time Server Stratum Levels Explained

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When it comes to time synchronisation and using Network Time Protocol (NTP) to ensure accuracy on a computer network, it is important to understand the hierarchy of NTP and how it affects distance and accuracy.

NTP has a hierarchical structure known as stratum levels. In principle the lower the stratum number the closer the device is (in accuracy terms) to an original time source.

NTP time servers work by receiving a single time source and using this as a basis for all time on the network, however, a synchronised network will be only as accurate as the original time source and this is where stratum levels come in.

And atomic clock, either one sat in a large scale physics laboratory, or those aboard GPS satellites, are stratum 0 devices. In other words these are the devices that actually generate the time.

Stratum 1 devices are NTP time servers that get their source of time directly from these stratum 0 atomic clocks. Either by using a GPS receiver or a radio referenced NTP server, a stratum 1 device is as accurate as you can get without having your own multi-million dollar atomic clock in the server room. A stratum 1 NTP time server will typically be accurate to within a millisecond of the atomic clock time.

Stratum 2 devices are the next step down on stratum level chain. These are time servers that receive their time from a stratum 1 device. Most online time servers, for instance, are stratum 2 devices, getting their time from another NTP time server. Stratum 2 devices are obviously further away from the original time source and therefore are not quite as accurate.

The stratum levels on an NTP network continue on, with devices connecting to devices going all the way down to stratum 10, 11, 12 and so on – obviously the more links in the chain the less accurate the device will be.

Dedicated stratum 1 NTP time servers are by far the most accurate, reliable and secure method of synchronising a computer network and no business network should really be without one.

Time Synchronisation of Technology

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Many technologies are reliant and precise, accurate and reliable time. Time synchronisation is vital in many technical systems that we encounter everyday, from CCTV cameras and ATMs to air traffic control and telecommunication systems.

Without synchronisation and accuracy many of these technologies would become unreliable and in could cause major problems, even catastrophic ones in the case of air traffic controllers.

Precise time and synchronisation also plays an increasingly important part in modern computer networking, ensuring the network is secure, data is not lost, and the network can be debugged. Failing to ensure a network is synchronised properly can lead to many unexpected problems and security issues.

Ensuring accuracy

To ensure accuracy and precise time synchronisation modern technologies and computer networks the time controlling Network Time Protocol (NTP) is most commonly employed. NTP ensures all devices on a network, whether they are computers, routers, CCTV cameras or almost any other technology, are maintained at the exact same time as every other device on the network.

It works by using a single time source that it then distributes around the network, checking for drift, and correcting devices to ensure parity with the time source. It has many other features such as being able to assess errors and calculating the best time from multiple sources.

Obtaining the time

When using NTP, getting the most accurate source of time allows you to keep your network synchronised – not just together but also synchronised to every other device or network that uses that same time source.

A global timescale known as Coordinated Universal Time (UTC) is what most NTP servers and technologies use. A sit is a global timescale, and is not concerned with time zones and daylight saving, UTC allows networks across the world to communicate precisely with the exact same time source.

NTP time servers

Despite their being many sources of UTC across the internet, these are not recommended for accuracy and security reasons; to receive an accurate source of NTP there are really only two options: using a NTP time server that can receive radio transmissions from atomic clock laboratories or by using the time signals from GPS satellites.

NTP Servers Which Signal is Best Radio or GPS?

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NTP time servers (Network Time Protocol) are an essential aspect of any computer or technology network. So many applications require accurate timing information that failing to synchronize a network adequately and precisely can lead to all sorts of errors and problems – especially when communicating with other networks.

Accuracy, when it comes to time synchronization, means only one thing – atomic clocks. No other method of keeping time is as accurate or reliable as an atomic clock. In comparison to an electronic clock, such as a digital watch, which will lose up to a second a day – an atomic clock will remain accurate to a second over 100,000 years.

Atomic clocks are not something that can be housed in an average server room though; atomic clocks are very expensive, fragile and require full time technicians to control so are usually only found in large scale physics laboratories such as the ones run by NIST (National Institute of Standards and Time – USA) and NPL (National Physical Laboratory – UK).

Getting a source of accurate time from an atomic clock is relatively easy. For a secure and reliable source of atomic clock time there are only two options (the internet can neither be described as secure nor reliable as a source of time):

  • GPS time
  • UTC time broadcast on long-wave

GPS time, from the USA’s Global Positioning System, is a time stamp generated onboard the atomic clocks on the satellites. There is one distinct advantage about using GPS as a source of time: it is available anywhere on the planet.

All that is required to receive and utilise GPS time is a GPS time sever and antenna; a good clear view of the sky is also needed for an assured signal. Whilst not strictly UTC time (Coordinated Universal Time) being broadcast by GPS (UTC has had 17 leap seconds added to it since the satellites were launched) the timestamp included the information needed for NTP to convert it to the universal time standard.

UTC, however, is broadcast directly from physics laboratories and is available by using a radio referenced NTP server. These signals are not available everywhere but in the USA (the signal is known as WWVB) and most of Europe (MSF and DCF) are covered. These too are highly accurate atomic clock generated time sources and as both methods come from a secure source the computer network will remain secure.

The World Cup and the NTP Server

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As half the world is engrossed in the four yearly football tournament, it is a good opportunity to highlight the importance of accurate time and how it enables the entire world to watch events such as the Fifa World Cup.

Many of us have been glued to the love football coverage that is being broadcast by a multitude of different broadcasters and TV companies to nearly all countries across the globe.

But nearly all the technologies that enable this mass global live transmission: from the communication satellites that beam the signal across the globe, to the receivers that distribute them to our dishes, cable boxes and aerials.

And with online broadcasting now part and parcel of the whole live sporting event package – accurate time is even more important.

NTP time servers

With signals being bounced from football stadiums to satellites and then to our homes, it is essential that all the technologies involved are synchronised as accurately as possible. Failure to do so could cause the signals to get lost, create interferences or cause a qhole host of other problems.

Most technologies rely on time servers to ensure accuracy and synchronisation. Most time synchronisation servers use the protocol NTP (Network Time Protocol) to distribute time across technology networks.

These devices use a single time source, often acquired from an external atomic clock that is used to set all system clocks on devices to.

Most modern computer networks have a NTP time server that controls the time. These devices are simple to set up and in a modern, global world, are a must have for anybody conscious about accuracy and security (Many security and malicious network attacks are caused due to a lack of synchronisation).

A single NTP time server can keep a network of hundreds and even thousands of machines accurate to within a few milliseconds to the world’s global timescale UTC (Coordinated Universal Time).

Ensure Accurate Time with an Atomic Wall Clock

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Written By Richard Williams for Galleon Systems

Accuracy in timekeeping is forever becoming more important in the modern global economy. Industries and business around the globe are now often communicating with each despite the time zone differences.

There was a time when a few minutes here or there rarely mattered but now, knowing exactly what time it is has become more and more important as conference calls and over-the-internet webinars are often scheduled as part of regular business.

Global Timescale

Fortunately, to prevent the headache of working out all the different time-zones you may have to deal with, there is a global timescale that is now adopted by the global community. UTC (Coordinated Universal Time) is an atomic clock controlled time used globally and kept precise and accurate by physics laboratories around the world.

UTC enables accurate communication and forms and is used by many high end technologies to ensure accuracy such as the network time server (NTP server – Network Time Protocol). Often these devices receive the UTC time directly from atomic clocks thanks to radio broadcasts from people like NIST (USA’s National Institute for Standards and Time) and NPL (UK’s National Physical Laboratory)

Atomic Wall Clocks

And when it comes to people telling the time, these same radio signals can also be utilised by an atomic wall clock. Atomic wall clocks, despite what the name suggests, are not atomic clocks. In essence they are comprised of a standard clock device and a radio antenna and receive. The atomic clocks signals broadcast by the physics laboratories can be received and the clock regularly adjusts itself to ensure that the clock is accurate to UTC to the second.

Understanding GPS Time in Relation to UTC

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Accurate time is so important for modern computer systems that it is now unimaginable for any network administer to configure a computer system without any regard to synchronisation.

Ensuring all machines are running an accurate and precise time, and that the entire network is synchronised together, will prevent problems arising such as data loss, failure of time sensitive transactions and enable debugging and error management which can be near impossible on networks that lack synchronicity.

There are many sources of accurate time for use with NTP time servers (Network Time Protocol). NTP servers tend to use time that is controlled by atomic clocks to ensure accuracy, and there are advantages and disadvantages to each system.

Ideally as a source of time you want it to be a source of UTC (Coordinated Universal Time) as this is the international time standard as used by computer systems worldwide. But UTC is not always accessible but there is an alternative.

GPS time

GPS time is the time as relayed by the atomic clocks on board GPS satellites. These clocks form the basic technology for the Global Positioning System and their signals are what are used to work out positing information.

But GPS time signals can also provide an accurate source of time for computer networks – although strictly speaking GPS time does differ to UTC.

No Leap Seconds

GPS time is broadcast as an integer. The signal contains the number of seconds from when the GPS clocks were first turned on (January 1980).

Originally GPS time was set to UTC but since GPS satellite have been in space the last thirty years, unlike UTC, there has been no increase to account for leap seconds – so currently GPS is running exactly 17 seconds behind UTC.

Conversion

Whilst GPS time and UTC are not strictly the same as they were originally based on the same time and only the lack of leap seconds not added to GPS makes the difference, and as this is exact in seconds, conversion of GPS time is simple.

Many GPS NTP servers will convert GPS time to UTC time (and local time if you so wish) ensuring you can always have an accurate, stable, secure and reliable source of atomic clock based time.

Choosing a Source of Time for Computer Network Synchronization

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You don’t need me to tell you how important computer network time synchronization is. If you are reading this then you are probably well aware of the importance in ensuring all your computers, routers and devices on your network are running the same time.

Failure to synchronize a network can cause all sorts of problems, although with a lack of synchronicity the problems may go unnoticed as error finding and debugging a network can be nigh on impossible without a source of synchronized time.

There are multiple options for finding a source of accurate time too. Most time sources used for synchronisation are a source of UTC (Coordinated Universal Time) which is the international timescale.
However, there are pro’s and con’s to all sources:

Internet time

There are an almost an endless number of sources of UTC time on the internet. Some of these time sources are wholly inaccurate and unreliable but there are some trusted sources put out by people like NIST (National Institute for Standards and Time) and Microsoft.

However, regardless of how trusted the time source is, there are two problems with internet time sources. Firstly, an internet time server is actually a stratum 2 device. In other words, an internet time server is connected to another time server that gets its time from an atomic clock, usually from one of the sources below. So an internet source of time is never going to be as accurate or precise as using a stratum 1 time server yourself.

Secondly, and more importantly, internet sources of time operate through the firewall so a potential security breach is available to any malicious user who wishes to take advantage of the open ports.

GPS Time

GPS time is far more secure. Not only is a GPS time signal available anywhere with a line of sight view of the sky, but also GPS time signals can be received externally to the network. By using a GPS time server the GPS time signals can be received and by using NTP (Network Time Protocol) this time can be converted to UTC (GPS time is currently 17 seconds exactly behind GPS time) then distributed around the network.

MSF/WWVB Time

Radio broadcasts in long wave are transmitted by several national physics labs. NIST and the UK’s NPL are two such organisations and they transmit the UTC signals MSF (UK) and WWVB (USA) which can be received and utilised by a radio referenced NTP server.