Category: ntp server

From Pennies to NTP Servers the Intricacies of Keeping Time

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Keeping accurate time is an essential aspect of our day to day lives. Nearly everything we do is reliant on time from getting up for work in the morning to arranging meetings, nights out or just when it’s time for dinner.

Most of us carry some kind of clock or watch with us but these timepieces are prone to drift which is why most people regularly use another clock of device to set their time too.

In London, by far the most common timepiece that people use to set their watches too is Big Ben. This world famous clock can be seen for miles, which is why so many Londoners use it to ensure their watches and clocks are accurate – but have you ever wondered how Big Ben keeps itself accurate?

Well the unlikely truth lies in a pile of old coins. Big Ben’s clock mechanism uses a pendulum but for fine tuning and ensuring accuracy a small pile of gold coins resting on the top of the pendulum.  If just one coin is removed then the clock’s speed will change by nearly half a second

Ensuring accuracy on a computer network is far less archaic. All computer networks need to run accurate and synchronised time as computers too are completely reliant on knowing the time.

Fortunately, NTP time servers are designed to accurately and reliably keep entire computer networks synchronised. NTP (Network Time Protocol) is a software protocol designed to keep networks accurate and it works by using a single time source that it uses to correct drift on

Most network operators synchronise their computers to a form of UTC time (Coordinated Universal Time) as this is governed by atomic clocks (highly accurate timepieces that never drift – not for several thousand years, anyway).

A source of atomic clock time can be received by a NTP server by using either GPS satellite (Global Positioning System) signals or radio frequencies broadcast by national physics laboratories.

NTP servers ensure that computer networks all across the globe are synchronised, accurate and reliable.

Time Synchronisation Getting it Right

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Time is essential for computers, networks and technology. It is the only reference technology has to ascertain if a task has happened or is due to take place. As time, in the from of timestamps, is so important for technology, when there is uncertainty over time, due to different devices on a network having different times, it can cause untold errors.

The problem with time in computing is that all devices, from routers to desktop PCs, have their own onboard timepiece that governs the system clocks. These system clocks are just normal electronic oscillators, they type commonly found in battery powered watches, and while these are adequate for humans to tell the time, the drifting of these clocks can see devices on a network, seconds and even minutes out of sync.

There are two rules for time synchronisation:

  • All devices on a network should be synchronised together
  • The network should be synchronised to UTC (Coordinated Universal Time)

 

NTP

To synchronise a network you need to make use of Network Time Protocol (NTP). NTP is designed for accurate network time synchronisation.  IT works by using a single source of time which it then distributes it to all devices on the NTP network.

NTP continually checks the devices for any drift and then adjusts to ensure the entire network is within a few milliseconds of the reference time.

UTC

Coordinated Universal Time is a global timescale that is kept true by atomic clocks. By synchronising a network to UTC you are in effect ensuring your network is synchronised to every other UTC network on the planet.

Using UTC as a reference source is a simple affair too. NTP time servers are the best way to find a secure source of UTC time. They use either GPS (Global Positioning System) as a source of this atomic clock time or specialist radio signals keeping the UTC time source external to the network for security reasons.

A single NTP server can synchronise a network of hundreds and even thousands of devices ensuring the entire network is to within a few milliseconds of UTC.

The Time According to UTC (Coordinated Universal Time)

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The modern world is a small one. These days, in business you are just as likely to be communicating across the Atlantic as you are trading with you neighbour but this can cause difficulties – as anybody trying to get hold of somebody across the other-side of the world will know.

The problem, of course, is time. There are 24 time zones on Earth which means that people you may wish to talk to across the other side of the world, are in bed when you are awake – and vice versa.

Communication is not jus a problem for us humans either; much of our communication is conducted through computers and other technologies that can cause even more problems. Not just because time-zones are different but clocks, whether they are those that power a computer, or an office wall clock, can drift.

Time synchronisation is therefore important to ensure that the device you are communicating with has the same time otherwise whatever transaction you are conducting may result in errors such as the application failing, data getting lost or the machines believing an action has taken place  when it has not.

Coordinated Universal Time

Coordinated Universal Time (UTC) is an international timescale. It pays no heed to time-zones and is kept true by a constellation of atomic clocks – accurate timepieces that do not suffer from drift.

UTC also compensates for the slowing of the Earth’s spin by adding leap seconds to ensure there is no drift that would eventually cause noon to drift towards night (albeit in many millennia; so slow is the slowing of the Earth).

Most technologies and computer networks across the globe use UTC as their source of time, making global communication more feasible.

Network Time Protocol and NTP Time Servers

Receiving UTC time for a computer network is the job of the NTP time server. These devices use Network Time Protocol to distribute the time to all technologies on the NTP network. NTP time servers receive the source of time from a number of different sources.

  • The internet – although  internet time sources can be insecure and unreliable
  • The GPS (Global Positioning System) – using the onboard atomic clocks from navigation satellites.
  • Radio signals – broadcast by national physics laboratories like NPL and NIST.

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.

Windows Server and the Importance of NTP

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Windows Server is the most common operating system used by business networks. Whether it is the latest Windows Server 2008 or a previous incarnation such as 2003, most computer networks used in trade and business have a version.

These network operating systems make use of the time synchronization protocol NTP (Network Time Protocol) to ensure synchronicity between all devices connected to the network. This is vital in the modern world of global communication and trade as a lack of synchronization can cause untold problems; data can get lost, errors can go undetected, debugging becomes near impossible and time sensitive transactions can fail if there is no synchronization.

NTP works by selecting a single time source and it be checking the time on all devices on the network, and adjusting them, it ensures the time is synchronised throughout. NTP is capable of keeping all PCs, routers and other devices on a network to within a few milliseconds of each other.

The only requirement for network administrators is to select a time source – and this is where many IT professionals commonly go wrong.

Internet time servers

Any source of time to synchronize a network to should be UTC (Coordinated Universal Time) which is a global timescale controlled by the world’s most accurate atomic clocks and the number one source for finding a UTC time server is the internet.

And many network administrators opt to use these online time servers thinking they are an accurate and secure source of time; however, this is not strictly the case. Internet time servers send the time signal through the network firewall which means viruses and malicious users can take advantage of this ‘hole.’

Another problem with internet time servers is that their accuracy can’t be guaranteed. Often they are not as accurate as a profession network requires and factors such as distance away from the host can make differences in the time.

Dedicated NTP time server

Dedicated NTP time servers, however, get the time directly from atomic clocks – either from the GPS network or via secure radio transmissions from national physics laboratories. These signals are millisecond accurate and 100% secure.

For anyone running a network using Windows Server 2008 or other Microsoft operating system should seriously consider using a dedicated NTP server rather than the internet to ensure accuracy, reliability and security.

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 Time According to Cumbria Using the UKs MSF Time and Frequency Signal

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Getting an accurate source of time for computer networks and other technologies is increasingly becoming more important. As technologies advance and global communications mean that we are just as liable to communicate with technology across the other side of the planet as we are at home.

The need for accurate time is therefore essential if you wish to prevent time sensitive applications on your network failing or to avoid debugging problems – not too mention keeping your system secure.

NTP time servers (Network Time Protocol) are common devices that many computer networks use to provide a source of accurate time as NTP is able to ensure entire networks are synchronised to just a few milliseconds to the time reference.

The time reference that NTP servers use can come from several locations:

  • The internet
  • GPS satellite
  • And National Physical Laboratories

In the UK, the National Physical Laboratory (NPL) produce a time signal that can be received by radio referenced NTP time servers. This used to be broadcast from rugby in central England but in recent years the transmission has been moved to Cumbria.

The Cumbrian signal, known as MSF, is broadcast from Anthorn with a signal strength of 100 microvolts per metre at a distance of 1000 km. This should mean that the signal is available everywhere in the UK; however, this is not strictly the case as many MSF clocks and time servers can run into trouble when first trying to receive this atomic clock generated signal.

However, a simple checklist should ensure that no matter what your location you should be able to receive a signal to your MSF clock or NTP time server:

  • Check the power. Perhaps the most common problem ensure the battery is inserted and if the clock uses both mains power and a battery, remember to switch the mains power on. It can take quite a few minutes for the clock to pick up the MSF signal, so be patient.
  • Try rotating the clock or time server. As the MSF signal is long wave the antenna needs to be perpendicular to the signal for best reception.
  • If all else fails move the clock or time server to a different location. The signal can be blocked by local interference from electrical and mechanical devices.

* Note the MSF signal is down for scheduled maintenence on Tuesday 9 September 2010 from 10:00 BST to 14:00 BST

 

An End to British Summer Time?

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The new UK government is to look again at the perennial debate about changing the clocks during the summer months from GMT (Greenwich Mean Time) to British Summer Time (BST).

While the move is controversial, with many in Scotland in the north of the UK, unwilling to adopt the change due to the longer dark days of winter they experience over the rest of the country – the move would help synchronise Britain with the rest of Europe.

Despite its positing in the European Union, Britain holds a different timescale to the rest of Europe. People from the UK who travel abroad have to advance their watches an hour every-time they travel to mainland Europe.

In the new proposals, daylight saving time will still continue but the standard winter time will be advanced an hour and a further advancement of an hour for the summer – know as double British Summertime – allowing the UK to have the same time as Europe.

However, despite the problems such a change would have to people; technology will not be affected by any alteration in daylight saving time.

UTC Time

Technology, such as computer networks, all use a universal time – UTC (Coordinated Universal Time). UTC is a global timescale, kept true by an international conglomeration of atomic clocks. This means whether you have a UK based computer network, or a one on the other side of the world, to the technologies – the time is the same.

Most technologies receive this time from an atomic clock source using devices known as NTP servers (after the time protocol: Network Time Protocol). NTP servers take advantage of the atomic clocks onboard GPS satellites so they can not only supply an accurate source of time but they can assure that the time source never drifts.

Other methods of getting an atomic clock source of time include using medium wave transmissions broadcast by places like the UK’s National Physical Laboratory (NPL) or the American National Institute for Standards and Time.

NTP servers ensure that no matter where you are in the world the source of time your computers and technology utilise is always Coordinated Universal Time – no matter what the time of year.



GPS Time Servers Precise Time all the Time

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Keeping computer networks accurate and synchronised can’t be emphasised highly enough. Accurate time is essential in the modern global economy as computer networks across the globe are required to constantly talk to each other.

Failing to ensure a network is accurate and precise can lead to headache after headache: transactions can fail, data can get lost, and error logging and debugging can be virtually impossible.

Atomic Clocks

Atomic clocks form the basis of the global timescale – UTC (Coordinated Universal Time). UTC is used across the globe by technology and computer networks enabling the entire commercial and technological world to communicate in synchronicity together.

But as atomic clocks are highly technical (and expensive) pieces of hardware that require a team of technicians to control – where do people get a source of such accurate time?

The answer is quite simple; atomic clock timestamps are transmitted by physics laboratories and are avlaible from a whole host of sources – kept accurate by the time software NTP (Network Time Protocol).

NTP Time Servers

The most common location for sources of atomic clock generated UTC is the internet. A whole host of online time servers are avlaible for synchronisation but these can vary in their accuracy and precision. Furthermore, using a source of internet time can create vulnerabilities in the network as the firewall has to allow these timestamps through and therefore can be utilised by viruses and malicious software.

By far the most secure and accurate method of receiving a source of atomic clock generated time is to utilise the GPS network (Global Positioning System).

GPS time servers are unique in that as long as there is a clear view of the sky they can receive a source of time – anywhere on the globe, 24 hours-a-day, 365 days a year.

They are also highly accurate with a single GPS NTP time server able to synchronise entire networks to just a few milliseconds of UTC.