Maintaining accurate and synchronised time has never been so important for businesses and organisations. In today’s world, where so many transactions take place online, having a synchronised and accurate network time is crucial for businesses, especially those organisations that conduct their business over the internet or with other computer networks.
In a global economy time has become a more crucial than ever before. As people across the globe, communicate, conference and buy and sell from each other, being aware of the each other’s time is vital for conducting business successfully.
And with the internet, global communication and time awareness are even more important as computers require a source of time for nearly all their applications and processes. The difficulty with computer communication, however, is that if different machines are running different times, all sorts of errors can occur. Data can get lost, errors fail to log; the system can become unsecure, unstable and unreliable.
Time synchronisation for computer networks communicating with each other is, therefore, essential – but how is it achieved when different networks are in different time-zones?
The answer lies with Universal Coordinated Time (UTC) an international time-zones developed in the 1970’2 that is based on accurate atomic clocks. UTC is set the same the world over, with no accounting for time-zones so the time on a network in the UK – will be identical to the network time in the USA.
UTC time on a computer network is also kept synchronised through the use of NTP (Network Time Protocol) and an NTP server. NTP ensures all devices on a networked system have exactly the right time as different computer clocks will drift at varying rates – even if the machines are identical.
While UTC makes no accounting for time-zones system clocks can still be set to the local time-zone but the applications and functions of a computer will use UTC.
UTC time is delivered to computer networks through a variety of sources: radio signals, the GPS signal, or across the internet (although the accuracy of internet time is debatable). Most computer networks have a NTP time server somewhere in their server room which will receive the time signal and distribute it through the network ensuring all machines are within a few milliseconds of UTC and that the time on your network corresponds to every other UTC network on the globe.
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.
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.
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
Time synchronisation is a critical aspect to modern computing, especially when computers are on a network or need to communicate with other networked machines.
Timestamps are crucial for computers to acknowledge when an event occurred and it is the only information they have to ascertain if an event has occurred. Without accurate time stamps the consequences can include:
• Loss of data
• Difficult to log errors
• Difficult to debug
• Failure to save
• Time sensitive applications may fail
Modern operating systems like Windows 7 have automatic synchronisation software already installed. W32Time has been a part of Microsoft’s different generations of operating systems for some time but in Windows 7 it is set to be automatically on (Rather than the user having to set it) – synchronising your PC straight out of the box.
With such NTP (Network Time Protocol) based synchronisation available by using internet time servers (normally Microsoft and NIST) many people may wonder if a dedicated time server is still required.
Problems with Internet Time Servers
There are several drawbacks to using this Internet time as a source of UTC (Coordinated Universal Time – the global timescale often referred to as GMT).
The first and most important drawback to internet time servers is their location through the firewall. Having to rely on a source of time across the internet means keeping the TCP port open – a crucial security weakness that can be used by malicious users or bots.
Another downside to internet time servers is their lack of guaranteed accuracy. While places like NIST (National Institute for Standards and Time) and Microsoft have reliable and accurate time servers – the accuracy can be dependent on how far away you are peering from. And many other time servers available as a source of internet time are less reliable – and as NTP can’t authenticate a time signal from across the internet – it can be difficult to assess.
Benefits of an External NTP Server
Dedicated external NTP servers are far more secure. They receive their tie from GPS satellites of Long Wave transmissions so the signals can’t be intercepted by computer hackers or malicious software. Also, NTP can authenticate the signals ensuring you know where they are coming from and how accurate they are.
With time being so important on modern networked computers, taking a risk with internet time may cost a lot more than any minor investment in a dedicated NTP time server.
NTP (Network Time Protocol) is perhaps the oldest and most commonly used protocol employed by computers and yet it is probably the least understood.
NTP is used by nearly all computers, networks and other devices that are involved in communicating across the internet or internal networks. It was developed in the very earliest stages of the internet when it became evident that some method of ensuring accuracy over distance was required.
The protocol works by selecting a single time source, of which NTP has the ability to establish the accuracy and reliability of, which it then distributes around every device on the NTP network.
Each device is regularly checked against this reference clock and adjusted if any drift is noticed. A version of NTP is now deployed with virtually every operating system allowing any machine to be synchronized to a single time source.
Obviously if every network in the world selected a different time source as its reference, the reason for of all this synchronization would be lost.
Fortunately, a global timescale based on an international consortium of atomic clocks has been developed to provide a single time source for the purposes of global synchronisation.
UTC (Coordinated Universal Time) is used by computer networks worldwide as a time reference which means any device that is synchronised to UTC with NTP will in effect be synchronised with every network that uses UTC as its base time.
There are many different methods that NTP can access UTC time. The internet is a common location although this does provide security and firewall issues. A more secure (and accurate) method is to use a dedicated NTP time server that takes the time from external sources such as the GPS network (GPS works by broadcasting an atomic clock timestamp that is easily converted to UTC by a NTP server).
With NTP, a dedicated time server and access to UTC an entire network can be synchronised to within a few milliseconds of the universal time providing a secure and accurate network that can operate in complete synchronicity with other networks across the globe.
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.
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.