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.

Whilst GPS is commonly associated with satellite navigation and wayfinding, many technologies and computer networks rely on the GPS satellite system for a source of accurate time.

GPS time servers utilise the onboard atomic clocks of the global positing satellites and use this stable and accurate time source as a basis for their NTP synchronisation (Network Time Protocol)

GPS has become the preferred source of atomic clock time for many network operators. There are other methods where UTC (Coordinated Universal Time) can be used; radio signals and across the internet to name but two sources, but none is as secure or readily available as GPS.

Unlike radio signals, GPS is available everywhere on the planet, is never down for scheduled maintenance and is not commonly vulnerable to interference. It also doesn’t have any security implications like connecting across an internet firewall to an online time server can.

However, this doesn’t mean GPS is completely invulnerable as recent news reports have suggested.
It has been recently reported that a sunspot (sunspot 1092) the size of the Earth has flared up and a massive coronal ejection (solar flare), described in the press as a “solar tsunami” which was suggested to be large enough to satellites and wreck power and communications grids.

Solar activity, such as sunspots and solar flares (ejected hot plumes of plasma and radiation from the sun), have long been known to be able to damage and even disable satellites.

GPS is particularly vulnerable because of the high orbits of geostationary satellites (some 22,000 miles up) this leaves them unprotected by the earth’s magnetic field.

However, following the recent solar activity there has been no reported damage to the GPS system but as so many people rely on satellite navigation and GPS time for NTP servers could a future solar storm lead to havoc on Earth?

Well the short answer is yes; GPS satellites have been in orbit for several decades and while redundant satellites were introduced into the system many have been used up due to previous failures and it would only take a couple of disabled satellite to cause real problems for the network.

Fortunately, help is at hand as the Europeans, Russians and Chinese are all working on their own GPS equivalents which should work hand-in-hand with the American GPS network allowing GPS receivers to pick and choose from all four GNSS networks (Global Navigational Satellite Systems) ensuring that even if a really violent solar storm hits in the future there will be more than enough geo stationary satellites to ensure no loss of signal.

Time synchronisation becomes more and more relevant as we become more dependent on the internet. With so many time sensitive transactions conducted across the globe, from banking and commerce to sending emails, the correct and accurate time is vital in preventing errors and ensuring security.

Increasingly, more and more people are relying on sources of internet time especially with many of the modern flavours of Microsoft’s Windows such as Windows 7 having NTP and time synchronisation abilities already installed.

Windows 7 and Time Synchronisation

Windows 7 will, straight out of the box, attempt to find a source of internet time; however, for a networked machine this does not necessarily mean the computer will be synchronised accurately or securely.

Internet time sources can be wholly unreliable and unsecure for a modern computer network. Internet time has to come through the firewall and as a gap is left for these time codes to come through, malicious software can take advantage of this firewall hole too.

Not only can the accuracy of these devices vary depending on the distance away your network is but also an internet time source very rarely comes direct from an atomic clock.

In fact, most internet time sources are known as stratum 2 devices. This means they connect to another device – a stratum 1 device – namely a NTP time server which gets the time directly from the clock and transmits it to the stratum 2 device.

Stratum 1 NTP time servers

For true accuracy and security, there is no replacement for your network’s own stratum 1 NTP server. Not only are these devices secure, receiving a time source externally to the firewall (often using GPS) but also they receive these signals direct from atomic clocks (The GPS satellite that transmits this signal has an onboard atomic clock that generates the time.

The UK’s time and frequency signal MSF, provided by the National Physical Laboratory out of Cumbria, will be down for essential maintenance on 26 and 27 July.

The unplanned downtime is to allow essential maintenance to be carried out in safety. The MSF transmitter will stop broadcasting the MSF signal on 26 and 27 July between 08.00 and 20.00 (BST – 07:00 GMT/UTC) although it is possible the maintenance may be finished ahead of schedule in which case the signal will be turned on earlier.

Future maintenance is scheduled for the following times when the signal will also be turned off:

• 9 September 2010 from 10:00 BST to 14:00 BST
• 9 December 2010 from 10:00 UTC to 14:00 UTC
• 10 March 2011 from 10:00 UTC to 14:00 UTC

Problems for Time Synchronisation

Generally, most NTP time servers should be able to maintain a stable time during these brief outages and users of MSF time synchronisation devices should not experience any difficulties with the lack of MSF signal.

However, those users who require high levels of accuracy and reliability and find the MSF outages affect them should perhaps look to a GPS NTP server.

GPS time servers receive their time signals from the GPS network which is available 24 hours a day, 365 days a year and never experiences any outages.

Accurate and precise time is increasingly becoming a necessity for computer systems. From corporate networks to public service technologies such as ATMs, traffic lights or CCTV cameras – precise time is what keeps them ticking.

Inaccurate or unsynchronised time is the root cause for many technology breakdowns and failures.  For instance, failing to synchronize a traffic lights system can lead to all sorts of confusion of the lights change at the wrong time – and the consequences for systems belonging to industries such as air traffic control could be even worse.

And even a standard computer network such as those used in most offices requires accurate synchronisation to prevent errors, enable debugging and to ensure the system is secure.

Most system administrators are now aware of the importance of accurate and precise time synchronisation but getting a source of accurate time is often where many people make mistakes.

Many network administrators are aware of the time protocol NTP (Network Time Protocol) which is used to ensure accurate synchronisation between computers.

However, many administrators make the mistake of using a source of time from across the internet to distribute with NTP – a common pitfall that can have disastrous consequences.

The internet is not the best source of tine. While it is true, many online NTP servers are available as a source of atomic time or UTC (Coordinated Universal Time) but are they accurate. The truth is it is almost impossible to know. Internet time sources can be affected by the distance of the client (the network) from the time source – it also can’t be authenticated by NTP.

Even more important, internet time sources operate through the firewall which can allow the time signal to be hijacked by malicious programs.

The only secure and accurate method of synchronising a computer network or other technology system is to use an NTP server. These devices receive an external atomic clock time signal often by GPS or even by radio transmissions.

These signals are come direct from atomic clocks so are highly accurate they also can’t be hijacked as they are not connected to the internet.

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.

Written by Richard N Williams for Galleon Systems

Since its release to the civilian population the Global Positioning System (GPS) has greatly improved and enhanced our world. From satellite navigation to the precise time used by NTP servers (Network Time Protocol) and much or our modern world’s technology.

And GPS has for several years been the only Global Navigation Satellite Systems (GNSS) and is used the world over, however, times are now changing.

There are now three other GNSS systems on the horizon that will not only act as competition for GPS but will also increase its precision and accuracy.

Glonass is a Russian GNSS system that was developed during the Cold War. However, after the fall of the Soviet Union the system fell into disrepair but it has finally been revamped and is now back up and running.

The Glonass system is now being used as a navigational aid by Russian airlines and their emergency services with in-car GNSS receivers also being rolled out for the general population to use. And the Glonass system is also allowing time synchronisation using NTP time servers as it uses the same atomic clock technology as GPS.

And Glonass is not the only competition for GPS either. The European Galileo system is on track with the first satellites expected to be launched at the end of 2010 and the Chinese Compass system is also expected to be online soon which will make four fully operational GNSS systems orbiting above Earth’s orbit.

And this is good news for those interested in ultra high time synchronisation as the systems should all be interoperable meaning anyone looking to GNSS satellites can use multiple systems to ensure even greater accuracy.

It is expected that interoperable GNSS NTP time servers will soon be available to make use of these new technologies.

The long awaited European rival to the USA Global Positioning System, Galileo, has taken a step forward to realisation with the delivery of the payload for first satellite.

The payload, which contains the “brains” of the Galileo satellite, includes the atomic clocks that are the basis for all global navigation satellite systems (GNSS) and provide both the positing information and the GPS time signal used by so many GPS NTP time servers for network synchronisation.

Galileo is set to not only rival the current American run GPS system, but for time synchronisation applications it is expected to operate in tandem ensuring even greater accuracy for those seeking a source of UTC time.

Galileo has undergone a lot of uncertainty since the multi-billion Euro project was first designed over a decade ago but the delivery of the first satellite’s payload to Rome, where the equipment is being finalised in preparation for launch early next year, is a real boon to the project which has often fallen into doubt.

Just like GPS, Galileo will be a fully operation navigational satellite system but will offer even greater accuracy that its aging predecessor and provide Europe with their own navigational system that isn’t owned and controlled by the US military.

As well as the positing information that will be used by motorists, pilots and other travellers, Galileo will also provide a secure and accurate source of time for the world’s computer networks and technologies to ensure synchronicity.

Currently, GPS is alone in providing this secure service, although radio transmissions in some countries provide an alternative to the GPS time server signals, although they are not as wide spread as GPS.

The first Galileo satellite is expected to reach orbit in early 2011, with the entire network planned to be operation in 2014 – although if past experiences with the project are anything to go on – you should expect at least a few delays.

Accurate time is essential in the modern world of internet banking, online auctions and global finance. Any computer network that is involved in global communication needs to have an accurate source of the global timescale UTC (Coordinated Universal Time) to be able to talk to other networks.

Receiving UTC is simple enough. It is available from multiple sources but some are more reliable than others:

Internet Time Sources

The internet is awash with time sources. These vary in reliability and accuracy but some trusted organisations like NIST (National Institute of Standards and Time) and Microsoft. However, there are disadvantages with internet time sources:

Reliability – The demand for internet sources of UTC often means it can be difficult to access them

Accuracy – most internet time servers are stratum 2 devices which means they rely on a source of time themselves. Often errors can occur and many sources of time can be very inaccurate.

Security – Perhaps the biggest issue with internet time sources is the risk they pose to security. To receive a time stamp from across the internet the firewall needs to have an opening to allow the signals to pass through; this can lead to malicious users taking advantage.

Radio Referenced Time Servers.

A secure method of receiving UTC time stamps is available by using a NTP time server that can receive radio signals from labs like NIST and NPL (National Physical Laboratory. Many countries have these broadcasted time signals which are highly accurate, reliable and secure.

GPS Time servers

Another source for dedicated time servers is GPS. The big advantage of a GPS NTP time server is that the time source is available everywhere on the planet with a clear view of the sky. GPS time servers are also highly accurate, reliable and just as secure as radio referenced time servers.

Atomic clocks are the most accurate timekeeping devices known to man. There accuracy is incomparable to other clocks and chronometers in that whilst even the most sophisticated electronic clock will drift by a second every week or two, the most modern atomic clocks can keep running for thousands of years and not lose even a fraction of a second.

The accuracy of an atomic clock is down to what they use as their basis for time measurement. Instead of relying on an electronic current running through a crystal like an electronic clock, an atomic clock uses the hyperfine transition of an atom in two energy states. Whilst this may sound complicated, it is just an unfaltering reverberation that ‘ticks’ over 9 billion times each second, every second.

But why such accuracy really necessary and what technologies are atomic clocks employed in?

It is by examining the technologies that utilise atomic clocks that we can see why such high levels of accuracy are required.

GPS – Satellite navigation

Satellite navigation is a huge industry now. Once just a technology for the military and aviators, GPS satellite navigation is now used by road users across the globe. However, the navigational information provided by satellite navigation systems like GPS is solely reliant on the accuracy of atomic clocks.

GPS works by triangulating several timing signals that are deployed from atomic clocks onboard the GPS satellites. By working out when the timing signal was released from the satellite the satellite navigational receiver can just how far away it is from the satellite and by using multiple signals calculate where it is in the world.

Because of these timing signals travel at the speed of light, just one second inaccuracy within the timing signals could lead to the positing information being thousands of miles out. It is testament to the accuracy of GPS atomic clocks that currently a satellite navigation receiver is accurate to within five metres.