Modern businesses are no longer local. The internet and global communications means that even a small business might have to regularly trade overseas and often across time zones, and this means that accurate time is crucial. On a computer network, virtually every transaction is reliant on time. Time stamps are the only means a computer has of knowing when and if a transaction or process has taken place. Accurate stamps from a time server are required for billing systems, database sorting, network diagnostics and for nearly all transactions conducted over the internet. If any of this applies to your business, perhaps it’s time to ask yourself “What Time Server Do I Need?” (more…)

They buzz away next to the system’s servers and few people ever give them a moment’s thought, but network time servers are a crucial aspect to any computer network. Understanding their importance is important for maintain a healthy network, as time errors can lead to all sorts of problems, such as security breaches, data loss, or application failure. (more…)

Most of us know how useful the GPS network is. The Global Positioning System has changed the way we navigate on the road, and most modern cars are sold complete with some form of satellite navigation system already installed. However, the Global Positioning System is not only useful for satellite navigation; it has other uses too, especially as a source of accurate time for synchronising a computer network and other such technologies with the aid of a GPS network time server.

Need for Synchronisation

Time synchronisation is vital for all sorts of technologies, especially computer networks. Having different machines with a different time can lead to all sorts of untold problems, from data getting lost to simple things such as emails arriving before they were technically sent. Without accurate synchronisation or a network time server, it is nearly impossible to keep a network running smoothly and pinpoint errors and bugs.

Other technologies too need complete synchronicity. CCTV cameras, cash machines and safety systems such as air traffic control all have to be precisely synchronised. Imagine the chaos if your local cash machine told a different time from the one next to it. In effect, you could withdraw money from one machine, while the one next to it would consider a transaction that hadn’t happened yet, allowing you to withdraw the same amount again.

GPS Time

The Global Positioning System doesn’t actually transmit any positioning information. The reason that satellite navigational systems can work out accurate positioning is due to the time signals that the GPS satellites transmit. Onboard each GPS satellite is a couple of atomic clocks. These clocks transmit their times and exact position of the satellite and it’s this information, triangulated from three or more satellites that a navigational system uses to work out exactly where it is in the world.

Atomic clocks have to be used for this process because the signals are travelling at the speed of light. A one-second inaccuracy in the time signal would lead a satellite navigational system to be in error of over 300,000 km. And it’s a testament to the atomic clocks on GPS satellites that most sat nav systems are accurate to within a few metres.

GPS Network Time Server

Because of the accuracy of the GPS time signals, and the fact that the signal are available anywhere on the planet, the GPS network is ideal for use as a master time source for computer network time synchronisation. To synchronise a computer network or other technology systems to GPS time, all that is required is a GPS network time server.

GPS network time servers do all the work for you. By use of a rooftop antenna, the time server receives the GPS signal and distributes it around a network of machines. By use of time synchronisation protocols such as NTP (Network Time Protocol), all devices can be kept within a few milliseconds of the original GPS time source. And you don’t need multiple time servers for large networks either. A single device can synchronise hundreds of devices to GPS time.

GPS network time servers are simple to install, simple to use and can maintain millisecond accuracy for all sorts of technologies. Used by organisations as diverse as stock exchanges, air traffic control and banking systems, GPS time servers provide an efficient and cost effective solution to maintain network synchronicity.

Time is essential to all of us, and losing track of time can be costly. Missing meetings, being late for work or not catching the last bus home can all be a nuisance, but all this pales in comparison to what happens when a computer network loses track of time.

Time is critical for computer systems. It is the only reference a network has for knowing when applications and processes need to be, or have been, done. Alter the network time, allow the clocks to drift or fail to synchronise everything properly and a whole host of problems can arise.

Affects of Time Failure

Firstly, if network time goes wrong, processes and applications due to take place may not happen. This is because if the time is wrong a PC may assume the application has already happened. Secondly, data can easily be lost as timestamps are used in the storing process, and if there is a problem with the time, data may just get dumped. Thirdly, when it comes to debugging a system, without accurate synchronisation it can be nearly impossible. Knowing when something went wrong is essential for any error correction.

Finally, network security is reliant on secure and accurate time. Hackers and malicious software can use any discrepancies in a system’s time to gain access to a network. It only takes a second or two of discrepancy to provide enough access to unauthorised access. And if the time source itself is attacked, the effects can be even more severe

Time Server Security

Many computer networks use online NTP time servers (Network Time Protocol). These are accessed across the internet and send a regular timestamp to which a network synchronises. The problem with these online time server systems is that if the time server is wrong, so the network will be. Also, if a time server itself gets attacked by hackers or malicious software, the effects can be catastrophic. Imagine you network suddenly thinking it’s a year in the future, or in the past, the entire network could be open to all sorts of abuse.

The accuracy of these online time servers can never be guaranteed and are affected by all sorts of things such as the distance away, and the speed of the connection, and they also require an open port in the firewall, through which they send their time signals, and this port could also be used by malicious users.

The NTP Time Server

The solution for ensuring network security is fairly simple and relatively inexpensive – the NTP time server. These dedicated devices receive the time directly from an atomic clock source such as the GPS network (Global Positioning System). This not only makes them highly secure methods of synchronising network time, but also highly accurate, often to within a few milliseconds.

The cost of an NTP server is relatively low, especially when you consider the cost of failing to have accurate and secure network time will cost you. As a single NTP server is able to synchronise a network of hundreds of machines, securely, and offers peace of mind and a cost effective and secure method of keeping your network healthy.

Network time Protocol (NTP) is used as a synchronisation tool by most computer networks. NTP distributes a single time source around a network and ensures all devices are running in synchronisation with it. NTP is highly accurate and able to keep all machines on a network to within a few milliseconds of the time source. However, where this time source comes from can lead to problems in time synchronisation within a network. (more…)

Leap Seconds have been in use since the development of atomic clocks and the introduction of the global timescale UTC (Coordinated Universal Time). Leap Seconds prevent the actual time as told by atomic clocks and the physical time, governed by the sun being highest at noon, from drifting apart.

Since UTC began in the 1970’s when UTC was introduced, 24 Leap Seconds have been added. Leap seconds are a point of controversy, but without them, the day would slowly drift into night (albeit after many centuries); however, they do cause problems for some technologies.

NTP servers (Network Time Protocol) implement Leap Seconds by repeating the final second of the day when a Leap Second is introduced. While Leap Second introduction is a rare event, occurring only once or twice a year, for some complex systems that process thousands of events a second this repetition causes problems.

For search engine giants, Google, Leap Seconds can lead to their systems from working during this second, such as in 2005 when some of its clustered systems stopped accepting work. While this didn’t lead to their site from going down, Google wanted to address the problem to prevent any future problems caused by this chronological fudge.

Its solution was to write a program that essentially lied to their computer servers during the day of a Leap Second, making the systems believe the time was slightly ahead of what the NTP servers were telling it.

This gradual speeding up time meant that at the end of a day, when a Leap Second is added, Google’s timeservers do not have to repeat the extra second as the time on its servers would already be a second behind by that point.

Galleon GPS NTP server

Whilst Google’s solution to the Leap Second is ingenious, for most computer systems Leap Seconds cause no problems at all. With a computer network synchronised with an NTP server, Leap Seconds are adjusted automatically at the end of a day and occur only rarely, so most computer systems never notice this small hiccup in time.

Most people will have heard of atomic clocks, most people, probably without realising have even used them; however, I doubt many people reading this will have ever seen one. Atomic clocks are highly technical and complicated pieces of machinery. Relying on vacuums, super-coolants such as liquid nitrogen and even lasers, most atomic clocks are only found in laboratories such as NIST (National Institute for Standards and Time) in the US, or NPL (National Physical Laboratory) in the UK.

NPL's atomic clock

No other form of timekeeping is as accurate as an atomic clock. Atomic clocks form the basis of world’s global timescale UTC (Coordinated Universal Time). Even the length Earth’s spin requires manipulation by the addition of leap seconds to UTC to keep the day synchronised.

Atomic clocks work by using the oscillating changes of atoms during different energy states. Caesium is the preferred atom used in atomic clocks, which oscillates 9,192,631,770 times a second. This is a constant effect too, so much so that a second is now defined by this many oscillations of the caesium atom.

Louis Essen built the first accurate atomic clock in 1955 at the National Physical Laboratory in the UK, since then atomic clocks have become increasingly more accurate with modern atomic clocks able to maintain time for over a million years without ever losing a second.

In 1961, UTC became the world’s global timescale, and by 1967, the International System of Units adopted the Caesium frequency as the official second.

Since then, atomic clocks have become part of modern technology. Onboard every GPS satellite, atomic clocks beam time signals to Earth, enabling satellite navigation systems in car, boats and aeroplanes to judge their locations precisely.

UTC time is also essential for trade in the modern world. With computer networks speaking to each other across timezones, using atomic clocks as a reference prevents errors, ensures security and provides reliable data transfer.

Receiving a signal from an atomic clock for computer time synchronisation is incredibly easy. NTP time servers that receive the time signal from GPS satellites, or those broadcast on radio waves from places NPL and NIST, enable computer networks across the globe to keep secure and accurate time.

NPL's atomic clock

Researchers have discovered that the British atomic clock controlled by the UK’s National Physical Laboratory (NPL) is the most accurate in the world.

NPL’s CsF2 caesium fountain atomic clock is so accurate that it wouldn’t drift by a second in 138 million years, nearly twice as accurate as first thought.

Researchers have now discovered the clock is accurate to one part in 4,300,000,000,000,000 making it the most accurate atomic clock in the world.

The CsF2 clock uses the energy state of caesium atoms to keep time. With a frequency of 9,192,631,770 peaks and troughs every second, this resonance now governs the international standard for an official second.

The international standard of time—UTC—is governed by six atomic clocks, including the CsF2, two clocks in France, one in Germany and one in the USA, so this unexpected increase in accuracy means the global timescale is even more reliable than first thought.

UTC is essential for modern technologies, especially with so much global communication and trade being conducted across the internet, across borders, and across timezones.

UTC enables separate computer networks in different parts of the world to keep exactly the same time, and because of its importance accuracy and precision is essential, especially when you consider the types of transactions now conducted online, such as the buying of stocks and shares and global banking.

Receiving UTC requires the use of a time server and the protocol NTP (Network Time Protocol). Time servers receive a source of UTC direct from atomic clocks sources such as NPL, who broadcast a time signal over long wave radio, and the GPS network (GPS satellites all transmit atomic clock time signals, which is how satellite navigation systems calculate position by working out the difference in time between multiple GPS signals.)

NTP keeps all computers accurate to UTC by continuously checking each system clock and adjusting for any drift compared to the UTC time signal. By using an NTP time server, a network of computers is able to remain within a few milliseconds of UTC preventing any errors, ensuring security and providing an attestable source of accurate time.

Computer hacking is a common subject in the news. Some of the biggest companies have fallen victim to hackers, and for a myriad of reasons. Protecting computer networks from invasion from malicious users is an expensive and sophisticated industry as hackers use many methods to invade a system.

Various forms of security exist to defend against unauthorised access to computer networks such as antivirus software and firewalls.

One area often overlooked, however, is where a computer network gets it source of time from, which can often be a vulnerable aspect to a network and a way in for hackers.

NTP servers helps secure computer networks

Most computer networks use NTP (Network Time Protocol) as a method of keeping synchronised. NTP is excellent at keeping computers at the same time, often to within a few milliseconds, but is dependent on a single source of time.

Because computer networks from different organisations need to communicate together, having the same source of time makes sense, which is the reason most computer networks synchronise to a source of UTC (Coordinated Universal Time).

UTC, the world’s global timescale, is kept true by atomic clocks and various methods of utilising UTC are available.

Quite often, computer networks use an internet time source to obtain UTC but this is often when they run into security issues.

Using internet time sources leave a computer network open to several vulnerabilities. Firstly, to allow access to the internet time source, a port needs keeping open in the system firewall (UDP 123). As with any open port, unauthorised users could take advantage of this, using the open port as a way into the network.

Secondly, if the internet time source itself if tampered with, such as by BGP injection (Border Gateway Protocol) this could lead to all sorts of problems. By telling internet time servers it was a different time or date, major havoc could ensue with data getting lost, system crashes—a type of Y2K effect!

Finally, internet time servers can’t be authenticated by NTP and can also be inaccurate. Vulnerable to latency and affected to distance, errors can also occur; earlier this year some reputable time servers lost several minutes, leading to thousands of computer networks receiving the wrong time.

To ensure complete protection, dedicated and external time servers, such as Galleon’s NTS 6001 are the only secure method of receiving UTC. Using GPS (or a radio transmission) an external NTP time server can’t be manipulated by malicious users, is accurate to a few milliseconds, can’t drift and is not susceptible to timing errors.

Britain’s speaking clock celebrates its 75^th birthday this week, with the service still providing the time to over 30 million callers a year.

75 Years of the speaking clock

The service, available by dialling 123 on any BT landline (British Telecom), began in 1936 when the General Post Office (GPO) controlled the telephone network. Back then, most people used mechanical clocks, which were prone to drift. Today, despite the prevalence of digital clocks, mobile phones, computers and a myriad number of other devices, the BT speaking clock still provides the time to 30 million callers a year, and other networks implement their own speaking clock systems.

Much of the speaking clock’s continuing success is perhaps down to the accuracy that it keeps. The modern speaking clock is accurate to five milliseconds (5/1000ths of a second), and kept precise by the atomic clock signals provided by NPL (National Physical Laboratory) and the GPS network.

But the announcer declaring the time ‘after the third stroke’ provides people with a human voice, something other time-telling methods don’t provide, and may have something to do with why so many people still use it.

Four people have had the honour of providing the voice for the speaking clock; the current voice of the BT clock is Sara Mendes da Costa, who has provided the voice since 2007.

Of course, many modern technologies require an accurate source of time. Computer networks that need to keep synchronised, for security reasons and to prevent of errors, require a source of atomic clock time.

Network time servers, commonly called NTP servers after Network Time Protocol that distributes the time across the computers on a network, use either GPS signals, which contain atomic clock time signals, or by radio signals broadcast by places like NPL and NIST (National Institute for Standards and Time) in the US.