London 2012 will be the 30th modern Olympic Games, and in its 116-year history, UY98UZDDVGGJ the Olympics have gone through many changes. New events have been introduced, records have been broken and different cities have played host to the games, but one constant has remained – the need to time competitors accurately during the different events. (more…)
Archive for the ‘ntp server’ Category
All sorts of technologies rely on precise and exact time, from cash machines and CCTV cameras, to speed cameras and computer networks. For computer networks, accurate time is essential for preventing errors, fraud and ensures security. Without it, many organisations, industries and modern applications couldn’t function. Everything from internet banking to air traffic control relies on precise and accurate time, but many organisations take unnecessary risks when it comes to the time on their networks and rely on online time servers. (more…)
When it comes to network time synchronisation, Network Time Protocol (NTP) is by far the most widely used software protocol. Whether it’s for keeping a network of hundreds or thousands of machines synchronised, or keeping a single machine running true, NTP offers the solution. Without NTP, and the NTP server, many of the tasks we perform on the internet, from shopping to online banking, simply wouldn’t be possible. (more…)
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…)
As British summer time officially ended last weekend, with the clocks going back to bring the UK back to GMT (Greenwich Mean Time), the debate about the annual clock changing has started again. The Coalition Government has proposed plans to change the way Britain keeps time by shifting the clocks forward another hour, and in effect reverting to Central European Time (ECT)..
ECT, would mean that Britain would remain an hour ahead of GMT in the winter and two hours ahead in the summer, providing lighter evenings but darker mornings, especially for those north of the border.
However, any proposed plans have stiff opposition from the Scottish Government who suggest that by altering the clocks, many areas in Scotland wouldn’t see daylight during winter until about 10am, meaning many children would have to go to school in the dark.
Other opponents, include traditionalists, argue that GMT has been the basis for British time for over a century, and that any change would be simply … unBritish.
However, a change to ECT would make things easier for businesses that trade with Europe, keeping British workers on a similar timescale to their European neighbours.
Whatever the outcome of the proposed changes to GMT, little will change when it comes to technology and computer networks as they already keep the same timescale all over the globe: UTC (Coordinated Universal Time).
UTC is a global timescale kept true by an array of atomic clocks and is used by all sorts of technologies such as computer networks, CCTV cameras, bank telling machines, air traffic control systems and stock exchanges.
Based on GMT, UTC remains the same the world over, enabling global communication and the transfer of data across time zones without error. The reason for UTC is obvious when you consider the amount of trade that goes on across borders. With industries such as the stock exchange, where stocks and shares fluctuate in price continuously, split second accuracy is essential for global traders. The same is true for computer networks, as computers use time as the only reference as to when an event has taken place. Without adequate synchronisation, a computer network may lose data and international transactions would become impossible.
Most technologies keep synchronised to UTC by using NTP time servers (Network Time Protocol), which continually check system clocks across whole networks to ensure that they all are synced to UTC.
NTP time servers receive atomic clock signals, either by GPS (Global Positioning Systems) or by radio signal broadcast by national physics laboratories such as NIST in the United States or NPL in the UK. These signals provide millisecond accuracy for technologies, so no matter what time zone a computer network is, and no matter where it is in the world, it can have the same time as every other computer network across the globe that it has to communicate with.
International Telecommunications Union (ITU), based in Geneva, is voting in January to finally get rid of the leap second, effectively scrapping Greenwich Meantime.
UTC (Coordinated Universal Time) has been around since the 1970’s, and already effectively governs the world’s technologies by keeping computer networks synchronised by way of NTP time servers (Network Time Protocol), but it does have one flaw: UTC is too accurate, that is to say, UTC is governed by atomic clocks, not by the rotation of the Earth. While atomic clocks relay an accurate, unchanging form of chronology, the Earth’s rotation varies slightly from day-to-day, and in essence is slowing down by a second or two a year.
To prevent noon, when the sun is highest in the sky, from slowly getting later and later, Leap Seconds are added to UTC as a chronological fudge, ensuring that UTC matches GMT (governed by when the sun is directly above by the Greenwich Meridian Line, making it 12 noon).
The use of leap seconds is a subject of continuous debate. The ITU argue that with the development of satellite navigation systems, the internet, mobile phones and computer networks all reliant on a single, accurate form of time, a system of timekeeping needs to be precise as possible, and that leap seconds causes problems for modern technologies.
This against changing the Leap Second and in effect retaining GMT, suggest that without it, day would slowly creep into night, albeit in many thousands of years; however, the ITU suggest that large-scale changes could be made, perhaps every century or so.
If leap seconds are abandoned, it will effectively end Greenwich Meantime’s guardianship of the world’s time that has lasted over a century. Its function of signalling noon when the sun is above the meridian line started 127 years ago, when railways and telegraphs made a requirement for a standardised timescale.
If leap seconds are abolished, few of us will notice much difference, but it may make life easier for computer networks that synchronised by NTP time servers as Leap Second delivery can cause minor errors in very complicated systems. Google, for instance, recently revealed it had written a program to specifically deal with leap seconds in its data centres, effectively smearing the leap second throughout a day.
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.
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 of us think we know what the time it is. At a glance of our wristwatches or wall clocks, we can tell what time it is. We also think we have a pretty good idea of the speed time move forwards, a second, a minute, an hour or a day are pretty well-defined; however, these units of time are completely man-made and are not as constant as we may think.
Time is an abstract concept, while we may think it is the same for everybody, time is affected by its interaction with the universe. Gravity, for instance, as Einstein observed, has the ability to warp space-time altering the speed in which time passes, and while we all live on the same planet, under the same gravitational forces, there are subtle differences in the speed in which time passes.
Using atomic clocks, scientists are able to establish the effect Earth’s gravity has on time. The high above sea level an atomic clock is placed, the quicker time travels. While these differences are minute, these experiments clearly demonstrate that Einstein’s postulations were correct.
Atomic clocks have been used to demonstrate some of Einstein’s other theories regarding time too. In his theories of relativity, Einstein argued that speed is another factor that affects the speed at which time passes. By placing atomic clocks on orbiting spacecraft or aeroplanes travelling at speed, the time measured by these clocks differs to clocks left static on Earth, another indication that Einstein was right.
Before atomic clocks, measuring time to such degrees of accuracy was impossible, but since their invention in the 1950’s, not only have Einstein’s postulations proved right, but also we have discovered some other unusual aspects to how we regard time.
While most of us think of a day as 24-hours, with every day being the same length, atomic clocks have shown that each day varies. Furthermore, atomic clocks have also shown that the Earth’s rotation is gradually slowing down, meaning that days are getting slowly longer.
Because of these changes to time, the world’s global timescale, UTC (Coordinated Universal Time) needs occasional adjustments. Every six months or so, leap seconds are added to ensure UTC runs at the same rate as an Earth day, accounting for the gradual slowing down of the planet’s spin.
For technologies that require high levels of accuracy, these regular adjustments of time are accounted for by the time protocol NTP (Network Time Protocol) so a computer network using an NTP time server is always kept true to UTC.
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.