At the end of June this year, several high profiles websites suffered disruption and went down due the inclusion of an additional second to the international time system. The websites, including the social news and networking sites Reddit, Foursquare and Linkedin, were disrupted for several hours thanks to the inclusion of a Leap Second to Coordinated Universal Time (UTC), the world’s global timescale. (more…)
Archive for the ‘advanced NTP’ Category
Keeping a computer network healthy and secure is a full time job. Ensuring the firewall is secure, the anti-virus software is up-to-date and the network has no vulnerabilities is essential in the modern world of computer hacking. It only takes a brief lapse in network security for malicious users to take advantage, which is why it is imperative that a secure atomic clock time reference for PC is used for synchronisation. (more…)
Computer networks need to be synchronised. Keeping an accurate, precise and synchronised form or time is essential for security, preventing errors and communicating with other computer networks. If two computers are running different time scales, all sorts of problems can ensue, from information getting lost, applications failing to occur and the whole network becoming vulnerable to unauthorised and malicious intrusion. (more…)
The stock market has been in the news a lot lately. As global uncertainty about national debts rise, the markets are in flux, with prices changing incredibly quickly. On a trading floor, every second counts and precise time is essential for global buying and selling of commodities, bonds and shares.
The international stock exchanges such as the NASDAQ and London Stock Exchange all require accurate and precise time. With traders buying and selling shares for customers across the globe, a few seconds of inaccuracy could cost millions as share prices fluctuate.
NTP servers linked to atomic clock timing signals ensure that the stock exchange keeps an accurate and precise time. As computers across the globe all receive the stock prices, as and when they change, these two use NTP server systems to maintain time.
The global timescale UTC (Coordinated Universal Time) is used as the basis for atomic clock timing, so no matter where a trader is on the globe, the same timescale prevents confusion and errors when dealing with stocks and shares.
Because of the billions of pounds worth of stocks and shares that are bought and sold on trading floors every day, security is essential. NTP servers work externally to networks, getting their time from sources such as GPS (Global Positioning System) or radio signals put out by organisations like the National Physical Laboratory (NPL) or the National Institute for Standards and Time (NIST).
The stock exchanges can’t use a source of internet because of the risk this could pose. Hackers and malicious users could tamper with the time source, leading to mayhem and cost millions and perhaps billions if the wrong time was spread around the exchanges.
The precision of internet time is limited too. Latency over distance can create delays, which could lead to errors, and if the time source ever went down, the stock markets could hit trouble.
It is not only stock markets that need precise and accurate time, computer networks across the globe concerned about security use dedicated NTP servers like Galleon Systems’ NTS 6001. Providing accurate time from both GPS and radio signals from NPL and NIST, the NTS 6001 ensure accurate, precise and secure time every day of the year.
A day is something most of us take for granted, but the length of a day is not as simple as we may think.
A day, as most of us know, is the time it takes for the Earth to spin on its axis. Earth takes 24 hours to do one complete revolution, but other planets in our solar system have day lengths far different to ours.
The largest planet, Jupiter, for instance, takes less than ten hours to spin a revolution making a Jovian day less than half of that of Earth, while a day on Venus is longer than its year with a Venusian day 224 Earth days.
And if you think of those plucky astronauts on the international Space Station, hurtling around the Earth at over 17,000 mph, a day for them is just 90 minutes long.
Of course, few of us will ever experience a day in space or on another planet, but the 24-hour day we take for granted is not as steadfast as you may think.
Several influences govern the revolution of the Earth, such as the movement of tidal forces and the effect of the Moon’s gravity. Millions of years ago, the Moon was much closer to Earth as it is now, which caused much higher tides, as a consequence the length of Earth’s day was shorter—just 22.5 hours during the time of the dinosaurs. And ever since the earth has been slowing.
When atomic clocks were first developed in the 1950’s, it was noticed that the length of a day varied. With the introduction of atomic time, and then Coordinated Universal Time (UTC), it became apparent that the length of a day was gradually lengthening. While this change is very minute, chorologists decided that to ensure equilibrium of UTC and the actual time on Earth—noon signifying when the sun is at its highest above the meridian—additional seconds needed to be added, once or twice a year.
So far, 24 of these ‘Leap Seconds’ have been since 1972 when UTC first became the international timescale.
Most technologies dependent on UTC use NTP servers like Galleon’s NTS 6001, which receives accurate atomic clock time from GPS satellites. With an NTP time server, automatic leap second calculations are done by the hardware ensuring all devices are kept accurate and precise to UTC.
Cloud computing has been foreseen as being the next big step in the development of information technology with more and more businesses and IT networks becoming cloud reliant and doing away with traditional methods.
The term ‘Cloud Computing’ refers to the use of on demand programs and services online including the storing of information over the internet, and using applications not installed on host machines.
Cloud computing mean that users no longer need to own, install and run software in individual machines, and doesn’t require large capacity storage. It also allows remote computing, enabling users to use the same services, work on the same documents, or access the network at any workstation able to log onto the cloud service.
While these advantages are appealing to businesses enabling them to lower IT costs while providing the same network capabilities, there are disadvantages to cloud computing.
Firstly, to work on the cloud you are reliant on a working network connection. If there is a problem with the line, whether in your locale or with the cloud service provider, you can’t work—even offline.
Secondly, peripherals such as printers and back up drives may not work properly on a cloud-orientated machine, and if you are using a non-specified computer, you won’t be able to access any network hardware unless the specific drivers and software are installed on the machine.
Lack of control is another issue. Being part of a cloud service means that you have to adhere to the terms and conditions of the cloud host, which may affect all sorts of issues such as data ownership and the number of users that can access the system.
Time synchronisation is essential for cloud services, with precise and accurate time needed to ensure that every device that connects to the cloud is logged accurately. Failure to ensure precise time could lead to data getting lost or the wrong version of a job overriding new versions.
To ensure precise time for cloud services, NTP time servers, receiving the time from an atomic clock, are used to maintain accurate and reliable time. A cloud service will essentially be governed by an atomic clock once it is synchronised to an NTP server, so no matter where users are in the world, the cloud service can ensure the correct time is logged preventing data loss and errors.
Most towns and cities would have a main clock, such as Big Ben in London, and for those living near-by, it was fairly easy to look out the window and adjust the office or factory clock to ensure synchronicity; however, for those not in view of these tower clocks, other systems were used.
Commonly, somebody with a pocket watch would set the time by the tower clock in the morning and then go around businesses and for a small fee, let people know exactly what the time was, thus enabling them to adjust the office or factory clock to suit.
When, however, the railways began, and timetables became important it was clear a more accurate method of time keeping was needed, and it was then that the first official time-scale was developed.
As clocks were still mechanical, and therefore inaccurate and prone to drift, society again turned to that more accurate chronometer, the sun.
It was decided that when the sun was directly above a certain location, that would signal noon on this new time-scale. The location: Greenwich, in London, and the time-scale, originally called railway time, eventually became Greenwich Meantime (GMT), a time-scale that was used until the 1970’s.
Now of course, with atomic clocks, time is based on an international time-scale UTC (Coordinated Universal Time) although its origins are still based on GMT and often UTC is still referred to as GMT.
Now with the advent of international trade and global computer networks, UTC is used as the basis of nearly all international time. Computer networks deploy NTP servers to ensure that the time on their networks are accurate, often to a thousandth of a second to UTC, which means all around the world computers are ticking with the same accurate time – whether it is in London, Paris, or New York, UTC is used to ensure that computers everywhere can accurately communicate with each other, preventing the errors that poor time synchronisation can cause.
NTP servers (Network Time Protocol) are an essential tool in the modern computer network. They control the time, ensuring every device on the network is synchronised.
Because of the importance of time in controlling nearly every aspect of computer networking accurate and synchronised time is essential which is why so many system administrators deploy a NTP time server.
These time servers use a single time source as a base to set all the clocks on a network to; the time is often got from the GPS network or radio signals broadcast from physics laboratories such as NPL in the UK (whose signal is broadcast from Cumbria).
Once this signal is received by the time server, the time protocol NTP then distributes it around the network – comparing the system clock of every device to the time reference and adjusting each device. By regularly assessing the drift of these devices and correcting for them NTP keeps clocks accurate to within milliseconds of the time signal and when this signal emanates from an atomic clock – it ensures the network is as accurate as physically possible, but what happens if you lose the time signal?
Damaged GPS antennas, maintenance of time signal transmitters or technical faults can lead to a NTP time sever failing to receive a time signal. Often, this is only temporary and normal service is resumed within a few hours but what happens if it doesn’t, and what is the effect of having a failed time signal?
Fortunately, NTP has back-up systems for just such an eventuality. If a time signal fails and there is no other source of time, NTP cleverly uses the average time from all the clocks on its network. So if some clocks have drifted a few milliseconds faster, and others a few milliseconds slower – then NTP takes the average of this drift ensuring that the time remains accurate for as long as possible.
Even if a signal has failed for several days – or even weeks – without knowledge of the system users, this does not mean the network will drift apart. NTP will still keep the entire network synchronised together, using the average drift, and while the longer the time signal remains off the les accurate the network will be it can still provide millisecond accuracy even after a few days of no time reference.
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)
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.
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.
Ask anybody what the key to network timing is and you will probably get the response NTP (Network Time Protocol). NTP is a protocol that distributes and checks the time on all network devices to a reference clock – and it is this reference which is the true key to network time synchronisation.
Whilst a version of NTP is easy to obtain – it is normally installed on most operating systems, or is otherwise free to download – but getting a source of time is where the true key to network time synchronisation lies.
Atomic clocks govern the global timescale UTC (Coordinated Universal Time) and it is this timescale that is best for network timing as synchronising all devices on a network to UTC is equivalent of having you network synchronised with every other UTC synced network on Earth.
So getting a source of UTC time is the true key to accurate network time synchronisation, so what are the options?
Internet Time Sources
The obvious choice for most NTP users, but internet time suffers from two major flaws; firstly, internet time operates through the firewall and is therefore fraught with security risks – if the time can get through your firewall, then other things can too. Secondly, internet time sources can be hit and miss with their accuracy.
Due to the fact most internet time sources are stratum 2 devices (they connect to another device that receives the UTC source time) and the distance from client to host can never be truly ascertained or accounted for – it can make them inaccurate – with some internet time sources minutes, hours and even days away from true UTC time.
Radio Referenced Time Server
Another source of UTC time which doesn’t suffer from either security or accuracy flaws is receiving the time from long wave radio signals that some country’s national physics laboratories broadcast. While these signals are available throughout the USA (courtesy of NIST) the UK (NPL) and several other European countries and can be picked up witha basic radio referenced NTP server they are not available everywhere and the signals can be difficult to receive in some urban locations or anywhere where there is electrical interference.
For completely accurate, secure and a reliable source of UTC time there is no substitute for GPS time. GPS timing signals are beamed directly from atomic clocks onboard the GPS satellites (Global Positioning System) and received by GPS NTP time servers. These can then distribute the atomic clock time around the network.
GPS timing sources are accurate, secure and available literally anywhere on the planet 24 hours a day.
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