To explain “What is NTP Time?” a brief introduction of how important time synchronization is, is required. Time synchronisation is essential for computer networks, especially those that conduct time sensitive transactions. Time, in the form of time stamps, is used by computers to identify when a transaction has taken place or needs to take place. Therefore, if time differs across a network all sorts of things can go wrong, from transactions not occurring to data getting lost. (more…)
Archive for the ‘NTP Basics’ Category
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…)
The recent and tragic earthquake that has left so much devastation in Japan has also highlighted an interesting aspect about the measurement of time and the rotation of the Earth.
So powerful was the 9.0 magnitude earthquake, it actually shifted Earth axis by 165mm (6½ inches) according to NASA.
The quake, one of the most powerful felt on Erath over the last millennia, altered the distribution of the planet’s mass, causing the Earth to rotate on its axis that little bit faster and therefore, shortening the length of every day that will follow.
Fortunately, this change is so minute it is not noticeable in our day to day activities as the Earth slowed by less than a couple of microseconds (just over a millionth of a second), and it isn’t unusual for natural events to slow down the speed of the Earth’s rotation.
In fact, since the development of the atomic clock in the 1950’s, it has been realised the Earth’s rotation is never continual and in fact has been increasing very slightly, most probably for billions of years.
These changes in the Earth’s rotation, and the length of a day, are caused by the effects of the moving oceans, wind and the gravitational pull of the moon. Indeed, it has been estimated that before humans arrived on Earth, the length of a day during the Jurassic period (40-100 million years ago) the length of a day was only 22.5 hours.
These natural changes to the Earth’s rotation and the length of a day, are only noticeable to us thanks to the precise nature of atomic clocks which have to account for these changes to ensure that the global timescale UTC (Coordinated Universal Time) doesn’t drift away from mean solar time (in other words noon needs to remain when the sun is highest during the day).
To achieve this, extra seconds are occasionally added onto UTC. These extra seconds are known as leap seconds and over thirty have been added to UTC since the 1970’s.
Many modern computer networks and technologies rely on UTC to keep devices synchronised, usually by receiving a time signal via a dedicated NTP time server (Network Time Protocol).
NTP time servers are designed to accommodate these leap seconds, enabling computer systems and technologies to remain accurate, precise and synchronised.
While many of us are aware of GPS (Global Positioning System) as a navigational tool and many of us have ‘sat navs’ in our cars, but the GPS network has another use that is also important to our day-to-day lives but few people realise it.
GPS satellites contain atomic clocks which transmit to earth an accurate time signal; it is this broadcast that satellite navigation devices use to calculate global position. However, there are other uses for this time signal besides navigation.
Nearly all computer networks are kept accurate to an atomic clock. This is because miniscule accuracies across a network can lead to until problems, from security issues to data loss. Most networks use a form of NTP (Network Time Protocol) to synchronise their networks, but NTP requires a main time source to sync to.
GPS is ideal for this, not only is it an atomic clocks source, which NTP can calculate UTC (Coordinated Universal Time) from, which means that the network will be synchronised to every other UTC network on the globe.
GPS is an ideal source of time as it is available literally everywhere on the planet as long as the GPS antenna has a clear view of the sky. And it is not only computer networks that require atomic clock time, all sorts of technologies require accurate synchronisation: traffic lights, CCTV cameras, air traffic control, internet servers, indeed many modern applications and technology without us realising is being kept true by GPS time.
Top use GPS as a source of time, a GPS NTP server is required. These connect to routers, switches or other technology and receive a regular time signal from the GPS satellites. The NTP server then distributes this time across the network, with the protocol NTP continually checking each device to ensure it is not drifting.
GPS NTP servers are not only accurate they are also highly secure. Some network administrators use internet time servers as a source of time but this can lead to problems. Not only is the accuracy of many of these sources questionable, but the signals can be hijacked by malicious software which can breach the network firewall and cause mayhem.
Atomic clock and NTP server specialists, Galleon Systems, have relaunched their website providing an improved platform to showcase their wide range of time synchronisation and network time server products.
Galleon Systems, who have been providing atomic clock and time server products to industry and commerce for over a decade, have redesigned their website to ensure the company continues to be world leaders in providing accurate, secure and reliable time synchronisation products.
With detailed descriptions of their product range, new product pictures and a revamped menu system to provided better functionality and user experience, the new website includes all of Galleons extensive range of NTP server systems (Network Time Protocol) and atomic clock synchronisation products.
Time servers from Galleon Systems are accurate to within a fraction of a second and are a secure and reliable method of getting a source of atomic clock time for computer networks and technological applications.
Using either GPS or the UKs MSF radio signal (DSF in Europe WWVB in the USA), time servers from Galleon Systems can keep hundreds of devices on a network accurate to within a few milliseconds of the international timescale UTC (Coordinated Universal Time).
Galleon Systems product range includes a variety of NTP time servers that can receive either GPS or radio referenced signals, dual systems that can receive both, simple radio controlled atomic clock servers, and a range of large network digital and analogue wall clocks.
Manufactured in the UK, Galleon Systems have a wide range of NTP and time synchronisation devices used worldwide by thousands of organizations who need accurate, reliable and precise time. For more information please visit their new website: www.galsys.co.uk
With so much automated in the modern world and with computer networks running everything from finance to health services, keeping, storing and transferring information needs to be secure, accurate and reliable.
The time is crucial for computer systems to ensure this. Timestamps are the only information computers have to assess if a task has been completed, is due, or that information has been successfully received, sent or stored. One of the most common causes of computer errors comes from inadequate synchronisation of timings.
All computer networks need to be synchronised, and not just all the devices on a network, either. With so much global communication these days, all computer networks across the globe need to be synchronised together, otherwise when they communicate errors may occur, data can get lost, and it can pave the way for security problems as time discrepancies can be used by malicious users and software.
But how do computers synchronise together? Well, it is made possible by to innovations. The first is the international timescale, UTC (Coordinated Universal Time), kept true by atomic clocks and the same the world over, regardless of time-zones. The second, NTP (Network Time Protocol) is a computer program designed to keep PCs synchronised together.
Both NTP and UTC operate in tandem. The computer time server (NTP server) receives a UTC time source, either from radio, GPS (Global Positioning System) or the internet (although an insecure method of receiving UTC and not recommended).
NTP then distributes this time around a network, checking the time on each device at periodic intervals and adjusts them for any drift in time. Most computer networks that utilise NTP time servers in this way have each machine on the network within milliseconds of UTC time, enabling accurate and precise global communication.
NTP time servers are the only secure and accurate method of computer network synchronisation and should be used by any computer system that requires reliability, accuracy and security.
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.
Computers advance at a remarkable rate; in effect computers double in power, speed and memory every five years, and with such advances in technology many people assume that the clocks that control the time of a computer are just as powerful.
However, nothing could be further from the truth; most system clocks are crude crystal oscillators that are prone to drift, which is why computer time synchronisation is so important.
In modern computing, nearly every aspect of managing a network is reliant on time. Timestamps are the only frame of reference a computer has to ascertain if an event has occurred, is due to, or shouldn’t occur.
From debugging, to conducting time sensitive transactions over the internet, accurate time is essential. But how accurate does it have to be?
Coordinated Universal Time
Coordinated Universal Time (UTC) is a global timescale derived from atomic clocks. UTC was developed to allow technological devices, such as computer networks, to communicate with a single time.
Most computer networks use time servers governed by NTP (Network Time Protocol) to distribute UTC across the network. For most applications, accuracy to within a few hundred milliseconds is sufficient – but achieving this accuracy is where the difficulty lies.
Getting an accurate source of time
There are several options for synchronizing a network to UTC. Firstly, there is the internet. The internet is awash with time servers that proclaim to supply an accurate source of UTC. However, surveys of these online sources of time indicate that many of them are wholly inaccurate being seconds, minutes and even days out.
And even the most accurate and respected sources from NIST (National Institute of Standards and Time) and Microsoft, can vary depending on the distance your network is away.
Dedicated Time servers
Dedicated NTP time servers use a more direct approach to achieve accurate synchronisation. Using atomic clocks, either from the GPS satellite network or from physics laboratories (like NIST and the UKs NPL); the time is beamed directly to the NTP time server that is connected to the network.
Because dedicated devices like this receive the time directly from atomic clocks they are incredibly accurate, enabling the entire network to be synchronised to within just a few milliseconds of NTP.
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.
Accurate time is so important for modern computer systems that it is now unimaginable for any network administer to configure a computer system without any regard to synchronisation.
Ensuring all machines are running an accurate and precise time, and that the entire network is synchronised together, will prevent problems arising such as data loss, failure of time sensitive transactions and enable debugging and error management which can be near impossible on networks that lack synchronicity.
There are many sources of accurate time for use with NTP time servers (Network Time Protocol). NTP servers tend to use time that is controlled by atomic clocks to ensure accuracy, and there are advantages and disadvantages to each system.
Ideally as a source of time you want it to be a source of UTC (Coordinated Universal Time) as this is the international time standard as used by computer systems worldwide. But UTC is not always accessible but there is an alternative.
GPS time is the time as relayed by the atomic clocks on board GPS satellites. These clocks form the basic technology for the Global Positioning System and their signals are what are used to work out positing information.
But GPS time signals can also provide an accurate source of time for computer networks – although strictly speaking GPS time does differ to UTC.
No Leap Seconds
GPS time is broadcast as an integer. The signal contains the number of seconds from when the GPS clocks were first turned on (January 1980).
Originally GPS time was set to UTC but since GPS satellite have been in space the last thirty years, unlike UTC, there has been no increase to account for leap seconds – so currently GPS is running exactly 17 seconds behind UTC.
Whilst GPS time and UTC are not strictly the same as they were originally based on the same time and only the lack of leap seconds not added to GPS makes the difference, and as this is exact in seconds, conversion of GPS time is simple.
Many GPS NTP servers will convert GPS time to UTC time (and local time if you so wish) ensuring you can always have an accurate, stable, secure and reliable source of atomic clock based time.
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