Category: timing source

Five Reasons Why Your Business Needs an NTP Server (Part 2)

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3. Security Breaches:

When networks are not synchronised log files are not recorded properly or in the right order which means that hackers and malicious users can breach security unnoticed. Many security software programs are also reliant on timestamps with anti-virus updates failing to happen or scheduled tasks falling behind. If your network controls time-sensitive transactions then this can even result in fraud if there is a lack of synchronisation.

4. Legal Vulnerability:

Time is not just used by computers to order events it is used in the legal world too. Contracts, receipts, proof-of-purchase are all reliant on time. If a network is not synchronised then it becomes difficult to prove when transactions actually took place and it will prove difficult to audit them. Furthermore, when it comes to serious matters such as fraud or other criminality a dedicated NTP server or other network time server device synchronised to UTC is legally auditable, its time can not be argued with!

5. Company Credibility:

Succumbing to any of these potential hazards can not just have devastating effects on your own business but also that of your clients and suppliers too. And the business grapevine being what it is any potential failing on your part will soon become common knowledge amongst your competitors, customers and suppliers and be seen as bad business practices.

Running a synchronised network adhering to UTC is not difficult. Many network administrators think that synchronisation just means an occasional time request to an online NTP time source; however, doing so will leave a system just as vulnerable to fraud and malicious users as having no synchronisation. This is because to use an Internet time source would require leaving a permanent port open in the firewall.

The solution is to use a dedicated NTP time server that receives a UTC time source from either a radio transmission (broadcast by national physics laboratories) or the GPS network (Global Positioning System). These are secure and can keep a network running to within a few milliseconds of UTC.

Leap Second Errors and Configuration

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Apart from the usual celebrations and revelry the end of December brought with the addition of another Leap Second to UTC time (Coordinated Universal Time).

UTC is the global timescale used by computer networks across the world ensuring that everybody is keeping the same time. Leap Seconds are added to UTC by the International Earth Rotation Service (IERS) in response to the slowing of the Earth’s rotation due to tidal forces and other anomalies. Failure to insert a leap second would mean that UTC would drift away from GMT (Greenwich Meantime) – often referred to as UT1. GMT is based on the position of the celestial bodies so at midday the sun is at its highest above the Greenwich Meridian.

If UTC and GMT were to drift apart it would make life difficult for people like astronomers and farmers and eventually night and day would drift (albeit in a thousand years or so).

Normally leap seconds are added to the very last minute of December 31 but occasionally if more than one is required in a year then is added in the summer.

Leap seconds, however, are controversial and can also cause problems if equipment isn’t designed with leap seconds in mind. For instance, the most recent leap second was added on 31 December and it caused database giant Oracle’s Cluster Ready Service to fail. It resulted in the system automatically rebooting itself on New Year.

Leap Seconds can also cause problems if networks are synchronised using Internet time sources or devices that require manual intervention.  Fortunately most dedicated NTP servers are designed with Leap Seconds in mind. These devices require no intervention and will automatically adjust the entire network to the correct time when there is a Leap Second.

A dedicated NTP server is not only self-adjusting requiring no manual intervention  but also they are highly accurate being stratum 1 servers (most Internet time sources are stratum 2 devices in other words devices that receive time signals from stratum 1 devices then reissue it) but they are also highly secure being external devices not required to be behind the firewall.

2008 Will be a second longer Leap Second to be added to UTC

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New Year’s celebrations will have to wait another second this year as the International Earth Rotation and Reference Systems Service (IERS) have decided to 2008 is to have Leap Second added.

IERS announced in Paris in July that a positive Leap Second was to be added to 2008, the first since Dec. 31, 2005. Leap Seconds were introduced to compensate for the unpredictability of the Earth’s rotation and to keep UTC (Coordinated Universal Time) with GMT (Greenwich Meantime).

The new extra second will be added on the last day of this year at 23 hours, 59 minutes and 59 seconds Coordinated Universal Time — 6:59:59 pm Eastern Standard Time. 33 Leap Seconds have been added since 1972

NTP server systems controlling time synchronisation on computer networks are all governed by UTC (Coordinated Universal Time). When an additional second is added at the end of the year UTC will automatically be altered as the additional second. #

Whether a NTP server receives a time signal fro transmissions such as MSF, WWVB or DCF or from the GPS network the signal will automatically carry the Leap Second announcement.

Notice of Leap Second from the International Earth Rotation and Reference Systems Service (IERS)

SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE

SERVICE DE LA ROTATION TERRESTRE
OBSERVATOIRE DE PARIS
61, Av. de l’Observatoire 75014 PARIS (France)
Tel.      : 33 (0) 1 40 51 22 26
FAX       : 33 (0) 1 40 51 22 91
e-mail    : services.iers@obspm.fr
https://hpiers.obspm.fr/eop-pc

Paris, 4 July 2008

Bulletin C 36

To authorities responsible for the measurement and distribution of time

UTC TIME STEP
on the 1st of January 2009

A positive leap second will be introduced at the end of December 2008.
The sequence of dates of the UTC second markers will be:

2008 December 31,     23h 59m 59s
2008 December 31,     23h 59m 60s
2009 January   1,      0h  0m  0s

The difference between UTC and the International Atomic Time TAI is:

from 2006 January 1, 0h UTC, to 2009 January 1  0h UTC  : UTC-TAI = – 33s
from 2009 January 1, 0h UTC, until further notice       : UTC-TAI = – 34s

Leap seconds can be introduced in UTC at the end of the months of December

Atomic Clocks and the NTP Server Using Quantum Mechanics to Tell the Time

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Telling the time is not as straight forward as most people think. In fact the very question, ‘what is the time?’ is a question that even modern science can fail to answer. Time, according to Einstein, is relative; it’s passing changes for different observers, affected by such things as speed and gravity.

Even when we all live on the same planet and experience the passing of time in a similar way, telling the time can be increasingly difficult. Our original method of using the Earth’s rotation has since been discovered to be inaccurate as the Moon’s gravity causes some days to be longer than 24 hours and a few to be shorter. In fact when the early dinosaurs were roaming the Earth a day was only 22 hours long!

Whilst mechanical and electronic clocks have provided us with some degree accuracy, our modern technologies have required far more accurate time measurements. GPS, Internet trading and air traffic control are just three industries were split second timing is incredibly important.

So how do we keep track of time? Using the Earth’s rotation has proven unreliable whilst electrical oscillators (quartz clocks) and mechanical clocks are only accurate to a second or two per day. Unfortunately for many of our technologies a second inaccuracy can be far too long. In satellite navigation, light can travel 300,000 km in just over a second, making the average sat-nav unit useless if there was one second of inaccuracy.

The solution to finding an accurate method of measuring time has been to examine the very small – quantum mechanics. Quantum mechanics is the study of the atom and its properties and how they interact. It was discovered that electrons, the tiny particles that orbit atoms changed the path that they orbit and released a precise amount of energy when they do so.

In the case of the caesium atom this occurs nearly nine billion times a second and this number never alters and so can be used as an ultra reliable method of keeping track of time. Caesium atoms are use din atomic clocks and in fact the second is now defined as just over 9 billion cycles of radiation of the caesium atom.

Atomic clocks are the foundation for many of our technologies. The entire global economy relies on them with the time relayed by NTP time servers on computer networks or beamed down by GPS satellites; ensuring the entire world keeps the same, accurate and stable time.

An official global timescale, Coordinated Universal Time (UTC) has been developed thanks to atomic clocks allowing the whole world to run the same time to within a few thousandths of a second from each other.

MSF Outage 11 December No MSF signal

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NPL Time & Frequency Services


Notice of Interruption MSF 60 kHz Time and Frequency Signal

The MSF 60 kHz time and frequency signal broadcast from Anthorn Radio Station will be shut down over the period:

11 December 2008
from 10:00 UTC to 14:00 UTC

The interruption to the transmission is required to allow scheduled maintenance work to be carried out in safety.

If you would like to download a PDF of this notice, please click here.

If you require any additional information, please contact time@npl.co.uk

Or alternatively please see our website: www.npl.co.uk/time

 

Arranging a NTP Server Stratum Tree

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NTP (Network Time Protocol) is the most widely used time synchronisation protocol on the Internet. The reason for its success is that is both flexible and highly accurate (as well as being free). NTP is also arranged into a hierarchical structure allowing thousands of machines to be able to receive a timing signal from just one NTP server.

Obviously, if a thousand machines on a network all attempted to receive a timing signal from the NTP server at the same time the network would become bottlenecked and the NTP server would be rendered useless.

For this reason, the NTP stratum tree exists. At the top of the tree is the NTP time server which is a stratum 1 device (a stratum 0 device being the atomic clock that the server receives its time from). Below the NTP server, several servers or computers receive timing information from the stratum 1 device. These trusted devices become stratum 2 servers, which in turn distribute their timing information to another layer of computers or servers. These then become stratum 3 devices which in turn can distribute timing information to lower strata (stratum 4, stratum 5 etc).

In all NTP can support up to nine stratum levels although the further away from the original stratum 1 device they are the less accurate the synchronisation. For an example of how a NTP hierarchy is setup please see this stratum tree

The WWVB Time Signal

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The WWVB time signal is a dedicated radio broadcast providing an accurate and reliable source of United States civil time, based on the global time scale UTC (Coordinated Universal Time), the WWVB signal is broadcast and maintained by the United States’ NIST laboratory (National Institute for Standards and Time).

The WWVB time signal can be utilised by anyone requiring accurate timing information although its main use is as a source of UTC time for administrators synchronising a computer network with a radio clock. Radio clocks are really another term for a network time server that utilises a radio transmission as a timing source.

Most radio based network time servers use NTP (Network Time Protocol) to distribute the timing information throughout the network.

The WWVB signal is broadcast from Fort Collins, Colorado. It is available 24 hours a day across most of the USA and Canada, although the signal is vulnerable to interference and local topography. Users of the WWVB service receive predominantly a ‘ground wave’ signal. However, there is also a residual ‘sky wave’ which is reflected off the ionosphere and is much stronger at night; this can result in a total received signal that is either stronger or weaker.

The WWVB signal is carried on a frequency of 60 kHz (to within 2 parts in 1012) and is controlled by a caesium atomic clock based at NIST

The signal’s field strength exceeds 100 µV/m (microvolts a meter) at a distance of 1000 km from Colorado – covering much of the USA.

The WWVB signal is in the form of a simple binary code containing time and date information The WWVB  time and date code includes the following information: year, month, day of month,  day of week,  hour, minute, Summer Time (in effect or imminent).

Keeping Time with Network Time Protocol

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NTP (Network Time Protocol) is the most flexible, accurate and popular method of sending time over the Internet. It is perhaps the Internet’s oldest protocol having been around in one form or another since the mid 1980’s.

The main purpose of NTP is to ensure that all devices on a network are synchronised to the same time and to compensate for some network time delays. Across a LAN or WAN NTP manages to maintain an accuracy of a few milliseconds (Across the Internet, time transfer if far less accurate due to network traffic and distance).

NTP is by far the most widely used time synchronisation protocol (somewhere in the region of 95% of all time servers use NTP) and it owes much of its success to its continual updates and its flexibility. NTP will run on UNIX, LINUX, and Windows based operating systems (it is also free, another possible reason for its huge success).

NTP uses a single time source that it distributes among all devices on a network; it also checks each device for drift (the gaining or losing of time) and adjusts for each.  It is also hierarchical in that literally thousands of machines can be controlled using just one NTP server as each machine can in itself be used by neighbouring machines as a time server.

NTP is also highly secure (when using an external time reference not when using the Internet for a timing source) with an authentication protocol able to establish exactly where a timing source comes from.

For a network to be really effective most NTP time servers use an atomic clock as a basis for their time synchronisation. An international timescale based on the time told by atomic clocks has been developed for this very purpose. UTC (Coordinated Universal Time).

There are really two methods to receive a secure UTC atomic clock time signal to be utilised by NTP. The first being the time and frequency transmissions that several national physics laboratories broadcast on long wave around the world; the second (and by far the most readily available) is by using the timing information in the GPS satellite transmissions. These can be picked up anywhere on the globe and provide safe, secure and highly accurate timing information.

The importance of time synchronisation in the modern world

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Time has always played an important part in civilisation. Understanding and monitoring time has been one of the pre-occupations of mankind since prehistory and the ability to keep track of time was as important to the ancients as it is to us.

Our ancestors needed to know when the best time was to plant crops or when to gather for religious celebrations and knowing the time means making sure it is the same as everyone else’s.

Time synchronization is the key to accurate time keeping as arranging an event at a particular time is only worthwhile if everybody is running at the same time. In the modern world, as business has moved from a paper-based system to an electronic one, the importance of time synchronisation and the search for ever better accuracy is even more crucial.

Computer networks are now communicating with each other from across the globe conducting billions of dollars worth of transactions every second, millisecond accuracy is now part of business success.

Computer networks can be comprised of hundreds and thousands of computers, servers and routers and while they all have an internal clock, unless they are synchronised perfectly together a myriad of potential problems could occur.

Security breaches, data loss, frequent crashes and breakdowns, fraud and customer credibility are all potential hazards of poor computer time synchronisation. Computers rely on time as the only point of reference between events and many applications and processes are time dependent.

Even discrepancies of a few milliseconds between devices can cause problems particularly in the world of global finance where millions are gained or lost in a second. For this reason most computer networks are controlled by a time server. These devices receive a time signal from an atomic clock. This signal is then distributed to every device on the network, ensuring that all machines have the identical time.

Most synchronisation devices are controlled by the computer program NTP (Network Time Protocol). This software regularly checks each device’s clock for drift (slowing or accelerating from the desired time) and corrects it ensuring the devices never waver from the synchronised time.

The MSF Time Signal

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The MSF time signal is a dedicated radio broadcast providing an accurate and reliable source of UK civil time, based on the global time scale UTC (Coordinated Universal Time), the MSF signal is broadcast and maintained by the UK’s National Physical Laboratory (NPL).

The MSF time signal can be utilised by anyone requiring accurate timing information its main use however is as a source of UTC time for administrators synchronising a computer network with a radio clock. Radio clocks are really another term for a network time server that utilises a radio transmission as a timing source.

Most radio based network time servers use NTP (Network Time Protocol) to distribute the timing information throughout the network.

The MSF signal is broadcast from Anthorn Radio station in Cumbria by VT communications under contract to the NPL.  It is available 24 hours a day across the whole of the UK and beyond, although the signal is vulnerable to interference and local topography. Users of the MSF service receive predominantly a ‘ground wave’ signal. However, there is also a residual ‘sky wave’ which is reflected off the ionosphere and is much stronger at night; this can result in a total received signal that is either stronger or weaker.

The MSF signal is carried on a frequency of 60 kHz (to within 2 parts in 1012) and is controlled by a Caesium atomic clock based at the radio station.

The antenna at Anthorn is at 54° 55′ N latitude, and 3° 15′ W longitude. The signal’s field strength exceeds 100 µV/m(micro volts a metre) at a distance of 1000 km from Anthorn, covering the whole of the UK, and can even be received throughout some of northern and western Europe.

The MSF transmits a simple binary code containing time and date information The MSF time and date code includes the following information: year, month, day of month,  day of week,  hour, minute, British Summer Time (in effect or imminent),  DUT1 (a parameter giving UT1-UTC)